| 124. | K. Staszek Fully analytical approach to calibration of six-port reflectometers using matched load and unknown loads for one-port measurements Journal Article IEEE Transactions on Microwave Theory and Techniques, 72 (1), pp. 183-193, 2024. @article{Staszek2024, title = {Fully analytical approach to calibration of six-port reflectometers using matched load and unknown loads for one-port measurements}, author = {K. Staszek}, editor = {IEEE}, doi = {10.1109/TMTT.2023.3291758}, year = {2024}, date = {2024-01-12}, journal = {IEEE Transactions on Microwave Theory and Techniques}, volume = {72}, number = {1}, pages = {183-193}, abstract = {In this paper the first fully analytical procedure for calibration of six-port reflectometers with a match load and unknown calibration loads, allowing for relative measurements of complex reflection coefficient, is proposed. The utilized loads may vary in both magnitudes and phases, with no particular requirement on their values, however, for a good performance, they should be reasonably spread over the complex plane. The proposed closed-form solution for six-port reflectometers’ calibration does not require any sophisticated numerical algorithm or convergence analysis. Hence, it is significantly simpler to implement even in systems with reduced computational resources. The comparison against previously reported numerical solution shows that the execution time is reduced by the factor of 800. The calibration is validated with the use of two six-port reflectometers with integrated power detectors over a bandwidth 2.5 GHz – 3.5 GHz. The results confirm high robustness to imperfect power measurement and very good agreement with values measured using a commercial vector network analyzer for a large range of both magnitude and phase of the measured reflection coefficients.}, keywords = {}, pubstate = {published}, tppubtype = {article} } In this paper the first fully analytical procedure for calibration of six-port reflectometers with a match load and unknown calibration loads, allowing for relative measurements of complex reflection coefficient, is proposed. The utilized loads may vary in both magnitudes and phases, with no particular requirement on their values, however, for a good performance, they should be reasonably spread over the complex plane. The proposed closed-form solution for six-port reflectometers’ calibration does not require any sophisticated numerical algorithm or convergence analysis. Hence, it is significantly simpler to implement even in systems with reduced computational resources. The comparison against previously reported numerical solution shows that the execution time is reduced by the factor of 800. The calibration is validated with the use of two six-port reflectometers with integrated power detectors over a bandwidth 2.5 GHz – 3.5 GHz. The results confirm high robustness to imperfect power measurement and very good agreement with values measured using a commercial vector network analyzer for a large range of both magnitude and phase of the measured reflection coefficients. |
| 123. | S. Gruszczyński, K. Staszek, K. Wincza Parallel-coupled bandpass filters with directly coupled input and output resonators Journal Article International Journal of Electronics and Communications, 172 (154974), pp. 1-6, 2023. @article{Gruszczyński2023, title = {Parallel-coupled bandpass filters with directly coupled input and output resonators}, author = {S. Gruszczyński, K. Staszek, K. Wincza}, editor = {Elsevier}, doi = {10.1016/j.aeue.2023.154974}, year = {2023}, date = {2023-12-01}, journal = {International Journal of Electronics and Communications}, volume = {172}, number = {154974}, pages = {1-6}, abstract = {A novel method for modifying input and output coupling in the parallel-coupled bandpass filters, which allows for direct connection of source and load to the outer resonators, is proposed. In the filter modification a coupled-resonator approach is utilized, which allows one for calculating both the impedance of the introduced new quarter-wave section and the necessary coupling modification of the first and second resonators. The proposed filter modification allows for realization of wider bandwidth filters by removing the necessity of narrow gap realization. Further the following gap in the filter is also enhanced, what helps in wide band filter realization. The presented theoretical approach has been confirmed by theoretically calculated responses of three- and seven-resonator filters. The theoretically investigated filter modification has been confirmed with the experiment in which a seven-resonator modified bandpass filter has been fabricated and measured. The presented measurement results confirm the theoretical predictions and prove the proposed design method.}, keywords = {}, pubstate = {published}, tppubtype = {article} } A novel method for modifying input and output coupling in the parallel-coupled bandpass filters, which allows for direct connection of source and load to the outer resonators, is proposed. In the filter modification a coupled-resonator approach is utilized, which allows one for calculating both the impedance of the introduced new quarter-wave section and the necessary coupling modification of the first and second resonators. The proposed filter modification allows for realization of wider bandwidth filters by removing the necessity of narrow gap realization. Further the following gap in the filter is also enhanced, what helps in wide band filter realization. The presented theoretical approach has been confirmed by theoretically calculated responses of three- and seven-resonator filters. The theoretically investigated filter modification has been confirmed with the experiment in which a seven-resonator modified bandpass filter has been fabricated and measured. The presented measurement results confirm the theoretical predictions and prove the proposed design method. |
| 122. | R. Smolarz, K. Staszek, S. Gruszczyński, K. Wincza Broadband monolithic GaN balanced amplifier composed of mixed cascade-tandem directional couplers and cascode stages Journal Article Access, 11 , pp. 129425-129435, 2023. @article{Smolarz2023, title = {Broadband monolithic GaN balanced amplifier composed of mixed cascade-tandem directional couplers and cascode stages}, author = {R. Smolarz, K. Staszek, S. Gruszczyński, K. Wincza}, editor = {IEEE}, doi = {10.1109/ACCESS.2023.3334015}, year = {2023}, date = {2023-11-16}, journal = {Access}, volume = {11}, pages = {129425-129435}, abstract = {In this paper we present a broadband monolithic balanced amplifi er reaching 30 dBm output power over a range from 5.7 GHz up to 35.1 GHz. To the best of our knowledge, such broad operational bandwidth has never been reported in literature for balanced topology. The amplifi er is composed of broadband tandem-cascade directional couplers and amplifying blocks designed in cascode topology. It is worth noticing that for the fi rst time the mixed tandem-cascade couplers have been integrated in monolithic process, in which only one metallization layer is available for transmission-line structures. The broadband balanced amplifi er has been fabricated in high power GH15 gallium nitride (GaN) process offered by United Monolithic Semiconductors (UMS). The measured saturation output power and 1-dB compression point are equal to 30 dBm and 27.8 dBm, respectively.}, keywords = {}, pubstate = {published}, tppubtype = {article} } In this paper we present a broadband monolithic balanced amplifi er reaching 30 dBm output power over a range from 5.7 GHz up to 35.1 GHz. To the best of our knowledge, such broad operational bandwidth has never been reported in literature for balanced topology. The amplifi er is composed of broadband tandem-cascade directional couplers and amplifying blocks designed in cascode topology. It is worth noticing that for the fi rst time the mixed tandem-cascade couplers have been integrated in monolithic process, in which only one metallization layer is available for transmission-line structures. The broadband balanced amplifi er has been fabricated in high power GH15 gallium nitride (GaN) process offered by United Monolithic Semiconductors (UMS). The measured saturation output power and 1-dB compression point are equal to 30 dBm and 27.8 dBm, respectively. |
| 121. | J. Majcher, M. Kafarski, A. Szypłowska, A. Wilczek, A. Lewandowski, W. Skierucha, K. Staszek Prototype of a sensor for measuring moisture of a single rapeseed (Brassica napus L.) using microwave reflectometry Journal Article Measurement, 214 (112787), pp. 1-9, 2023, ISBN: 0263-2241. @article{Majcher2023, title = {Prototype of a sensor for measuring moisture of a single rapeseed (Brassica napus L.) using microwave reflectometry}, author = {J. Majcher, M. Kafarski, A. Szypłowska, A. Wilczek, A. Lewandowski, W. Skierucha, K. Staszek}, editor = {Elsevier}, doi = {doi.org/10.1016/j.measurement.2023.112787}, isbn = {0263-2241}, year = {2023}, date = {2023-03-28}, journal = {Measurement}, volume = {214}, number = {112787}, pages = {1-9}, abstract = {Rapeseed moisture content is one of the key physicochemical parameters of the seeds, because of its importance for ensuring optimal conditions for seed storage, as well as for determining the time of harvesting. There are many devices available on the market for measuring rapeseed moisture content. Measurement techniques usually use a large sample of seeds (in the case of capacitance meters e.g., 100 g). Therefore, the obtained result is an average value representative for the tested sample, but does not give the range of moisture of single seeds in a given batch of material. The paper presents a prototype of a sensor and a method of measuring moisture content of individual rapeseeds. The system utilizes multiple measurements of a complex reflection coefficient that correspond to different positions and orientations of a seed under test along the sensor. As a result, the impact of non-uniform shape and inner heterogeneity of the seeds on the measurement results is limited. A novel robust algorithm for moisture determination is proposed, which does not need any calibration of the microwave measurement circuitry realized as a six-port reflectometer operating at 2.4 GHz.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Rapeseed moisture content is one of the key physicochemical parameters of the seeds, because of its importance for ensuring optimal conditions for seed storage, as well as for determining the time of harvesting. There are many devices available on the market for measuring rapeseed moisture content. Measurement techniques usually use a large sample of seeds (in the case of capacitance meters e.g., 100 g). Therefore, the obtained result is an average value representative for the tested sample, but does not give the range of moisture of single seeds in a given batch of material. The paper presents a prototype of a sensor and a method of measuring moisture content of individual rapeseeds. The system utilizes multiple measurements of a complex reflection coefficient that correspond to different positions and orientations of a seed under test along the sensor. As a result, the impact of non-uniform shape and inner heterogeneity of the seeds on the measurement results is limited. A novel robust algorithm for moisture determination is proposed, which does not need any calibration of the microwave measurement circuitry realized as a six-port reflectometer operating at 2.4 GHz. |
| 120. | A. Dudek, P. Kanios, K. Staszek, S. Gruszczynski, K. Wincza Scalable antenna arrays featuring stable radiation pattern in multioctave bandwidth Journal Article IEEE Transactions on Antennas and Propagation, 71 (2), pp. 1478-1492, 2023. @article{Dudek2023, title = {Scalable antenna arrays featuring stable radiation pattern in multioctave bandwidth}, author = {A. Dudek, P. Kanios, K. Staszek, S. Gruszczynski, K. Wincza}, editor = {IEEE}, doi = {10.1109/TAP.2022.3217646}, year = {2023}, date = {2023-02-03}, journal = {IEEE Transactions on Antennas and Propagation}, volume = {71}, number = {2}, pages = {1478-1492}, abstract = {This article proposes a novel concept of antenna arrays operating in the multiple-octave frequency range. The antenna arrays ensure steady half-power beamwidth (HPBW) in 2N :1 bandwidth (BW) due to the proper placement of radiating elements and appropriate signal switching between them. The proposed arrays consist of N + 1 centered subarrays that are electrically similar at successive frequencies. The antenna arrays are fed by networks composed of power dividers and directional filters responsible for gradual RF power shift from the elements operating at the lowest frequency to the elements operating at the highest frequency. The directional filters utilize the same properly scaled switching function for every frequency octave in the operational frequency range. The presented concept has been verified by the design of antenna arrays operating over 1.2–4.8 (4:1 BW) and 1.2–9.6 GHz (8:1 BW) frequency ranges.}, keywords = {}, pubstate = {published}, tppubtype = {article} } This article proposes a novel concept of antenna arrays operating in the multiple-octave frequency range. The antenna arrays ensure steady half-power beamwidth (HPBW) in 2N :1 bandwidth (BW) due to the proper placement of radiating elements and appropriate signal switching between them. The proposed arrays consist of N + 1 centered subarrays that are electrically similar at successive frequencies. The antenna arrays are fed by networks composed of power dividers and directional filters responsible for gradual RF power shift from the elements operating at the lowest frequency to the elements operating at the highest frequency. The directional filters utilize the same properly scaled switching function for every frequency octave in the operational frequency range. The presented concept has been verified by the design of antenna arrays operating over 1.2–4.8 (4:1 BW) and 1.2–9.6 GHz (8:1 BW) frequency ranges. |
| 119. | A. Paleczek, D. Grochala, K. Staszek, S. Gruszczynski, E. Maciak, Z. Opilski, P. Kałużyński, M. Wójcikowski, T. Cao, A. Rydosz An NO2 sensor based on WO3 thin films for automotive applications in the microwave frequency range Journal Article Sensors and Actuators B-Chemical, 376 (Part B), pp. 1-13, 2023. @article{Paleczek2023, title = {An NO2 sensor based on WO3 thin films for automotive applications in the microwave frequency range}, author = {A. Paleczek, D. Grochala, K. Staszek, S. Gruszczynski, E. Maciak, Z. Opilski, P. Kałużyński, M. Wójcikowski, T. Cao, A. Rydosz}, doi = {10.1016/j.snb.2022.132964}, year = {2023}, date = {2023-02-01}, journal = {Sensors and Actuators B-Chemical}, volume = {376}, number = {Part B}, pages = {1-13}, abstract = {A microwave system dedicated to the detection of nitrogen dioxide in the harsh environment of the Norway highways is proposed. An optimized transmission line type of sensor coated with a tungsten trioxide thin film that changes its electrical properties under NO2 gas exposure is developed. The sensors ’ response (S) is given in deg/GHz and it is calculated based on wideband measurements. The advantage of wideband measurements in comparison to a single value is based on multiple measurements taken at different frequencies, which greatly suppresses noise and enables measuring low target-gas concentrations within environments of high interfering compounds. Herein, the developed system works in 1.5 GHz – 4.5 GHz, and NO2 varies in the 0 – 20 ppm range. The optimal thickness of the gas-sensing layer is estimated to be around 410 nm taking the advantage of the magnetron sputtering technology with the glancing angle deposition technique. The advantage of the developed sensor is the possibility to work at ambient temperature without the need to heat up the sensors. The disad-vantage of the developed sensors is longer response and recovery times; however, this issue will be a subject of research in the future.}, keywords = {}, pubstate = {published}, tppubtype = {article} } A microwave system dedicated to the detection of nitrogen dioxide in the harsh environment of the Norway highways is proposed. An optimized transmission line type of sensor coated with a tungsten trioxide thin film that changes its electrical properties under NO2 gas exposure is developed. The sensors ’ response (S) is given in deg/GHz and it is calculated based on wideband measurements. The advantage of wideband measurements in comparison to a single value is based on multiple measurements taken at different frequencies, which greatly suppresses noise and enables measuring low target-gas concentrations within environments of high interfering compounds. Herein, the developed system works in 1.5 GHz – 4.5 GHz, and NO2 varies in the 0 – 20 ppm range. The optimal thickness of the gas-sensing layer is estimated to be around 410 nm taking the advantage of the magnetron sputtering technology with the glancing angle deposition technique. The advantage of the developed sensor is the possibility to work at ambient temperature without the need to heat up the sensors. The disad-vantage of the developed sensors is longer response and recovery times; however, this issue will be a subject of research in the future. |
| 118. | Kamil Staszek Six-port reflectometer insensitive to power detectors' impedance mismatch Journal Article IEEE Access, 10 , pp. 89072-89082, 2022, ISSN: 2169-3536. @article{Staszek2022, title = {Six-port reflectometer insensitive to power detectors' impedance mismatch}, author = {Kamil Staszek}, doi = {10.1109/ACCESS.2022.3201126}, issn = {2169-3536}, year = {2022}, date = {2022-08-29}, journal = {IEEE Access}, volume = {10}, pages = {89072-89082}, abstract = {This paper presents the first six-port reflectometer, which is insensitive to power detectors’ impedance mismatch. It exhibits optimum measurement conditions and provides low measurement error regardless the reflection coefficient of the used power detectors. Simultaneously, the developed six-port is of low complexity, comparable to other solutions. A theoretical analysis reveals that by application of identical power detectors the impact of their impedance mismatch on the six-port’s measurement performance is completely eliminated. To validate this concept experimentally two six-port reflectometers are developed i.e., the proposed one and a reference six-port, which for ideally matched power detectors provides theoretically identical power distribution. Both reflectometers are calibrated and applied to measure reflection coefficients over the frequency range from 5.7 GHz to 5.9 GHz with both well-matched and highly reflective power detectors. The obtained results clearly show that the proposed six-port provides low measurement errors for both types of power detectors, whereas the reference six-port cannot operate properly with highly reflective power detectors.}, keywords = {}, pubstate = {published}, tppubtype = {article} } This paper presents the first six-port reflectometer, which is insensitive to power detectors’ impedance mismatch. It exhibits optimum measurement conditions and provides low measurement error regardless the reflection coefficient of the used power detectors. Simultaneously, the developed six-port is of low complexity, comparable to other solutions. A theoretical analysis reveals that by application of identical power detectors the impact of their impedance mismatch on the six-port’s measurement performance is completely eliminated. To validate this concept experimentally two six-port reflectometers are developed i.e., the proposed one and a reference six-port, which for ideally matched power detectors provides theoretically identical power distribution. Both reflectometers are calibrated and applied to measure reflection coefficients over the frequency range from 5.7 GHz to 5.9 GHz with both well-matched and highly reflective power detectors. The obtained results clearly show that the proposed six-port provides low measurement errors for both types of power detectors, whereas the reference six-port cannot operate properly with highly reflective power detectors. |
| 117. | A. Dudek, P. Kanios, K. Staszek, S. Gruszczynski, K. Wincza Octave-band four-beam antenna arrays with stable beam direction fed by broadband 4 × 4 Butler matrix Journal Article MDPI Electronics, 10 (2712), pp. 1-14, 2021, ISBN: 2079-9292. @article{Dudek2021, title = {Octave-band four-beam antenna arrays with stable beam direction fed by broadband 4 × 4 Butler matrix}, author = {A. Dudek, P. Kanios, K. Staszek, S. Gruszczynski, K. Wincza}, doi = {10.3390/electronics10212712}, isbn = {2079-9292}, year = {2021}, date = {2021-11-07}, journal = {MDPI Electronics}, volume = {10}, number = {2712}, pages = {1-14}, abstract = {A novel concept of four-beam antenna arrays operating in a one-octave frequency range that allows stable beam directions and beamwidths to be achieved is proposed. As shown, such radiation patterns can be obtained when radiating elements are appropriately spaced and fed by a broadband 4 × 4 Butler matrix with directional ?lters connected to its outputs. In this solution, broadband radiating elements are arranged in such a way that, for the lower and upper frequencies, two separate subarrays can be distinguished, each one consisting of identically arranged radiating elements. The subarrays are fed by a broadband Butler matrix at the output to which an appropriate feeding network based on directional ?lters is connected. These ?lters ensure smooth signal switching across the operational bandwidth between elements utilized at lower and higher frequency bands. Therefore, as shown, it is possible to control both beamwidths and beam directions of the resulting multi-beam antenna arrays. Moreover, two different concepts of the feeding network connected in between the Butler matrix and radiating elements for lowering the sidelobes are discussed. The theoretical analyses of the proposed antenna arrays are shown and con?rmed by measurements of the developed two-antenna arrays consisting of eight and twelve radiating elements, operating in a 2–4 GHz frequency range.}, keywords = {}, pubstate = {published}, tppubtype = {article} } A novel concept of four-beam antenna arrays operating in a one-octave frequency range that allows stable beam directions and beamwidths to be achieved is proposed. As shown, such radiation patterns can be obtained when radiating elements are appropriately spaced and fed by a broadband 4 × 4 Butler matrix with directional ?lters connected to its outputs. In this solution, broadband radiating elements are arranged in such a way that, for the lower and upper frequencies, two separate subarrays can be distinguished, each one consisting of identically arranged radiating elements. The subarrays are fed by a broadband Butler matrix at the output to which an appropriate feeding network based on directional ?lters is connected. These ?lters ensure smooth signal switching across the operational bandwidth between elements utilized at lower and higher frequency bands. Therefore, as shown, it is possible to control both beamwidths and beam directions of the resulting multi-beam antenna arrays. Moreover, two different concepts of the feeding network connected in between the Butler matrix and radiating elements for lowering the sidelobes are discussed. The theoretical analyses of the proposed antenna arrays are shown and con?rmed by measurements of the developed two-antenna arrays consisting of eight and twelve radiating elements, operating in a 2–4 GHz frequency range. |
| 116. | Ilona Piekarz, Jakub Sorocki, Robert Smolarz, Krzysztof Wincza, Slawomir Gruszczynski Four-Node Antenna Feeding Network for Interfacing with Differential Front-End Electronics Journal Article IEEE Access, 9 , pp. 103728-103736, 2021. @article{10.1109/ACCESS.2021.3093656, title = {Four-Node Antenna Feeding Network for Interfacing with Differential Front-End Electronics}, author = {Ilona Piekarz, Jakub Sorocki, Robert Smolarz, Krzysztof Wincza, Slawomir Gruszczynski}, url = {https://ieeexplore.ieee.org/document/9468631}, doi = {10.1109/ACCESS.2021.3093656}, year = {2021}, date = {2021-09-01}, journal = {IEEE Access}, volume = {9}, pages = {103728-103736}, abstract = {A novel concept of a differential feeding network for four-node antenna/antenna arrays is proposed. The network is constructed out of a four-strip coupled-line directional coupler operating in a mixed differential-nodal mode enabling direct interfacing of differential front-ends with single-ended antennas. It is shown, that such a configuration provides at the outputs of the proposed feeding network four signals, which are equal in amplitude and with phase progression of 90°. Thus, such a network can be utilized for generating either dual-circular polarization from a 2× 2 antenna array or can constitute simultaneously two out-of-phase power dividers and a directional coupler resulting in a two-beam antenna array in one cut-plane and two-element array in the other one. The dual-circular excitation is of particular interest for modern-day transceivers as it enables polarization-division-duplex communication. The presented concept is confirmed by measurements of two different antenna arrays operating at 2.5 GHz frequency range featuring dual-circular and dual-beam properties, respectively.}, keywords = {}, pubstate = {published}, tppubtype = {article} } A novel concept of a differential feeding network for four-node antenna/antenna arrays is proposed. The network is constructed out of a four-strip coupled-line directional coupler operating in a mixed differential-nodal mode enabling direct interfacing of differential front-ends with single-ended antennas. It is shown, that such a configuration provides at the outputs of the proposed feeding network four signals, which are equal in amplitude and with phase progression of 90°. Thus, such a network can be utilized for generating either dual-circular polarization from a 2× 2 antenna array or can constitute simultaneously two out-of-phase power dividers and a directional coupler resulting in a two-beam antenna array in one cut-plane and two-element array in the other one. The dual-circular excitation is of particular interest for modern-day transceivers as it enables polarization-division-duplex communication. The presented concept is confirmed by measurements of two different antenna arrays operating at 2.5 GHz frequency range featuring dual-circular and dual-beam properties, respectively. |
| 115. | Kinga Gaweł, Magda Kalawska, Kamil Staszek, Robert Smolarz, Sławomir Gruszczyński, Krzysztof Wincza Broadband equal-split directional couplers composed of cascade- and tandem-connected coupled-line sections having unequal lengths Journal Article IEEE Access, 9 , pp. 117434-117443, 2021, ISSN: 2169-3536. @article{Gaweł2021, title = {Broadband equal-split directional couplers composed of cascade- and tandem-connected coupled-line sections having unequal lengths}, author = {Kinga Gaweł, Magda Kalawska, Kamil Staszek, Robert Smolarz, Sławomir Gruszczyński, Krzysztof Wincza}, url = {https://ieeexplore.ieee.org/document/9521241}, doi = {10.1109/ACCESS.2021.3106901}, issn = {2169-3536}, year = {2021}, date = {2021-08-24}, journal = {IEEE Access}, volume = {9}, pages = {117434-117443}, abstract = {A new concept of broadband equal-split coupled-line directional couplers is proposed. The proposed couplers are based on coupled-line sections, all having the same coupling coefficient, and feature frequency characteristics similar to the ones obtained for classic symmetrical three-section coupled-line couplers. It is shown that appropriate cascade- and tandem-connected coupled-line sections, having all the same coupling coefficients and different electrical lengths allow for achieving equal power split in a broadband frequency range together with the quadrature differential phase response. Therefore, a very flexible design process is possible, in which directional couplers with different bandwidths and coupling imbalances can be realized by changing solely the electrical lengths of the coupled-line sections. Moreover, the proposed networks require significantly lower coupling coefficients and feature slightly shorter overall electrical lengths than their classic counterparts. The theoretical analysis of the proposed circuits is shown in the paper and is followed by the design and measurements of two broadband equal-split quadrature directional couplers operating at the center frequency of 2 GHz.}, keywords = {}, pubstate = {published}, tppubtype = {article} } A new concept of broadband equal-split coupled-line directional couplers is proposed. The proposed couplers are based on coupled-line sections, all having the same coupling coefficient, and feature frequency characteristics similar to the ones obtained for classic symmetrical three-section coupled-line couplers. It is shown that appropriate cascade- and tandem-connected coupled-line sections, having all the same coupling coefficients and different electrical lengths allow for achieving equal power split in a broadband frequency range together with the quadrature differential phase response. Therefore, a very flexible design process is possible, in which directional couplers with different bandwidths and coupling imbalances can be realized by changing solely the electrical lengths of the coupled-line sections. Moreover, the proposed networks require significantly lower coupling coefficients and feature slightly shorter overall electrical lengths than their classic counterparts. The theoretical analysis of the proposed circuits is shown in the paper and is followed by the design and measurements of two broadband equal-split quadrature directional couplers operating at the center frequency of 2 GHz. |
| 114. | Jakub Sorocki, Ilona Piekarz, Maurizio Bozzi Broadband Permittivity and Permeability Extraction of 3D-Printed Magneto-Dielectric Substrates Journal Article Forthcoming IEEE Microwave and Wireless Components Letters, Forthcoming. @article{10.1109/LMWC.2021.3100394, title = {Broadband Permittivity and Permeability Extraction of 3D-Printed Magneto-Dielectric Substrates}, author = {Jakub Sorocki, Ilona Piekarz, Maurizio Bozzi}, doi = {10.1109/LMWC.2021.3100394}, year = {2021}, date = {2021-08-17}, journal = {IEEE Microwave and Wireless Components Letters}, abstract = {A broadband microwave magneto-dielectric spectroscopy technique is introduced dedicated to the characterization of 3D-printed magneto-dielectric substrates. Complex permittivity and permeability are extracted for the material-under-test fabricated in the same manner and with the same orientation of the EM field as in the intended applications that include e.g., miniaturized, and efficient antennas. The information is derived from the measured characteristic impedance and propagation constant of a test microstrip transmission line. To exclude the influence of the coaxial-to-microstrip transitions, printed launchers are proposed with puzzle-like interlock to test substrate which is used together with a printed Thru-Reflect-Line de-embedding set. The presented technique was experimentally validated on an example of specialized magnetic Polylactic Acid (PLA) filament printed substrate in the frequency range of 0.1 GHz to 6 GHz and a reference PLA substrate measured with two different techniques to yield comparable results.}, keywords = {}, pubstate = {forthcoming}, tppubtype = {article} } A broadband microwave magneto-dielectric spectroscopy technique is introduced dedicated to the characterization of 3D-printed magneto-dielectric substrates. Complex permittivity and permeability are extracted for the material-under-test fabricated in the same manner and with the same orientation of the EM field as in the intended applications that include e.g., miniaturized, and efficient antennas. The information is derived from the measured characteristic impedance and propagation constant of a test microstrip transmission line. To exclude the influence of the coaxial-to-microstrip transitions, printed launchers are proposed with puzzle-like interlock to test substrate which is used together with a printed Thru-Reflect-Line de-embedding set. The presented technique was experimentally validated on an example of specialized magnetic Polylactic Acid (PLA) filament printed substrate in the frequency range of 0.1 GHz to 6 GHz and a reference PLA substrate measured with two different techniques to yield comparable results. |
| 113. | Kamil Staszek Balanced Six-Port Reflectometer With Nonmatched Power Detectors Journal Article IEEE Transactions on Microwave Theory and Techniques, 69 (11), pp. 4869-4878, 2021, ISSN: 1557-9670. @article{Staszek2021, title = {Balanced Six-Port Reflectometer With Nonmatched Power Detectors}, author = {Kamil Staszek}, url = {https://ieeexplore.ieee.org/document/9509345}, doi = {10.1109/TMTT.2021.3101701}, issn = {1557-9670}, year = {2021}, date = {2021-08-09}, journal = {IEEE Transactions on Microwave Theory and Techniques}, volume = {69}, number = {11}, pages = {4869-4878}, abstract = {In this article, a six-port reflectometer is proposed, which utilizes nonmatched power detectors. In the presented solution, the signals reflected from power detectors are efficiently used to obtain a signal flow required for correct measurements. As a consequence, impedance matching networks for power detectors are no longer needed. Simultaneously, due to its balanced topology, the developed six-port exhibits advantageous measurement conditions and theoretically ideal matching at both its input and measurement ports. To experimentally validate the proposed concept, a six-port reflectometer operating at 2.4 GHz is designed, manufactured, and utilized in reflection coefficient measurements. The obtained results are consistent with the values measured using a commercial vector network analyzer. For additional verification, the impact of power detectors' asymmetry is investigated theoretically and experimentally.}, keywords = {}, pubstate = {published}, tppubtype = {article} } In this article, a six-port reflectometer is proposed, which utilizes nonmatched power detectors. In the presented solution, the signals reflected from power detectors are efficiently used to obtain a signal flow required for correct measurements. As a consequence, impedance matching networks for power detectors are no longer needed. Simultaneously, due to its balanced topology, the developed six-port exhibits advantageous measurement conditions and theoretically ideal matching at both its input and measurement ports. To experimentally validate the proposed concept, a six-port reflectometer operating at 2.4 GHz is designed, manufactured, and utilized in reflection coefficient measurements. The obtained results are consistent with the values measured using a commercial vector network analyzer. For additional verification, the impact of power detectors' asymmetry is investigated theoretically and experimentally. |
| 112. | Krzysztof Wincza; Kamil Staszek; Slawomir Gruszczynski Reduced-length tandem directional couplers composed of coupled-line sections with fixed coupling coefficient Journal Article IEEE Transactions on Microwave Theory and Techniques, 69 (3), pp. 1625-1634, 2021, ISSN: 1557-9670. @article{10.1109/TMTT.2021.3053619, title = {Reduced-length tandem directional couplers composed of coupled-line sections with fixed coupling coefficient}, author = {Krzysztof Wincza; Kamil Staszek; Slawomir Gruszczynski}, url = {https://ieeexplore.ieee.org/document/9345488}, doi = {10.1109/TMTT.2021.3053619}, issn = {1557-9670}, year = {2021}, date = {2021-03-04}, journal = {IEEE Transactions on Microwave Theory and Techniques}, volume = {69}, number = {3}, pages = {1625-1634}, abstract = {A novel concept of tandem coupled-line directional couplers has been proposed. The proposed couplers consist of coupled-line sections having different electrical lengths and fixed identical coupling coefficients regardless of the required nominal coupling of the entire tandem coupler. It is proved that available coupling in coupled-line sections constituting tandem directional couplers can be utilized for overall electrical length reduction of the entire network. As shown this allows not only for reduction of the circuit’s size, but also enables flexible design of such couplers, since tuning of the coupling characteristics can be easily achieved by change of solely electrical lengths of the coupled-sections with no change of their coupling coefficients. The thorough theoretical investigation has been presented of such tandem couplers composed of two and three coupled-line sections having fixed coupling coefficients followed, by measurements of four manufactured networks operating at the center frequency of 2 GHz.}, keywords = {}, pubstate = {published}, tppubtype = {article} } A novel concept of tandem coupled-line directional couplers has been proposed. The proposed couplers consist of coupled-line sections having different electrical lengths and fixed identical coupling coefficients regardless of the required nominal coupling of the entire tandem coupler. It is proved that available coupling in coupled-line sections constituting tandem directional couplers can be utilized for overall electrical length reduction of the entire network. As shown this allows not only for reduction of the circuit’s size, but also enables flexible design of such couplers, since tuning of the coupling characteristics can be easily achieved by change of solely electrical lengths of the coupled-sections with no change of their coupling coefficients. The thorough theoretical investigation has been presented of such tandem couplers composed of two and three coupled-line sections having fixed coupling coefficients followed, by measurements of four manufactured networks operating at the center frequency of 2 GHz. |
| 111. | Robert Smolarz; Kamil Staszek; Krzysztof Wincza; Slawomir Gruszczynski A 24 GHz microwave sensor with built-in calibration capability designed in MMIC technology Journal Article IEEE Access, 9 , pp. 31513-31524, 2021, ISSN: 2169-3536. @article{10.1109/ACCESS.2021.3060517, title = {A 24 GHz microwave sensor with built-in calibration capability designed in MMIC technology}, author = {Robert Smolarz; Kamil Staszek; Krzysztof Wincza; Slawomir Gruszczynski}, url = {https://ieeexplore.ieee.org/document/9358169}, doi = {10.1109/ACCESS.2021.3060517}, issn = {2169-3536}, year = {2021}, date = {2021-03-01}, journal = {IEEE Access}, volume = {9}, pages = {31513-31524}, abstract = {A microwave sensor realized in monolithic technology, intended for permittivity estimation with the use of a highly sensitive coupled-line section, is presented in this paper. It also contains a dedicated measurement circuitry realized as a five-port correlator, therefore, a simple scalar power measurement can be utilized to obtain vector signal corresponding to the measured material without the usage of an external vector network analyzer. To suppress systematic measurement errors arising from the manufactured circuit’s imperfections it is equipped with an integrated calibration block, the parameters of which can be simply tuned with two biasing voltages. The sensor is calibrated following a recently reported procedure, which requires neither known nor specific calibration values, in contrast to other methods with much stronger constraints. It is shown for the first time, that a measurement system incorporating a multiport correlator can be successfully calibrated with such arbitrarily chosen settings of the calibration block. To experimentally validate correctness of the calibration’s convergence, the developed sensor is calibrated multiple times with different sets of the calibration block’s settings, each time resulting in the same output values. It proves that the approach to calibration of measurement systems incorporating the multiport correlator can be significantly simplified with no impact on calibration accuracy. Finally, the measurement of the sensor’s response for two dielectric samples clearly demonstrates the advantages of the utilized calibration.}, keywords = {}, pubstate = {published}, tppubtype = {article} } A microwave sensor realized in monolithic technology, intended for permittivity estimation with the use of a highly sensitive coupled-line section, is presented in this paper. It also contains a dedicated measurement circuitry realized as a five-port correlator, therefore, a simple scalar power measurement can be utilized to obtain vector signal corresponding to the measured material without the usage of an external vector network analyzer. To suppress systematic measurement errors arising from the manufactured circuit’s imperfections it is equipped with an integrated calibration block, the parameters of which can be simply tuned with two biasing voltages. The sensor is calibrated following a recently reported procedure, which requires neither known nor specific calibration values, in contrast to other methods with much stronger constraints. It is shown for the first time, that a measurement system incorporating a multiport correlator can be successfully calibrated with such arbitrarily chosen settings of the calibration block. To experimentally validate correctness of the calibration’s convergence, the developed sensor is calibrated multiple times with different sets of the calibration block’s settings, each time resulting in the same output values. It proves that the approach to calibration of measurement systems incorporating the multiport correlator can be significantly simplified with no impact on calibration accuracy. Finally, the measurement of the sensor’s response for two dielectric samples clearly demonstrates the advantages of the utilized calibration. |
| 110. | Andrzej Kruk; Jakub Sorocki; Ilona Piekarz; Dominika Madej; Piotr Kolenderski A novel method for ceramic characterisation by high frequency microwave energy absorption Journal Article Measurement, 167 , pp. 108160, 2021, ISSN: 0263-2241. @article{10.1016/j.measurement.2020.108160, title = {A novel method for ceramic characterisation by high frequency microwave energy absorption}, author = {Andrzej Kruk and Jakub Sorocki and Ilona Piekarz and Dominika Madej and Piotr Kolenderski}, url = {http://www.sciencedirect.com/science/article/pii/S0263224120306989}, doi = {10.1016/j.measurement.2020.108160}, issn = {0263-2241}, year = {2021}, date = {2021-01-01}, journal = {Measurement}, volume = {167}, pages = {108160}, abstract = {A novel method enabling low-cost and very fast determination of physicochemical properties of solids exploring the microwave energy absorption phenomena is proposed and studied. A set of La,Nd-doped Y2O3 ceramic samples was manufactured using the sol–gel process and free sintering. XRD analysis revealed that the crystallite size of samples is in the nanometer range A test vehicle in a form of a microstrip transmission line was tested and developed for the experiment and its shape studied enabling determination of microwave energy absorption properties of a specimen. The conducted study revealed existence of a series of narrow absorption peaks within 10 GHz−43.5 GHz correlate to the particular sample composition independent on the microstructure. The absorption peaks are shifted into lower frequency with increasing of temperature of sample. As such the proposed measurement technique was experimentally proven to be well suited for chemical composition determination.}, keywords = {}, pubstate = {published}, tppubtype = {article} } A novel method enabling low-cost and very fast determination of physicochemical properties of solids exploring the microwave energy absorption phenomena is proposed and studied. A set of La,Nd-doped Y2O3 ceramic samples was manufactured using the sol–gel process and free sintering. XRD analysis revealed that the crystallite size of samples is in the nanometer range A test vehicle in a form of a microstrip transmission line was tested and developed for the experiment and its shape studied enabling determination of microwave energy absorption properties of a specimen. The conducted study revealed existence of a series of narrow absorption peaks within 10 GHz−43.5 GHz correlate to the particular sample composition independent on the microstructure. The absorption peaks are shifted into lower frequency with increasing of temperature of sample. As such the proposed measurement technique was experimentally proven to be well suited for chemical composition determination. |
| 109. | Ilona Piekarz; Krzysztof Wincza; Slawomir Gruszczynski; Jakub Sorocki Detection of methanol contamination in ethyl alcohol employing a purpose-designed high-sensitivity microwave sensor Journal Article Measurement, 174 , pp. 108993, 2021, ISSN: 0263-2241. @article{PIEKARZ2021108993, title = {Detection of methanol contamination in ethyl alcohol employing a purpose-designed high-sensitivity microwave sensor}, author = {Ilona Piekarz and Krzysztof Wincza and Slawomir Gruszczynski and Jakub Sorocki}, url = {https://www.sciencedirect.com/science/article/pii/S0263224121000294}, doi = {https://doi.org/10.1016/j.measurement.2021.108993}, issn = {0263-2241}, year = {2021}, date = {2021-01-01}, journal = {Measurement}, volume = {174}, pages = {108993}, abstract = {A novel method for detection of low methanol contamination in ethyl alcohol is introduced. The approach is centered around sensing the electrical permittivity of the solution at low microwave frequency range where the difference in permittivity between two liquids is very high. A high-sensitivity substrate-less coplanar strip sensor is employed featuring an application-specific design maximizing sensitivity. The open-ended one-port-differential sensor is immersed in a methanol-ethanol solution and its differential reflection coefficient is measured, out of which the concentration of methanol can be determined in real time. The sensor‘s design procedure is provided that relies on analysis of the predicted solution‘s permittivity. The theoretical study was validated by measurements of a solutions with gradually increasing methanol concentration. The obtained results show the possibility to detect methanol content in ethyl alcohol being as low as 0.02% and prove the usefulness of the presented approach for, among others, neutral spirit quality control.}, keywords = {}, pubstate = {published}, tppubtype = {article} } A novel method for detection of low methanol contamination in ethyl alcohol is introduced. The approach is centered around sensing the electrical permittivity of the solution at low microwave frequency range where the difference in permittivity between two liquids is very high. A high-sensitivity substrate-less coplanar strip sensor is employed featuring an application-specific design maximizing sensitivity. The open-ended one-port-differential sensor is immersed in a methanol-ethanol solution and its differential reflection coefficient is measured, out of which the concentration of methanol can be determined in real time. The sensor‘s design procedure is provided that relies on analysis of the predicted solution‘s permittivity. The theoretical study was validated by measurements of a solutions with gradually increasing methanol concentration. The obtained results show the possibility to detect methanol content in ethyl alcohol being as low as 0.02% and prove the usefulness of the presented approach for, among others, neutral spirit quality control. |
| 108. | Jakub Sorocki; Krzysztof Wincza; Slawomir Gruszczynski; Ilona Piekarz Direct Broadband Dielectric Spectroscopy of Liquid Chemicals Using Microwave-Fluidic Two-Wire Transmission Line Sensor Journal Article IEEE Transactions on Microwave Theory and Techniques, pp. 1-1, 2021. @article{9363631, title = {Direct Broadband Dielectric Spectroscopy of Liquid Chemicals Using Microwave-Fluidic Two-Wire Transmission Line Sensor}, author = {Jakub Sorocki and Krzysztof Wincza and Slawomir Gruszczynski and Ilona Piekarz}, doi = {10.1109/TMTT.2021.3059646}, year = {2021}, date = {2021-01-01}, journal = {IEEE Transactions on Microwave Theory and Techniques}, pages = {1-1}, abstract = {A novel robust approach for permittivity measurements of liquid materials in a wide frequency range is proposed. A high-sensitivity microwave-fluidic sensor is developed enabling direct determination of liquid samples' permittivity from the measured sensor's propagation constant. Importantly, neither sensor calibration using liquid standards nor sensor's geometry (except length) information is required, which is very advantageous for industrial applications. This is achieved through the sensor's geometry, which is a two-wire transmission line (TWL) encapsulated in a 3-D printed container, and thus, the liquid-under-test fully encloses the propagating electromagnetic waves. The measurement setup comprises the sensor cascaded between two microstrip-to-TWL transitions for which a simplified de-embedding procedure is proposed using only a THRU standard. For demonstration, a setup was developed with transitions operating within 1-10 GHz and tested up to 18 GHz by measurement of a set of alcohols to produce useful data within the transition bandwidth, which can be extended at the cost of increased uncertainty by postprocessing. Finally, the measurement error study has shown that a relatively low uncertainty and error with respect to the reference is obtained, verifying the usability of the developed measurement technique.}, keywords = {}, pubstate = {published}, tppubtype = {article} } A novel robust approach for permittivity measurements of liquid materials in a wide frequency range is proposed. A high-sensitivity microwave-fluidic sensor is developed enabling direct determination of liquid samples' permittivity from the measured sensor's propagation constant. Importantly, neither sensor calibration using liquid standards nor sensor's geometry (except length) information is required, which is very advantageous for industrial applications. This is achieved through the sensor's geometry, which is a two-wire transmission line (TWL) encapsulated in a 3-D printed container, and thus, the liquid-under-test fully encloses the propagating electromagnetic waves. The measurement setup comprises the sensor cascaded between two microstrip-to-TWL transitions for which a simplified de-embedding procedure is proposed using only a THRU standard. For demonstration, a setup was developed with transitions operating within 1-10 GHz and tested up to 18 GHz by measurement of a set of alcohols to produce useful data within the transition bandwidth, which can be extended at the cost of increased uncertainty by postprocessing. Finally, the measurement error study has shown that a relatively low uncertainty and error with respect to the reference is obtained, verifying the usability of the developed measurement technique. |
| 107. | Jakub Sorocki; Artur Rydosz; Kamil Staszek Wideband microwave multiport-based system for low gas concentration sensing and its application for acetone detection Journal Article Sensors and Actuators B: Chemical, 323 , pp. 128710, 2020. @article{10.1016/j.snb.2020.128710, title = {Wideband microwave multiport-based system for low gas concentration sensing and its application for acetone detection}, author = {Jakub Sorocki and Artur Rydosz and Kamil Staszek}, url = {https://www.sciencedirect.com/science/article/pii/S0925400520310571}, doi = {10.1016/j.snb.2020.128710}, year = {2020}, date = {2020-01-01}, journal = {Sensors and Actuators B: Chemical}, volume = {323}, pages = {128710}, publisher = {Elsevier}, abstract = {A microwave system dedicated to low gas concentrations sensing at room temperature is proposed. An optimized transmission line type sensor coated with a thin film, that changes electrical properties under target gas exposure is developed. The sensor’s response, namely its reflection coefficient is measured using a novel wideband multiport reflectometer. The instrument exhibits an advantageous measurement uncertainty, which can be adjusted to precisely measure small reflection coefficient changes over a wide bandwidth. Broadband data is used to extract the system’s response to gas defined as the reflection coefficient’s phase slope over frequency. The developed sensor covered with acetone-sensitive copper-oxide film together with a reflectometer operating over 1.5 GHz – 4.5 GHz band were incorporated in a gas measurement system to test its response to low acetone concentrations in the range of 0.5 ppm – 5 ppm. Due to high sensor’s sensitivity, optimum measurement conditions provided by the dedicated reflectometer and wideband analysis of the collected data, a robust and low-noise signal proportional to acetone concentration is achieved. The tested concentrations result in measured system’s response in the range of 0.02°/GHz – 0.29°/GHz @ 20 °C and 50 % of relative humidity derived with uncertainty of ±0.022°/GHz being 3 times lower than for a commercial instrument. Additionally, humidity dependence, stability, repeatability, reproducibility, and selectivity are investigated.}, keywords = {}, pubstate = {published}, tppubtype = {article} } A microwave system dedicated to low gas concentrations sensing at room temperature is proposed. An optimized transmission line type sensor coated with a thin film, that changes electrical properties under target gas exposure is developed. The sensor’s response, namely its reflection coefficient is measured using a novel wideband multiport reflectometer. The instrument exhibits an advantageous measurement uncertainty, which can be adjusted to precisely measure small reflection coefficient changes over a wide bandwidth. Broadband data is used to extract the system’s response to gas defined as the reflection coefficient’s phase slope over frequency. The developed sensor covered with acetone-sensitive copper-oxide film together with a reflectometer operating over 1.5 GHz – 4.5 GHz band were incorporated in a gas measurement system to test its response to low acetone concentrations in the range of 0.5 ppm – 5 ppm. Due to high sensor’s sensitivity, optimum measurement conditions provided by the dedicated reflectometer and wideband analysis of the collected data, a robust and low-noise signal proportional to acetone concentration is achieved. The tested concentrations result in measured system’s response in the range of 0.02°/GHz – 0.29°/GHz @ 20 °C and 50 % of relative humidity derived with uncertainty of ±0.022°/GHz being 3 times lower than for a commercial instrument. Additionally, humidity dependence, stability, repeatability, reproducibility, and selectivity are investigated. |
| 106. | Ilona Piekarz; Sabina Gorska; Szczepan Odrobina; Marek Drab; Krzysztof Wincza; Andrzej Gamian; Slawomir Gruszczynski A microwave matrix sensor for multipoint label-free Escherichia coli detection Journal Article Biosensors and Bioelectronics, 147 , pp. 111784, 2020, ISSN: 0956-5663. @article{j.bios.2019.111784, title = {A microwave matrix sensor for multipoint label-free Escherichia coli detection}, author = {Ilona Piekarz and Sabina Gorska and Szczepan Odrobina and Marek Drab and Krzysztof Wincza and Andrzej Gamian and Slawomir Gruszczynski}, url = {http://www.sciencedirect.com/science/article/pii/S0956566319308632}, doi = {10.1016/j.bios.2019.111784}, issn = {0956-5663}, year = {2020}, date = {2020-01-01}, journal = {Biosensors and Bioelectronics}, volume = {147}, pages = {111784}, publisher = {Elsevier}, abstract = {This paper presents a microwave sensor designed as a capacitive matrix for label-free Escherichia coli detection. The mean value of capacitances’ change in the capacitive matrix sensor is an indicator of the bacteria detection. The theoretical analysis was confirmed by the realization of an exemplary sensor chip manufactured using the United Monolithic Semiconductor (UMS) PH25 process on a 100 μm thick GaAs substrate and measurements of various concentrations of Escherichia coli in the frequency range 1–3 GHz. The matrix topology of the sensor together with biofunctionalization of the sensor surface with polyclonal anti-Escherichia coli antibody allow to obtain high detection sensitivity on various concentrations of Escherichia coli reaching 103 CFU/ml. The obtained results are promising for future biomedical applications, in terms of specific bacteria presence detection.}, keywords = {}, pubstate = {published}, tppubtype = {article} } This paper presents a microwave sensor designed as a capacitive matrix for label-free Escherichia coli detection. The mean value of capacitances’ change in the capacitive matrix sensor is an indicator of the bacteria detection. The theoretical analysis was confirmed by the realization of an exemplary sensor chip manufactured using the United Monolithic Semiconductor (UMS) PH25 process on a 100 μm thick GaAs substrate and measurements of various concentrations of Escherichia coli in the frequency range 1–3 GHz. The matrix topology of the sensor together with biofunctionalization of the sensor surface with polyclonal anti-Escherichia coli antibody allow to obtain high detection sensitivity on various concentrations of Escherichia coli reaching 103 CFU/ml. The obtained results are promising for future biomedical applications, in terms of specific bacteria presence detection. |
| 105. | Kamil Staszek; Slawomir Gruszczynski; Krzysztof Wincza Broadband feeding networks based on directional filters for two-beam antenna arrays Journal Article Journal of Electromagnetic Waves and Applications, 34 (9), pp. 1300-1307, 2020. @article{09205071.2019.1657964, title = {Broadband feeding networks based on directional filters for two-beam antenna arrays}, author = {Kamil Staszek and Slawomir Gruszczynski and Krzysztof Wincza}, url = {https://www.tandfonline.com/doi/abs/10.1080/09205071.2019.1657964?journalCode=tewa20}, doi = {10.1080/09205071.2019.1657964}, year = {2020}, date = {2020-01-01}, journal = {Journal of Electromagnetic Waves and Applications}, volume = {34}, number = {9}, pages = {1300-1307}, publisher = {Taylor and Francis}, abstract = {An alternative approach for the design of feeding networks designated for two-beam antenna arrays that ensure similar radiation patterns in a very broad frequency range has been proposed. The presented concept is based on directional filters that are utilized for smooth change of excitation signals of two broadband radiating elements and a broadband directional coupler used for ensuring quadrature excitations between two identical parts of the antenna arrays. The proposed concept has been confirmed by measurements of two-beams antenna arrays operating in frequency ratio fH /fL ≈ 2:1 and 3:1.}, keywords = {}, pubstate = {published}, tppubtype = {article} } An alternative approach for the design of feeding networks designated for two-beam antenna arrays that ensure similar radiation patterns in a very broad frequency range has been proposed. The presented concept is based on directional filters that are utilized for smooth change of excitation signals of two broadband radiating elements and a broadband directional coupler used for ensuring quadrature excitations between two identical parts of the antenna arrays. The proposed concept has been confirmed by measurements of two-beams antenna arrays operating in frequency ratio fH /fL ≈ 2:1 and 3:1. |
| 104. | Jakub Sorocki; Ilona Piekarz; Krzysztof Wincza; Slawomir Gruszczynski; John Papapolymerou Broadband Microwave Microfluidic Coupled-Line Sensor With 3-D-Printed Channel for Industrial Applications Journal Article IEEE Transactions on Microwave Theory and Techniques, 68 (7), pp. 2808-2822, 2020. @article{TMTT.2020.2972525, title = {Broadband Microwave Microfluidic Coupled-Line Sensor With 3-D-Printed Channel for Industrial Applications}, author = {Jakub Sorocki and Ilona Piekarz and Krzysztof Wincza and Slawomir Gruszczynski and John Papapolymerou}, url = {https://ieeexplore.ieee.org/abstract/document/9005412}, doi = {10.1109/TMTT.2020.2972525}, year = {2020}, date = {2020-01-01}, journal = {IEEE Transactions on Microwave Theory and Techniques}, volume = {68}, number = {7}, pages = {2808-2822}, publisher = {IEEE}, abstract = {In this article, a novel microwave microfluidic coupled-line sensor allowing for monitoring of proportional quantities and determination of complex permittivity of liquid dielectric samples through simple analytical formulas is proposed. The application of broadside coupling configuration enabled the sample to be placed in-between coupled strips, thus a high sensitivity can be obtained as the electric field for differential excitation is confined within the sample's volume. Moreover, the use of 3-D printing technology allowed for the realization of an insert with the microfluidic channel and dedicated liquid inlet/outlet. The sensitivity analysis of such a sensor is provided along with the system calibration technique, which is straightforward because of a fixed and well-defined geometry of the sensor-sample setup. An exemplary, general-purpose sensor along with a cal-kit was realized in a stripline structure and manufactured using a combination of laminate and PolyJet 3-D printing technologies. The broadband measurement results are provided for a water-ethanol solution with variable solvent content up to 12 GHz and for various alcohols featuring frequency-dependent complex permittivity up to 5 GHz. The sensor's performance is assessed and discussed.}, keywords = {}, pubstate = {published}, tppubtype = {article} } In this article, a novel microwave microfluidic coupled-line sensor allowing for monitoring of proportional quantities and determination of complex permittivity of liquid dielectric samples through simple analytical formulas is proposed. The application of broadside coupling configuration enabled the sample to be placed in-between coupled strips, thus a high sensitivity can be obtained as the electric field for differential excitation is confined within the sample's volume. Moreover, the use of 3-D printing technology allowed for the realization of an insert with the microfluidic channel and dedicated liquid inlet/outlet. The sensitivity analysis of such a sensor is provided along with the system calibration technique, which is straightforward because of a fixed and well-defined geometry of the sensor-sample setup. An exemplary, general-purpose sensor along with a cal-kit was realized in a stripline structure and manufactured using a combination of laminate and PolyJet 3-D printing technologies. The broadband measurement results are provided for a water-ethanol solution with variable solvent content up to 12 GHz and for various alcohols featuring frequency-dependent complex permittivity up to 5 GHz. The sensor's performance is assessed and discussed. |
| 103. | Slawomir Gruszczynski; Robert Smolarz; Krzysztof Wincza Differential Bi-Level Microstrip Directional Coupler with Equalized Coupling Coefficients for Directivity Improvement Journal Article Electronics, 9 (4), pp. 547, 2020. @article{electronics9040547, title = {Differential Bi-Level Microstrip Directional Coupler with Equalized Coupling Coefficients for Directivity Improvement}, author = {Slawomir Gruszczynski and Robert Smolarz and Krzysztof Wincza}, url = {https://www.mdpi.com/2079-9292/9/4/547}, doi = {10.3390/electronics9040547}, year = {2020}, date = {2020-01-01}, journal = {Electronics}, volume = {9}, number = {4}, pages = {547}, publisher = {MDPI}, abstract = {In this paper, a bi-level microstrip differential directional coupler has been investigated. It has been shown that the equalization of coupling coefficients can be successfully made with the use of appropriate dielectric stack-up and conductor geometry. The application of additional top dielectric layer can ensure proper equalization of coupling coefficients by lowering the value of capacitive coupling coefficient to the value of the inductive one. The theoretically investigated coupled-line section has been used for the design of a 3-dB differential directional coupler. The measurement results are compared with the theoretical ones.}, keywords = {}, pubstate = {published}, tppubtype = {article} } In this paper, a bi-level microstrip differential directional coupler has been investigated. It has been shown that the equalization of coupling coefficients can be successfully made with the use of appropriate dielectric stack-up and conductor geometry. The application of additional top dielectric layer can ensure proper equalization of coupling coefficients by lowering the value of capacitive coupling coefficient to the value of the inductive one. The theoretically investigated coupled-line section has been used for the design of a 3-dB differential directional coupler. The measurement results are compared with the theoretical ones. |
| 102. | Jakub Sorocki; Ilona Piekarz IEEE Access, 8 , pp. 128766-128775, 2020. @article{ACCESS.2020.3008934, title = {Low-Cost Microwave Components’ Fabrication in Hybrid Technology of Laminates and Additive Manufacturing on an Example of Miniaturized Suspended Directional Coupler}, author = {Jakub Sorocki and Ilona Piekarz}, url = {https://ieeexplore.ieee.org/abstract/document/9139503}, doi = {10.1109/ACCESS.2020.3008934}, year = {2020}, date = {2020-01-01}, journal = {IEEE Access}, volume = {8}, pages = {128766-128775}, publisher = {IEEE}, abstract = {A low-cost approach for the fabrication of low-loss microwave components in hybrid technology of laminates and additive manufacturing is presented in this paper. A standard copper-cladded printed circuit board technology is used in combination with a basic stereolithographic 3D printing technology and industry-standard physical vapor deposition technology of aluminum for manufacturing one of the basic building blocks of microwave systems - a 3-dB coupled-line directional coupler in suspended technique operating at 2.0 GHz band. A thin laminate with the coupler traces' mosaic is suspended inside a metal-coated 3D printed enclosure. The presented study explores the performance of the circuit in terms of total power loss vs. the properties of deposited metallization layer serving as a ground plane. It is shown that when the surface roughness of the 3D printed enclosure is low enough, which can be achieved with the use of a layer of lacquer primer before metal deposition, the conductor-related power losses are lowered to an acceptable level. An exemplary directional coupler was developed along with three variants of the enclosure and the reference one. The measurement results validate the potential of this hybrid technique to deliver fully valuable microwave components at a very low manufacturing cost.}, keywords = {}, pubstate = {published}, tppubtype = {article} } A low-cost approach for the fabrication of low-loss microwave components in hybrid technology of laminates and additive manufacturing is presented in this paper. A standard copper-cladded printed circuit board technology is used in combination with a basic stereolithographic 3D printing technology and industry-standard physical vapor deposition technology of aluminum for manufacturing one of the basic building blocks of microwave systems - a 3-dB coupled-line directional coupler in suspended technique operating at 2.0 GHz band. A thin laminate with the coupler traces' mosaic is suspended inside a metal-coated 3D printed enclosure. The presented study explores the performance of the circuit in terms of total power loss vs. the properties of deposited metallization layer serving as a ground plane. It is shown that when the surface roughness of the 3D printed enclosure is low enough, which can be achieved with the use of a layer of lacquer primer before metal deposition, the conductor-related power losses are lowered to an acceptable level. An exemplary directional coupler was developed along with three variants of the enclosure and the reference one. The measurement results validate the potential of this hybrid technique to deliver fully valuable microwave components at a very low manufacturing cost. |
| 101. | Walter A Lyons; Eric C Bruning; Tom A Warner; Donald R MacGorman; Samantha Edgington; Clemens Tillier; Janusz Mlynarczyk Megaflashes: Just How Long Can a Lightning Discharge Get? Journal Article Bulletin of the American Meteorological Society, 101 (1), pp. E73-E86, 2020, ISSN: 0003-0007. @article{10.1175/BAMS-D-19-0033.1, title = {Megaflashes: Just How Long Can a Lightning Discharge Get?}, author = {Walter A Lyons and Eric C Bruning and Tom A Warner and Donald R MacGorman and Samantha Edgington and Clemens Tillier and Janusz Mlynarczyk}, url = {https://doi.org/10.1175/BAMS-D-19-0033.1}, doi = {10.1175/BAMS-D-19-0033.1}, issn = {0003-0007}, year = {2020}, date = {2020-01-01}, journal = {Bulletin of the American Meteorological Society}, volume = {101}, number = {1}, pages = {E73-E86}, abstract = {The existence of mesoscale lightning discharges on the order of 100 km in length has been known since the radar-based findings of Ligda in the mid-1950s. However, it took the discovery of sprites in 1989 to direct significant attention to horizontally extensive “megaflashes” within mesoscale convective systems (MCSs). More recently, 3D Lightning Mapping Arrays (LMAs) have documented sprite-initiating lightning discharges traversing several hundred kilometers. One such event in a 2007 Oklahoma MCS having an LMA-derived length of 321 km, has been certified by the WMO as the longest officially documented lightning flash. The new Geostationary Lightning Mapper (GLM) sensor on GOES-16/17 now provides an additional tool suited to investigating mesoscale lightning. On 22 October 2017, a quasi-linear convective system moved through the central United States. At 0513 UTC, the GLM indicated a lightning discharge originated in northern Texas, propagated north-northeast across Oklahoma, fortuitously traversed the Oklahoma LMA (OKLMA), and finally terminated in southeastern Kansas. This event is explored using the OKLMA, the National Lightning Detection Network (NLDN), and the GLM. The NLDN reported 17 positive cloud-to-ground flashes (+CGs), 23 negative CGs (−CGs), and 37 intracloud flashes (ICs) associated with this massive discharge, including two +CGs capable of inducing sprites, with others triggering upward lightning from tall towers. Combining all available data confirms the megaflash, which illuminated 67,845 km2, was at least 500 km long, greatly exceeding the current official record flash length. Yet even these values are being superseded as GLM data are further explored, revealing that such vast discharges may not be all that uncommon.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The existence of mesoscale lightning discharges on the order of 100 km in length has been known since the radar-based findings of Ligda in the mid-1950s. However, it took the discovery of sprites in 1989 to direct significant attention to horizontally extensive “megaflashes” within mesoscale convective systems (MCSs). More recently, 3D Lightning Mapping Arrays (LMAs) have documented sprite-initiating lightning discharges traversing several hundred kilometers. One such event in a 2007 Oklahoma MCS having an LMA-derived length of 321 km, has been certified by the WMO as the longest officially documented lightning flash. The new Geostationary Lightning Mapper (GLM) sensor on GOES-16/17 now provides an additional tool suited to investigating mesoscale lightning. On 22 October 2017, a quasi-linear convective system moved through the central United States. At 0513 UTC, the GLM indicated a lightning discharge originated in northern Texas, propagated north-northeast across Oklahoma, fortuitously traversed the Oklahoma LMA (OKLMA), and finally terminated in southeastern Kansas. This event is explored using the OKLMA, the National Lightning Detection Network (NLDN), and the GLM. The NLDN reported 17 positive cloud-to-ground flashes (+CGs), 23 negative CGs (−CGs), and 37 intracloud flashes (ICs) associated with this massive discharge, including two +CGs capable of inducing sprites, with others triggering upward lightning from tall towers. Combining all available data confirms the megaflash, which illuminated 67,845 km2, was at least 500 km long, greatly exceeding the current official record flash length. Yet even these values are being superseded as GLM data are further explored, revealing that such vast discharges may not be all that uncommon. |
| 100. | Robert Smolarz; Krzysztof Wincza; Slawomir Gruszczynski Modal phase velocity compensation in multilayer differentially fed directional couplers Journal Article Microwave and Optical Technology Letters, 62 (5), pp. 1882-1887, 2020. @article{10.1002/mop.32252, title = {Modal phase velocity compensation in multilayer differentially fed directional couplers}, author = {Robert Smolarz and Krzysztof Wincza and Slawomir Gruszczynski}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/mop.32252}, doi = {10.1002/mop.32252}, year = {2020}, date = {2020-01-01}, journal = {Microwave and Optical Technology Letters}, volume = {62}, number = {5}, pages = {1882-1887}, publisher = {Wiley and Sons}, abstract = {Abstract In this article, we present for the first time the possibility of the modal phase velocity compensation in differentially fed directional couplers designed in inhomogeneous dielectric media. It is shown that in an appropriate, inhomogeneous dielectric structure, the equalization of even- and odd-mode phase velocities propagating in such couplers can be made. The presented method has been verified experimentally by design and measurements of a fabricated coupler to show the correctness and applicability of the proposed solution. A 8-dB differentially fed directional coupler has been designed as a edgewise structure operating at 1 GHz center frequency.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Abstract In this article, we present for the first time the possibility of the modal phase velocity compensation in differentially fed directional couplers designed in inhomogeneous dielectric media. It is shown that in an appropriate, inhomogeneous dielectric structure, the equalization of even- and odd-mode phase velocities propagating in such couplers can be made. The presented method has been verified experimentally by design and measurements of a fabricated coupler to show the correctness and applicability of the proposed solution. A 8-dB differentially fed directional coupler has been designed as a edgewise structure operating at 1 GHz center frequency. |
| 99. | Slawomir Gruszczynski; Robert Smolarz; Changying Wu; Krzysztof Wincza Monolithic Miniaturized Differentially-Fed Branch-Line Directional Coupler in GaAs Monolithic Technology Journal Article Electronics, 9 (3), pp. 446, 2020. @article{10.3390/electronics9030446, title = {Monolithic Miniaturized Differentially-Fed Branch-Line Directional Coupler in GaAs Monolithic Technology}, author = {Slawomir Gruszczynski and Robert Smolarz and Changying Wu and Krzysztof Wincza}, url = {https://www.mdpi.com/2079-9292/9/3/446}, doi = {10.3390/electronics9030446}, year = {2020}, date = {2020-01-01}, journal = {Electronics}, volume = {9}, number = {3}, pages = {446}, publisher = {MDPI}, abstract = {In this paper, a design of a miniaturized branch-line directional coupler is presented. The coupler is designed with balanced coupled-line sections, which are electrically shortened by the application of lumped capacitors. To measure the parameters of the coupler, appropriate baluns have been designed. The coupler has been designed in a GaAs PH25 UMS (united monolithic semiconductor) technology with the center frequency of 24 GHz. The measured power split equals 3 dB with the transmission/coupling imbalance not exceeding 0.6 dB. The measured return losses equal 17 dB at the center frequency, whereas the isolation reaches 17 dB. The fabricated coupler‘s size equals 630 um × 487 um, which is 0.19 of the full size of the directional coupler in the chosen technology (1191 um × 1170 um)}, keywords = {}, pubstate = {published}, tppubtype = {article} } In this paper, a design of a miniaturized branch-line directional coupler is presented. The coupler is designed with balanced coupled-line sections, which are electrically shortened by the application of lumped capacitors. To measure the parameters of the coupler, appropriate baluns have been designed. The coupler has been designed in a GaAs PH25 UMS (united monolithic semiconductor) technology with the center frequency of 24 GHz. The measured power split equals 3 dB with the transmission/coupling imbalance not exceeding 0.6 dB. The measured return losses equal 17 dB at the center frequency, whereas the isolation reaches 17 dB. The fabricated coupler‘s size equals 630 um × 487 um, which is 0.19 of the full size of the directional coupler in the chosen technology (1191 um × 1170 um) |
| 98. | Kamil Staszek; Jakub Sorocki; Slawomir Gruszczynski; Krzysztof Wincza Multisection tandem couplers with coupled-line sections having unequal lengths Journal Article Microwave and Optical Technology Letters, 62 (7), pp. 2488-2492, 2020. @article{10.1002/mop.32349, title = {Multisection tandem couplers with coupled-line sections having unequal lengths}, author = {Kamil Staszek and Jakub Sorocki and Slawomir Gruszczynski and Krzysztof Wincza}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/mop.32349}, doi = {10.1002/mop.32349}, year = {2020}, date = {2020-01-01}, journal = {Microwave and Optical Technology Letters}, volume = {62}, number = {7}, pages = {2488-2492}, abstract = {Abstract A novel concept of multisection tandem couplers composed of 2 quarter wavelength coupled-line sections in between which a 270°-long section is inserted has been proposed. The presented couplers feature relaxed coupling coefficients' requirements and a shorter overall electrical length with respect to the classic multisection tandem couplers, preserving simultaneously similar frequency characteristics to the ones obtainable in classic solutions. The proposed concept has been verified by the design and measurements of the developed tandem coupler operating at the center frequency 2 GHz with amplitude characteristics of a three-section directional coupler.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Abstract A novel concept of multisection tandem couplers composed of 2 quarter wavelength coupled-line sections in between which a 270°-long section is inserted has been proposed. The presented couplers feature relaxed coupling coefficients' requirements and a shorter overall electrical length with respect to the classic multisection tandem couplers, preserving simultaneously similar frequency characteristics to the ones obtainable in classic solutions. The proposed concept has been verified by the design and measurements of the developed tandem coupler operating at the center frequency 2 GHz with amplitude characteristics of a three-section directional coupler. |
| 97. | Jakub Sorocki; Artur Rydosz A Prototype of a Portable Gas Analyzer for Exhaled Acetone Detection Journal Article Applied Sciences, 9 (13), pp. 2605, 2019, ISSN: 0956-5663. @article{10.3390/app9132605, title = {A Prototype of a Portable Gas Analyzer for Exhaled Acetone Detection}, author = {Jakub Sorocki and Artur Rydosz}, url = {https://www.mdpi.com/2076-3417/9/13/2605}, doi = {10.3390/app9132605}, issn = {0956-5663}, year = {2019}, date = {2019-06-27}, journal = {Applied Sciences}, volume = {9}, number = {13}, pages = {2605}, publisher = {MDPI}, abstract = {The paper presents the development of a portable gas analyzer prototype for exhaled acetone detection, employing an application-suited gas sensor array and 3D printing technology. The device provides the functionality to monitor exhaled acetone levels, which could be used as a potential tool for non-invasive diabetes monitoring. The relationship between exhaled acetone concentrations and glucose in blood is confirmed in the literature, including research carried out by the authors. The design process is presented including a general consideration for the sensor array construction, which is the core for sensing gases, as well as requirements for the measurement chamber it is to be placed in. Moreover, the mechanical design of the 3D-printed housing is discussed to ensure the ergonomics of use as a hand-held device while keeping the hardware integrity. Also, the processing hardware is discussed to provide sufficient computing power to handle the stand-alone operation while being energy efficient, enabling long battery-powered operation. Finally, calibration and measurement, as well as the analyzer operation, are shown, validating the proposed class of exhaled acetone-detection capable meters.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The paper presents the development of a portable gas analyzer prototype for exhaled acetone detection, employing an application-suited gas sensor array and 3D printing technology. The device provides the functionality to monitor exhaled acetone levels, which could be used as a potential tool for non-invasive diabetes monitoring. The relationship between exhaled acetone concentrations and glucose in blood is confirmed in the literature, including research carried out by the authors. The design process is presented including a general consideration for the sensor array construction, which is the core for sensing gases, as well as requirements for the measurement chamber it is to be placed in. Moreover, the mechanical design of the 3D-printed housing is discussed to ensure the ergonomics of use as a hand-held device while keeping the hardware integrity. Also, the processing hardware is discussed to provide sufficient computing power to handle the stand-alone operation while being energy efficient, enabling long battery-powered operation. Finally, calibration and measurement, as well as the analyzer operation, are shown, validating the proposed class of exhaled acetone-detection capable meters. |
| 96. | Jakub Sorocki; Ilona Piekarz; Slawomir Gruszczynski; Krzysztof Wincza; John Papapolymerou Application of 3-D Printing Technology for the Realization of High-Performance Directional Couplers in Suspended Stripline Technique Journal Article IEEE Transactions on Components, Packaging and Manufacturing Technology, 9 (8), pp. 1652-1658, 2019. @article{10.1109/TCPMT.2019.2903437, title = {Application of 3-D Printing Technology for the Realization of High-Performance Directional Couplers in Suspended Stripline Technique}, author = {Jakub Sorocki and Ilona Piekarz and Slawomir Gruszczynski and Krzysztof Wincza and John Papapolymerou}, url = {https://ieeexplore.ieee.org/document/8662686}, doi = {10.1109/TCPMT.2019.2903437}, year = {2019}, date = {2019-01-01}, journal = {IEEE Transactions on Components, Packaging and Manufacturing Technology}, volume = {9}, number = {8}, pages = {1652-1658}, publisher = {IEEE}, abstract = {In this paper, a novel approach for the realization of high-performance coupled-line directional couplers in suspended stripline technique is proposed, taking advantage of the recent development in 3-D printing technology. An enhanced 2.5-D dielectric structure is introduced, allowing to combine the advantages of strip transmission line techniques, for which the circuit can still be considered as a quasi-planar structure, with the 3-D printing flexibility allowing to realize locally variable air layer thicknesses limited only by technological constraints. It is shown that the proposed approach is especially useful when tight coupling, as for which thick air layer in the coupled-line region is required and compact structure is of need. Moreover, compensating elements, often required to improve couplers' performance, can easily be realized as a combination of a circuit mosaic and varied ground plane for better circuit volume utilization. An example of a 3-dB coupled-line directional coupler operating within the ISM 5.8-GHz band is designed, manufactured, and measured for the experimental verification. The obtained results confirm the applicability of the proposed approach.}, keywords = {}, pubstate = {published}, tppubtype = {article} } In this paper, a novel approach for the realization of high-performance coupled-line directional couplers in suspended stripline technique is proposed, taking advantage of the recent development in 3-D printing technology. An enhanced 2.5-D dielectric structure is introduced, allowing to combine the advantages of strip transmission line techniques, for which the circuit can still be considered as a quasi-planar structure, with the 3-D printing flexibility allowing to realize locally variable air layer thicknesses limited only by technological constraints. It is shown that the proposed approach is especially useful when tight coupling, as for which thick air layer in the coupled-line region is required and compact structure is of need. Moreover, compensating elements, often required to improve couplers' performance, can easily be realized as a combination of a circuit mosaic and varied ground plane for better circuit volume utilization. An example of a 3-dB coupled-line directional coupler operating within the ISM 5.8-GHz band is designed, manufactured, and measured for the experimental verification. The obtained results confirm the applicability of the proposed approach. |
| 95. | Ilona Piekarz; Jalub Sorocki; Michael T Craton; Krzysztof Wincza; Slawomir Gruszczynski; John Papapolymerou Application of Aerosol Jet 3-D Printing With Conductive and Nonconductive Inks for Manufacturing mm-Wave Circuits Journal Article IEEE Transactions on Components, Packaging and Manufacturing Technology, 9 (3), pp. 586-595, 2019. @article{10.1109/TCPMT.2018.2889698, title = {Application of Aerosol Jet 3-D Printing With Conductive and Nonconductive Inks for Manufacturing mm-Wave Circuits}, author = {Ilona Piekarz and Jalub Sorocki and Michael T Craton and Krzysztof Wincza and Slawomir Gruszczynski and John Papapolymerou}, url = {https://ieeexplore.ieee.org/document/8589025}, doi = {10.1109/TCPMT.2018.2889698}, year = {2019}, date = {2019-01-01}, journal = {IEEE Transactions on Components, Packaging and Manufacturing Technology}, volume = {9}, number = {3}, pages = {586-595}, publisher = {IEEE}, abstract = {In this paper, an application of aerosol jet 3-D printing with conductive and nonconductive inks for the realization of millimeter (mm)-wave circuits well above 30 GHz is presented and investigated. The Optomec 5X aerosol jet 3-D printing system is used together with polyimide (PI) and silver inks to fully-additive manufacture various microstrip circuits. A section of microstrip transmission line with a transition to a via-less conductor-backed coplanar waveguide was designed together with a T-junction and a branch-line coupler. These circuits were designed to operate within the Ka and V frequency bands. The measured thickness of the PI dielectric substrate is 20.7 ± 1.35 μm, while the silver traces are 2.6 ± 1.35 μm. A section of the transmission line with the developed transitions was measured up to the W-band, exhibiting a total loss of 0.65 dB/mm at 100 GHz. The T-junction power divider yielded a total loss at its center frequency of 34 GHz of 0.55 dB. The 3-dB branch-line coupler yielded a loss at its center frequency at 42 GHz of 1.1 dB. The experimental results demonstrate the application of this approach for fast and high-resolution mm-wave circuit fabrication.}, keywords = {}, pubstate = {published}, tppubtype = {article} } In this paper, an application of aerosol jet 3-D printing with conductive and nonconductive inks for the realization of millimeter (mm)-wave circuits well above 30 GHz is presented and investigated. The Optomec 5X aerosol jet 3-D printing system is used together with polyimide (PI) and silver inks to fully-additive manufacture various microstrip circuits. A section of microstrip transmission line with a transition to a via-less conductor-backed coplanar waveguide was designed together with a T-junction and a branch-line coupler. These circuits were designed to operate within the Ka and V frequency bands. The measured thickness of the PI dielectric substrate is 20.7 ± 1.35 μm, while the silver traces are 2.6 ± 1.35 μm. A section of the transmission line with the developed transitions was measured up to the W-band, exhibiting a total loss of 0.65 dB/mm at 100 GHz. The T-junction power divider yielded a total loss at its center frequency of 34 GHz of 0.55 dB. The 3-dB branch-line coupler yielded a loss at its center frequency at 42 GHz of 1.1 dB. The experimental results demonstrate the application of this approach for fast and high-resolution mm-wave circuit fabrication. |
| 94. | Kamil Staszek; Szczepan Odrobina; Krzysztof Wincza; Slawomir Gruszczynski Broadband matrix-type feeding networks for two-beam antennas with constant beamwidth and efficient aperture utilization Journal Article Journal of Electromagnetic Waves and Applications, 33 (2), pp. 236-248, 2019. @article{10.1080/09205071.2018.1536565, title = {Broadband matrix-type feeding networks for two-beam antennas with constant beamwidth and efficient aperture utilization}, author = {Kamil Staszek and Szczepan Odrobina and Krzysztof Wincza and Slawomir Gruszczynski}, url = {https://doi.org/10.1080/09205071.2018.1536565}, doi = {10.1080/09205071.2018.1536565}, year = {2019}, date = {2019-01-01}, journal = {Journal of Electromagnetic Waves and Applications}, volume = {33}, number = {2}, pages = {236-248}, publisher = {Taylor & Francis}, abstract = {We report a novel approach for the design of a Butler matrix-type feeding network that allows for achieving two-beam antenna arrays in a very broad frequency range. The proposed solution is based on a 2 × 4 frequency-selective beamforming network which changes its frequency characteristics across the bandwidth. The utilized network features three different properties at three different frequencies. Therefore, such a network allows for achieving two-beam radiation pattern with similar beamwidths and beam directions over 3:1 bandwidth in conjunction with four broadband radiating elements. The presented concept has been verified by the design and measurements of a two-beam antenna array operating in 1–3 GHz frequency range.}, keywords = {}, pubstate = {published}, tppubtype = {article} } We report a novel approach for the design of a Butler matrix-type feeding network that allows for achieving two-beam antenna arrays in a very broad frequency range. The proposed solution is based on a 2 × 4 frequency-selective beamforming network which changes its frequency characteristics across the bandwidth. The utilized network features three different properties at three different frequencies. Therefore, such a network allows for achieving two-beam radiation pattern with similar beamwidths and beam directions over 3:1 bandwidth in conjunction with four broadband radiating elements. The presented concept has been verified by the design and measurements of a two-beam antenna array operating in 1–3 GHz frequency range. |
| 93. | Konrad Janisz; Ilona Piekarz; Kamil Staszek; Krzysztof Wincza; Slawomir Gruszczynski Differentially fed impedance-transforming directional coupler Journal Article Electronics Letters, 55 (1), pp. 34-36, 2019. @article{10.1049/el.2018.6867, title = {Differentially fed impedance-transforming directional coupler}, author = {Konrad Janisz and Ilona Piekarz and Kamil Staszek and Krzysztof Wincza and Slawomir Gruszczynski}, url = {https://ieeexplore.ieee.org/document/8605324}, doi = {10.1049/el.2018.6867}, year = {2019}, date = {2019-01-01}, journal = {Electronics Letters}, volume = {55}, number = {1}, pages = {34-36}, publisher = {IET}, abstract = {In this Letter, a differentially fed impedance-transforming directional coupler is considered. The utilisation of recently introduced unequal-width differentially fed coupled conductors allows for setting independently terminating impedances for each of coupled lines as well as for coupling control in a chosen dielectric stack-up. The theoretical analysis is confirmed by experimental verification, in which an impedance transforming 70-50 Ω 3 dB single-section directional coupler has been designed and measured.}, keywords = {}, pubstate = {published}, tppubtype = {article} } In this Letter, a differentially fed impedance-transforming directional coupler is considered. The utilisation of recently introduced unequal-width differentially fed coupled conductors allows for setting independently terminating impedances for each of coupled lines as well as for coupling control in a chosen dielectric stack-up. The theoretical analysis is confirmed by experimental verification, in which an impedance transforming 70-50 Ω 3 dB single-section directional coupler has been designed and measured. |
| 92. | Ilona Piekarz; Jakub Sorocki; Krzysztof Wincza; Slawomir Gruszczynski; John Papapolymerou High-performance differentially fed coupled-line directional couplers realised in inhomogeneous medium Journal Article IET Microwaves, Antennas Propagation, 13 (12), pp. 2005-2012, 2019. @article{10.1049/iet-map.2018.5737, title = {High-performance differentially fed coupled-line directional couplers realised in inhomogeneous medium}, author = {Ilona Piekarz and Jakub Sorocki and Krzysztof Wincza and Slawomir Gruszczynski and John Papapolymerou}, url = {https://ieeexplore.ieee.org/document/8859717}, doi = {10.1049/iet-map.2018.5737}, year = {2019}, date = {2019-01-01}, journal = {IET Microwaves, Antennas Propagation}, volume = {13}, number = {12}, pages = {2005-2012}, publisher = {IEEE}, abstract = {In this study, a generalised approach for the design of high-performance differentially fed coupled-line directional couplers in inhomogeneous medium is presented for the first time. Conditions for the realisation of ideal coupled-line section under differential excitation are provided and it is shown that generally in such medium couplers feature different capacitive and inductive coupling coefficients, which significantly deteriorate circuits' performance. Therefore, the compensation technique is proposed allowing for equalisation of the differential coupling coefficients by adding appropriate compensating elements to the per-unit-length capacitance and inductance matrices of the coupled-line section. The proposed approach allows for realisation of quasi-ideal differential coupled-line couplers designed in arbitrarily chosen dielectric stack-up, and almost for arbitrarily chosen coupling. The provided theoretical analysis and resulting design methodology are verified experimentally with a 3-dB differential coupler operating at f 0 = 1.5 GHz and realised in suspended microstrip technique. Moreover, a combination of laminate and additive manufacturing technologies was used for higher design flexibility and low-cost manufacturing.}, keywords = {}, pubstate = {published}, tppubtype = {article} } In this study, a generalised approach for the design of high-performance differentially fed coupled-line directional couplers in inhomogeneous medium is presented for the first time. Conditions for the realisation of ideal coupled-line section under differential excitation are provided and it is shown that generally in such medium couplers feature different capacitive and inductive coupling coefficients, which significantly deteriorate circuits' performance. Therefore, the compensation technique is proposed allowing for equalisation of the differential coupling coefficients by adding appropriate compensating elements to the per-unit-length capacitance and inductance matrices of the coupled-line section. The proposed approach allows for realisation of quasi-ideal differential coupled-line couplers designed in arbitrarily chosen dielectric stack-up, and almost for arbitrarily chosen coupling. The provided theoretical analysis and resulting design methodology are verified experimentally with a 3-dB differential coupler operating at f 0 = 1.5 GHz and realised in suspended microstrip technique. Moreover, a combination of laminate and additive manufacturing technologies was used for higher design flexibility and low-cost manufacturing. |
| 91. | Kamil Staszek High-performance differentially fed coupled-line directional couplers realised in inhomogeneous medium Journal Article IET Microwaves, Antennas Propagation, 9 (1), pp. 30-33, 2019, ISSN: 2010-3719. @article{10.18178/IJIEE.2019.9.1.700, title = {High-performance differentially fed coupled-line directional couplers realised in inhomogeneous medium}, author = {Kamil Staszek}, url = {http://www.ijiee.org/index.php?m=content&c=index&a=show&catid=84&id=803;}, doi = {10.18178/IJIEE.2019.9.1.700}, issn = {2010-3719}, year = {2019}, date = {2019-01-01}, journal = {IET Microwaves, Antennas Propagation}, volume = {9}, number = {1}, pages = {30-33}, abstract = {In this paper a general investigation on the uncertainty of reflection coefficient measurements with the use of six-port reflectometer is presented. A wide range of both power measurement uncertainty and limited dynamics of the power meters utilized in the six-port systems are incorporated. Based on the conducted analysis the optimum parameters of six-port reflectometer are derived, which provide the lowest possible measurement uncertainty distribution for all reflection coefficients of passive devices.}, keywords = {}, pubstate = {published}, tppubtype = {article} } In this paper a general investigation on the uncertainty of reflection coefficient measurements with the use of six-port reflectometer is presented. A wide range of both power measurement uncertainty and limited dynamics of the power meters utilized in the six-port systems are incorporated. Based on the conducted analysis the optimum parameters of six-port reflectometer are derived, which provide the lowest possible measurement uncertainty distribution for all reflection coefficients of passive devices. |
| 90. | Martin Füllekrug; Stanislaus Nnadih; Serge Soula; Janusz Mlynarczyk; Micheal Stock; Jeff Lapierre; Michael Kosch Maximum Sprite Streamer Luminosity Near the Stratopause Journal Article Geophysical Research Letters, 46 (21), pp. 12572-12579, 2019. @article{10.1029/2019GL084331, title = {Maximum Sprite Streamer Luminosity Near the Stratopause}, author = {Martin Füllekrug and Stanislaus Nnadih and Serge Soula and Janusz Mlynarczyk and Micheal Stock and Jeff Lapierre and Michael Kosch}, url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2019GL084331}, doi = {10.1029/2019GL084331}, year = {2019}, date = {2019-01-01}, journal = {Geophysical Research Letters}, volume = {46}, number = {21}, pages = {12572-12579}, abstract = {Abstract Sprites are composed of numerous streamers which exhibit transient luminosities in the upper middle atmosphere above thunderclouds after initiation by an intense positive lightning discharge, often followed by lightning continuing current. Here we report the discovery of a sprite which exhibits its main luminosity near the stratopause. This novel phenomenon is attributed to a sudden surge of intracloud lightning leader activity, based on a rigorous analysis of our observed electromagnetic waveforms. Each lightning leader discharge causes an additional electric field that generates a small amount of electromagnetic energy near the stratopause and thereby contributes to the overall sprite luminosity morphology. The observation of sprite streamers near the stratopause is important because it is relevant for the ongoing assessment of the lightning impact on N2 and CO2 with emissions from the near to far infrared part of the spectrum.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Abstract Sprites are composed of numerous streamers which exhibit transient luminosities in the upper middle atmosphere above thunderclouds after initiation by an intense positive lightning discharge, often followed by lightning continuing current. Here we report the discovery of a sprite which exhibits its main luminosity near the stratopause. This novel phenomenon is attributed to a sudden surge of intracloud lightning leader activity, based on a rigorous analysis of our observed electromagnetic waveforms. Each lightning leader discharge causes an additional electric field that generates a small amount of electromagnetic energy near the stratopause and thereby contributes to the overall sprite luminosity morphology. The observation of sprite streamers near the stratopause is important because it is relevant for the ongoing assessment of the lightning impact on N2 and CO2 with emissions from the near to far infrared part of the spectrum. |
| 89. | Artur Rydosz; Andrzej Brudnik; Kamil Staszek Metal Oxide Thin Films Prepared by Magnetron Sputtering Technology for Volatile Organic Compound Detection in the Microwave Frequency Range Journal Article Materials, 12 (877), 2019. @article{10.3390/ma12060877, title = {Metal Oxide Thin Films Prepared by Magnetron Sputtering Technology for Volatile Organic Compound Detection in the Microwave Frequency Range}, author = {Artur Rydosz and Andrzej Brudnik and Kamil Staszek}, url = {https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6471264/}, doi = {10.3390/ma12060877}, year = {2019}, date = {2019-01-01}, journal = {Materials}, volume = {12}, number = {877}, publisher = {MDPI}, abstract = {Metal oxide thin films such as copper oxide, titanium dioxide, and tin dioxide deposited by magnetron sputtering technology were verified as a gas-sensitive layer in microwave-based gas sensors operated at 2.4 GHz. The developed gas sensors were tested at room temperature (23 °C) and 50% relative humidity (RH) under exposure to 0–200 ppm of selected volatile organic compounds (acetone, ethanol, and methanol) that are of high interest in industry and biomedical applications. The highest responses to acetone were obtained for CuO-based gas sensors, to ethanol for SnO2-based gas sensors, while for methanol detection both dioxides, SnO2 and TiO2, exhibited good sensitivity.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Metal oxide thin films such as copper oxide, titanium dioxide, and tin dioxide deposited by magnetron sputtering technology were verified as a gas-sensitive layer in microwave-based gas sensors operated at 2.4 GHz. The developed gas sensors were tested at room temperature (23 °C) and 50% relative humidity (RH) under exposure to 0–200 ppm of selected volatile organic compounds (acetone, ethanol, and methanol) that are of high interest in industry and biomedical applications. The highest responses to acetone were obtained for CuO-based gas sensors, to ethanol for SnO2-based gas sensors, while for methanol detection both dioxides, SnO2 and TiO2, exhibited good sensitivity. |
| 88. | Kamil Staszek; Aleksandra Szkudlarek; Michal Kawa; Artur Rydosz Microwave system with sensor utilizing GO-based gas-sensitive layer and its application to acetone detection Journal Article Sensors and Actuators B: Chemical, 297 (15), pp. 126699, 2019. @article{10.1016/j.snb.2019.126699, title = {Microwave system with sensor utilizing GO-based gas-sensitive layer and its application to acetone detection}, author = {Kamil Staszek and Aleksandra Szkudlarek and Michal Kawa and Artur Rydosz}, url = {https://www.sciencedirect.com/science/article/abs/pii/S0925400519309001#!}, doi = {10.1016/j.snb.2019.126699}, year = {2019}, date = {2019-01-01}, journal = {Sensors and Actuators B: Chemical}, volume = {297}, number = {15}, pages = {126699}, publisher = {Elsevier}, abstract = {A novel microwave-based gas sensor realized as a coupled-line section covered with a graphene oxide (GO) film as a gas-sensitive layer is proposed and verified. It is shown that the developed sensor’s reflection coefficient, measured at 2.4 GHz with the aid of a dedicated five-port reflectometer featuring decreased measurement uncertainty, can be used for estimating the gas concentration with a high level of accuracy. The developed microwave-based sensors were tested at room temperature under exposure to various volatile organic compounds: ethanol, acetone, methanol and isopropanol in the 0–200 ppm concentration range, with the highest response for acetone. Moreover, the simple circuitry of the proposed system together with its high performance enables its application in portable devices.}, keywords = {}, pubstate = {published}, tppubtype = {article} } A novel microwave-based gas sensor realized as a coupled-line section covered with a graphene oxide (GO) film as a gas-sensitive layer is proposed and verified. It is shown that the developed sensor’s reflection coefficient, measured at 2.4 GHz with the aid of a dedicated five-port reflectometer featuring decreased measurement uncertainty, can be used for estimating the gas concentration with a high level of accuracy. The developed microwave-based sensors were tested at room temperature under exposure to various volatile organic compounds: ethanol, acetone, methanol and isopropanol in the 0–200 ppm concentration range, with the highest response for acetone. Moreover, the simple circuitry of the proposed system together with its high performance enables its application in portable devices. |
| 87. | Slawomir Gruszczynski; Robert Smolarz; Krzysztof Wincza Realization of High-Performance Broadband Quadrature Directional Couplers in UMS PH25 Technology Journal Article Electronics, 8 (1520), pp. 1-17, 2019. @article{10.3390/electronics8121520, title = {Realization of High-Performance Broadband Quadrature Directional Couplers in UMS PH25 Technology}, author = {Slawomir Gruszczynski and Robert Smolarz and Krzysztof Wincza}, url = {https://www.mdpi.com/2079-9292/8/12/1520}, doi = {10.3390/electronics8121520}, year = {2019}, date = {2019-01-01}, journal = {Electronics}, volume = {8}, number = {1520}, pages = {1-17}, publisher = {MDPI}, abstract = {The problem of the realization of broadband quadrature directional couplers in UMS (United Monolithic Semiconductors) PH25 is thoroughly investigated. The limitations of the selected technology are discussed with respect to directional couplers’ design. It is shown that, in such technologies, two major problems have to be overcome to achieve the high-performance of the resulting integrated couplers, i.e., the realization of appropriate coupling together with appropriate characteristic impedances, and the equalization of inductive and capacitive coupling coefficients that are inherently different in inhomogeneous dielectric structures. Three different solutions that allow for achieving strong coupling in the selected UMS PH25 process were selected and experimentally investigated, showing the possibility of such circuits’ realization. In each of the presented integrated couplers, capacitive compensation techniques were applied for coupling coefficients’ equalization.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The problem of the realization of broadband quadrature directional couplers in UMS (United Monolithic Semiconductors) PH25 is thoroughly investigated. The limitations of the selected technology are discussed with respect to directional couplers’ design. It is shown that, in such technologies, two major problems have to be overcome to achieve the high-performance of the resulting integrated couplers, i.e., the realization of appropriate coupling together with appropriate characteristic impedances, and the equalization of inductive and capacitive coupling coefficients that are inherently different in inhomogeneous dielectric structures. Three different solutions that allow for achieving strong coupling in the selected UMS PH25 process were selected and experimentally investigated, showing the possibility of such circuits’ realization. In each of the presented integrated couplers, capacitive compensation techniques were applied for coupling coefficients’ equalization. |
| 86. | Jakub Sorocki; Kamil Staszek; Ilona Piekarz; Slawomir Gruszczynski; Krzysztof Wincza Selectivity improved directional filters using cross-coupling introduced transmission zeros Journal Article Journal of Electromagnetic Waves and Applications, 33 (16), pp. 2126-2141, 2019. @article{10.1080/09205071.2019.1663371, title = {Selectivity improved directional filters using cross-coupling introduced transmission zeros}, author = {Jakub Sorocki and Kamil Staszek and Ilona Piekarz and Slawomir Gruszczynski and Krzysztof Wincza}, url = {https://doi.org/10.1080/09205071.2019.1663371}, doi = {10.1080/09205071.2019.1663371}, year = {2019}, date = {2019-01-01}, journal = {Journal of Electromagnetic Waves and Applications}, volume = {33}, number = {16}, pages = {2126-2141}, publisher = {Taylor & Francis}, abstract = {In this paper, the realization of traveling-wave directional filters allowing for selectivity improvement without increasing filter’s order is presented and studied. It is shown that the introduction of loose cross-coupling between #(n-1)th loop resonator and isolated port of the nth-order directional filter allows for generating transmission zeros in the bandpass branch and thus to improve the filter`s roll-off. Moreover, the electrical length of the cross-coupling connecting transmission line allows for adjusting the location of transmission zeros and realizing symmetric or asymmetric frequency response. The presented approach is theoretically analyzed and experimentally verified. Exemplary second- and third-order directional filters with symmetrically placed transmission zeros were designed to operate at f0 = 1 GHz, manufactured and measured. The obtained results prove their applicability towards the realization of frequency multiplexers.}, keywords = {}, pubstate = {published}, tppubtype = {article} } In this paper, the realization of traveling-wave directional filters allowing for selectivity improvement without increasing filter’s order is presented and studied. It is shown that the introduction of loose cross-coupling between #(n-1)th loop resonator and isolated port of the nth-order directional filter allows for generating transmission zeros in the bandpass branch and thus to improve the filter`s roll-off. Moreover, the electrical length of the cross-coupling connecting transmission line allows for adjusting the location of transmission zeros and realizing symmetric or asymmetric frequency response. The presented approach is theoretically analyzed and experimentally verified. Exemplary second- and third-order directional filters with symmetrically placed transmission zeros were designed to operate at f0 = 1 GHz, manufactured and measured. The obtained results prove their applicability towards the realization of frequency multiplexers. |
| 85. | Artur Rydosz; Kamil Staszek; Andrzej Brudnik; Slawomir Gruszczynski Tin Dioxide Thin Film with UV-enhanced Acetone Detection in Microwave Frequency Range Journal Article Micromachines, 10 (9), pp. 574, 2019. @article{10.3390/mi10090574, title = {Tin Dioxide Thin Film with UV-enhanced Acetone Detection in Microwave Frequency Range}, author = {Artur Rydosz and Kamil Staszek and Andrzej Brudnik and Slawomir Gruszczynski}, url = {https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6780249/}, doi = {10.3390/mi10090574}, year = {2019}, date = {2019-01-01}, journal = {Micromachines}, volume = {10}, number = {9}, pages = {574}, abstract = {In this paper, the UV illumination effect for microwave gas sensors based on the tin dioxide was verified. A UV LED with emission wavelength close to the absorption edge of the SnO2 gas-sensing layer was selected as the UV source. The developed gas sensors were tested under exposure to acetone in the 0–200 ppm range at room temperature. The sensor’s complex reflection coefficient corresponding to target gas concentration was measured with the use of a five-port reflectometer system exhibiting enhanced uncertainty distribution, which allows for the detection of low gas concentration. The UV illumination significantly emphasizes the sensors’ response in terms of both magnitude and phase for low gas concentrations, in contrast to previously reported results, in which only the reflection coefficient’s phase was affected. The highest responses were obtained for modulated UV illumination.}, keywords = {}, pubstate = {published}, tppubtype = {article} } In this paper, the UV illumination effect for microwave gas sensors based on the tin dioxide was verified. A UV LED with emission wavelength close to the absorption edge of the SnO2 gas-sensing layer was selected as the UV source. The developed gas sensors were tested under exposure to acetone in the 0–200 ppm range at room temperature. The sensor’s complex reflection coefficient corresponding to target gas concentration was measured with the use of a five-port reflectometer system exhibiting enhanced uncertainty distribution, which allows for the detection of low gas concentration. The UV illumination significantly emphasizes the sensors’ response in terms of both magnitude and phase for low gas concentrations, in contrast to previously reported results, in which only the reflection coefficient’s phase was affected. The highest responses were obtained for modulated UV illumination. |
| 84. | Szczepan Odrobina; Kamil Staszek Wideband two-port with programmable scattering parameters Journal Article IET Microwaves, Antennas & Propagations, 13 (14), pp. 2525-2530, 2019. @article{10.1049/iet-map.2018.5816, title = {Wideband two-port with programmable scattering parameters}, author = {Szczepan Odrobina and Kamil Staszek}, url = {https://digital-library.theiet.org/content/journals/10.1049/iet-map.2018.5816}, doi = {10.1049/iet-map.2018.5816}, year = {2019}, date = {2019-01-01}, journal = {IET Microwaves, Antennas & Propagations}, volume = {13}, number = {14}, pages = {2525-2530}, publisher = {IET}, abstract = {A two-port network featuring programmable reflection and transmission coefficients is proposed. The network exhibits a simple structure and can operate over a wide frequency range. A detailed description of the presented system is given, including the theoretical analysis and derivation of design equations. To assess the performance of the manufactured system, the tuning range of reflection and transmission coefficients was measured in the frequency range from 0.5 to 2.0 GHz. The obtained results show good agreement with the theoretical results over the entire two-octave operational bandwidth. Moreover, the potential application of the developed two-port for the generation of various reflection coefficients in calibration of a multiport reflectometer is demonstrated.}, keywords = {}, pubstate = {published}, tppubtype = {article} } A two-port network featuring programmable reflection and transmission coefficients is proposed. The network exhibits a simple structure and can operate over a wide frequency range. A detailed description of the presented system is given, including the theoretical analysis and derivation of design equations. To assess the performance of the manufactured system, the tuning range of reflection and transmission coefficients was measured in the frequency range from 0.5 to 2.0 GHz. The obtained results show good agreement with the theoretical results over the entire two-octave operational bandwidth. Moreover, the potential application of the developed two-port for the generation of various reflection coefficients in calibration of a multiport reflectometer is demonstrated. |
| 83. | Ilona Piekarz; Jakub Sorocki Charakteryzacja materiałów dielektrycznych z wykorzystaniem pobudzonych różnicowo sekcji linii sprzężonych Journal Article Przeglad Telekomunikacyjny, (6), 2019. @article{10.15199/59.2019.6.68, title = {Charakteryzacja materiałów dielektrycznych z wykorzystaniem pobudzonych różnicowo sekcji linii sprzężonych}, author = {Ilona Piekarz and Jakub Sorocki}, url = {https://sigma-not.pl/publikacja-120936-charakteryzacja-materia%C5%82%C3%B3w-dielektrycznych-z-wykorzystaniem-pobudzonych-r%C3%B3%C5%BCnicowo-sekcji-linii-sprz%C4%99%C5%BConych-przeglad-telekomunikacyjny-2019-6.html}, doi = {10.15199/59.2019.6.68}, year = {2019}, date = {2019-01-01}, journal = {Przeglad Telekomunikacyjny}, number = {6}, publisher = {Sigma-Not}, abstract = {W artykule zostały przedstawione nowe metody pomiaru umożliwiające charakteryzację materiałów dielektrycznych z wykorzystaniem dwu-paskowej sekcji sprzężonej zwartej lub rozwartej na końcu, zrealizowanej w jednowarstwowej strukturze mikropaskowej. Zaproponowana technika pomiarowa umożliwia wyznaczenie zespolonej przenikalności elektrycznej mierzonej próbki na podstawie zmierzonej zespolonej efektywnej przenikalności rodzaju nieparzystego sensora pokrytego próbką.}, keywords = {}, pubstate = {published}, tppubtype = {article} } W artykule zostały przedstawione nowe metody pomiaru umożliwiające charakteryzację materiałów dielektrycznych z wykorzystaniem dwu-paskowej sekcji sprzężonej zwartej lub rozwartej na końcu, zrealizowanej w jednowarstwowej strukturze mikropaskowej. Zaproponowana technika pomiarowa umożliwia wyznaczenie zespolonej przenikalności elektrycznej mierzonej próbki na podstawie zmierzonej zespolonej efektywnej przenikalności rodzaju nieparzystego sensora pokrytego próbką. |
| 82. | Izabela Slomian Projektowanie zasilanych szeregowo planarnych mikroskopowych szyków antenowych NxN o podwójnej polaryzacji Journal Article Przeglad Telekomunikacyjny, (6), pp. 241-244, 2019. @article{10.15199/59.2019.6.68b, title = {Projektowanie zasilanych szeregowo planarnych mikroskopowych szyków antenowych NxN o podwójnej polaryzacji}, author = {Izabela Slomian}, doi = {10.15199/59.2019.6.23}, year = {2019}, date = {2019-01-01}, journal = {Przeglad Telekomunikacyjny}, number = {6}, pages = {241-244}, publisher = {Sigma-Not}, abstract = {W artykule opisana została nowa klasa planarnych zasilanych szeregowo układów antenowych o podwójnej polaryzacji, w których zastosowanie symetrycznego pobudzenia oraz dzielników mocy wykorzystujących szczelinę sprzęgającą w ekranie umożliwiło uzyskanie kierunku maksymalnego promieniowania prostopadłego do płaszczyzny anteny w szerokim zakresie częstotliwości. Dodatkowo, opracowano dedykowane, zintegrowane sieci formowania wiązki pozwalające na uzyskanie polaryzacji podwójnej kołowej oraz podwójnej liniowej.}, keywords = {}, pubstate = {published}, tppubtype = {article} } W artykule opisana została nowa klasa planarnych zasilanych szeregowo układów antenowych o podwójnej polaryzacji, w których zastosowanie symetrycznego pobudzenia oraz dzielników mocy wykorzystujących szczelinę sprzęgającą w ekranie umożliwiło uzyskanie kierunku maksymalnego promieniowania prostopadłego do płaszczyzny anteny w szerokim zakresie częstotliwości. Dodatkowo, opracowano dedykowane, zintegrowane sieci formowania wiązki pozwalające na uzyskanie polaryzacji podwójnej kołowej oraz podwójnej liniowej. |
| 81. | Michael W Coughlin; Alessio Cirone; Patrick Meyers; Sho Atsuta; Valerio Boschi; Andrea Chincarini; Nelson L Christensen; Rosario De Rosa; Anamaria Effler; Irene Fiori; Mark Gołkowski; Melissa Guidry; Jan Harms; Kazuhiro Hayama; Yuu Kataoka; Jerzy Kubisz; Andrzej Kulak; Michael Laxen; Andrew Matas; Janusz Mlynarczyk; Tsutomu Ogawa; Federico Paoletti; Jacobo Salvador; Robert Schofield; Kentaro Somiya; Eric Thrane Measurement and subtraction of Schumann resonances at gravitational-wave interferometers Journal Article Physical Review D, 97 , pp. 102007, 2018. @article{10.1103/PhysRevD.97.102007, title = {Measurement and subtraction of Schumann resonances at gravitational-wave interferometers}, author = {Michael W Coughlin and Alessio Cirone and Patrick Meyers and Sho Atsuta and Valerio Boschi and Andrea Chincarini and Nelson L Christensen and Rosario De Rosa and Anamaria Effler and Irene Fiori and Mark Goł{}kowski and Melissa Guidry and Jan Harms and Kazuhiro Hayama and Yuu Kataoka and Jerzy Kubisz and Andrzej Kulak and Michael Laxen and Andrew Matas and Janusz Mlynarczyk and Tsutomu Ogawa and Federico Paoletti and Jacobo Salvador and Robert Schofield and Kentaro Somiya and Eric Thrane}, url = {https://link.aps.org/doi/10.1103/PhysRevD.97.102007}, doi = {10.1103/PhysRevD.97.102007}, year = {2018}, date = {2018-05-01}, journal = {Physical Review D}, volume = {97}, pages = {102007}, publisher = {American Physical Society}, abstract = {Correlated magnetic noise from Schumann resonances threatens to contaminate the observation of a stochastic gravitational-wave background in interferometric detectors. In previous work, we reported on the first effort to eliminate global correlated noise from the Schumann resonances using Wiener filtering, demonstrating as much as a factor of two reduction in the coherence between magnetometers on different continents. In this work, we present results from dedicated magnetometer measurements at the Virgo and KAGRA sites, which are the first results for subtraction using data from gravitational-wave detector sites. We compare these measurements to a growing network of permanent magnetometer stations, including at the LIGO sites. We show the effect of mutual magnetometer attraction, arguing that magnetometers should be placed at least one meter from one another. In addition, for the first time, we show how dedicated measurements by magnetometers near to the interferometers can reduce coherence to a level consistent with uncorrelated noise, making a potential detection of a stochastic gravitational-wave background possible.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Correlated magnetic noise from Schumann resonances threatens to contaminate the observation of a stochastic gravitational-wave background in interferometric detectors. In previous work, we reported on the first effort to eliminate global correlated noise from the Schumann resonances using Wiener filtering, demonstrating as much as a factor of two reduction in the coherence between magnetometers on different continents. In this work, we present results from dedicated magnetometer measurements at the Virgo and KAGRA sites, which are the first results for subtraction using data from gravitational-wave detector sites. We compare these measurements to a growing network of permanent magnetometer stations, including at the LIGO sites. We show the effect of mutual magnetometer attraction, arguing that magnetometers should be placed at least one meter from one another. In addition, for the first time, we show how dedicated measurements by magnetometers near to the interferometers can reduce coherence to a level consistent with uncorrelated noise, making a potential detection of a stochastic gravitational-wave background possible. |
| 80. | Izabela Slomian; Krzysztof Wincza; Slawomir Gruszczynski Composite right-/left-handed leaky-wave antenna utilizing coupled-line sections Journal Article Journal of Electromagnetic Waves and Applications, 32 (6), pp. 768-780, 2018. @article{10.1080/09205071.2017.1405745, title = {Composite right-/left-handed leaky-wave antenna utilizing coupled-line sections}, author = {Izabela Slomian and Krzysztof Wincza and Slawomir Gruszczynski}, url = {https://doi.org/10.1080/09205071.2017.1405745}, doi = {10.1080/09205071.2017.1405745}, year = {2018}, date = {2018-01-01}, journal = {Journal of Electromagnetic Waves and Applications}, volume = {32}, number = {6}, pages = {768-780}, publisher = {Taylor & Francis}, abstract = {A novel method of realization of composite right-/left-handed leaky-wave antennas featuring through broadside-beam-scanning capability and utilizing coupled-line sections has been proposed. The unique feature of the presented concept is that it allows to adjust both the beam-scanning bandwidth and the distance between consecutive unit cells thanks to the introduction of additional identical transmission-line sections to the unit cell. The concept has been theoretically analyzed as well as experimentally verified by the simulations and measurements of the developed antenna operating with the transition frequency of 3 GHz.}, keywords = {}, pubstate = {published}, tppubtype = {article} } A novel method of realization of composite right-/left-handed leaky-wave antennas featuring through broadside-beam-scanning capability and utilizing coupled-line sections has been proposed. The unique feature of the presented concept is that it allows to adjust both the beam-scanning bandwidth and the distance between consecutive unit cells thanks to the introduction of additional identical transmission-line sections to the unit cell. The concept has been theoretically analyzed as well as experimentally verified by the simulations and measurements of the developed antenna operating with the transition frequency of 3 GHz. |
| 79. | Konrad Janisz; Ilona Piekarz; Kamil Staszek; Krzysztof Wincza; Slawomir Gruszczynski Differentially Fed Directional Couplers With Coupled-Conductors of Unequal Widths Journal Article IEEE Microwave and Wireless Components Letters, 28 (9), pp. 759-761, 2018. @article{10.1109/LMWC.2018.2853585, title = {Differentially Fed Directional Couplers With Coupled-Conductors of Unequal Widths}, author = {Konrad Janisz and Ilona Piekarz and Kamil Staszek and Krzysztof Wincza and Slawomir Gruszczynski}, url = {https://ieeexplore.ieee.org/document/8418804}, doi = {10.1109/LMWC.2018.2853585}, year = {2018}, date = {2018-01-01}, journal = {IEEE Microwave and Wireless Components Letters}, volume = {28}, number = {9}, pages = {759-761}, abstract = {In this letter, coupled-line directional couplers with differentially excited balanced coupled lines are considered in which balanced lines having different widths are proposed. Different conductor widths allow for coupling control within a chosen dielectric stack-up and give design freedom in terms of coupling adjustment. The theoretical analysis is confirmed by experimental verification, in which a broadband asymmetrical 3-dB two-section directional coupler has been designed and measured.}, keywords = {}, pubstate = {published}, tppubtype = {article} } In this letter, coupled-line directional couplers with differentially excited balanced coupled lines are considered in which balanced lines having different widths are proposed. Different conductor widths allow for coupling control within a chosen dielectric stack-up and give design freedom in terms of coupling adjustment. The theoretical analysis is confirmed by experimental verification, in which a broadband asymmetrical 3-dB two-section directional coupler has been designed and measured. |
| 78. | Sabina Gorska; Artur Rydosz; Ewa Brzozowska; Marek Drab; Krzysztof Wincza; Andrzej Gamian; Slawomir Gruszczynski Effectiveness of Sensors Contact Metallization (Ti, Au, and Ru) and Biofunctionalization for Escherichia coli Detection Journal Article Sensors, 18 (9), pp. 2912, 2018. @article{10.3390/s18092912, title = {Effectiveness of Sensors Contact Metallization (Ti, Au, and Ru) and Biofunctionalization for Escherichia coli Detection}, author = {Sabina Gorska and Artur Rydosz and Ewa Brzozowska and Marek Drab and Krzysztof Wincza and Andrzej Gamian and Slawomir Gruszczynski}, url = {https://www.mdpi.com/1424-8220/18/9/2912}, doi = {10.3390/s18092912}, year = {2018}, date = {2018-01-01}, journal = {Sensors}, volume = {18}, number = {9}, pages = {2912}, abstract = {In designing a bacteria biosensor, various issues must be addressed: the specificity of bacteria recognition, the immobilization of biomolecules that act as the bacteria receptor, and the selectivity of sensor surface. The aim of this paper was to examine how the biofunctionalized surface of Ti, Au, and Ru metals reacts in contact with strains of Escherichia coli (E. coli). The focus on metal surfaces results from their future use as electrodes in high frequency biosensors, e.g., resonant circuits or transmission-line sections. First, the surfaces of different metals were chemically functionalized with 3-aminopropyltriethoxysilane (APTES) and glutaraldehyde or with 3-glycidylooxypropyltrimethoxysilane (GPTMS) followed by N-(5-amino-1-carboxypentyl) iminodiacetic acid (AB-NTA) and NiCl2. Secondly, the lipopolysaccharide binding protein (LBP), polyclonal anti-Escherichia coli antibody and bacteriophage protein gp37 were tested as bacteria receptors. The selectivity and specificity have been confirmed by the Enzyme-Linked Immunosorbent Assay (ELISA) and visualized by scanning electron microscopy at low landing energies. We noticed that LBP, polyclonal antibody, and gp37 were successfully immobilized on all studied metals and recognized the E. coli bacteria selectively. However, for the antibody, the highest reactivity was observed when Ti surface was modified, whereas the bacteria binding was comparable between LBP and gp37 on the functionalized Ru surfaces, independent from modification. Thus, all surfaces were biocompatible within the scope of biosensor functionality, with titanium functionalization showing the best performance.}, keywords = {}, pubstate = {published}, tppubtype = {article} } In designing a bacteria biosensor, various issues must be addressed: the specificity of bacteria recognition, the immobilization of biomolecules that act as the bacteria receptor, and the selectivity of sensor surface. The aim of this paper was to examine how the biofunctionalized surface of Ti, Au, and Ru metals reacts in contact with strains of Escherichia coli (E. coli). The focus on metal surfaces results from their future use as electrodes in high frequency biosensors, e.g., resonant circuits or transmission-line sections. First, the surfaces of different metals were chemically functionalized with 3-aminopropyltriethoxysilane (APTES) and glutaraldehyde or with 3-glycidylooxypropyltrimethoxysilane (GPTMS) followed by N-(5-amino-1-carboxypentyl) iminodiacetic acid (AB-NTA) and NiCl2. Secondly, the lipopolysaccharide binding protein (LBP), polyclonal anti-Escherichia coli antibody and bacteriophage protein gp37 were tested as bacteria receptors. The selectivity and specificity have been confirmed by the Enzyme-Linked Immunosorbent Assay (ELISA) and visualized by scanning electron microscopy at low landing energies. We noticed that LBP, polyclonal antibody, and gp37 were successfully immobilized on all studied metals and recognized the E. coli bacteria selectively. However, for the antibody, the highest reactivity was observed when Ti surface was modified, whereas the bacteria binding was comparable between LBP and gp37 on the functionalized Ru surfaces, independent from modification. Thus, all surfaces were biocompatible within the scope of biosensor functionality, with titanium functionalization showing the best performance. |
| 77. | Jakub Sorocki; Ilona Piekarz; Konrad Janisz; Slawomir Gruszczynski; Krzysztof Wincza Frequency Multiplexer With Improved Selectivity Using Asymmetric Response Directional Filters Journal Article IEEE Microwave and Wireless Components Letters, 28 (6), pp. 491-493, 2018. @article{10.1109/LMWC.2018.2832846, title = {Frequency Multiplexer With Improved Selectivity Using Asymmetric Response Directional Filters}, author = {Jakub Sorocki and Ilona Piekarz and Konrad Janisz and Slawomir Gruszczynski and Krzysztof Wincza}, url = {https://ieeexplore.ieee.org/document/8361770}, doi = {10.1109/LMWC.2018.2832846}, year = {2018}, date = {2018-01-01}, journal = {IEEE Microwave and Wireless Components Letters}, volume = {28}, number = {6}, pages = {491-493}, abstract = {In this letter, a novel approach to the design of frequency multiplexers consisting of cascaded directional filters (DFs) is proposed. It is shown that when channels are spaced closely enough, their selectivity can be improved without increasing the filters' order by taking advantage of two phenomena. Asymmetric frequency response of a constitutive DF allows to increase the attenuation slope on the one side of the multiplexer channel. In addition, the slope on the other side can be increased due to the creation of additional transmission zero resulting from the fact that bandstop response of the previous DFs within the cascade directly affects the response of the following channel. Theoretical analysis is provided together with the applicability condition and multiplexer design procedure. Moreover, an exemplary four-channel S-band multiplexer was manufactured and measured showing the selectivity improvement of as much as ~1.3 times.}, keywords = {}, pubstate = {published}, tppubtype = {article} } In this letter, a novel approach to the design of frequency multiplexers consisting of cascaded directional filters (DFs) is proposed. It is shown that when channels are spaced closely enough, their selectivity can be improved without increasing the filters' order by taking advantage of two phenomena. Asymmetric frequency response of a constitutive DF allows to increase the attenuation slope on the one side of the multiplexer channel. In addition, the slope on the other side can be increased due to the creation of additional transmission zero resulting from the fact that bandstop response of the previous DFs within the cascade directly affects the response of the following channel. Theoretical analysis is provided together with the applicability condition and multiplexer design procedure. Moreover, an exemplary four-channel S-band multiplexer was manufactured and measured showing the selectivity improvement of as much as ~1.3 times. |
| 76. | Robert Smolarz; Krzysztof Wincza; Slawomir Gruszczynski Impedance transforming rat-race couplers with modified Lange section Journal Article Journal of Electromagnetic Waves and Applications, 32 (8), pp. 972-983, 2018. @article{10.1080/09205071.2017.1411836, title = {Impedance transforming rat-race couplers with modified Lange section}, author = {Robert Smolarz and Krzysztof Wincza and Slawomir Gruszczynski}, url = {https://www.tandfonline.com/doi/abs/10.1080/09205071.2017.1411836}, doi = {10.1080/09205071.2017.1411836}, year = {2018}, date = {2018-01-01}, journal = {Journal of Electromagnetic Waves and Applications}, volume = {32}, number = {8}, pages = {972-983}, abstract = {The relation between load impedances and the characteristic impedance of the rat-race ring has been derived. To minimize the circuit size, the 270°-long section has been replaced by a shorted coupled-line section. Moreover, to achieve appropriate coupling coefficient in the required coupled-line section, a modified Lange structure consisting of five-coupled lines has been applied. Furthermore, the second structure has been proposed having improved operational bandwidth, in which coupled-line matching sections are added. The theoretical analysis has been verified by measurements of the fabricated rat-race couplers operating at the center frequency 1 GHz. The designed couplers transforms 50 Ω input impedance into 10 Ω, which proves their practical applications.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The relation between load impedances and the characteristic impedance of the rat-race ring has been derived. To minimize the circuit size, the 270°-long section has been replaced by a shorted coupled-line section. Moreover, to achieve appropriate coupling coefficient in the required coupled-line section, a modified Lange structure consisting of five-coupled lines has been applied. Furthermore, the second structure has been proposed having improved operational bandwidth, in which coupled-line matching sections are added. The theoretical analysis has been verified by measurements of the fabricated rat-race couplers operating at the center frequency 1 GHz. The designed couplers transforms 50 Ω input impedance into 10 Ω, which proves their practical applications. |
| 75. | Robert Smolarz; Krzysztof Wincza; Slawomir Gruszczynski Impedance Transforming Tandem Couplers With Increased Bandwidth and Transformation Ratio Journal Article Journal of Electromagnetic Waves and Applications, 28 (4), pp. 299-301, 2018. @article{10.1109/LMWC.2018.2808421, title = {Impedance Transforming Tandem Couplers With Increased Bandwidth and Transformation Ratio}, author = {Robert Smolarz and Krzysztof Wincza and Slawomir Gruszczynski}, url = {https://ieeexplore.ieee.org/document/8316248}, doi = {10.1109/LMWC.2018.2808421}, year = {2018}, date = {2018-01-01}, journal = {Journal of Electromagnetic Waves and Applications}, volume = {28}, number = {4}, pages = {299-301}, abstract = {A novel concept of impedance transforming directional couplers for applications in balanced networks has been proposed. The proposed networks consist of a tandem connection of two asymmetric directional couplers having different coupling coefficients. Theoretical analysis of the proposed networks has been shown and the maximum achievable transformation ratio versus the required reflection coefficient has been given in a tabular form. The concept has been verified by measurements of an impedance transforming directional coupler operating at the center frequency 1 GHz, in which impedance transformation ratio equal R = 5 has been assumed.}, keywords = {}, pubstate = {published}, tppubtype = {article} } A novel concept of impedance transforming directional couplers for applications in balanced networks has been proposed. The proposed networks consist of a tandem connection of two asymmetric directional couplers having different coupling coefficients. Theoretical analysis of the proposed networks has been shown and the maximum achievable transformation ratio versus the required reflection coefficient has been given in a tabular form. The concept has been verified by measurements of an impedance transforming directional coupler operating at the center frequency 1 GHz, in which impedance transformation ratio equal R = 5 has been assumed. |