B. Roma Rao, D.N. Jones, R. Davis, R. Vessey, T. Engbring, Z.V. Moseley
The authors describe the analysis that was conducted using the NEC3-method of moments code to predict the input impedance and far-field patterns of two types of HF antennas for the US Coast Guard HH-60J helicopter. The operating frequencies for these antennas are 3.123, 5.696 (primary frequency), 8.984 (secondary frequency), 11.201, and 15.084 MHz. The calculated results have been validated by comparison with measurements on the real helicopter as well as on a 1:7.5 scaled down model of the helicopter. The impact of tuning reactance on the radiation efficiency of the antennas, as well as the relative performance of the two antennas for high angle sky wave and ground wave communications over mixed land and sea paths, has been investigated.<>
{"title":"Modelling and measurement of high frequency antennas for the U.S. Coast Guard HH-60J helicopter","authors":"B. Roma Rao, D.N. Jones, R. Davis, R. Vessey, T. Engbring, Z.V. Moseley","doi":"10.1109/APS.1993.385558","DOIUrl":"https://doi.org/10.1109/APS.1993.385558","url":null,"abstract":"The authors describe the analysis that was conducted using the NEC3-method of moments code to predict the input impedance and far-field patterns of two types of HF antennas for the US Coast Guard HH-60J helicopter. The operating frequencies for these antennas are 3.123, 5.696 (primary frequency), 8.984 (secondary frequency), 11.201, and 15.084 MHz. The calculated results have been validated by comparison with measurements on the real helicopter as well as on a 1:7.5 scaled down model of the helicopter. The impact of tuning reactance on the radiation efficiency of the antennas, as well as the relative performance of the two antennas for high angle sky wave and ground wave communications over mixed land and sea paths, has been investigated.<<ETX>>","PeriodicalId":138141,"journal":{"name":"Proceedings of IEEE Antennas and Propagation Society International Symposium","volume":"34 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":"116481243","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 radiating or receiving characteristics of array elements are changed from that of isolated elements due to the mutual coupling effects and the array performance becomes different from that originally designed by assuming isolated elements. In the present work, the effects of element pattern on the performance of a rectangular array with triangular geometry of dipoles above a ground plane are investigated. The concept of element gain function is used to examine the array performance in terms of mainbeam width and sidelobe level with respect to uniformly spaced and space-tapered arrays.<>
{"title":"Effects of element pattern on the performance of a rectangular array","authors":"B. Chang, B. Johnson","doi":"10.1109/APS.1993.385120","DOIUrl":"https://doi.org/10.1109/APS.1993.385120","url":null,"abstract":"The radiating or receiving characteristics of array elements are changed from that of isolated elements due to the mutual coupling effects and the array performance becomes different from that originally designed by assuming isolated elements. In the present work, the effects of element pattern on the performance of a rectangular array with triangular geometry of dipoles above a ground plane are investigated. The concept of element gain function is used to examine the array performance in terms of mainbeam width and sidelobe level with respect to uniformly spaced and space-tapered arrays.<<ETX>>","PeriodicalId":138141,"journal":{"name":"Proceedings of IEEE Antennas and Propagation Society International Symposium","volume":"125 1-3 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":"123575577","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 enhanced model for characterizing optically controlled dielectric resonators is presented. The practical details of the structure are taken into account including the light injection hole etched on the upper shielding metallic plate, the inhomogeneous distribution of the induced excess carrier concentrations due to surface recombination and diffusion, substrate surface waves, and radial radiation if the side wall is absent. In addition, the model allows the semiconductor sample and the dielectric rod to have different radii. The model is based on the dyadic Green's function in a cylindrical coordinate system in conjunction with the equivalence principle. The infinite integrals involved in the matrix elements of the resultant characteristic equation are completed by deforming the integral contour off the real k/sub /spl rho// axis to include the contribution due to the surface wave poles.<>
{"title":"Characteristics of optically controlled dielectric resonators with light injection hole","authors":"A. Rong, Z.L. Sun","doi":"10.1109/APS.1993.385482","DOIUrl":"https://doi.org/10.1109/APS.1993.385482","url":null,"abstract":"An enhanced model for characterizing optically controlled dielectric resonators is presented. The practical details of the structure are taken into account including the light injection hole etched on the upper shielding metallic plate, the inhomogeneous distribution of the induced excess carrier concentrations due to surface recombination and diffusion, substrate surface waves, and radial radiation if the side wall is absent. In addition, the model allows the semiconductor sample and the dielectric rod to have different radii. The model is based on the dyadic Green's function in a cylindrical coordinate system in conjunction with the equivalence principle. The infinite integrals involved in the matrix elements of the resultant characteristic equation are completed by deforming the integral contour off the real k/sub /spl rho// axis to include the contribution due to the surface wave poles.<<ETX>>","PeriodicalId":138141,"journal":{"name":"Proceedings of IEEE Antennas and Propagation Society International Symposium","volume":"112 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":"121959309","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 algorithm is presented for plotting the magnitude and direction of a vector field described over a triangular mesh. Once the critical points (zeros) of the vector field are found, the plotting procedure becomes a function of the paradigms of the viewer. The algorithm is developed for any three-dimensional surface represented by a triangular grid. The method uses color-shaded magnitude contours and directed vector lines to characterize a vector field. The algorithm was tested by plotting the far-zone field vector direction and magnitude.<>
{"title":"Visualizing the magnitude and direction of three-dimensional vector fields","authors":"T. Peters","doi":"10.1109/APS.1993.385152","DOIUrl":"https://doi.org/10.1109/APS.1993.385152","url":null,"abstract":"An algorithm is presented for plotting the magnitude and direction of a vector field described over a triangular mesh. Once the critical points (zeros) of the vector field are found, the plotting procedure becomes a function of the paradigms of the viewer. The algorithm is developed for any three-dimensional surface represented by a triangular grid. The method uses color-shaded magnitude contours and directed vector lines to characterize a vector field. The algorithm was tested by plotting the far-zone field vector direction and magnitude.<<ETX>>","PeriodicalId":138141,"journal":{"name":"Proceedings of IEEE Antennas and Propagation Society International Symposium","volume":"5 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":"117046303","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 structure of a linearly polarized radial line slot antenna (LP-RLSA) for realizing dual beam operation is presented. The beam-tilt mechanism by the shift of feed point is explained. A model antenna with two feed points demonstrated the dual beam operation, and efficiencies of 33 and 45% were realized. This beam-tilt mechanism can be applied to the narrow range beam scanning.<>
{"title":"A dual beam linearly-polarized radial line slot antenna","authors":"J. Takada, T. Tanahashi, K. Ito, M. Ando","doi":"10.1109/APS.1993.385509","DOIUrl":"https://doi.org/10.1109/APS.1993.385509","url":null,"abstract":"The structure of a linearly polarized radial line slot antenna (LP-RLSA) for realizing dual beam operation is presented. The beam-tilt mechanism by the shift of feed point is explained. A model antenna with two feed points demonstrated the dual beam operation, and efficiencies of 33 and 45% were realized. This beam-tilt mechanism can be applied to the narrow range beam scanning.<<ETX>>","PeriodicalId":138141,"journal":{"name":"Proceedings of IEEE Antennas and Propagation Society International Symposium","volume":"52 22","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120817582","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 modal propagation algorithm (MPA) for the computation of backscattering from arbitrarily shaped ducts in the intermediate frequency ranges is presented. The fields are propagated from the aperture toward the termination one small step at a time while ignoring reflections. Mode conversion from one section to the next is taken into account by a model conversion matrix which converts the modes in one section into the modes in the next section. For 3-D arbitrary geometries, the propagating modes in each section are found through solving a 2-D eigenvalue problem with the aid of the finite difference method. The same modal propagation steps are repeated to propagate the fields from the termination out to the aperture opening. The radar cross section (RCS) of the duct can then be found through the standard radiation integral. A comparison between the results generated by the present modal propagation algorithm and a reference hybrid ray-mode solution for a 2-D S-shaped duct is shown. Very good agreement is observed.<>
{"title":"Modal propagation algorithm for RCS prediction of inlet ducts","authors":"H. Kim, H. Ling","doi":"10.1109/APS.1993.385458","DOIUrl":"https://doi.org/10.1109/APS.1993.385458","url":null,"abstract":"A modal propagation algorithm (MPA) for the computation of backscattering from arbitrarily shaped ducts in the intermediate frequency ranges is presented. The fields are propagated from the aperture toward the termination one small step at a time while ignoring reflections. Mode conversion from one section to the next is taken into account by a model conversion matrix which converts the modes in one section into the modes in the next section. For 3-D arbitrary geometries, the propagating modes in each section are found through solving a 2-D eigenvalue problem with the aid of the finite difference method. The same modal propagation steps are repeated to propagate the fields from the termination out to the aperture opening. The radar cross section (RCS) of the duct can then be found through the standard radiation integral. A comparison between the results generated by the present modal propagation algorithm and a reference hybrid ray-mode solution for a 2-D S-shaped duct is shown. Very good agreement is observed.<<ETX>>","PeriodicalId":138141,"journal":{"name":"Proceedings of IEEE Antennas and Propagation Society International Symposium","volume":"262 ","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120881925","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 lens design method is introduced for curved radiating arrays, taking into account the fact that some of the elements of the curved radiating arrays do not make any significant contribution to the directions of some of the main beams, due to shadowing and directional patterns of the radiating antenna elements. With this method, the degrees of freedom available in designing the lenses are used to get correct phase fronts for a number of chosen directions for each of the points on the radiating array curve. For a chosen radiating array, the lengths of the transmission lines and the positions of the antenna elements on the inner surface are calculated such that the path lengths from a certain feed point to the phase fronts are equal to a predetermined constant, for a number of chosen phase fronts. These phase fronts are different for each of the elements and are chosen to be in the directions that the radiating elements illuminate. The results of a computer study showing the feasibility of these lenses are presented.<>
{"title":"Bootlace lenses for curved arrays","authors":"A. Y. Niazi, R. Uyguroglu","doi":"10.1109/APS.1993.385511","DOIUrl":"https://doi.org/10.1109/APS.1993.385511","url":null,"abstract":"A novel lens design method is introduced for curved radiating arrays, taking into account the fact that some of the elements of the curved radiating arrays do not make any significant contribution to the directions of some of the main beams, due to shadowing and directional patterns of the radiating antenna elements. With this method, the degrees of freedom available in designing the lenses are used to get correct phase fronts for a number of chosen directions for each of the points on the radiating array curve. For a chosen radiating array, the lengths of the transmission lines and the positions of the antenna elements on the inner surface are calculated such that the path lengths from a certain feed point to the phase fronts are equal to a predetermined constant, for a number of chosen phase fronts. These phase fronts are different for each of the elements and are chosen to be in the directions that the radiating elements illuminate. The results of a computer study showing the feasibility of these lenses are presented.<<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":"123971722","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 for calculating this parameter is provided. The parameter values of some special targets are given.<>
给出了一种计算该参数的方法。给出了一些特殊目标的参数值。
{"title":"The rotating-symmetric parameter of the radar targets","authors":"J. Yang, S.-M. Lin","doi":"10.1109/APS.1993.385584","DOIUrl":"https://doi.org/10.1109/APS.1993.385584","url":null,"abstract":"A method for calculating this parameter is provided. The parameter values of some special targets are given.<<ETX>>","PeriodicalId":138141,"journal":{"name":"Proceedings of IEEE Antennas and Propagation Society International Symposium","volume":"6 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":"124675127","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 polarization effects on two-dimensional quasi-exact active imaging for conducting objects buried in a dielectric half-space are investigated for plane wave incidence. It was found from numerical simulations that for TM (transverse magnetic) wave incidence the upper contour of the buried object is well reconstructed, but the lower side could not be reconstructed, while for TE (transverse electric) wave incidence both sides can be reconstructed for thin objects.<>
{"title":"Polarization effects on two-dimensional active imaging of conducting objects buried in a dielectric half-space","authors":"T. Uno, Y. He, T. Saito, S. Adachi","doi":"10.1109/APS.1993.385294","DOIUrl":"https://doi.org/10.1109/APS.1993.385294","url":null,"abstract":"The polarization effects on two-dimensional quasi-exact active imaging for conducting objects buried in a dielectric half-space are investigated for plane wave incidence. It was found from numerical simulations that for TM (transverse magnetic) wave incidence the upper contour of the buried object is well reconstructed, but the lower side could not be reconstructed, while for TE (transverse electric) wave incidence both sides can be reconstructed for thin objects.<<ETX>>","PeriodicalId":138141,"journal":{"name":"Proceedings of IEEE Antennas and Propagation Society International Symposium","volume":"22 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":"124758648","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}
Two off-axis dual-band feeds may be used with a symmetric or shaped Cassegrain antenna. As an example, a Cassegrain antenna with a main reflector diameter of 300 inches and a focal length of 250 inches is considered. Radiation patterns are presented.<>
{"title":"Design of quad-band reflector antennas without using frequency selective surfaces","authors":"M. Sanad","doi":"10.1109/APS.1993.385226","DOIUrl":"https://doi.org/10.1109/APS.1993.385226","url":null,"abstract":"Two off-axis dual-band feeds may be used with a symmetric or shaped Cassegrain antenna. As an example, a Cassegrain antenna with a main reflector diameter of 300 inches and a focal length of 250 inches is considered. Radiation patterns are presented.<<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":"129402799","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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