Pub Date : 2009-11-01DOI: 10.1109/COMCAS.2009.5386039
R. Rotman, M. Tur
This review presentation will look at the unique requirements for the antenna and beamformer for today's wideband systems which need high resolution. Unlike quasi monochromatic phased array technology, when dealing with wideband phased arrays, the designer needs to take into account the transfer function of the element as a function of scan angle, redefining the phased array problem and leading to new fields of research. Various types of wideband beamforming — analog (i.e. Rotman lens), digital and photonic will be reviewed and compared, based on the new criteria of the transfer function.
{"title":"Antenna and beamformer requirements for wideband phased array systems: A review","authors":"R. Rotman, M. Tur","doi":"10.1109/COMCAS.2009.5386039","DOIUrl":"https://doi.org/10.1109/COMCAS.2009.5386039","url":null,"abstract":"This review presentation will look at the unique requirements for the antenna and beamformer for today's wideband systems which need high resolution. Unlike quasi monochromatic phased array technology, when dealing with wideband phased arrays, the designer needs to take into account the transfer function of the element as a function of scan angle, redefining the phased array problem and leading to new fields of research. Various types of wideband beamforming — analog (i.e. Rotman lens), digital and photonic will be reviewed and compared, based on the new criteria of the transfer function.","PeriodicalId":372928,"journal":{"name":"2009 IEEE International Conference on Microwaves, Communications, Antennas and Electronics Systems","volume":"90 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133413940","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-11-01DOI: 10.1109/COMCAS.2009.5386038
G. Samelsohn, E. Gruzdev
In this work we study the relation between time reversal and wave localization in (mainly two-dimensional) systems with anisotropic disorder. It is shown, in particular, that for relatively short wavelengths which are comparable to the correlation scales of the disorder, the transport properties of random media are essentially different in the directions along and across the correlation ellipse. There exists a frequency-dependent critical value of the aspect ratio, below which waves are localized at all angles of propagation. Above this critical value, the radiation is localized only within some angular sectors centered at the short axis of the correlation ellipse and is extended in other directions. Also, extensive numerical time reversal experiments aimed at studying the resolution in both space focusing and time compression of ultra-wideband signals have been performed. The resolution obtained is shown to depend essentially on both the propagation angle and the aspect ratio of the random structure.
{"title":"Time reversal of electromagnetic waves in random channels with anisotropic disorder","authors":"G. Samelsohn, E. Gruzdev","doi":"10.1109/COMCAS.2009.5386038","DOIUrl":"https://doi.org/10.1109/COMCAS.2009.5386038","url":null,"abstract":"In this work we study the relation between time reversal and wave localization in (mainly two-dimensional) systems with anisotropic disorder. It is shown, in particular, that for relatively short wavelengths which are comparable to the correlation scales of the disorder, the transport properties of random media are essentially different in the directions along and across the correlation ellipse. There exists a frequency-dependent critical value of the aspect ratio, below which waves are localized at all angles of propagation. Above this critical value, the radiation is localized only within some angular sectors centered at the short axis of the correlation ellipse and is extended in other directions. Also, extensive numerical time reversal experiments aimed at studying the resolution in both space focusing and time compression of ultra-wideband signals have been performed. The resolution obtained is shown to depend essentially on both the propagation angle and the aspect ratio of the random structure.","PeriodicalId":372928,"journal":{"name":"2009 IEEE International Conference on Microwaves, Communications, Antennas and Electronics Systems","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127064367","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-11-01DOI: 10.1109/COMCAS.2009.5385965
J. Park, S. Gelfand, M. Fitz
The optimization of baseband processing is proposed to compensate for high power amplifier (HPA) nonlinear distortion and channel noise, and to meet an output spectral constraint without the use of a spectral containment filter. Global compensation data predistortion with memory and square root raised cosine pulse shaping are employed, and the spectral regrowth and nonlinear intersymbol interference are evaluated as functions of the average output power back-off of the HPA and the roll-off of the pulse. These parameters are then jointly optimized by minimizing the total degradation subject to the output spectral constraint. Results are given for single carrier 12/4-QAM with 750MHz symbol rate and a standard HPA model.
{"title":"Joint optimization of data predistortion and baseband pulse shaping in high speed transmission nonlinear systems","authors":"J. Park, S. Gelfand, M. Fitz","doi":"10.1109/COMCAS.2009.5385965","DOIUrl":"https://doi.org/10.1109/COMCAS.2009.5385965","url":null,"abstract":"The optimization of baseband processing is proposed to compensate for high power amplifier (HPA) nonlinear distortion and channel noise, and to meet an output spectral constraint without the use of a spectral containment filter. Global compensation data predistortion with memory and square root raised cosine pulse shaping are employed, and the spectral regrowth and nonlinear intersymbol interference are evaluated as functions of the average output power back-off of the HPA and the roll-off of the pulse. These parameters are then jointly optimized by minimizing the total degradation subject to the output spectral constraint. Results are given for single carrier 12/4-QAM with 750MHz symbol rate and a standard HPA model.","PeriodicalId":372928,"journal":{"name":"2009 IEEE International Conference on Microwaves, Communications, Antennas and Electronics Systems","volume":"43 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114812966","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-11-01DOI: 10.1109/COMCAS.2009.5385984
N. Love, L. H. Jones, S. Stegmann
Spectrum management (SM) is a well known important issue [1]. Demand for RF spectrum already exceeds supply [2]. The advent of cognitive radio functionality and other SM advances, while important, have actually been constrained by an almost exclusive focus on omni-directional antennas, with scant attention paid to the spectrum deconfliction benefits accrued from advanced aperture technologies. Advanced apertures with directional beam steering capabilities can reduce a network's electromagnetic “footprint”, and consequently its vulnerability to unintentional interference, while maintaining connectivity. These devices will have a profound impact on SM and software-defined radio (SDR) technologies.
{"title":"Directional antennas and radio networks","authors":"N. Love, L. H. Jones, S. Stegmann","doi":"10.1109/COMCAS.2009.5385984","DOIUrl":"https://doi.org/10.1109/COMCAS.2009.5385984","url":null,"abstract":"Spectrum management (SM) is a well known important issue [1]. Demand for RF spectrum already exceeds supply [2]. The advent of cognitive radio functionality and other SM advances, while important, have actually been constrained by an almost exclusive focus on omni-directional antennas, with scant attention paid to the spectrum deconfliction benefits accrued from advanced aperture technologies. Advanced apertures with directional beam steering capabilities can reduce a network's electromagnetic “footprint”, and consequently its vulnerability to unintentional interference, while maintaining connectivity. These devices will have a profound impact on SM and software-defined radio (SDR) technologies.","PeriodicalId":372928,"journal":{"name":"2009 IEEE International Conference on Microwaves, Communications, Antennas and Electronics Systems","volume":"248 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116284900","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-11-01DOI: 10.1109/COMCAS.2009.5386052
S. Marcus, Y. Levi, E. Tomer
A correspondence is shown between anomalous sightings of ships by a weather radar with an upward tilted beam, and the existence of surface based ducts determined from numerical weather prediction (NWP) models. Since these forecasts are available several days in advance, the existence of such ducts can be predicted in advance. The parameters of these ducts are used in a propagation model to determine regions from which targets can be detected by the radar. Such regions were found to include those where ships were sighted by the radar.
{"title":"The predictability of anomalous propagation environments","authors":"S. Marcus, Y. Levi, E. Tomer","doi":"10.1109/COMCAS.2009.5386052","DOIUrl":"https://doi.org/10.1109/COMCAS.2009.5386052","url":null,"abstract":"A correspondence is shown between anomalous sightings of ships by a weather radar with an upward tilted beam, and the existence of surface based ducts determined from numerical weather prediction (NWP) models. Since these forecasts are available several days in advance, the existence of such ducts can be predicted in advance. The parameters of these ducts are used in a propagation model to determine regions from which targets can be detected by the radar. Such regions were found to include those where ships were sighted by the radar.","PeriodicalId":372928,"journal":{"name":"2009 IEEE International Conference on Microwaves, Communications, Antennas and Electronics Systems","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130749521","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-11-01DOI: 10.1109/COMCAS.2009.5386077
R. Tomar, P. Bhartia
The accuracy of well-known commercially available 3D electromagnetic simulation tools has been examined through designing, building, and testing several original Microwave Integrated Circuits. It turns out that the accuracy of the tools considered is acceptable for most practical purposes, for frequencies up to 3GHz (upper limit of our investigation).
{"title":"The use of 3D electromagnetic simulation tools in the design of Microwave Integrated Circuits: An accuracy assessment","authors":"R. Tomar, P. Bhartia","doi":"10.1109/COMCAS.2009.5386077","DOIUrl":"https://doi.org/10.1109/COMCAS.2009.5386077","url":null,"abstract":"The accuracy of well-known commercially available 3D electromagnetic simulation tools has been examined through designing, building, and testing several original Microwave Integrated Circuits. It turns out that the accuracy of the tools considered is acceptable for most practical purposes, for frequencies up to 3GHz (upper limit of our investigation).","PeriodicalId":372928,"journal":{"name":"2009 IEEE International Conference on Microwaves, Communications, Antennas and Electronics Systems","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133006187","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-11-01DOI: 10.1109/COMCAS.2009.5386015
Yan Li, Dongri Meng, Jerry Lopez, D. Lie, Kevin Chen, Stanley Wu, T. Yang
A decresting algorithm for mobile WiMAX has been developed using time domain clipping and filtering processes for a polar transmitter (TX) using Envelope-Tracking (ET) and a monolithic SiGe power amplifier (PA). RF/Analog/Digital system and circuits co-design simulations have been performed for mobile WiMAX with 64 QAM OFDM modulation format. It is found that higher power-to-average ratio (PAR) decresting can improve the adjacent channel power ratio (ACPR) and the overall TX system efficiency, but at the cost of its EVM degradation. Our system simulations show that careful design of signal decresting can improve the overall polar TX system efficiency from 28.1% to 30.3% while the TX output can still meet the stringent WiMAX TX mask and EVM specs.
{"title":"A de-cresting technique for polar transmitters using Envelope-Tracking (ET) and SiGe power amplifiers for mobile-WiMAX","authors":"Yan Li, Dongri Meng, Jerry Lopez, D. Lie, Kevin Chen, Stanley Wu, T. Yang","doi":"10.1109/COMCAS.2009.5386015","DOIUrl":"https://doi.org/10.1109/COMCAS.2009.5386015","url":null,"abstract":"A decresting algorithm for mobile WiMAX has been developed using time domain clipping and filtering processes for a polar transmitter (TX) using Envelope-Tracking (ET) and a monolithic SiGe power amplifier (PA). RF/Analog/Digital system and circuits co-design simulations have been performed for mobile WiMAX with 64 QAM OFDM modulation format. It is found that higher power-to-average ratio (PAR) decresting can improve the adjacent channel power ratio (ACPR) and the overall TX system efficiency, but at the cost of its EVM degradation. Our system simulations show that careful design of signal decresting can improve the overall polar TX system efficiency from 28.1% to 30.3% while the TX output can still meet the stringent WiMAX TX mask and EVM specs.","PeriodicalId":372928,"journal":{"name":"2009 IEEE International Conference on Microwaves, Communications, Antennas and Electronics Systems","volume":"42 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132266916","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-11-01DOI: 10.1109/COMCAS.2009.5386041
Inbal Gronich
The proposed antenna is a small ultra-wideband antenna with an omni-directional pattern in the azimuth plane and with two lobes tilted several degrees from the horizon in the elevation plane. The antenna is a biconical antenna consisting of two cones in which the differences in their diameter determine the tilt of the pattern. The antenna has a unique shape, having a half sphere placed above the top cone's base. A frequency band of two octaves was realized. Simulations and measurements were performed by locating the antenna above a flat finite ground plane. There was a good match between the simulations and the measurements. Further work will be done to determine the effect of a radome on the antenna's performance.
{"title":"Omni directional ultra wideband asymmetric biconical antenna","authors":"Inbal Gronich","doi":"10.1109/COMCAS.2009.5386041","DOIUrl":"https://doi.org/10.1109/COMCAS.2009.5386041","url":null,"abstract":"The proposed antenna is a small ultra-wideband antenna with an omni-directional pattern in the azimuth plane and with two lobes tilted several degrees from the horizon in the elevation plane. The antenna is a biconical antenna consisting of two cones in which the differences in their diameter determine the tilt of the pattern. The antenna has a unique shape, having a half sphere placed above the top cone's base. A frequency band of two octaves was realized. Simulations and measurements were performed by locating the antenna above a flat finite ground plane. There was a good match between the simulations and the measurements. Further work will be done to determine the effect of a radome on the antenna's performance.","PeriodicalId":372928,"journal":{"name":"2009 IEEE International Conference on Microwaves, Communications, Antennas and Electronics Systems","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127858747","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-11-01DOI: 10.1109/COMCAS.2009.5385986
L. Felman, A. Sofer, H. Matzner
A microstrip circuit is matched by using three parasitic elements, where by "parasitic" we mean that there is no physical connection between the matching elements and the main circuit. A 1:2 microstrip divider is used as an example, for which two parasitic elements are located on the output strips of the divider and a single matching element is located on the input strip. The divider was simulated and measured, showing a very good level of matching quality, as well as very good agreement between simulation and measurement.
{"title":"Impedance matching using 3 parasitic elements","authors":"L. Felman, A. Sofer, H. Matzner","doi":"10.1109/COMCAS.2009.5385986","DOIUrl":"https://doi.org/10.1109/COMCAS.2009.5385986","url":null,"abstract":"A microstrip circuit is matched by using three parasitic elements, where by \"parasitic\" we mean that there is no physical connection between the matching elements and the main circuit. A 1:2 microstrip divider is used as an example, for which two parasitic elements are located on the output strips of the divider and a single matching element is located on the input strip. The divider was simulated and measured, showing a very good level of matching quality, as well as very good agreement between simulation and measurement.","PeriodicalId":372928,"journal":{"name":"2009 IEEE International Conference on Microwaves, Communications, Antennas and Electronics Systems","volume":"44 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125515915","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-11-01DOI: 10.1109/COMCAS.2009.5385961
Shefali Saxena, Shikha Porwal, Komal Soni, P. Chhawchharia, S. Koul
This paper reports analysis and design of bandstop filter utilizing E-shaped dual mode resonator. The basic structure of the bandstop filter consists of E-shaped resonator parallel to microstrip transmission line and an open stub inverter. Parametric analysis is carried out using Micro-Stripes software and the design is optimized to get stop band with high rejection level at 6 GHz centre frequency. Simulated and measured results of both single and double dual mode resonator bandstop filters are presented. Simulations of the bandstop filter using both edge-coupled and the side- coupled resonators are also reported. No significant improvement in the characteristics of bandstop filters using edge-coupled design was observed. However, side-coupled design showed remarkable improvement in the stop band characteristics as compared with the single resonator bandstop filter. The experimental and simulated results presented show good agreement.
{"title":"Analysis and design of bandstop filter using E-shaped dual mode resonator","authors":"Shefali Saxena, Shikha Porwal, Komal Soni, P. Chhawchharia, S. Koul","doi":"10.1109/COMCAS.2009.5385961","DOIUrl":"https://doi.org/10.1109/COMCAS.2009.5385961","url":null,"abstract":"This paper reports analysis and design of bandstop filter utilizing E-shaped dual mode resonator. The basic structure of the bandstop filter consists of E-shaped resonator parallel to microstrip transmission line and an open stub inverter. Parametric analysis is carried out using Micro-Stripes software and the design is optimized to get stop band with high rejection level at 6 GHz centre frequency. Simulated and measured results of both single and double dual mode resonator bandstop filters are presented. Simulations of the bandstop filter using both edge-coupled and the side- coupled resonators are also reported. No significant improvement in the characteristics of bandstop filters using edge-coupled design was observed. However, side-coupled design showed remarkable improvement in the stop band characteristics as compared with the single resonator bandstop filter. The experimental and simulated results presented show good agreement.","PeriodicalId":372928,"journal":{"name":"2009 IEEE International Conference on Microwaves, Communications, Antennas and Electronics Systems","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126693242","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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