| 24. | Jakub Sorocki; Ilona Piekarz; Krzysztof Wincza; Slawomir Gruszczynski Semi-Distributed Approach to Dual-Composite Right/Left-Handed Transmission Lines and Their Application to Bandstop Filters Journal Article IEEE Microwave and Wireless Components Letters, 25 (12), pp. 784-786, 2015. @article{10.1109/LMWC.2015.2495114, title = {Semi-Distributed Approach to Dual-Composite Right/Left-Handed Transmission Lines and Their Application to Bandstop Filters}, author = {Jakub Sorocki and Ilona Piekarz and Krzysztof Wincza and Slawomir Gruszczynski}, url = {https://ieeexplore.ieee.org/document/7317605}, doi = {10.1109/LMWC.2015.2495114}, year = {2015}, date = {2015-01-01}, journal = {IEEE Microwave and Wireless Components Letters}, volume = {25}, number = {12}, pages = {784-786}, abstract = {In this letter, an innovative approach for realization of artificial transmission lines featuring a dual-composite right/left-handed character is presented. The circuits utilize a novel semi-distributed unit cell which is composed of sections of conventional transmission lines and a lumped capacitor. Such an approach allows for efficient modeling and convenient translation of model parameters (characteristic impedance and electrical length of transmission lines) into physical realization. Moreover, a single-layer microstrip realization is possible, making the unit cell attractive in practical applications. The proposed concept has been experimentally verified by the design and measurements of an exemplary transmission line section, and discussed in a context of possible applications in bandstop filters.}, keywords = {}, pubstate = {published}, tppubtype = {article} } In this letter, an innovative approach for realization of artificial transmission lines featuring a dual-composite right/left-handed character is presented. The circuits utilize a novel semi-distributed unit cell which is composed of sections of conventional transmission lines and a lumped capacitor. Such an approach allows for efficient modeling and convenient translation of model parameters (characteristic impedance and electrical length of transmission lines) into physical realization. Moreover, a single-layer microstrip realization is possible, making the unit cell attractive in practical applications. The proposed concept has been experimentally verified by the design and measurements of an exemplary transmission line section, and discussed in a context of possible applications in bandstop filters. |
| 23. | S Soula; E Defer; M Füllekrug; O van der Velde; J Montanya; O Bousquet; J Mlynarczyk; S Coquillat; J -P Pinty; W Rison; P R Krehbiel; R Thomas; S Pedeboy Time and space correlation between sprites and their parent lightning flashes for a thunderstorm observed during the HyMeX campaign Journal Article Journal of Geophysical Research: Atmospheres, 120 (22), pp. 11,552-11,574, 2015. @article{10.1002/2015JD023894, title = {Time and space correlation between sprites and their parent lightning flashes for a thunderstorm observed during the HyMeX campaign}, author = {S Soula and E Defer and M Füllekrug and O van der Velde and J Montanya and O Bousquet and J Mlynarczyk and S Coquillat and J -P Pinty and W Rison and P R Krehbiel and R Thomas and S Pedeboy}, url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1002/2015JD023894}, doi = {10.1002/2015JD023894}, year = {2015}, date = {2015-01-01}, journal = {Journal of Geophysical Research: Atmospheres}, volume = {120}, number = {22}, pages = {11,552-11,574}, abstract = {Abstract During the night of 22–23 October 2012, together with the Hydrology cycle in the Mediterranean eXperiment (HyMeX) Special Observation Period 1 campaign, optical observations of sprite events were performed above a leading stratiform Mesoscale Convective System in southeastern France. The total lightning activity of the storm was monitored in three dimensions with the HyMeX Lightning Mapping Array. Broadband Extremely Low Frequency/Very Low Frequency records and radar observations allowed characterizing the flashes and the regions of the cloud where they propagated. Twelve sprite events occurred over the stratiform region, during the last third of the lightning activity period, and well after the coldest satellite-based cloud top temperature (−62°C) and the maximum total lightning flash rate (11 min−1). The sprite-producing positive cloud-to-ground (SP + CG) strokes exhibit peak current from 14 to 247 kA, Charge Moment Changes (CMC) from 625 to 3086 C km, and Impulsive CMC (iCMC) between 242 and 1525 C km. The +CG flashes that do not trigger sprites are initiated outside the main convective core, have much lower CMC values, and in average, shorter durations, lower peak currents, and shorter distances of propagation. The CMC appears to be the best sprite predictor. The delay between the parent stroke and the sprite allows classifying the events as short delayed (<20 ms) and long delayed (>20 ms). All long-delayed sprites, i.e., most of the time carrot sprites, are produced by SP + CG strokes with low iCMC values. All SP + CG flashes initiate close to the convective core and generate leaders in opposite directions. Negative leaders finally propagate toward lower altitudes, within the stratiform region that coincides with the projected location of the sprite elements.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Abstract During the night of 22–23 October 2012, together with the Hydrology cycle in the Mediterranean eXperiment (HyMeX) Special Observation Period 1 campaign, optical observations of sprite events were performed above a leading stratiform Mesoscale Convective System in southeastern France. The total lightning activity of the storm was monitored in three dimensions with the HyMeX Lightning Mapping Array. Broadband Extremely Low Frequency/Very Low Frequency records and radar observations allowed characterizing the flashes and the regions of the cloud where they propagated. Twelve sprite events occurred over the stratiform region, during the last third of the lightning activity period, and well after the coldest satellite-based cloud top temperature (−62°C) and the maximum total lightning flash rate (11 min−1). The sprite-producing positive cloud-to-ground (SP + CG) strokes exhibit peak current from 14 to 247 kA, Charge Moment Changes (CMC) from 625 to 3086 C km, and Impulsive CMC (iCMC) between 242 and 1525 C km. The +CG flashes that do not trigger sprites are initiated outside the main convective core, have much lower CMC values, and in average, shorter durations, lower peak currents, and shorter distances of propagation. The CMC appears to be the best sprite predictor. The delay between the parent stroke and the sprite allows classifying the events as short delayed (<20 ms) and long delayed (>20 ms). All long-delayed sprites, i.e., most of the time carrot sprites, are produced by SP + CG strokes with low iCMC values. All SP + CG flashes initiate close to the convective core and generate leaders in opposite directions. Negative leaders finally propagate toward lower altitudes, within the stratiform region that coincides with the projected location of the sprite elements. |
| 22. | Krzysztof Wincza; Ilona Piekarz; Slawomir Gruszczynski Two-section asymmetric coupled-line impedance transforming directional couplers Journal Article IET Microwaves, Antennas & Propagation, 9 (4), pp. 343 - 350, 2015. @article{10.1049/iet-map.2014.0338, title = {Two-section asymmetric coupled-line impedance transforming directional couplers}, author = {Krzysztof Wincza and Ilona Piekarz and Slawomir Gruszczynski}, url = {https://ieeexplore.ieee.org/document/7061941}, doi = {10.1049/iet-map.2014.0338}, year = {2015}, date = {2015-01-01}, journal = {IET Microwaves, Antennas & Propagation}, volume = {9}, number = {4}, pages = {343 - 350}, abstract = {Two-section impedance transforming directional couplers have been proposed. It has been shown that such asymmetric coupled-line directional couplers can provide equal power split between the coupled and transmission ports as well as impedance transformation in the same broad frequency range, as classic two-section coupled-line couplers. The theoretical analysis has been presented and appropriate formulas allowing for calculation the required per-unit-length parameters of broadband two-section impedance transforming couplers have been derived. Moreover, it has been shown that the impedance transformation ratio of the presented coupler can be increased by the appropriate modification of the two-section coupled-line directional coupler in a way that the directly fed and coupled-line transformation ratios are different. The proposed modification allows for the design of broadband impedance transforming directional couplers with increased transformation ratio over the limit fixed by the coupling coefficient of the tightly coupled section and having at the same time acceptable impedance match and isolation between the respective ports. The presented theory has been confirmed by the measurements of a two-section 3 dB impedance transforming directional coupler having bandwidth f u / f l = 3:1 and impedance transformation ratio R = 2.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Two-section impedance transforming directional couplers have been proposed. It has been shown that such asymmetric coupled-line directional couplers can provide equal power split between the coupled and transmission ports as well as impedance transformation in the same broad frequency range, as classic two-section coupled-line couplers. The theoretical analysis has been presented and appropriate formulas allowing for calculation the required per-unit-length parameters of broadband two-section impedance transforming couplers have been derived. Moreover, it has been shown that the impedance transformation ratio of the presented coupler can be increased by the appropriate modification of the two-section coupled-line directional coupler in a way that the directly fed and coupled-line transformation ratios are different. The proposed modification allows for the design of broadband impedance transforming directional couplers with increased transformation ratio over the limit fixed by the coupling coefficient of the tightly coupled section and having at the same time acceptable impedance match and isolation between the respective ports. The presented theory has been confirmed by the measurements of a two-section 3 dB impedance transforming directional coupler having bandwidth f u / f l = 3:1 and impedance transformation ratio R = 2. |
| 21. | Kamil Staszek; Slawomir Gruszczynski; Krzysztof Wincza Ultrabroadband multiprobe reflectometer Journal Article Microwave and Optical Technology Letters, 57 (8), pp. 1968-1971, 2015. @article{10.1002/mop.29228, title = {Ultrabroadband multiprobe reflectometer}, author = {Kamil Staszek and Slawomir Gruszczynski and Krzysztof Wincza}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/mop.29228}, doi = {10.1002/mop.29228}, year = {2015}, date = {2015-01-01}, journal = {Microwave and Optical Technology Letters}, volume = {57}, number = {8}, pages = {1968-1971}, abstract = {Novel synthesis of multiprobe reflectometers is presented. A developed estimation of measurement conditions allows for the choice of spacings between probes ensuring wideband operation. To verify the proposed concept, the multiprobe reflectometer having bandwidth 0.15–8GHz has been manufactured. The measurement results are close to ones obtained using vector network analyzer (VNA). © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1968–1971, 2015}, keywords = {}, pubstate = {published}, tppubtype = {article} } Novel synthesis of multiprobe reflectometers is presented. A developed estimation of measurement conditions allows for the choice of spacings between probes ensuring wideband operation. To verify the proposed concept, the multiprobe reflectometer having bandwidth 0.15–8GHz has been manufactured. The measurement results are close to ones obtained using vector network analyzer (VNA). © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1968–1971, 2015 |
| 20. | Kamil Staszek; Jakub Sorocki; Piotr Kaminski; Krzysztof Wincza; Sławomir Gruszczynski A Broadband 3 dB Tandem Coupler Utilizing Right/Left Handed Transmission Line Sections Journal Article IEEE Microwave and Wireless Components Letters, 24 (4), pp. 236-238, 2014. @article{10.1109/LMWC.2014.2299546, title = {A Broadband 3 dB Tandem Coupler Utilizing Right/Left Handed Transmission Line Sections}, author = {Kamil Staszek and Jakub Sorocki and Piotr Kaminski and Krzysztof Wincza and Sławomir Gruszczynski}, url = {https://ieeexplore.ieee.org/document/6712927}, doi = {10.1109/LMWC.2014.2299546}, year = {2014}, date = {2014-01-01}, journal = {IEEE Microwave and Wireless Components Letters}, volume = {24}, number = {4}, pages = {236-238}, abstract = {A new type of broadband 3 dB tandem coupler has been proposed featuring frequency characteristics of the resulting coupling similar to those of a classic 3 dB two-section asymmetric coupled-line directional coupler. The coupler is composed of two loosely coupled-line sections having electrical lengths close to quarter-wavelength connected by right-handed and left-handed transmission line sections. Theoretical analysis and design equations have been presented with an exemplary realization. Measurements of the manufactured tandem coupler operating at f 0 = 1 GHz having wide operational bandwidth have been shown to validate the presented analysis.}, keywords = {}, pubstate = {published}, tppubtype = {article} } A new type of broadband 3 dB tandem coupler has been proposed featuring frequency characteristics of the resulting coupling similar to those of a classic 3 dB two-section asymmetric coupled-line directional coupler. The coupler is composed of two loosely coupled-line sections having electrical lengths close to quarter-wavelength connected by right-handed and left-handed transmission line sections. Theoretical analysis and design equations have been presented with an exemplary realization. Measurements of the manufactured tandem coupler operating at f 0 = 1 GHz having wide operational bandwidth have been shown to validate the presented analysis. |
| 19. | Kamil Staszek; Slawomir Gruszczynski; Krzysztof Wincza Accurate broadband multiport reflectometer Journal Article Microwave and Optical Technology Letters, 56 (12), pp. 2884-2887, 2014. @article{10.1002/mop.28729, title = {Accurate broadband multiport reflectometer}, author = {Kamil Staszek and Slawomir Gruszczynski and Krzysztof Wincza}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/mop.28729}, doi = {10.1002/mop.28729}, year = {2014}, date = {2014-01-01}, journal = {Microwave and Optical Technology Letters}, volume = {56}, number = {12}, pages = {2884-2887}, abstract = {A novel broadband multiport reflectometer, consisting of a standard 4 × 4 Butler matrix and an additional directional coupler is proposed. It is shown that such a reflectometer provides highly uniform tunable measurement conditions allowing for measurement precision enhancement. The impact of the applied directional coupler's imperfections on the measurement conditions has been theoretically analyzed. The high measurement accuracy of the proposed reflectometer has been proved experimentally by reflection coefficient measurements over the frequency range of 1–5 GHz, which show a good agreement with the results obtained using VNA. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:2884–2887, 2014}, keywords = {}, pubstate = {published}, tppubtype = {article} } A novel broadband multiport reflectometer, consisting of a standard 4 × 4 Butler matrix and an additional directional coupler is proposed. It is shown that such a reflectometer provides highly uniform tunable measurement conditions allowing for measurement precision enhancement. The impact of the applied directional coupler's imperfections on the measurement conditions has been theoretically analyzed. The high measurement accuracy of the proposed reflectometer has been proved experimentally by reflection coefficient measurements over the frequency range of 1–5 GHz, which show a good agreement with the results obtained using VNA. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:2884–2887, 2014 |
| 18. | Michal Dyrda; Andrzej Kulak; Janusz Mlynarczyk; Michał Ostrowski; Jerzy Kubisz; Adam Michalec; Zenon Nieckarz Application of the Schumann resonance spectral decomposition in characterizing the main African thunderstorm center Journal Article Journal of Geophysical Research: Atmospheres, 119 (23), pp. 13,338-13,349, 2014. @article{10.1002/2014JD022613, title = {Application of the Schumann resonance spectral decomposition in characterizing the main African thunderstorm center}, author = {Michal Dyrda and Andrzej Kulak and Janusz Mlynarczyk and Michał Ostrowski and Jerzy Kubisz and Adam Michalec and Zenon Nieckarz}, url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1002/2014JD022613}, doi = {10.1002/2014JD022613}, year = {2014}, date = {2014-01-01}, journal = {Journal of Geophysical Research: Atmospheres}, volume = {119}, number = {23}, pages = {13,338-13,349}, abstract = {In this paper we present a new method for quantifying the main tropical thunderstorm regions based on extremely low frequency (ELF) electromagnetic wave measurements from a single station—the Hylaty ELF station in Central Europe. Our approach is based on Schumann resonance (SR) measurements, which we apply as an example to thunderstorms in Africa. By solving the inverse problem, using the SR power spectrum templates derived analytically, we calculate distances to the most powerful thunderstorm centers and present simplified 1-D thunderstorm lightning activity “maps” in absolute units C2m2/s. We briefly describe our method of SR power spectrum analysis and present how this method is used with real observational data. We obtained the monthly lightning activity maps of the African storm centers with a spatial resolution of 1° and temporal resolution of 10 min for January and August 2011. This allowed us to study the varying location and intensities of the African storm centers in different seasons of the year. A cross check of the obtained lightning activity maps with Tropical Rainfall Measuring Mission satellite data recorded by the Lightning Imaging Sensor and the derived correlation coefficients between SR and optical data were used to validate the proposed method. We note that modeling a maximum possible number of resonance modes in the SR power spectra (in our case, seven resonances) is essential in application of the proposed approach.}, keywords = {}, pubstate = {published}, tppubtype = {article} } In this paper we present a new method for quantifying the main tropical thunderstorm regions based on extremely low frequency (ELF) electromagnetic wave measurements from a single station—the Hylaty ELF station in Central Europe. Our approach is based on Schumann resonance (SR) measurements, which we apply as an example to thunderstorms in Africa. By solving the inverse problem, using the SR power spectrum templates derived analytically, we calculate distances to the most powerful thunderstorm centers and present simplified 1-D thunderstorm lightning activity “maps” in absolute units C2m2/s. We briefly describe our method of SR power spectrum analysis and present how this method is used with real observational data. We obtained the monthly lightning activity maps of the African storm centers with a spatial resolution of 1° and temporal resolution of 10 min for January and August 2011. This allowed us to study the varying location and intensities of the African storm centers in different seasons of the year. A cross check of the obtained lightning activity maps with Tropical Rainfall Measuring Mission satellite data recorded by the Lightning Imaging Sensor and the derived correlation coefficients between SR and optical data were used to validate the proposed method. We note that modeling a maximum possible number of resonance modes in the SR power spectra (in our case, seven resonances) is essential in application of the proposed approach. |
| 17. | Jakub Sorocki; Ilona Piekarz; Krzysztof Wincza; Slawomir Gruszczynski Bandwidth improvement of rat-race couplers having left-handed transmission-line sections Journal Article International Journal of RF and Microwave Computer-Aided Engineering, 24 (3), pp. 341-347, 2014. @article{10.1002/mmce.20766, title = {Bandwidth improvement of rat-race couplers having left-handed transmission-line sections}, author = {Jakub Sorocki and Ilona Piekarz and Krzysztof Wincza and Slawomir Gruszczynski}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/mmce.20766}, doi = {10.1002/mmce.20766}, year = {2014}, date = {2014-01-01}, journal = {International Journal of RF and Microwave Computer-Aided Engineering}, volume = {24}, number = {3}, pages = {341-347}, abstract = {A novel broadband rat-race coupler has been investigated. The coupler utilizes an artificial left-handed transmission line section for broadband phase response realization. Moreover, a narrowband model of left-handed section has been shown to prove the couplers equivalent circuit at the center frequency. To broaden the operational bandwidth multisection quarter-wave transformers have been proposed. The exemplary rat-race coupler with two-section impedance transformers has been designed and manufactured. © 2013 Wiley Periodicals, Inc. Int J RF and Microwave CAE 24:341–347, 2014.}, keywords = {}, pubstate = {published}, tppubtype = {article} } A novel broadband rat-race coupler has been investigated. The coupler utilizes an artificial left-handed transmission line section for broadband phase response realization. Moreover, a narrowband model of left-handed section has been shown to prove the couplers equivalent circuit at the center frequency. To broaden the operational bandwidth multisection quarter-wave transformers have been proposed. The exemplary rat-race coupler with two-section impedance transformers has been designed and manufactured. © 2013 Wiley Periodicals, Inc. Int J RF and Microwave CAE 24:341–347, 2014. |
| 16. | Oscar A van der Velde; Joan Montanyà; Serge Soula; Nicolau Pineda; Janusz Mlynarczyk Journal of Geophysical Research: Atmospheres, 119 (22), pp. 12,755-12,779, 2014. @article{10.1002/2013JD021291, title = {Bidirectional leader development in sprite-producing positive cloud-to-ground flashes: Origins and characteristics of positive and negative leaders}, author = {Oscar A van der Velde and Joan Montanyà and Serge Soula and Nicolau Pineda and Janusz Mlynarczyk}, url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1002/2013JD021291}, doi = {10.1002/2013JD021291}, year = {2014}, date = {2014-01-01}, journal = {Journal of Geophysical Research: Atmospheres}, volume = {119}, number = {22}, pages = {12,755-12,779}, abstract = {Thirty-five sprite-producing lightning flashes were recorded in nine nights in different seasons at the east coast of Spain with a 3D Lightning Mapping Array (LMA) since July 2011. A low-frequency time-of-arrival network provided data on emissions from return strokes and intracloud processes and a very-high-frequency interferometer network produced complementary lightning data. This study analyzes the bidirectional development of flashes in order to understand the positioning and timing of the positive cloud-to-ground stroke (+CG) and its consequences for charge neutralization by negative leaders, affecting sprite morphology. A summary of negative leader extents, altitudes, and speeds before and after the + CG stroke is provided, as well as positive leader origins and inferred speeds. Negative leader speeds exhibited modes at 105 and 5 × 105 m s−1. Five examples with different evolutions are discussed: (1) Slow bidirectional development with negative leader termination before the + CG stroke; (2) Fast bidirectional development with the negative leader continuing after the + CG stroke. (3) Slow-fast bidirectional development with a negative leader exhibiting a sudden lowering and speed increase; (4) Fast secondary bidirectional development from an in-cloud horizontal positive leader. Negative leaders propagated rapidly into the upper positive charge layer, continuing after the + CG stroke; (5) Slow bidirectional development with a long negative leader (50 km) subject to cutoff while the original positive leader remained trapped inside negative charge. A + CG stroke subsequently occurred under the old negative leader channel. Carrot sprites tended to be associated with fast extending leaders after the stroke, columniform/mixed sprites with slower side branches.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Thirty-five sprite-producing lightning flashes were recorded in nine nights in different seasons at the east coast of Spain with a 3D Lightning Mapping Array (LMA) since July 2011. A low-frequency time-of-arrival network provided data on emissions from return strokes and intracloud processes and a very-high-frequency interferometer network produced complementary lightning data. This study analyzes the bidirectional development of flashes in order to understand the positioning and timing of the positive cloud-to-ground stroke (+CG) and its consequences for charge neutralization by negative leaders, affecting sprite morphology. A summary of negative leader extents, altitudes, and speeds before and after the + CG stroke is provided, as well as positive leader origins and inferred speeds. Negative leader speeds exhibited modes at 105 and 5 × 105 m s−1. Five examples with different evolutions are discussed: (1) Slow bidirectional development with negative leader termination before the + CG stroke; (2) Fast bidirectional development with the negative leader continuing after the + CG stroke. (3) Slow-fast bidirectional development with a negative leader exhibiting a sudden lowering and speed increase; (4) Fast secondary bidirectional development from an in-cloud horizontal positive leader. Negative leaders propagated rapidly into the upper positive charge layer, continuing after the + CG stroke; (5) Slow bidirectional development with a long negative leader (50 km) subject to cutoff while the original positive leader remained trapped inside negative charge. A + CG stroke subsequently occurred under the old negative leader channel. Carrot sprites tended to be associated with fast extending leaders after the stroke, columniform/mixed sprites with slower side branches. |
| 15. | Kamil Staszek; Slawomir Gruszczynski; Krzysztof Wincza Broadband Butler Matrices with the Use of High-Pass LC Sections as Left-Handed Transmission Lines Journal Article Radioengineering, 23 (01), pp. 236-243, 2014, ISSN: 1805-9600. @article{radioengineering2014, title = {Broadband Butler Matrices with the Use of High-Pass LC Sections as Left-Handed Transmission Lines}, author = {Kamil Staszek and Slawomir Gruszczynski and Krzysztof Wincza}, issn = {1805-9600}, year = {2014}, date = {2014-01-01}, journal = {Radioengineering}, volume = {23}, number = {01}, pages = {236-243}, abstract = {An application of left-handed transmission line sections in Butler matrices has been investigated. It has been shown, for the first time, that the utilization of both left-handed and right-handed transmission lines allows for broadband differential phase shifters’ realization, required in the Butler matrices. A complete theoretical analysis is given, for Butler matrices incorporating ideal transmission lines of both right- and left handed types and expressions for the achievable bandwidth and differential phase deviation are derived. The presented idea has been verified by the design of a 4 x 4 Butler matrix operating in a frequency range of 2.5 – 3.5 GHz. As an artificial left-handed transmission line, an equivalent high-pass LC circuit realized in a quasi-lumped element technique has been considered, and the resulting phase shift of such a circuit is given analytically. The obtained measurement results fully confirm the validity of the proposed idea of broadband Butler matrices’ realization}, keywords = {}, pubstate = {published}, tppubtype = {article} } An application of left-handed transmission line sections in Butler matrices has been investigated. It has been shown, for the first time, that the utilization of both left-handed and right-handed transmission lines allows for broadband differential phase shifters’ realization, required in the Butler matrices. A complete theoretical analysis is given, for Butler matrices incorporating ideal transmission lines of both right- and left handed types and expressions for the achievable bandwidth and differential phase deviation are derived. The presented idea has been verified by the design of a 4 x 4 Butler matrix operating in a frequency range of 2.5 – 3.5 GHz. As an artificial left-handed transmission line, an equivalent high-pass LC circuit realized in a quasi-lumped element technique has been considered, and the resulting phase shift of such a circuit is given analytically. The obtained measurement results fully confirm the validity of the proposed idea of broadband Butler matrices’ realization |
| 14. | Jakub Sorocki; Ilona Piekarz; Krzysztof Wincza; Slawomir Gruszczynski Broadband magic-Ts with the use of coupled-line directional couplers and left-handed transmission line sections Journal Article International Journal of RF and Microwave Computer-Aided Engineering, 24 (4), pp. 513-521, 2014. @article{10.1002/mmce.20793, title = {Broadband magic-Ts with the use of coupled-line directional couplers and left-handed transmission line sections}, author = {Jakub Sorocki and Ilona Piekarz and Krzysztof Wincza and Slawomir Gruszczynski}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/mmce.20793}, doi = {10.1002/mmce.20793}, year = {2014}, date = {2014-01-01}, journal = {International Journal of RF and Microwave Computer-Aided Engineering}, volume = {24}, number = {4}, pages = {513-521}, abstract = {The problem of broadband magic-T realization with the use of coupled-line directional couplers and left-handed (LH) transmission-line sections has been comprehensively investigated. Broadband amplitude characteristics of the proposed networks are ensured with the use of coupled-line couplers, whereas the required phase characteristics have been achieved by the appropriate selection of right- and left-handed transmission line sections. To analyze the properties of the proposed networks, a model of an ideal left-handed transmission line has been utilized. The presented concept has been verified by two designs of broadband magic-Ts operating in 2.5–3.5 GHz and 0.8–2.3 GHz, respectively. The obtained results proved that the proposed magic-T networks allows one to obtain broadband amplitude and phase responses together with its compact structure.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The problem of broadband magic-T realization with the use of coupled-line directional couplers and left-handed (LH) transmission-line sections has been comprehensively investigated. Broadband amplitude characteristics of the proposed networks are ensured with the use of coupled-line couplers, whereas the required phase characteristics have been achieved by the appropriate selection of right- and left-handed transmission line sections. To analyze the properties of the proposed networks, a model of an ideal left-handed transmission line has been utilized. The presented concept has been verified by two designs of broadband magic-Ts operating in 2.5–3.5 GHz and 0.8–2.3 GHz, respectively. The obtained results proved that the proposed magic-T networks allows one to obtain broadband amplitude and phase responses together with its compact structure. |
| 13. | Kamil Staszek; Slawomir Gruszczynski; Krzysztof Wincza Broadband Measurements of S-Parameters With the Use of a Single 8 × 8 Butler Matrix Journal Article IEEE Transactions on Microwave Theory and Techniques, 62 (2), pp. 352-360, 2014. @article{10.1109/TMTT.2013.2294597, title = {Broadband Measurements of S-Parameters With the Use of a Single 8 × 8 Butler Matrix}, author = {Kamil Staszek and Slawomir Gruszczynski and Krzysztof Wincza}, url = {https://ieeexplore.ieee.org/abstract/document/6692893/}, doi = {10.1109/TMTT.2013.2294597}, year = {2014}, date = {2014-01-01}, journal = {IEEE Transactions on Microwave Theory and Techniques}, volume = {62}, number = {2}, pages = {352-360}, abstract = {A novel application of an 8 × 8 Butler matrix in broadband multiport measuring systems has been presented. The proposed measuring system consists solely of a single broadband 8 × 8 Butler matrix and only one isolator allowing for measurements of all S-matrix coefficients of any two-port device. It has been shown that the properties of the applied 8 × 8 Butler matrix allow to obtain high measurement accuracy, which has been estimated with a numerical procedure for a different number of applied power detectors. The improved analytical procedure of calibration necessary for the transmission coefficient measurement has been presented. Performance of the proposed measuring system has been experimentally verified in a wide frequency range of 2-3.5 GHz, by measurements of S-parameters of seven exemplary attenuators and a narrowband bandpass filter. The measurement results are very close to the values obtained with the use of a commercial vector network analyzer.}, keywords = {}, pubstate = {published}, tppubtype = {article} } A novel application of an 8 × 8 Butler matrix in broadband multiport measuring systems has been presented. The proposed measuring system consists solely of a single broadband 8 × 8 Butler matrix and only one isolator allowing for measurements of all S-matrix coefficients of any two-port device. It has been shown that the properties of the applied 8 × 8 Butler matrix allow to obtain high measurement accuracy, which has been estimated with a numerical procedure for a different number of applied power detectors. The improved analytical procedure of calibration necessary for the transmission coefficient measurement has been presented. Performance of the proposed measuring system has been experimentally verified in a wide frequency range of 2-3.5 GHz, by measurements of S-parameters of seven exemplary attenuators and a narrowband bandpass filter. The measurement results are very close to the values obtained with the use of a commercial vector network analyzer. |
| 12. | Izabel Slomian; Slawomir Gruszczynski; Krzysztof Wincza Compact Integrated Feeding Network for Excitation of Dual-Circular Polarization in Series-Fed Antenna Lattice Journal Article IEEE Transactions on Antennas and Propagation, 62 (11), pp. 5876-5879, 2014. @article{10.1109/TAP.2014.2350506, title = {Compact Integrated Feeding Network for Excitation of Dual-Circular Polarization in Series-Fed Antenna Lattice}, author = {Izabel Slomian and Slawomir Gruszczynski and Krzysztof Wincza}, url = {https://ieeexplore.ieee.org/document/6880820}, doi = {10.1109/TAP.2014.2350506}, year = {2014}, date = {2014-01-01}, journal = {IEEE Transactions on Antennas and Propagation}, volume = {62}, number = {11}, pages = {5876-5879}, abstract = {A novel approach for realization of a feeding network allowing for achieving dual-circular polarization in the slot-coupled microstrip antenna lattice has been proposed. The presented feeding network is an eight-port composed of four 3mathchar"702DdB/90 ° directional couplers, and when appropriately integrated with the four-port series-fed antenna lattice ensures a full symmetry of the antenna layout and produces simultaneously right-handed and left-handed circular polarization. The proposed low-profile, low-cost solution can be easily integrated with the antenna lattice, and it allows for reduction of the introduced dissipation losses comparing to the known solutions, i.e., external feeding networks such as Butler matrices or power combiner/divider networks connected via coaxial cables. The proposed concept has been examined by measurements of the manufactured feeding network integrated with the previously developed antenna lattice operating at 5.4 GHz}, keywords = {}, pubstate = {published}, tppubtype = {article} } A novel approach for realization of a feeding network allowing for achieving dual-circular polarization in the slot-coupled microstrip antenna lattice has been proposed. The presented feeding network is an eight-port composed of four 3mathchar"702DdB/90 ° directional couplers, and when appropriately integrated with the four-port series-fed antenna lattice ensures a full symmetry of the antenna layout and produces simultaneously right-handed and left-handed circular polarization. The proposed low-profile, low-cost solution can be easily integrated with the antenna lattice, and it allows for reduction of the introduced dissipation losses comparing to the known solutions, i.e., external feeding networks such as Butler matrices or power combiner/divider networks connected via coaxial cables. The proposed concept has been examined by measurements of the manufactured feeding network integrated with the previously developed antenna lattice operating at 5.4 GHz |
| 11. | Kamil Staszek; Slawomir Gruszczynski; Krzysztof Wincza Complex permittivity and permeability estimation by reflection measurements of open and short coaxial transmission line Journal Article Microwave and Optical Technology Letters, 56 (3), pp. 727-732, 2014. @article{10.1002/mop.28132, title = {Complex permittivity and permeability estimation by reflection measurements of open and short coaxial transmission line}, author = {Kamil Staszek and Slawomir Gruszczynski and Krzysztof Wincza}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/mop.28132}, doi = {10.1002/mop.28132}, year = {2014}, date = {2014-01-01}, journal = {Microwave and Optical Technology Letters}, volume = {56}, number = {3}, pages = {727-732}, abstract = {A novel method for complex permittivity and permeability measurements of dielectrics has been shown. The method is based on a previously developed transmission-line technique, however, has been modified to allow for dielectric properties estimation with measurements of reflections only. The analysis of measurement errors, resulting from: sample length uncertainty, vector network analyzer uncertainty, and open-end inaccuracy, has been shown in the article. The calibration method using open/short/offset-short standards has been described. The method has been experimentally tested by measurements of three different reference liquid samples. A good agreement between measured values and previously published ones has been obtained.}, keywords = {}, pubstate = {published}, tppubtype = {article} } A novel method for complex permittivity and permeability measurements of dielectrics has been shown. The method is based on a previously developed transmission-line technique, however, has been modified to allow for dielectric properties estimation with measurements of reflections only. The analysis of measurement errors, resulting from: sample length uncertainty, vector network analyzer uncertainty, and open-end inaccuracy, has been shown in the article. The calibration method using open/short/offset-short standards has been described. The method has been experimentally tested by measurements of three different reference liquid samples. A good agreement between measured values and previously published ones has been obtained. |
| 10. | Jakub Sorocki; Kamil Staszek; Ilona Piekarz; Krzysztof Wincza; Slawomir Gruszczynski Directional couplers with reduced coupling requirements as connection of coupled-line sections and left-handed transmission lines Journal Article IET Microwaves, Antennas & Propagation, 8 (8), pp. 580-588, 2014. @article{10.1049/iet-map.2013.0369, title = {Directional couplers with reduced coupling requirements as connection of coupled-line sections and left-handed transmission lines}, author = {Jakub Sorocki and Kamil Staszek and Ilona Piekarz and Krzysztof Wincza and Slawomir Gruszczynski}, url = {https://ieeexplore.ieee.org/document/6831908}, doi = {10.1049/iet-map.2013.0369}, year = {2014}, date = {2014-01-01}, journal = {IET Microwaves, Antennas & Propagation}, volume = {8}, number = {8}, pages = {580-588}, abstract = {A new class of directional couplers realised as a connection of two symmetrically placed coupled-line sections and two sections of uncoupled left-handed (LH) transmission lines is proposed. It has been proved that such circuits allow for achieving a higher nominal coupling of the resulting coupler than the coupling level of the utilised coupled-line section. Moreover, the proposed networks feature the properties of the ideal coupled-line sections, therefore, they allow for the realisation of broadband, high-performance directional couplers with relaxed coupling coefficient requirements. The proposed directional couplers have been theoretically analysed, and approximate design equations have been derived, which allow for the calculation of the required electrical length of the LH sections against the assumed coupling of the applied coupled-line section. Moreover, it has been shown that in such circuits the required minimum coupling of the utilised coupled-line section depends on the assumed nominal coupling of the resulting coupler, and this dependence has been derived analytically. The presented theoretical analysis has been verified experimentally by the measurements of two planar 3-dB directional couplers. The obtained results proved the correctness of the presented analysis, and confirmed that the presented method allows for the realisation of the broadband 3-dB directional couplers with the use of a single layer microstrip structure.}, keywords = {}, pubstate = {published}, tppubtype = {article} } A new class of directional couplers realised as a connection of two symmetrically placed coupled-line sections and two sections of uncoupled left-handed (LH) transmission lines is proposed. It has been proved that such circuits allow for achieving a higher nominal coupling of the resulting coupler than the coupling level of the utilised coupled-line section. Moreover, the proposed networks feature the properties of the ideal coupled-line sections, therefore, they allow for the realisation of broadband, high-performance directional couplers with relaxed coupling coefficient requirements. The proposed directional couplers have been theoretically analysed, and approximate design equations have been derived, which allow for the calculation of the required electrical length of the LH sections against the assumed coupling of the applied coupled-line section. Moreover, it has been shown that in such circuits the required minimum coupling of the utilised coupled-line section depends on the assumed nominal coupling of the resulting coupler, and this dependence has been derived analytically. The presented theoretical analysis has been verified experimentally by the measurements of two planar 3-dB directional couplers. The obtained results proved the correctness of the presented analysis, and confirmed that the presented method allows for the realisation of the broadband 3-dB directional couplers with the use of a single layer microstrip structure. |
| 9. | Andrzej Kulak; Jerzy Kubisz; Slawomir Klucjasz; Adam Michalec; Janusz Mlynarczyk; Zenon Nieckarz; Michal Ostrowski; Stanislaw Zieba Extremely low frequency electromagnetic field measurements at the Hylaty station and methodology of signal analysis Journal Article Radio Science, 49 (6), pp. 361-370, 2014. @article{10.1002/2014RS005400, title = {Extremely low frequency electromagnetic field measurements at the Hylaty station and methodology of signal analysis}, author = {Andrzej Kulak and Jerzy Kubisz and Slawomir Klucjasz and Adam Michalec and Janusz Mlynarczyk and Zenon Nieckarz and Michal Ostrowski and Stanislaw Zieba}, url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1002/2014RS005400}, doi = {10.1002/2014RS005400}, year = {2014}, date = {2014-01-01}, journal = {Radio Science}, volume = {49}, number = {6}, pages = {361-370}, abstract = {We present the Hylaty geophysical station, a high-sensitivity and low-noise facility for extremely low frequency (ELF, 0.03–300 Hz) electromagnetic field measurements, which enables a variety of geophysical and climatological research related to atmospheric, ionospheric, magnetospheric, and space weather physics. The first systematic observations of ELF electromagnetic fields at the Jagiellonian University were undertaken in 1994. At the beginning the measurements were carried out sporadically, during expeditions to sparsely populated areas of the Bieszczady Mountains in the southeast of Poland. In 2004, an automatic Hylaty ELF station was built there, in a very low electromagnetic noise environment, which enabled continuous recording of the magnetic field components of the ELF electromagnetic field in the frequency range below 60 Hz. In 2013, after 8 years of successful operation, the station was upgraded by extending its frequency range up to 300 Hz. In this paper we show the station's technical setup, and how it has changed over the years. We discuss the design of ELF equipment, including antennas, receivers, the time control circuit, and power supply, as well as antenna and receiver calibration. We also discuss the methodology we developed for observations of the Schumann resonance and wideband observations of ELF field pulses. We provide examples of various kinds of signals recorded at the station.}, keywords = {}, pubstate = {published}, tppubtype = {article} } We present the Hylaty geophysical station, a high-sensitivity and low-noise facility for extremely low frequency (ELF, 0.03–300 Hz) electromagnetic field measurements, which enables a variety of geophysical and climatological research related to atmospheric, ionospheric, magnetospheric, and space weather physics. The first systematic observations of ELF electromagnetic fields at the Jagiellonian University were undertaken in 1994. At the beginning the measurements were carried out sporadically, during expeditions to sparsely populated areas of the Bieszczady Mountains in the southeast of Poland. In 2004, an automatic Hylaty ELF station was built there, in a very low electromagnetic noise environment, which enabled continuous recording of the magnetic field components of the ELF electromagnetic field in the frequency range below 60 Hz. In 2013, after 8 years of successful operation, the station was upgraded by extending its frequency range up to 300 Hz. In this paper we show the station's technical setup, and how it has changed over the years. We discuss the design of ELF equipment, including antennas, receivers, the time control circuit, and power supply, as well as antenna and receiver calibration. We also discuss the methodology we developed for observations of the Schumann resonance and wideband observations of ELF field pulses. We provide examples of various kinds of signals recorded at the station. |
| 8. | Ilona Piekarz; Jakub Sorocki; Slawomir Gruszczynski; Krzysztof Wincza Input Match and Output Balance Improvement of Marchand Balun With Connecting Line Journal Article IEEE Microwave and Wireless Components Letters, 24 (10), pp. 683-685, 2014. @article{10.1109/LMWC.2014.2342886, title = {Input Match and Output Balance Improvement of Marchand Balun With Connecting Line}, author = {Ilona Piekarz and Jakub Sorocki and Slawomir Gruszczynski and Krzysztof Wincza}, url = {https://ieeexplore.ieee.org/document/6870669}, doi = {10.1109/LMWC.2014.2342886}, year = {2014}, date = {2014-01-01}, journal = {IEEE Microwave and Wireless Components Letters}, volume = {24}, number = {10}, pages = {683-685}, abstract = {A novel method allowing for improvement of input match and output balance of Marchand balun with connecting line has been presented. The proposed compensation technique together with the ideal Marchand balun design formulas allow for achieving an arbitrary impedance transformation ratio even for the circuit having a long connecting line. The theoretical analysis has been verified by EM simulations and measurements of a Marchand balun composed of 3 dB coupled-line sections and 30° transmission line operating at the center frequency f 0 = 1.15 GHz and terminated at input and outputs with 50 Ω and 100 Ω, respectively.}, keywords = {}, pubstate = {published}, tppubtype = {article} } A novel method allowing for improvement of input match and output balance of Marchand balun with connecting line has been presented. The proposed compensation technique together with the ideal Marchand balun design formulas allow for achieving an arbitrary impedance transformation ratio even for the circuit having a long connecting line. The theoretical analysis has been verified by EM simulations and measurements of a Marchand balun composed of 3 dB coupled-line sections and 30° transmission line operating at the center frequency f 0 = 1.15 GHz and terminated at input and outputs with 50 Ω and 100 Ω, respectively. |
| 7. | Kamil Staszek; Slawomir Gruszczynski; Krzysztof Wincza Multisection Couplers With Coupled-Line Sections Having Unequal Lengths Journal Article IEEE Transactions on Microwave Theory and Techniques, 62 (7), pp. 1461-1469, 2014. @article{10.1109/TMTT.2014.2322819, title = {Multisection Couplers With Coupled-Line Sections Having Unequal Lengths}, author = {Kamil Staszek and Slawomir Gruszczynski and Krzysztof Wincza}, url = {https://ieeexplore.ieee.org/document/6816096}, doi = {10.1109/TMTT.2014.2322819}, year = {2014}, date = {2014-01-01}, journal = {IEEE Transactions on Microwave Theory and Techniques}, volume = {62}, number = {7}, pages = {1461-1469}, abstract = {A new type of broadband multisection coupled-line directional couplers is proposed. The investigated directional couplers are composed of coupled-line sections having unequal electrical lengths and a transmission-line section. The presented couplers feature similar bandwidth to the standard multisection directional couplers with significantly reduced maximum coupling coefficient, and the overall size smaller than in the case of tandem couplers. Moreover, it is shown that in the presented couplers an ideal 90 ° differential phase characteristic can be achieved when such couplers are solely composed of coupled-line sections having appropriate electrical lengths. Additionally, it is shown that the proposed couplers' bandwidth can be increased by increasing the number of quarter-wave-long coupled-line sections. Theoretical analysis has been validated by three designs of broadband directional couplers operating at a frequency f 0 =1.8 GHz. Measurements of the manufactured directional couplers have been shown to experimentally confirm their properties.}, keywords = {}, pubstate = {published}, tppubtype = {article} } A new type of broadband multisection coupled-line directional couplers is proposed. The investigated directional couplers are composed of coupled-line sections having unequal electrical lengths and a transmission-line section. The presented couplers feature similar bandwidth to the standard multisection directional couplers with significantly reduced maximum coupling coefficient, and the overall size smaller than in the case of tandem couplers. Moreover, it is shown that in the presented couplers an ideal 90 ° differential phase characteristic can be achieved when such couplers are solely composed of coupled-line sections having appropriate electrical lengths. Additionally, it is shown that the proposed couplers' bandwidth can be increased by increasing the number of quarter-wave-long coupled-line sections. Theoretical analysis has been validated by three designs of broadband directional couplers operating at a frequency f 0 =1.8 GHz. Measurements of the manufactured directional couplers have been shown to experimentally confirm their properties. |
| 6. | Kamil Staszek; Krzysztof Wincza; Slawomir Gruszczynski Phase Property of Central-Symmetric Four-Ports Applied to Quadrature Directional Coupler Design in Asymmetric Coupled-Line Technology Journal Article IEEE Microwave and Wireless Components Letters, 24 (6), pp. 370-372, 2014. @article{10.1109/LMWC.2014.2310487, title = {Phase Property of Central-Symmetric Four-Ports Applied to Quadrature Directional Coupler Design in Asymmetric Coupled-Line Technology}, author = {Kamil Staszek and Krzysztof Wincza and Slawomir Gruszczynski}, url = {https://ieeexplore.ieee.org/document/6776561}, doi = {10.1109/LMWC.2014.2310487}, year = {2014}, date = {2014-01-01}, journal = {IEEE Microwave and Wireless Components Letters}, volume = {24}, number = {6}, pages = {370-372}, abstract = {Properties of ideally matched lossless four-port networks having central symmetry have been investigated. It has been shown that such networks feature ideal quadrature differential phase characteristics. It is shown that this unique property can be utilized for phase improvement of asymmetric coupled-line directional couplers. The presented theoretical investigation has been proven by measurements of two different directional couplers with a central symmetry designed in technology of multilayer asymmetric coupled lines.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Properties of ideally matched lossless four-port networks having central symmetry have been investigated. It has been shown that such networks feature ideal quadrature differential phase characteristics. It is shown that this unique property can be utilized for phase improvement of asymmetric coupled-line directional couplers. The presented theoretical investigation has been proven by measurements of two different directional couplers with a central symmetry designed in technology of multilayer asymmetric coupled lines. |
| 5. | Kamil Staszek; Piotr Kaminski; Krzysztof Wincza; Slawomir Gruszczynski Phase Property of Central-Symmetric Four-Ports Applied to Quadrature Directional Coupler Design in Asymmetric Coupled-Line Technology Journal Article IEEE Microwave and Wireless Components Letters, 24 (6), pp. 376-378, 2014. @article{10.1109/LMWC.2014.2313477, title = {Phase Property of Central-Symmetric Four-Ports Applied to Quadrature Directional Coupler Design in Asymmetric Coupled-Line Technology}, author = {Kamil Staszek and Piotr Kaminski and Krzysztof Wincza and Slawomir Gruszczynski}, url = {https://ieeexplore.ieee.org/document/6784330}, doi = {10.1109/LMWC.2014.2313477}, year = {2014}, date = {2014-01-01}, journal = {IEEE Microwave and Wireless Components Letters}, volume = {24}, number = {6}, pages = {376-378}, abstract = {Broadband coupled-line directional couplers having the properties of two-section coupled-line directional couplers are proposed. The presented couplers are composed of two-coupled line sections having the same coupling coefficient which are connected with the use of two sections of uncoupled transmission lines. It is shown that in such a structure it is possible to achieve an equal-ripple coupling characteristic similar to the coupling response of classic-two section coupled-line couplers. It is also shown that, in comparison to the classic counterparts, in the proposed couplers the required coupling between the coupled-lines is slightly weaker and the overall electrical length is reduced. The theoretical analysis and measurement results of a 3 dB directional coupler operating at a center frequency of 1.8 GHz are presented.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Broadband coupled-line directional couplers having the properties of two-section coupled-line directional couplers are proposed. The presented couplers are composed of two-coupled line sections having the same coupling coefficient which are connected with the use of two sections of uncoupled transmission lines. It is shown that in such a structure it is possible to achieve an equal-ripple coupling characteristic similar to the coupling response of classic-two section coupled-line couplers. It is also shown that, in comparison to the classic counterparts, in the proposed couplers the required coupling between the coupled-lines is slightly weaker and the overall electrical length is reduced. The theoretical analysis and measurement results of a 3 dB directional coupler operating at a center frequency of 1.8 GHz are presented. |
| 4. | Izabela Slomian; Krzysztof Wincza; Slawomir Gruszczynski Series-Fed Microstrip Antenna Lattice With Switched Polarization Utilizing Butler Matrix Journal Article IEEE Transactions on Antennas and Propagation, 62 (1), pp. 145-152, 2014. @article{10.1109/TAP.2013.2287293, title = {Series-Fed Microstrip Antenna Lattice With Switched Polarization Utilizing Butler Matrix}, author = {Izabela Slomian and Krzysztof Wincza and Slawomir Gruszczynski}, url = {https://ieeexplore.ieee.org/document/6648439}, doi = {10.1109/TAP.2013.2287293}, year = {2014}, date = {2014-01-01}, journal = {IEEE Transactions on Antennas and Propagation}, volume = {62}, number = {1}, pages = {145-152}, abstract = {A novel concept of a series-fed microstrip antenna array with switched polarization has been proposed. The presented antenna array consists of radiating elements connected together with transmission line sections, creating a lattice with series connections between elements. The lattice is also series fed using slots in the common ground plane. Moreover, it is shown that the proposed antenna array is capable of providing linear, dual-linear, circular, and dual-circular polarization when appropriately fed by a Butler matrix. The theoretical analysis and measurement results of a 4 × 4 microstrip antenna array operating within 5.5-GHz frequency range are presented, showing the potential usefulness of such a structure.}, keywords = {}, pubstate = {published}, tppubtype = {article} } A novel concept of a series-fed microstrip antenna array with switched polarization has been proposed. The presented antenna array consists of radiating elements connected together with transmission line sections, creating a lattice with series connections between elements. The lattice is also series fed using slots in the common ground plane. Moreover, it is shown that the proposed antenna array is capable of providing linear, dual-linear, circular, and dual-circular polarization when appropriately fed by a Butler matrix. The theoretical analysis and measurement results of a 4 × 4 microstrip antenna array operating within 5.5-GHz frequency range are presented, showing the potential usefulness of such a structure. |
| 3. | Piotr Kaminski; Krzysztof Wincza; Slawomir Gruszczynski Switched-beam antenna array with broadside beam fed by modified butler matrix for radar receiver application Journal Article Microwave and Optical Technology Letters, 56 (3), pp. 732-735, 2014. @article{10.1002/mop.28131, title = {Switched-beam antenna array with broadside beam fed by modified butler matrix for radar receiver application}, author = {Piotr Kaminski and Krzysztof Wincza and Slawomir Gruszczynski}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/mop.28131}, doi = {10.1002/mop.28131}, year = {2014}, date = {2014-01-01}, journal = {Microwave and Optical Technology Letters}, volume = {56}, number = {3}, pages = {732-735}, abstract = {A novel approach to the design of switched-beam antennas with broadside beam has been presented. The presented antenna utilizes a modified Butler matrix as a feeding network. The proposed feeding network consists of only two 3-dB/0/180 directional couplers, a 3-dB/90° directional coupler and a 180° phase shifter. Moreover, an innovative arrangement of the network has been proposed, which allows for avoiding any crossings in the network, and allows for achieving fully planar realization of a complete antenna. Measurement results of the designed three-beam antenna are shown, and also the application of the presented concept in a simple Doppler radar receiver is proposed, in which fixed phase shifters are eliminated.}, keywords = {}, pubstate = {published}, tppubtype = {article} } A novel approach to the design of switched-beam antennas with broadside beam has been presented. The presented antenna utilizes a modified Butler matrix as a feeding network. The proposed feeding network consists of only two 3-dB/0/180 directional couplers, a 3-dB/90° directional coupler and a 180° phase shifter. Moreover, an innovative arrangement of the network has been proposed, which allows for avoiding any crossings in the network, and allows for achieving fully planar realization of a complete antenna. Measurement results of the designed three-beam antenna are shown, and also the application of the presented concept in a simple Doppler radar receiver is proposed, in which fixed phase shifters are eliminated. |
| 2. | Pawel Turcza; Janusz Mlynarczyk Szerokopasmowy, wieloantenowy odbiornik dla systemu bezprzewodowej rejestracji potencjałów neuronowych Journal Article Przeglad Elektotechniczny, 90 (5), pp. 172-175, 2014. @article{10.12915/pe.2014.05.41, title = {Szerokopasmowy, wieloantenowy odbiornik dla systemu bezprzewodowej rejestracji potencjałów neuronowych}, author = {Pawel Turcza and Janusz Mlynarczyk}, doi = {10.12915/pe.2014.05.41}, year = {2014}, date = {2014-01-01}, journal = {Przeglad Elektotechniczny}, volume = {90}, number = {5}, pages = {172-175}, abstract = {W artykule przedstawiono projekt szerokopasmowego wieloantenowego układu odbiorczego dla systemu bezprzewodowej rejestracji potencjałów neuronowych. Odbiornik pracuje w paśmie 4 GHz i wykorzystuje macierz anten szerokopasmowych celem zapewnienia wymaganego pasma transmisji w szerokim zakresie częstotliwości fali nośnej, zwiększenia zasięgu transmisji, oraz zapewnienia możliwości zgrubnej lokalizacji przestrzennej badanego obiektu. Proces dekodowania i demodulacji sygnałów realizowany jest w strukturze programowalnej FPGA.}, keywords = {}, pubstate = {published}, tppubtype = {article} } W artykule przedstawiono projekt szerokopasmowego wieloantenowego układu odbiorczego dla systemu bezprzewodowej rejestracji potencjałów neuronowych. Odbiornik pracuje w paśmie 4 GHz i wykorzystuje macierz anten szerokopasmowych celem zapewnienia wymaganego pasma transmisji w szerokim zakresie częstotliwości fali nośnej, zwiększenia zasięgu transmisji, oraz zapewnienia możliwości zgrubnej lokalizacji przestrzennej badanego obiektu. Proces dekodowania i demodulacji sygnałów realizowany jest w strukturze programowalnej FPGA. |
| 1. | Bogusław Cyganek; Sławomir Gruszczyński Hybrid computer vision system for drivers' eye recognition and fatigue monitoring Journal Article Neurocomputing, 126 , pp. 78 - 94, 2014, ISSN: 0925-2312, (Recent trends in Intelligent Data Analysis Online Data Processing). @article{10.1016/j.neucom.2013.01.048, title = {Hybrid computer vision system for drivers' eye recognition and fatigue monitoring}, author = {Bogusław Cyganek and Sławomir Gruszczyński}, url = {http://www.sciencedirect.com/science/article/pii/S0925231213006863}, doi = {10.1016/j.neucom.2013.01.048}, issn = {0925-2312}, year = {2014}, date = {2014-01-01}, journal = {Neurocomputing}, volume = {126}, pages = {78 - 94}, abstract = {This paper presents a hybrid visual system for monitoring driver's states of fatigue, sleepiness and inattention based on driver's eye recognition. Safe operation in car conditions and processing in daily and night conditions are obtained thanks to the custom setup of two cameras operating in the visible and near infra-red spectra, respectively. In each of these spectra image processing is performed by a cascade of two classifiers. The first classifier in a cascade is responsible for detection of eye regions based on the proposed eye models specific to each spectrum. The second classifier in each cascade is responsible for eye verification. It is based on the higher order singular value decomposition of the tensors of geometrically deformed versions of real eye prototypes, specific to the visible and NIR spectra. Experiments were performed in real car conditions in which four volunteer drivers participated. The obtained results show high recognition accuracy and real-time processing in software implementation. Thanks to these the system can become a part of the advanced driver’s assisting system.}, note = {Recent trends in Intelligent Data Analysis Online Data Processing}, keywords = {}, pubstate = {published}, tppubtype = {article} } This paper presents a hybrid visual system for monitoring driver's states of fatigue, sleepiness and inattention based on driver's eye recognition. Safe operation in car conditions and processing in daily and night conditions are obtained thanks to the custom setup of two cameras operating in the visible and near infra-red spectra, respectively. In each of these spectra image processing is performed by a cascade of two classifiers. The first classifier in a cascade is responsible for detection of eye regions based on the proposed eye models specific to each spectrum. The second classifier in each cascade is responsible for eye verification. It is based on the higher order singular value decomposition of the tensors of geometrically deformed versions of real eye prototypes, specific to the visible and NIR spectra. Experiments were performed in real car conditions in which four volunteer drivers participated. The obtained results show high recognition accuracy and real-time processing in software implementation. Thanks to these the system can become a part of the advanced driver’s assisting system. |
| 24. | Semi-Distributed Approach to Dual-Composite Right/Left-Handed Transmission Lines and Their Application to Bandstop Filters Journal Article IEEE Microwave and Wireless Components Letters, 25 (12), pp. 784-786, 2015. |
| 23. | Time and space correlation between sprites and their parent lightning flashes for a thunderstorm observed during the HyMeX campaign Journal Article Journal of Geophysical Research: Atmospheres, 120 (22), pp. 11,552-11,574, 2015. |
| 22. | Two-section asymmetric coupled-line impedance transforming directional couplers Journal Article IET Microwaves, Antennas & Propagation, 9 (4), pp. 343 - 350, 2015. |
| 21. | Ultrabroadband multiprobe reflectometer Journal Article Microwave and Optical Technology Letters, 57 (8), pp. 1968-1971, 2015. |
| 20. | A Broadband 3 dB Tandem Coupler Utilizing Right/Left Handed Transmission Line Sections Journal Article IEEE Microwave and Wireless Components Letters, 24 (4), pp. 236-238, 2014. |
| 19. | Accurate broadband multiport reflectometer Journal Article Microwave and Optical Technology Letters, 56 (12), pp. 2884-2887, 2014. |
| 18. | Application of the Schumann resonance spectral decomposition in characterizing the main African thunderstorm center Journal Article Journal of Geophysical Research: Atmospheres, 119 (23), pp. 13,338-13,349, 2014. |
| 17. | Bandwidth improvement of rat-race couplers having left-handed transmission-line sections Journal Article International Journal of RF and Microwave Computer-Aided Engineering, 24 (3), pp. 341-347, 2014. |
| 16. | Journal of Geophysical Research: Atmospheres, 119 (22), pp. 12,755-12,779, 2014. |
| 15. | Broadband Butler Matrices with the Use of High-Pass LC Sections as Left-Handed Transmission Lines Journal Article Radioengineering, 23 (01), pp. 236-243, 2014, ISSN: 1805-9600. |
| 14. | Broadband magic-Ts with the use of coupled-line directional couplers and left-handed transmission line sections Journal Article International Journal of RF and Microwave Computer-Aided Engineering, 24 (4), pp. 513-521, 2014. |
| 13. | Broadband Measurements of S-Parameters With the Use of a Single 8 × 8 Butler Matrix Journal Article IEEE Transactions on Microwave Theory and Techniques, 62 (2), pp. 352-360, 2014. |
| 12. | Compact Integrated Feeding Network for Excitation of Dual-Circular Polarization in Series-Fed Antenna Lattice Journal Article IEEE Transactions on Antennas and Propagation, 62 (11), pp. 5876-5879, 2014. |
| 11. | Complex permittivity and permeability estimation by reflection measurements of open and short coaxial transmission line Journal Article Microwave and Optical Technology Letters, 56 (3), pp. 727-732, 2014. |
| 10. | Directional couplers with reduced coupling requirements as connection of coupled-line sections and left-handed transmission lines Journal Article IET Microwaves, Antennas & Propagation, 8 (8), pp. 580-588, 2014. |
| 9. | Extremely low frequency electromagnetic field measurements at the Hylaty station and methodology of signal analysis Journal Article Radio Science, 49 (6), pp. 361-370, 2014. |
| 8. | Input Match and Output Balance Improvement of Marchand Balun With Connecting Line Journal Article IEEE Microwave and Wireless Components Letters, 24 (10), pp. 683-685, 2014. |
| 7. | Multisection Couplers With Coupled-Line Sections Having Unequal Lengths Journal Article IEEE Transactions on Microwave Theory and Techniques, 62 (7), pp. 1461-1469, 2014. |
| 6. | Phase Property of Central-Symmetric Four-Ports Applied to Quadrature Directional Coupler Design in Asymmetric Coupled-Line Technology Journal Article IEEE Microwave and Wireless Components Letters, 24 (6), pp. 370-372, 2014. |
| 5. | Phase Property of Central-Symmetric Four-Ports Applied to Quadrature Directional Coupler Design in Asymmetric Coupled-Line Technology Journal Article IEEE Microwave and Wireless Components Letters, 24 (6), pp. 376-378, 2014. |
| 4. | Series-Fed Microstrip Antenna Lattice With Switched Polarization Utilizing Butler Matrix Journal Article IEEE Transactions on Antennas and Propagation, 62 (1), pp. 145-152, 2014. |
| 3. | Switched-beam antenna array with broadside beam fed by modified butler matrix for radar receiver application Journal Article Microwave and Optical Technology Letters, 56 (3), pp. 732-735, 2014. |
| 2. | Szerokopasmowy, wieloantenowy odbiornik dla systemu bezprzewodowej rejestracji potencjałów neuronowych Journal Article Przeglad Elektotechniczny, 90 (5), pp. 172-175, 2014. |
| 1. | Hybrid computer vision system for drivers' eye recognition and fatigue monitoring Journal Article Neurocomputing, 126 , pp. 78 - 94, 2014, ISSN: 0925-2312, (Recent trends in Intelligent Data Analysis Online Data Processing). |