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":null,"pages":null},"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 authors describe the eight different types of antennas on the INTELSAT VII spacecraft. These antennas are: (1) C-band hemi/zone antennas, (2) C-band spot antenna, (3) Ku-band spot antennas, (4) C-band global antenna, (5) Ku-band beacon antenna, (6) C-band beacon antenna, (7) omni telemetry tracking and control antennas, and (8) telemetry directional antenna. All antennas are located on the earth panel of the satellite except the hemi/zone antennas, which are on the east and west sides of the spacecraft. All antennas have a clear view of earth with 'stay-away' regions to eliminate any scattering-related performance degradation.<>
{"title":"INTELSAT VII spacecraft antennas","authors":"L. Ersoy, G. Schennum","doi":"10.1109/APS.1989.134727","DOIUrl":"https://doi.org/10.1109/APS.1989.134727","url":null,"abstract":"The authors describe the eight different types of antennas on the INTELSAT VII spacecraft. These antennas are: (1) C-band hemi/zone antennas, (2) C-band spot antenna, (3) Ku-band spot antennas, (4) C-band global antenna, (5) Ku-band beacon antenna, (6) C-band beacon antenna, (7) omni telemetry tracking and control antennas, and (8) telemetry directional antenna. All antennas are located on the earth panel of the satellite except the hemi/zone antennas, which are on the east and west sides of the spacecraft. All antennas have a clear view of earth with 'stay-away' regions to eliminate any scattering-related performance degradation.<<ETX>>","PeriodicalId":11330,"journal":{"name":"Digest on Antennas and Propagation Society International Symposium","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1989-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80932912","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}
Describes a numerical optimization procedure based on the Powell (1965) nonlinear regression algorithm for measuring the complex dielectric constant of radome composite materials and coatings at millimeter wavelengths using free-space measurements of the transmission coefficient over a range of incidence angles and frequencies. Radomes usually need rain-erosion, antistatic, and hydrophobic coatings for environmental protection. In the present approach, the determination of the permittivity of these thin radome coatings is achieved by depositing the coating on a substrate of known dielectric constant and analyzing the transmission coefficient of the two-layer medium. Since the regression algorithm is used to analyze a large number of data points, it reduces the random errors in the experiments and yields more accurate information than the single-point free-space measurement methods used by other authors at millimeter wavelengths. The validity and accuracy of this technique were confirmed by making measurements on standard dielectrics such as polyethylene, nylon, and Teflon.<>
{"title":"Free-space millimeter-wave measurement of the complex dielectric constant of radome materials using nonlinear least-squares analysis","authors":"B. R. Rao","doi":"10.1109/APS.1989.135014","DOIUrl":"https://doi.org/10.1109/APS.1989.135014","url":null,"abstract":"Describes a numerical optimization procedure based on the Powell (1965) nonlinear regression algorithm for measuring the complex dielectric constant of radome composite materials and coatings at millimeter wavelengths using free-space measurements of the transmission coefficient over a range of incidence angles and frequencies. Radomes usually need rain-erosion, antistatic, and hydrophobic coatings for environmental protection. In the present approach, the determination of the permittivity of these thin radome coatings is achieved by depositing the coating on a substrate of known dielectric constant and analyzing the transmission coefficient of the two-layer medium. Since the regression algorithm is used to analyze a large number of data points, it reduces the random errors in the experiments and yields more accurate information than the single-point free-space measurement methods used by other authors at millimeter wavelengths. The validity and accuracy of this technique were confirmed by making measurements on standard dielectrics such as polyethylene, nylon, and Teflon.<<ETX>>","PeriodicalId":11330,"journal":{"name":"Digest on Antennas and Propagation Society International Symposium","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1989-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78359467","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}
Designing horn clusters for contoured beam antennas on board satellites (e.g. the ATLANTIS antenna) requires an accurate simulation of the copolar and cross-polar components of their field patterns. This simulation should include mutual couplings between horns and a suitable modeling of the horns' surroundings. The field pattern obtained with conical horns that open in a finite metallic plate is presented and compared with measurements. The proposed model uses a numerical integration procedure to calculate the mutual coupling between the different horn modes and to compute the radiated patterns and GTD to include the finite plate. This procedure makes it possible to analyze any type of horn (with analytic modes) placed on a conducting plate which is either polygonal or circular. The results obtained using cylindrical horns provide a better prediction than does a simple model without GTD.<>
{"title":"Aperture radiation analysis including plane finiteness and mutual coupling","authors":"L. de Haro, J. Besada","doi":"10.1109/APS.1989.135024","DOIUrl":"https://doi.org/10.1109/APS.1989.135024","url":null,"abstract":"Designing horn clusters for contoured beam antennas on board satellites (e.g. the ATLANTIS antenna) requires an accurate simulation of the copolar and cross-polar components of their field patterns. This simulation should include mutual couplings between horns and a suitable modeling of the horns' surroundings. The field pattern obtained with conical horns that open in a finite metallic plate is presented and compared with measurements. The proposed model uses a numerical integration procedure to calculate the mutual coupling between the different horn modes and to compute the radiated patterns and GTD to include the finite plate. This procedure makes it possible to analyze any type of horn (with analytic modes) placed on a conducting plate which is either polygonal or circular. The results obtained using cylindrical horns provide a better prediction than does a simple model without GTD.<<ETX>>","PeriodicalId":11330,"journal":{"name":"Digest on Antennas and Propagation Society International Symposium","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1989-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78820731","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 corner diffraction formula is derived by evaluating asymptotically the radiation integral using the equivalent edge current. Unlike the original equivalent current method, the equivalent edge current used here is in terms of the uniform general theory of diffraction (GTD) instead of Keller's GTD, and the result is uniformly continuous through the entire far-field region. A computation example is given to confirm the validity of the formula. A 1/4 lambda monopole located at the center of a square perfectly conducting plate was considered. Both in the diagonal plane and in the y-z plane, good agreement of the computed pattern with the measured one was achieved.<>
{"title":"A corner diffraction formula","authors":"X. Zhang, N. Inagaki, N. Kikuma","doi":"10.1109/APS.1989.134947","DOIUrl":"https://doi.org/10.1109/APS.1989.134947","url":null,"abstract":"A corner diffraction formula is derived by evaluating asymptotically the radiation integral using the equivalent edge current. Unlike the original equivalent current method, the equivalent edge current used here is in terms of the uniform general theory of diffraction (GTD) instead of Keller's GTD, and the result is uniformly continuous through the entire far-field region. A computation example is given to confirm the validity of the formula. A 1/4 lambda monopole located at the center of a square perfectly conducting plate was considered. Both in the diagonal plane and in the y-z plane, good agreement of the computed pattern with the measured one was achieved.<<ETX>>","PeriodicalId":11330,"journal":{"name":"Digest on Antennas and Propagation Society International Symposium","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1989-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76191089","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}
An efficient method is developed for the study of a grid of hexagonal meshes. An efficient grid of hexagonal meshes is envisaged where four-wire crosses in a rectangular mesh are replaced by symmetrical three-wire stars. After the current of a wire grid has been enumerated, the scattered field can be determined. The transmission through the screen or the reflection from the screen can then be evaluated by adding the incident field and the scattered field. Pictures illustrating the hexagonal-mesh grid are shown.<>
{"title":"Scattering of electromagnetic waves by a wire grid of hexagonal meshes","authors":"E. Yung, C. Cheng","doi":"10.1109/APS.1989.134793","DOIUrl":"https://doi.org/10.1109/APS.1989.134793","url":null,"abstract":"An efficient method is developed for the study of a grid of hexagonal meshes. An efficient grid of hexagonal meshes is envisaged where four-wire crosses in a rectangular mesh are replaced by symmetrical three-wire stars. After the current of a wire grid has been enumerated, the scattered field can be determined. The transmission through the screen or the reflection from the screen can then be evaluated by adding the incident field and the scattered field. Pictures illustrating the hexagonal-mesh grid are shown.<<ETX>>","PeriodicalId":11330,"journal":{"name":"Digest on Antennas and Propagation Society International Symposium","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1989-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78675025","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 boundary integral equation method for the analysis of stripline and microstrip lenses is presented. The field distributions across the port apertures surrounding the lens's cavity are described by a contour integral that satisfies the wave equation in the planar lens cavity. All mutual couplings and hence internal reflections between ports are taken into account. The model is used to predict the performance of a nonoptimal Rotman lens with 8 input ports and 20 output ports. There is a good agreement with the measured results for both port coupling and match.<>
{"title":"Planar waveguide model of Rotman lens","authors":"K.K. Chan","doi":"10.1109/APS.1989.134772","DOIUrl":"https://doi.org/10.1109/APS.1989.134772","url":null,"abstract":"A boundary integral equation method for the analysis of stripline and microstrip lenses is presented. The field distributions across the port apertures surrounding the lens's cavity are described by a contour integral that satisfies the wave equation in the planar lens cavity. All mutual couplings and hence internal reflections between ports are taken into account. The model is used to predict the performance of a nonoptimal Rotman lens with 8 input ports and 20 output ports. There is a good agreement with the measured results for both port coupling and match.<<ETX>>","PeriodicalId":11330,"journal":{"name":"Digest on Antennas and Propagation Society International Symposium","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1989-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74031341","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}
H. Zebker, D. Held, J. V. Zyl, P. Dubois, L. Norikane
The authors derive an algorithm to reduce required storage space for multipolarimetric synthetic aperture radar data which preserves signal integrity. The data reduction operation reduces the required storage by 12.8. The image synthesis process applied to a reduced data set can be applied to a standard image in two minutes on a VAX 785 when the compressed data format is used. This is ten times faster than image synthesis of the corresponding original data, due to the smaller volume of the compressed data (10 Mb compared with 128 Mb per image). The errors introduced in the output images are on the order of 10/sup -3/. Thus, operations with polarimetric data are greatly facilitated and are now within reach of small research groups.<>
{"title":"Data volume reduction for imaging radar polarimeter","authors":"H. Zebker, D. Held, J. V. Zyl, P. Dubois, L. Norikane","doi":"10.1109/APS.1989.134964","DOIUrl":"https://doi.org/10.1109/APS.1989.134964","url":null,"abstract":"The authors derive an algorithm to reduce required storage space for multipolarimetric synthetic aperture radar data which preserves signal integrity. The data reduction operation reduces the required storage by 12.8. The image synthesis process applied to a reduced data set can be applied to a standard image in two minutes on a VAX 785 when the compressed data format is used. This is ten times faster than image synthesis of the corresponding original data, due to the smaller volume of the compressed data (10 Mb compared with 128 Mb per image). The errors introduced in the output images are on the order of 10/sup -3/. Thus, operations with polarimetric data are greatly facilitated and are now within reach of small research groups.<<ETX>>","PeriodicalId":11330,"journal":{"name":"Digest on Antennas and Propagation Society International Symposium","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1989-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74364951","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 closed-form geodesic constant method (GCM) is developed to model the ray-geometric aspects of conformal arrays on QUACYLs (quadric cylinders). The formulation incorporates a shaping parameter, permitting the modeling of surfaces of different sharpness. Mutual coupling results for the general parabolic cylinder are presented to illustrate the application of the formulation.<>
{"title":"Closed form evaluation of element coupling coefficients ion conformal arrays on general quadric cylinders","authors":"R. Jha, S. Bokhari, V. Sudhakar, P. Mahapatra","doi":"10.1109/APS.1989.134868","DOIUrl":"https://doi.org/10.1109/APS.1989.134868","url":null,"abstract":"A closed-form geodesic constant method (GCM) is developed to model the ray-geometric aspects of conformal arrays on QUACYLs (quadric cylinders). The formulation incorporates a shaping parameter, permitting the modeling of surfaces of different sharpness. Mutual coupling results for the general parabolic cylinder are presented to illustrate the application of the formulation.<<ETX>>","PeriodicalId":11330,"journal":{"name":"Digest on Antennas and Propagation Society International Symposium","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1989-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75421630","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}
It is shown that by using the BEM (boundary-element method), it is possible to compute the whole-angle radiation patterns of offset cylindrical reflector antennas with aperture blockage. Consideration is given to a circular cylinder loaded near the aperture of a small offset cylindrical reflector antenna as the blocking model. The overall radiation patterns, including the strut-scattering effects, are predicted by using the BEM and compared with measured patterns (at a frequency of 8 GHz) for verification. Although there appears to be some differences of levels at some wide-angle regions (due probably to a misalignment or measuring setup errors), the entire radiation pattern is found to be well predicted by the numerical data, thus proving the validity of the method.<>
{"title":"An overall azimuthal pattern computation of blocked cylindrical reflector antennas","authors":"K. Miyata, I. Fukai","doi":"10.1109/APS.1989.134922","DOIUrl":"https://doi.org/10.1109/APS.1989.134922","url":null,"abstract":"It is shown that by using the BEM (boundary-element method), it is possible to compute the whole-angle radiation patterns of offset cylindrical reflector antennas with aperture blockage. Consideration is given to a circular cylinder loaded near the aperture of a small offset cylindrical reflector antenna as the blocking model. The overall radiation patterns, including the strut-scattering effects, are predicted by using the BEM and compared with measured patterns (at a frequency of 8 GHz) for verification. Although there appears to be some differences of levels at some wide-angle regions (due probably to a misalignment or measuring setup errors), the entire radiation pattern is found to be well predicted by the numerical data, thus proving the validity of the method.<<ETX>>","PeriodicalId":11330,"journal":{"name":"Digest on Antennas and Propagation Society International Symposium","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1989-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75767744","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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