摘要:

We investigate the plane-wave solution of Maxwell's equations for a stratified medium characterized by a slowly varying index n(z) . The study is carried out in the time domain. We show that the transmitted wave from a source generates reflected wavelets which are propagated in the opposite direction. The reflected wave may be interpreted as the propagation medium response to the source excitation. The medium is thus characterized by a transfer function and an impulse response exclusively dependent on the propagation velocity. Conversely, knowing the impulse response makes estimating the index n(z) possible.

ISSN:0920-5071    

DOI:10.1163/156939396X00757

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The analytical study of the electromagnetic field in a circular waveguide with linearly moving boundary has been made in [1]. In this paper, we analyse the case where the argument of the LEGENDRE's associate functions is superior to 1. The W.K.B. method is used for solving this problem. The expressions of field have been determined. It is shown that the field has a modal nature and the modes are dynamics, each having an instantaneous frequency. Also a criterium of precision is given.

ISSN:0920-5071    

DOI:10.1163/156939396X00766

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

A new effective numerical-analytical method of analysis of cylindrical structures with arbitrary cross-section is presented. The method is based on an inversion of the main singular part of an operator equation. The Galerkin method is used with basis functions that are the eigenfunctions of the boundary value problem for the electromagnetic wave diffraction by a circular cylinder. The method was used to investigate diffraction by inhomogeneous dielectric bodies, to treat discontinuities in a waveguide, and to analyze waveguides and strip lines with a complex cross-sections.

ISSN:0920-5071    

DOI:10.1163/156939396X00775

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The results of theoretical investigation on transformation of the character of polarization of electromagnetic wave under reflection from thin (comparing to the wavelength) solid-plasma (semiconductor) film are presented. The phenomenon of strong transformation is pointed out to occur when the wave frequency is close to the frequency of plasma resonance in the film. Various regimes of the transformation are studied. Influence of externally applied magnetostatic field and film inhomogeneity is investigated as well.

ISSN:0920-5071    

DOI:10.1163/156939396X00784

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

A uniform asymptotic high-frequency solution is developed for the problem of diffraction of plane waves by a slit in an impedance screen of finite thickness. By using the Fourier transform technique the boundary-value problem is formulated into a pair of simultaneous modified Wiener-Hopf equations of the third kind which are decoupled and solved approximately. Several numerical results illustrating the effects of the surface impedances, slit width and slit thickness on the diffraction phenomenon are presented.

ISSN:0920-5071    

DOI:10.1163/156939396X00793

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The problem of microstrip annular-ring patch antenna excited by a probe is solved using rigorous analysis. Minimal assumptions, except the uniform current distribution on the probe and zero thickness of the patch have been made in our analysis. By using the vector Hankel transforms, the problem is formulated in terms of vector dual-integral equations, from which the surface current on the patch can be solved for. The singular part of the current arising from the probe feed is extracted from the expansion series in order to accelerate convergence. It is shown that this analysis agrees with the single mode approximation (SMA) method when the substrate layer is thin, while it deviates from the SMA method drastically when the substrates become thick. Experimental results show that the analytical procedure used in this paper can greatly improve the accuracy of the computed input impedance of microstrip annular-ring patch antenna.

ISSN:0920-5071    

DOI:10.1163/156939396X00801

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

In this communication analysis of dielectric image guide structures using method of lines with nonequidistant discretization is presented. Accurate hybrid-mode dispersion characteristics for dominant and higher order modes of directly connected DIG and cladded single and coupled DIG are given. A new low loss DIG structure is proposed and its frequency dependent characteristics, for single and coupled configurations, with respect to the first few modes are also presented.

ISSN:0920-5071    

DOI:10.1163/156939396X00810

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

This paper describes a study which has shown the feasibility of using a Finite-Difference Time-Domain software package TSAR (Temporal Scattering and Response) to generate far-field scattered electric field patterns for the remote detection of dielectric and metallic inclusions in homogeneous dielectric structures. The far-field scattered patterns of a homogeneous dielectric structure of rectangular cross section, representing a typical rock sample whose dielectric properties have been measured were calculated using TSAR. Inclusions, both dielectric and metallic, of various sizes were placed at different locations in this homogeneous sample. The calculations showed that it was indeed possible to detect the presence, the size, type and location of these inclusions to sizes as small as 0.067% of the total sample volume, by observing the scattered electric field patterns. An application of this study would eventually be for the inverse scattering problem of microwave remote detection of minerals in rocks.

ISSN:0920-5071    

DOI:10.1163/156939396X00829

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The analysis deals with the formulation of a boundary value problem where the complex immitivity has a principal axis tilted to the interface between the regions. An example is a half-space model of the earth where the fine layering or striations are not parallel to the air interface. The objective is to obtain expressions for effective surface impedance when the source is an obliquely incident plane wave from the upper (air) region. The case treated in detail is when the magnetic field direction is parallel to the strike of the structure which is a purely 2D problem. The more difficult case is when the incidence is arbitrary which leads to coupled wave equations for the E and H fields parallel to the srike of the structure. We also deal with the simplification achieved when the conductivity of the structure is sufficiently high. The general layered case is also treated where the analogy with the layered isotropic media problem is exploited.

ISSN:0920-5071    

DOI:10.1163/156939396X00838

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

ISSN:0920-5071    

DOI:10.1163/156939396X00847

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor