摘要:

The main propagation effect on interference between a satellite system and an adjacent microwave terrestrial path is the differential rain attenuation. In the present paper, a modification of an existing method for the prediction of the differential rain attenuation is proposed. The modified model takes into account more realistic considerations for the rain height. The results of the predictive procedure are compared with the unique available set of experimental data taken from Yokosuka, Japan. The perturbation of the existing predictive results, due to the employment of the modified procedure, for various geographic latitudes and climatic zones, is finally examined.

ISSN:0920-5071    

DOI:10.1163/156939396X01170

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Several new ideas are provided for computing the spectral transverse dyadic Green's function (STDGF) of a stratified anisotropic medium in an accurate and efficient way. A modified version of the equivalent boundary method is developed which makes it possible to compute the asymptotic values of the aforementioned STDGF without employing exponential terms. This new technique for the computation of the STDGF of a stratified anisotropic medium has more numerical stability than the other techniques proposed so far, in which the use of exponential terms for the computation of the STDGF in all the range of variation of the spectral variables unavoidably leads to numerical problems for high values of the spectral variables. Also in this paper, it is shown how a two-step interpolation approach can be used for obtaining simple closed-form expressions of the STDGF of a stratified anisotropic medium in wide ranges of the spectral variables. It is expected that the use of this interpolation approach will introduce important CPU time savings in the spectral domain analysis of planar microwave circuits and printed antennas, where the STDGF of the substrate has to be calculated a large number of times.

ISSN:0920-5071    

DOI:10.1163/156939396X01189

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

We describe a formulation for the diffraction of a plane wave normally incident on a square array of perfectly conducting cylinders of specified length. This is a particular case of a thick capacitive grid, for which no previous rigorous model exists. The formulation is based on a modal description of the fields between the cylinders, and methods are specified for the determination of the three types of mode (TE, TM and TEM). Numerical tests on the formulation and examples of its results are presented.

ISSN:0920-5071    

DOI:10.1163/156939396X01198

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The optimal design of a nonuniform LCRG line connecting a supply line and a load is considered. An optimization method is used to achieve three particular designs, namely, design of filters, design of impedance matching sections, and design of impedance-matched voltage transformers. By introducing two auxiliary functions, the gradient of the objective functional is found as an explicit expression. Numerical results show that satisfactory designs can be achieved by the present algorithm.

ISSN:0920-5071    

DOI:10.1163/156939396X01206

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

ISSN:0920-5071    

DOI:10.1163/156939396X01215

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

This paper presents a numerical time-marching solution of the electric field integral equation (EFIE) suitable for simulation of transient scattering and radiation from perfectly conducting three-dimensional surfaces in a lossless isotropic medium. The method is capable of treating metallic scatterers of arbitrary shape modeled by arbitrary polygonal patches. Backscattering results for scatterers under an arbitrary time-dependent electromagnetic excitation may be obtained provided the tangential electric fields incident on the scatterer surface are known. By applying an expanded form of the EFIE free of spatial derivatives to simple piecewise-constant patch basis functions on polygonal surface patches, analytical simplifications then facilitate an iterative solution technique producing results free of numerical instabilities. Both near- and far-field transient scattering and radiation results can be obtained using this method.

ISSN:0920-5071    

DOI:10.1163/156939396X01224

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

ISSN:0920-5071    

DOI:10.1163/156939396X01233

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor