Mutual coupling results between individual elements in a conformal phased array on a general paraboloid of revolution are presented. The formulation presented yields all the surface ray geometric parameters required in the ray analysis in explicit one-parameter form. The parameter involved is the first geodesic constant h, whose determination involves a simple univariate search.<>
{"title":"Analytical evaluation of element coupling coefficients on general paraboloids of revolution (conformal phased array)","authors":"R. Jha, S. Bokhari, V. Sudhakar, P. Mahapatra","doi":"10.1109/APS.1989.134869","DOIUrl":"https://doi.org/10.1109/APS.1989.134869","url":null,"abstract":"Mutual coupling results between individual elements in a conformal phased array on a general paraboloid of revolution are presented. The formulation presented yields all the surface ray geometric parameters required in the ray analysis in explicit one-parameter form. The parameter involved is the first geodesic constant h, whose determination involves a simple univariate search.<<ETX>>","PeriodicalId":11330,"journal":{"name":"Digest on Antennas and Propagation Society International Symposium","volume":"17 1","pages":"1008-1011 vol.2"},"PeriodicalIF":0.0,"publicationDate":"1989-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82527992","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 computed and measured influences of a radome on both the input impedance and radiation pattern of an electromagnetically coupled dipole are described. The analysis proceeds from the integral equation technique solved by the moment method and associated with the simple one-port model. Return losses S/sub 11/ of electromagnetically coupled dipoles covered and uncovered by a radome are presented. As expected, with a radome a shift in the resonance frequency and also a degradation of the matching take place. Theoretical and experimental data agree within 0.3% for the frequency and 1.4% for the amplitude. Results show that the resonant frequency is shifted, the matching is significantly degraded, and the radiation pattern is not deeply altered.<>
{"title":"Radome effects on an electromagnetically coupled dipole","authors":"M. Gaouyer, J. Floch, J. Citerne","doi":"10.1109/APS.1989.134761","DOIUrl":"https://doi.org/10.1109/APS.1989.134761","url":null,"abstract":"The computed and measured influences of a radome on both the input impedance and radiation pattern of an electromagnetically coupled dipole are described. The analysis proceeds from the integral equation technique solved by the moment method and associated with the simple one-port model. Return losses S/sub 11/ of electromagnetically coupled dipoles covered and uncovered by a radome are presented. As expected, with a radome a shift in the resonance frequency and also a degradation of the matching take place. Theoretical and experimental data agree within 0.3% for the frequency and 1.4% for the amplitude. Results show that the resonant frequency is shifted, the matching is significantly degraded, and the radiation pattern is not deeply altered.<<ETX>>","PeriodicalId":11330,"journal":{"name":"Digest on Antennas and Propagation Society International Symposium","volume":"13 1","pages":"612-615 vol.2"},"PeriodicalIF":0.0,"publicationDate":"1989-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82662798","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 authors present an approach to the numerical modeling of three-dimensional scattering in conductive media. The particular class of problems of interest is that for which the conduction current is large enough that the displacement current may be neglected. The scattering objects of interest are those which are on the order of a skin depth in size. The approach is based on the unimoment method extended to scattering from arbitrary three-dimensional objects and conductive media. A flow diagram of the computational tasks which must be performed in order to generate a solution is presented.<>
{"title":"Numerical modeling of three dimensional scattering in conductive media","authors":"G. T. Shoemaker, L. Roemer","doi":"10.1109/APS.1989.134977","DOIUrl":"https://doi.org/10.1109/APS.1989.134977","url":null,"abstract":"The authors present an approach to the numerical modeling of three-dimensional scattering in conductive media. The particular class of problems of interest is that for which the conduction current is large enough that the displacement current may be neglected. The scattering objects of interest are those which are on the order of a skin depth in size. The approach is based on the unimoment method extended to scattering from arbitrary three-dimensional objects and conductive media. A flow diagram of the computational tasks which must be performed in order to generate a solution is presented.<<ETX>>","PeriodicalId":11330,"journal":{"name":"Digest on Antennas and Propagation Society International Symposium","volume":"206 1","pages":"1398-1401 vol.3"},"PeriodicalIF":0.0,"publicationDate":"1989-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89017269","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 authors have developed a spatial decomposition (SD) approach for the method of moments (MM) that shows substantial promise in reducing both the dimensionality and ill-conditioning of the computational burden. In fact, SD permits the maximum size of the MM system matrix that needs to be inverted to be strictly limited, regardless of the electrical size of the target being modeled. SD provides the means of implementing the combined-field surface-patching MM technique with a computer memory and execution time requirement of order M, where M is the number of spatial subzones. SD has been successfully applied to electrically large two-dimensional dielectric targets and three-dimensional conducting bodies of revolution.<>
{"title":"Spatial decomposition for the method of moments (EM field problems)","authors":"K. Umashankar, A. Taflove","doi":"10.1109/APS.1989.134751","DOIUrl":"https://doi.org/10.1109/APS.1989.134751","url":null,"abstract":"The authors have developed a spatial decomposition (SD) approach for the method of moments (MM) that shows substantial promise in reducing both the dimensionality and ill-conditioning of the computational burden. In fact, SD permits the maximum size of the MM system matrix that needs to be inverted to be strictly limited, regardless of the electrical size of the target being modeled. SD provides the means of implementing the combined-field surface-patching MM technique with a computer memory and execution time requirement of order M, where M is the number of spatial subzones. SD has been successfully applied to electrically large two-dimensional dielectric targets and three-dimensional conducting bodies of revolution.<<ETX>>","PeriodicalId":11330,"journal":{"name":"Digest on Antennas and Propagation Society International Symposium","volume":"7 1","pages":"576-577 vol.2"},"PeriodicalIF":0.0,"publicationDate":"1989-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89054679","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 design for a dual-reflector compact range system with axial-symmetric main reflector is proposed. The advantage of this design is that it provides a larger quiet zone area and reduces the manufacturing cost. The configuration consists of a large surface of revolution as primary mirror, and a conventional point-source spherical-wave feed. The point-source feed is located outside the column of parallel rays reflected from the primary mirror in the Z-axis. Using geometrical ray tracing, a subreflector contour can be generated. Since the proposed approach is based on the surface of revolution, either a paraboloid or a spherical surface can be chosen as the main reflector.<>
{"title":"Compact range design with axial-symmetric main reflector","authors":"D. Chang, S.-Y. Yang, M.-R. Ho","doi":"10.1109/APS.1989.134684","DOIUrl":"https://doi.org/10.1109/APS.1989.134684","url":null,"abstract":"A design for a dual-reflector compact range system with axial-symmetric main reflector is proposed. The advantage of this design is that it provides a larger quiet zone area and reduces the manufacturing cost. The configuration consists of a large surface of revolution as primary mirror, and a conventional point-source spherical-wave feed. The point-source feed is located outside the column of parallel rays reflected from the primary mirror in the Z-axis. Using geometrical ray tracing, a subreflector contour can be generated. Since the proposed approach is based on the surface of revolution, either a paraboloid or a spherical surface can be chosen as the main reflector.<<ETX>>","PeriodicalId":11330,"journal":{"name":"Digest on Antennas and Propagation Society International Symposium","volume":"122 1","pages":"328-331 vol.1"},"PeriodicalIF":0.0,"publicationDate":"1989-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88001203","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 authors present a study of the spectral properties of cascaded gratings whose individual gratings are placed at different angles with respect to each other at each different layer. The reflection and transmission profiles that result from such an arrangement are discussed and compared with the parallel arrangement. The special case of the unbonded mesh is compared with published data. Moreover, the effects of inserting dielectric slabs between the gratings in this type of cascaded structure are presented.<>
{"title":"Scattering from cascaded gratings with variable orientation at each layer","authors":"S. Shi, C. Christodoulou","doi":"10.1109/APS.1989.134884","DOIUrl":"https://doi.org/10.1109/APS.1989.134884","url":null,"abstract":"The authors present a study of the spectral properties of cascaded gratings whose individual gratings are placed at different angles with respect to each other at each different layer. The reflection and transmission profiles that result from such an arrangement are discussed and compared with the parallel arrangement. The special case of the unbonded mesh is compared with published data. Moreover, the effects of inserting dielectric slabs between the gratings in this type of cascaded structure are presented.<<ETX>>","PeriodicalId":11330,"journal":{"name":"Digest on Antennas and Propagation Society International Symposium","volume":"38 1","pages":"1064-1067 vol.2"},"PeriodicalIF":0.0,"publicationDate":"1989-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88341189","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 method is presented which reduces the complex scattering problem of objects buried inside a lossy ground to a simpler one for the solution of the standard magnetic-field integral equation and for determining the field of elementary sources located inside a lossy half-space. The scattering problem is formulated using both the electric-field integral equation and the magnetic-field integral equation unbounded region. Solutions are generated and numerical results are examined for a few limiting cases to confirm their accuracies. The method is then used to generate numerical results for fields at the interface over a buried spheroid.<>
{"title":"Scattering by a buried imperfectly conducting spheroid at low frequencies","authors":"A. Helaly, A. Sebak, L. Shafai","doi":"10.1109/APS.1989.134979","DOIUrl":"https://doi.org/10.1109/APS.1989.134979","url":null,"abstract":"A method is presented which reduces the complex scattering problem of objects buried inside a lossy ground to a simpler one for the solution of the standard magnetic-field integral equation and for determining the field of elementary sources located inside a lossy half-space. The scattering problem is formulated using both the electric-field integral equation and the magnetic-field integral equation unbounded region. Solutions are generated and numerical results are examined for a few limiting cases to confirm their accuracies. The method is then used to generate numerical results for fields at the interface over a buried spheroid.<<ETX>>","PeriodicalId":11330,"journal":{"name":"Digest on Antennas and Propagation Society International Symposium","volume":"36 1","pages":"1406-1409 vol.3"},"PeriodicalIF":0.0,"publicationDate":"1989-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89946035","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 overcome the limitations of previous methods (the spectral- and spatial-domain methods) for analyzing problems connected with the grounded double-layer (substrate-superstrate) configuration, the authors propose the use of an asymptotic closed-form representation of the spatial Green's function. This approach makes the mutual coupling computation extremely efficient and can be used even for relatively small lateral distances between source and observation points (usually down to a few tenths of the free-space wavelength). Numerical results are presented.<>
{"title":"An asymptotic closed-form representation for the substrate-superstrate Green's function (microstrip antennas)","authors":"M. Marin, P. Pathak","doi":"10.1109/APS.1989.135052","DOIUrl":"https://doi.org/10.1109/APS.1989.135052","url":null,"abstract":"In order to overcome the limitations of previous methods (the spectral- and spatial-domain methods) for analyzing problems connected with the grounded double-layer (substrate-superstrate) configuration, the authors propose the use of an asymptotic closed-form representation of the spatial Green's function. This approach makes the mutual coupling computation extremely efficient and can be used even for relatively small lateral distances between source and observation points (usually down to a few tenths of the free-space wavelength). Numerical results are presented.<<ETX>>","PeriodicalId":11330,"journal":{"name":"Digest on Antennas and Propagation Society International Symposium","volume":"167 1","pages":"1676-1679 vol.3"},"PeriodicalIF":0.0,"publicationDate":"1989-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90362912","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 key features of the TDRSS (tracking and data relay satellite system) antennas are presented. Descriptions are given of the multiple-access antenna, the two single-access antennas, the space-to-ground link antenna, and the omni antenna. Integration and tests are also discussed.<>
{"title":"TDRSS spacecraft antenna farm","authors":"G. Wong, S. Hamada, P. W. Low","doi":"10.1109/APS.1989.134732","DOIUrl":"https://doi.org/10.1109/APS.1989.134732","url":null,"abstract":"The key features of the TDRSS (tracking and data relay satellite system) antennas are presented. Descriptions are given of the multiple-access antenna, the two single-access antennas, the space-to-ground link antenna, and the omni antenna. Integration and tests are also discussed.<<ETX>>","PeriodicalId":11330,"journal":{"name":"Digest on Antennas and Propagation Society International Symposium","volume":"1 1","pages":"507-510 vol.1"},"PeriodicalIF":0.0,"publicationDate":"1989-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84041585","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}
Using an approximate synthesis procedure, a practical undersized backfire antenna (BFA) with a nonuniform corrugated rod structure was developed. Many backfire antenna designs with synthesized corrugated surface-wave rods were manufactured and tested. A comparison between the parameters of two long backfire antennas having the same basic dimensions but differing in the surface-wave (SW) structures (uniform and modulated) is presented. It is found that a BFA with a synthesized nonuniform SW structure has an optimum directivity. An undersized backfire antenna with a nonuniform corrugated rod designed for an optimum frequency of 2.0 GHz is described.<>
{"title":"Undersized long backfire antenna","authors":"H. Hristov, G. Kirov, J. Urumov","doi":"10.1109/APS.1989.134972","DOIUrl":"https://doi.org/10.1109/APS.1989.134972","url":null,"abstract":"Using an approximate synthesis procedure, a practical undersized backfire antenna (BFA) with a nonuniform corrugated rod structure was developed. Many backfire antenna designs with synthesized corrugated surface-wave rods were manufactured and tested. A comparison between the parameters of two long backfire antennas having the same basic dimensions but differing in the surface-wave (SW) structures (uniform and modulated) is presented. It is found that a BFA with a synthesized nonuniform SW structure has an optimum directivity. An undersized backfire antenna with a nonuniform corrugated rod designed for an optimum frequency of 2.0 GHz is described.<<ETX>>","PeriodicalId":11330,"journal":{"name":"Digest on Antennas and Propagation Society International Symposium","volume":"10 1","pages":"1382-1385 vol.3"},"PeriodicalIF":0.0,"publicationDate":"1989-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86048991","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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