An analytical model for solving the mutual coupling between an infinite array of dipoles and vertical wires is presented. The analysis is based on an infinite-array approach using periodic phased-array conditions. A computer program to implement this analysis has been developed. To verify the theoretical model, measurements of the radiation impedances with and without the coupling effects due to the vertical wires have also been conducted. As an example, a dipole array with eight vertical wires per unit cell of the dipole is considered. The predicted trend is in good agreement with measured results.<>
{"title":"Analysis of mutual coupling between an infinite phased array of horizontal dipoles and vertical wires","authors":"K. Lee, R. Chu","doi":"10.1109/APS.1989.134783","DOIUrl":"https://doi.org/10.1109/APS.1989.134783","url":null,"abstract":"An analytical model for solving the mutual coupling between an infinite array of dipoles and vertical wires is presented. The analysis is based on an infinite-array approach using periodic phased-array conditions. A computer program to implement this analysis has been developed. To verify the theoretical model, measurements of the radiation impedances with and without the coupling effects due to the vertical wires have also been conducted. As an example, a dipole array with eight vertical wires per unit cell of the dipole is considered. The predicted trend is in good agreement with measured results.<<ETX>>","PeriodicalId":11330,"journal":{"name":"Digest on Antennas and Propagation Society International Symposium","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1991-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81585050","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 a microwave radome gauge (MWRG) for verifying a radome's performance regardless of its size and for a wide range of shapes. The gauge consists of two parts: a microwave coupler and a conducting foil. The radome is placed between these two parts to form a cavity whose resonant frequency is measured. Changes in f/sub 0/ are used to verify its transmission characteristics. The radome is tested piecewide by placing the MWRG at various locations on the surface of the radome and verifying its transmission properties at these locations. A mathematical model of the MWRG based on conventional transmission line theory is described. That is, the radome and the short-circuited connection between the foil and the flange of the coupler are assumed to act as a section of dielectric-loaded waveguide. Analytic results determined that the allowable change in the thickness of the radome core materials and assembly could cause a shift in the resonant frequency up to 0.4%, if only one dimension is in error.<>
{"title":"A microwave radome performance verification gauge","authors":"L. Ricardi, X. P. Tran, S. Sutkin","doi":"10.1109/APS.1989.135015","DOIUrl":"https://doi.org/10.1109/APS.1989.135015","url":null,"abstract":"The authors describe a microwave radome gauge (MWRG) for verifying a radome's performance regardless of its size and for a wide range of shapes. The gauge consists of two parts: a microwave coupler and a conducting foil. The radome is placed between these two parts to form a cavity whose resonant frequency is measured. Changes in f/sub 0/ are used to verify its transmission characteristics. The radome is tested piecewide by placing the MWRG at various locations on the surface of the radome and verifying its transmission properties at these locations. A mathematical model of the MWRG based on conventional transmission line theory is described. That is, the radome and the short-circuited connection between the foil and the flange of the coupler are assumed to act as a section of dielectric-loaded waveguide. Analytic results determined that the allowable change in the thickness of the radome core materials and assembly could cause a shift in the resonant frequency up to 0.4%, if only one dimension is in error.<<ETX>>","PeriodicalId":11330,"journal":{"name":"Digest on Antennas and Propagation Society International Symposium","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1991-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88004920","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 postulated that numerical stability and reliability are increased by using an exact conjugate gradient algorithm with an approximate operator for the synthesis of planar arrays. Special computer architecture exists for vectorization and parallel computation of the matrix vector products found in the exact algorithm. The proposed synthesis method is illustrated for the case of a planar array of z directed dipoles with either constant amplitude variable phase excitation or variable amplitude and phase excitation. As expected, the main beamwidth is dominated by the equivalent aperture of the array rather than the amplitude and phase of the signal.<>
{"title":"Application of a conjugate gradient method to the synthesis of planar arrays","authors":"T. Peters","doi":"10.1109/APS.1989.134677","DOIUrl":"https://doi.org/10.1109/APS.1989.134677","url":null,"abstract":"It is postulated that numerical stability and reliability are increased by using an exact conjugate gradient algorithm with an approximate operator for the synthesis of planar arrays. Special computer architecture exists for vectorization and parallel computation of the matrix vector products found in the exact algorithm. The proposed synthesis method is illustrated for the case of a planar array of z directed dipoles with either constant amplitude variable phase excitation or variable amplitude and phase excitation. As expected, the main beamwidth is dominated by the equivalent aperture of the array rather than the amplitude and phase of the signal.<<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":"75463182","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}
Experimental results are presented on the cross-polarization characteristics of rectangular patch antennas. The rectangular patch was fabricated on cuflon substrate with relative permittivity epsilon r=2.1 and thickness t=10 mil (0.0254 cm) and 30 mil (0.0762 cm). It is found that the dependence of mod E/sub c//E/sub x/ mod /sup 2//sub max/ on the aspect ratio is different for E and H planes. A best value can be found to yield the largest mod E/sub c//E/sub x/ mod /sup 2//sub max/ for both planes, but this value depends on the thickness of the substrate. In addition, it has been found that mod E/sub c//E/sub x/ mod /sup 2//sub max/ decreases as the resonant frequency increases.<>
给出了矩形贴片天线交叉极化特性的实验结果。在相对介电常数r=2.1，厚度t=10 mil (0.0254 cm)和30 mil (0.0762 cm)的cuflon衬底上制备了矩形贴片。模型E/sub c//E/sub x/ mod /sup 2//sub max/对纵横比的依赖性在E和H平面上是不同的。可以找到一个最佳值，以产生两个平面的最大模E/sub c//E/sub x/ mod /sup 2//sub max/，但该值取决于基板的厚度。此外，还发现随着谐振频率的增加，模E/sub c//E/sub x/模/sup 2//sub max/减小。
{"title":"Experimental study of the cross polarization characteristics of rectangular patch antennas","authors":"R. Q. Lee, T. Huynh, Kai Fong Lee","doi":"10.1109/APS.1989.134767","DOIUrl":"https://doi.org/10.1109/APS.1989.134767","url":null,"abstract":"Experimental results are presented on the cross-polarization characteristics of rectangular patch antennas. The rectangular patch was fabricated on cuflon substrate with relative permittivity epsilon r=2.1 and thickness t=10 mil (0.0254 cm) and 30 mil (0.0762 cm). It is found that the dependence of mod E/sub c//E/sub x/ mod /sup 2//sub max/ on the aspect ratio is different for E and H planes. A best value can be found to yield the largest mod E/sub c//E/sub x/ mod /sup 2//sub max/ for both planes, but this value depends on the thickness of the substrate. In addition, it has been found that mod E/sub c//E/sub x/ mod /sup 2//sub max/ decreases as the resonant frequency increases.<<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":"75477846","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 formulas for moment method solutions to the electric-field integral equation of the TE polarization are developed to provide efficient and accurate field computations of two-dimensional problems. The new method has been extensively tested. A computer code, TDRS (Two-Dimensional Radiation and Scattering), has been developed for four geometries: a strip, a circular cylinder, a rectangular cylinder and an elliptical cylinder.<>
{"title":"Evaluation of diagonal impedance elements in TE polarization for two-dimensional field computations","authors":"K. Liu, C. Balanis","doi":"10.1109/APS.1989.134753","DOIUrl":"https://doi.org/10.1109/APS.1989.134753","url":null,"abstract":"Two formulas for moment method solutions to the electric-field integral equation of the TE polarization are developed to provide efficient and accurate field computations of two-dimensional problems. The new method has been extensively tested. A computer code, TDRS (Two-Dimensional Radiation and Scattering), has been developed for four geometries: a strip, a circular cylinder, a rectangular cylinder and an elliptical cylinder.<<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":"75522211","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}
Recently, the early-time response of a perfectly conducting circular cylinder to electromagnetic waves was studied by the authors (1988). The results obtained then for the shadow region using different approaches are in good agreement, while the results for the illuminated region can only be approximated to the physical optics solution. The authors use the Luneberg-Kline expansion to obtain a more accurate solution for the illuminated region. Computed results for the early-time currents in the illuminated region are shown. It can be seen that as time increases the results obtained on the basis of Luneberg-Kline expansion decrease more rapidly than those of the physical optics solution. For small times the results corresponding to the two different approaches are in better agreement.<>
{"title":"A Luneberg-Kline expansion solution for the transient scattering of cylindrical waves by a circular cylinder","authors":"J. Ma, I. Ciric","doi":"10.1109/APS.1989.135073","DOIUrl":"https://doi.org/10.1109/APS.1989.135073","url":null,"abstract":"Recently, the early-time response of a perfectly conducting circular cylinder to electromagnetic waves was studied by the authors (1988). The results obtained then for the shadow region using different approaches are in good agreement, while the results for the illuminated region can only be approximated to the physical optics solution. The authors use the Luneberg-Kline expansion to obtain a more accurate solution for the illuminated region. Computed results for the early-time currents in the illuminated region are shown. It can be seen that as time increases the results obtained on the basis of Luneberg-Kline expansion decrease more rapidly than those of the physical optics solution. For small times the results corresponding to the two different approaches are in better agreement.<<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":"75554576","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 slot line is investigated by using the time-domain finite-difference method. The field distribution is obtained by the numerical computation of time-dependent Maxwell's equations using Yee's mesh. The Fourier transform technique is employed to find the frequency dependence of parameters such as effective dielectric constant and complex characteristic impedance. Comparisons of the time domain results with those from Cohn's transverse resonance method are given, indicating a reasonable agreement over a wide frequency range. Numerical simulation results are given for a slot line on a GaAs substrate with relative dielectric constant epsilon /sub r/=13.0.<>
{"title":"On the characteristics of the slot line","authors":"G. Liang, Y. Liu, K. Mei","doi":"10.1109/APS.1989.134790","DOIUrl":"https://doi.org/10.1109/APS.1989.134790","url":null,"abstract":"The slot line is investigated by using the time-domain finite-difference method. The field distribution is obtained by the numerical computation of time-dependent Maxwell's equations using Yee's mesh. The Fourier transform technique is employed to find the frequency dependence of parameters such as effective dielectric constant and complex characteristic impedance. Comparisons of the time domain results with those from Cohn's transverse resonance method are given, indicating a reasonable agreement over a wide frequency range. Numerical simulation results are given for a slot line on a GaAs substrate with relative dielectric constant epsilon /sub r/=13.0.<<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":"74108714","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 integral ray geometric parameters consisting of the relation between the geodesic coordinates v and u, the arc length, and the generalized Fock parameter are presented for the complete class of QUASORs (quadric surfaces of revolution). A geodesic constant method permits the derivation of these ray parameters in terms of the geodesic constant h alone. Since h can be expressed in terms of the source and observation point coordinates in the case of the sphere and cone, in these cases the ray parameters are in closed form. On the other hand, in the case of the ellipsoid of revolution and the general paraboloid and hyperboloid of revolution, h can be obtained using a simple univariate search. Hence in these cases, the ray parameters are in a one-parameter dependent form. Using this approach, it is possible to readily calculate the various radiation characteristics of the antenna in the vicinity of a general QUASOR.<>
{"title":"Closed form expressions for integral ray geometric parameters for wave propagation on general quadric surfaces of revolution","authors":"R. Jha, S. Bokhari, V. Sudhakar, P. Mahapatra","doi":"10.1109/APS.1989.134651","DOIUrl":"https://doi.org/10.1109/APS.1989.134651","url":null,"abstract":"The integral ray geometric parameters consisting of the relation between the geodesic coordinates v and u, the arc length, and the generalized Fock parameter are presented for the complete class of QUASORs (quadric surfaces of revolution). A geodesic constant method permits the derivation of these ray parameters in terms of the geodesic constant h alone. Since h can be expressed in terms of the source and observation point coordinates in the case of the sphere and cone, in these cases the ray parameters are in closed form. On the other hand, in the case of the ellipsoid of revolution and the general paraboloid and hyperboloid of revolution, h can be obtained using a simple univariate search. Hence in these cases, the ray parameters are in a one-parameter dependent form. Using this approach, it is possible to readily calculate the various radiation characteristics of the antenna in the vicinity of a general QUASOR.<<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":"75998956","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 an examination of the equivalent source method and similar methods (generically called the generalized multipole technique), the authors investigate the effect of the edges of conducting wedges on the near field or the surface currents on the conducting scatterer. A finite conducting cylinder which is rotationally symmetric around the z-axis and whose edges along the circumferences on the top and bottom planes are rounded with a variable radius is considered as an example scatterer. The results obtained suggest the necessity of modifying the equivalent source method when it is applied to the far- and/or near-field calculations of three-dimensional scatterers with arbitrary shape.<>
{"title":"Near and far fields of scattering from finite bodies of perfect conductor: analyses by generalized multipole technique and others","authors":"H. Shigesawa, M. Tsuji, M. Nishimura","doi":"10.1109/APS.1989.134641","DOIUrl":"https://doi.org/10.1109/APS.1989.134641","url":null,"abstract":"In an examination of the equivalent source method and similar methods (generically called the generalized multipole technique), the authors investigate the effect of the edges of conducting wedges on the near field or the surface currents on the conducting scatterer. A finite conducting cylinder which is rotationally symmetric around the z-axis and whose edges along the circumferences on the top and bottom planes are rounded with a variable radius is considered as an example scatterer. The results obtained suggest the necessity of modifying the equivalent source method when it is applied to the far- and/or near-field calculations of three-dimensional scatterers with arbitrary shape.<<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":"75038663","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 examine the use of grids that are conformal with the geometry of the material boundaries and, consequently, reduce the discretization errors introduced by the stair-stepped approximation. However, it is found that the introduction of the nonuniformity in the grid gives rise to at least two difficulties in the implementation of the finite-difference time-domain algorithm. The first is the loss of accuracy in the computation of finite-difference derivatives when the field points are distributed nonuniformly. The second is implementation of the appropriate boundary conditions at the material interfaces. The authors address these problems and suggest some means for eradicating them. A scheme is presented that has the attractive feature that it reduces to the conventional finite-difference time-domain method if a uniform grid is used. To illustrate the proposed algorithm the authors consider a parallel plate waveguide which supports a single propagating mode.<>
{"title":"On the use of conformal grids for propagation and scattering problems in finite-difference time-domain computations","authors":"J. Joseph, R. Mittra","doi":"10.1109/APS.1989.134605","DOIUrl":"https://doi.org/10.1109/APS.1989.134605","url":null,"abstract":"The authors examine the use of grids that are conformal with the geometry of the material boundaries and, consequently, reduce the discretization errors introduced by the stair-stepped approximation. However, it is found that the introduction of the nonuniformity in the grid gives rise to at least two difficulties in the implementation of the finite-difference time-domain algorithm. The first is the loss of accuracy in the computation of finite-difference derivatives when the field points are distributed nonuniformly. The second is implementation of the appropriate boundary conditions at the material interfaces. The authors address these problems and suggest some means for eradicating them. A scheme is presented that has the attractive feature that it reduces to the conventional finite-difference time-domain method if a uniform grid is used. To illustrate the proposed algorithm the authors consider a parallel plate waveguide which supports a single propagating mode.<<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":"76481318","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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