The authors illustrate the application of multicriteria optimization technique to the synthesis of broadband microwave absorptive coatings. For many applications, the problem of designing a coating involves a tradeoff between conflicting goals, namely those of minimizing the total coating thickness while achieving maximum absorption. The authors propose a continuation of the work of Michielssen et al. (in press), by incorporating, within the genetic algorithm, a mechanism for investigating the tradeoff between coating thickness and absorption, by using the concepts of Pareto-optimality. Numerical results are presented.<>
{"title":"Pareto-optimal design of broadband microwave absorbers using genetic algorithms","authors":"E. Michielssen, J.M. Sajer, R. Mittra","doi":"10.1109/APS.1993.385141","DOIUrl":"https://doi.org/10.1109/APS.1993.385141","url":null,"abstract":"The authors illustrate the application of multicriteria optimization technique to the synthesis of broadband microwave absorptive coatings. For many applications, the problem of designing a coating involves a tradeoff between conflicting goals, namely those of minimizing the total coating thickness while achieving maximum absorption. The authors propose a continuation of the work of Michielssen et al. (in press), by incorporating, within the genetic algorithm, a mechanism for investigating the tradeoff between coating thickness and absorption, by using the concepts of Pareto-optimality. Numerical results are presented.<<ETX>>","PeriodicalId":138141,"journal":{"name":"Proceedings of IEEE Antennas and Propagation Society International Symposium","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115987817","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}
The author provides an overview of the use of both endogenous and exogenous electromagnetic fields in medical diagnostics, with particular emphasis on signals recorded from the brain and the problems inherent in source localization. Particular attention is given to the electroencephalogram and event-related responses.<>
{"title":"The use of electromagnetic fields in medical diagnostics","authors":"S. Baumann","doi":"10.1109/APS.1993.385290","DOIUrl":"https://doi.org/10.1109/APS.1993.385290","url":null,"abstract":"The author provides an overview of the use of both endogenous and exogenous electromagnetic fields in medical diagnostics, with particular emphasis on signals recorded from the brain and the problems inherent in source localization. Particular attention is given to the electroencephalogram and event-related responses.<<ETX>>","PeriodicalId":138141,"journal":{"name":"Proceedings of IEEE Antennas and Propagation Society International Symposium","volume":"829 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116422231","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}
Adaptive nulling in an array-fed offset paraboloidal reflector is considered. A narrow band system is assumed. It is also assumed that the signals received from the array feed can be weighted in both amplitude and phase and then summed to form the array output. The particular adaptive nulling algorithm used here is the generalized sidelobe canceller. H-plane design, adapted, and quiescent patterns are presented.<>
{"title":"Adaptive nulling in hybrid antennas","authors":"R. Shore","doi":"10.1109/APS.1993.385442","DOIUrl":"https://doi.org/10.1109/APS.1993.385442","url":null,"abstract":"Adaptive nulling in an array-fed offset paraboloidal reflector is considered. A narrow band system is assumed. It is also assumed that the signals received from the array feed can be weighted in both amplitude and phase and then summed to form the array output. The particular adaptive nulling algorithm used here is the generalized sidelobe canceller. H-plane design, adapted, and quiescent patterns are presented.<<ETX>>","PeriodicalId":138141,"journal":{"name":"Proceedings of IEEE Antennas and Propagation Society International Symposium","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122317680","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}
Monostatic radar signature measurement data are compared to CADDSCAT synthetic predictions for a standard set of primitive and complex targets. Prediction accuracy is compared for temporal, spatial, and spectral signature accuracy. The limitations of the CADDSCAT asymptotic predictions are assessed. CADDSCAT's implementation of the PO (physical optics), ILDC (incremental length diffraction coefficient), and SBR (shooting and bouncing rays) prediction methods is shown to provide excellent first-order radar signature predictions for complex, electrically large targets. The target measurements used have highlighted the limitation of PO-only predictions. The extension of the PO predictions to specular predictions of dielectric-coated targets was validated.<>
{"title":"Radar signature validation by comparison to measured data","authors":"B.B. Halama, D.J. Andersh, A. Terzuoli","doi":"10.1109/APS.1993.385457","DOIUrl":"https://doi.org/10.1109/APS.1993.385457","url":null,"abstract":"Monostatic radar signature measurement data are compared to CADDSCAT synthetic predictions for a standard set of primitive and complex targets. Prediction accuracy is compared for temporal, spatial, and spectral signature accuracy. The limitations of the CADDSCAT asymptotic predictions are assessed. CADDSCAT's implementation of the PO (physical optics), ILDC (incremental length diffraction coefficient), and SBR (shooting and bouncing rays) prediction methods is shown to provide excellent first-order radar signature predictions for complex, electrically large targets. The target measurements used have highlighted the limitation of PO-only predictions. The extension of the PO predictions to specular predictions of dielectric-coated targets was validated.<<ETX>>","PeriodicalId":138141,"journal":{"name":"Proceedings of IEEE Antennas and Propagation Society International Symposium","volume":"102 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122450392","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}
A novel implementation of a Luneburg lens has been developed to feed a circular array which can potentially radiate 36 simultaneous beams of 10/spl deg/ beamwidth. The Luneburg lens provides full 360/spl deg/ coverage and perfect focus. The motivation for this work comes from a requirement of Telecom Australia to investigate multiple beam antennas with 360/spl deg/ azimuth coverage as potential base station antennas in a cellular mobile telephone system in the frequency band of 825-896 MHz.<>
{"title":"A novel Luneburg lens feed for multiple beam antennas","authors":"M.J. Goonan, W. Davies","doi":"10.1109/APS.1993.385510","DOIUrl":"https://doi.org/10.1109/APS.1993.385510","url":null,"abstract":"A novel implementation of a Luneburg lens has been developed to feed a circular array which can potentially radiate 36 simultaneous beams of 10/spl deg/ beamwidth. The Luneburg lens provides full 360/spl deg/ coverage and perfect focus. The motivation for this work comes from a requirement of Telecom Australia to investigate multiple beam antennas with 360/spl deg/ azimuth coverage as potential base station antennas in a cellular mobile telephone system in the frequency band of 825-896 MHz.<<ETX>>","PeriodicalId":138141,"journal":{"name":"Proceedings of IEEE Antennas and Propagation Society International Symposium","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122703117","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}
A new electromagnetic modeling activity has been carried out resulting in a significant improvement in the design and optimization capability of a feed system consisting of horn connected to an ortho-mode-transducer (OMT). The tools for the analysis of the horn, the OMT, and their combination, resulting in an integral analysis of the feed system, are described. The adopted approach is suitable for the extension of the analysis to waveguide structures, like matching networks, typical of a feed system. Some of the analytical results are supported by experimental results. The recent development of two methods for analysis of the OMT is emphasized.<>
{"title":"Electromagnetic analysis of horn with ortho-mode transducer","authors":"G. Cazzatello, G. Figlia, C. Klooster, D. Savini","doi":"10.1109/APS.1993.385315","DOIUrl":"https://doi.org/10.1109/APS.1993.385315","url":null,"abstract":"A new electromagnetic modeling activity has been carried out resulting in a significant improvement in the design and optimization capability of a feed system consisting of horn connected to an ortho-mode-transducer (OMT). The tools for the analysis of the horn, the OMT, and their combination, resulting in an integral analysis of the feed system, are described. The adopted approach is suitable for the extension of the analysis to waveguide structures, like matching networks, typical of a feed system. Some of the analytical results are supported by experimental results. The recent development of two methods for analysis of the OMT is emphasized.<<ETX>>","PeriodicalId":138141,"journal":{"name":"Proceedings of IEEE Antennas and Propagation Society International Symposium","volume":"340 ","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114051802","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}
In order to obtain the solutions of the scattering field for large and complex bodies, a formula is derived from the Stratton-Chu integral equation under conditions of high-frequency, far-field, and the physical optics approximation. When calculating the surface integral, the impedance surfaces are divided into a large number of surface elements. These small grids are approximated by planar elements. the scattering field of the planar elements is expressed as an algebraic sum, so that the time-consuming integral operation can be avoided. The advantages of this method are simplicity and high speed. Numerical results on a coated plate and sphere show the validity of the method.<>
{"title":"Computation of scattering field for impedance coated bodies","authors":"M. Guo-zhong","doi":"10.1109/APS.1993.385390","DOIUrl":"https://doi.org/10.1109/APS.1993.385390","url":null,"abstract":"In order to obtain the solutions of the scattering field for large and complex bodies, a formula is derived from the Stratton-Chu integral equation under conditions of high-frequency, far-field, and the physical optics approximation. When calculating the surface integral, the impedance surfaces are divided into a large number of surface elements. These small grids are approximated by planar elements. the scattering field of the planar elements is expressed as an algebraic sum, so that the time-consuming integral operation can be avoided. The advantages of this method are simplicity and high speed. Numerical results on a coated plate and sphere show the validity of the method.<<ETX>>","PeriodicalId":138141,"journal":{"name":"Proceedings of IEEE Antennas and Propagation Society International Symposium","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114441371","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}
The equivalence principle and the generalized network formulation are used to model the tangential electric field of arbitrary apertures backed by a rectangular waveguide or cavity, in terms of equivalent magnetic currents. The result is an integral equation for the unknown aperture current. This integral equation is then reduced to a matrix equation using the method of moments. Specifically, the numerical technique is applied to end- and center-loaded slot antenna configurations backed by a rectangular waveguide.<>
{"title":"Numerical investigation of end- and centre-loaded slots","authors":"H. Moheb, L. Shafai, J. Shaker","doi":"10.1109/APS.1993.385172","DOIUrl":"https://doi.org/10.1109/APS.1993.385172","url":null,"abstract":"The equivalence principle and the generalized network formulation are used to model the tangential electric field of arbitrary apertures backed by a rectangular waveguide or cavity, in terms of equivalent magnetic currents. The result is an integral equation for the unknown aperture current. This integral equation is then reduced to a matrix equation using the method of moments. Specifically, the numerical technique is applied to end- and center-loaded slot antenna configurations backed by a rectangular waveguide.<<ETX>>","PeriodicalId":138141,"journal":{"name":"Proceedings of IEEE Antennas and Propagation Society International Symposium","volume":"11 2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116821147","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}
To enable the use of the FFT (fast Fourier transform) in connection with the tetrahedral edge-based finite element-boundary integral formulation the authors propose a new approach for combining finite element and boundary integral matrices. This approach makes use of the space transformation concept to map the irregular gridding onto a fictitious regular one. Since the transformation matrix is highly sparse and may be obtained in the preprocessing phase, no additional memory is required aside from that needed for the implementation of the FFT.<>
{"title":"Analysis of nonrectangular cavity-backed patch antennas using edge-based hybrid finite element method with BiCG-FFT solver","authors":"J. Gong, J. Volakis","doi":"10.1109/APS.1993.385189","DOIUrl":"https://doi.org/10.1109/APS.1993.385189","url":null,"abstract":"To enable the use of the FFT (fast Fourier transform) in connection with the tetrahedral edge-based finite element-boundary integral formulation the authors propose a new approach for combining finite element and boundary integral matrices. This approach makes use of the space transformation concept to map the irregular gridding onto a fictitious regular one. Since the transformation matrix is highly sparse and may be obtained in the preprocessing phase, no additional memory is required aside from that needed for the implementation of the FFT.<<ETX>>","PeriodicalId":138141,"journal":{"name":"Proceedings of IEEE Antennas and Propagation Society International Symposium","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129771648","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}
A study has been performed to demonstrate the efficiency of adaptive signal processing for NAVSTAR/GPS (Global Positioning System) signal reception in a jamming ECM (electronic countermeasures) environment. The role of an adaptive antenna for such a system is to increase the signal to noise plus interference ratio (SNIR) to a power sufficient for most commercially available GPS receptors. The GPS signal reception power is about -160 dBm at the antennas. The analog LMS (least mean square) algorithm has been chosen for its highspeed/simplicity and lowcost trade-off. Test show good results: 64 dB SNIR enhancement in less than 300 /spl mu/s. Practical implementation of the LMS algorithm leads to experimental results that agree with the numerical simulation predictions.<>
{"title":"An adaptative array processor using the analog L.M.S. algorithm: An efficient solution for a N.A.V.S.T.A.R./G.P.S. application","authors":"J. Milin, C. Terret, J.F. Diouris, J. Saillard","doi":"10.1109/APS.1993.385256","DOIUrl":"https://doi.org/10.1109/APS.1993.385256","url":null,"abstract":"A study has been performed to demonstrate the efficiency of adaptive signal processing for NAVSTAR/GPS (Global Positioning System) signal reception in a jamming ECM (electronic countermeasures) environment. The role of an adaptive antenna for such a system is to increase the signal to noise plus interference ratio (SNIR) to a power sufficient for most commercially available GPS receptors. The GPS signal reception power is about -160 dBm at the antennas. The analog LMS (least mean square) algorithm has been chosen for its highspeed/simplicity and lowcost trade-off. Test show good results: 64 dB SNIR enhancement in less than 300 /spl mu/s. Practical implementation of the LMS algorithm leads to experimental results that agree with the numerical simulation predictions.<<ETX>>","PeriodicalId":138141,"journal":{"name":"Proceedings of IEEE Antennas and Propagation Society International Symposium","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128286498","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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