摘要:

The effect of a thin, dielectric buffer layer on coplanar electrode structures is examined. The buffer layer is placed between the metal electrodes and the dielectric substrate. It is seen to have a significant effect on the charge distribution, field distribution, and capacitance. A new approximate formula is derived for the charge in the presence of the buffer layer, which allows the fields to be calculated efficiently. In addition, closed form approximate expressions are derived for the capacitance. The expression for the charge is based on the observation that it's distribution in the presence of a buffer layer is almost the same as that for a microstrip The formulas are compared to results from a moment method solution for the problem

ISSN:0272-6343    

DOI:10.1080/02726349408908375

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

A diffraction problem for a grating consisting of thin parallel cylinders (fibers) is considered in the low frequency approximation. Relative permittivity and permeability are supposed to be constant in each fiber. An electric field vector of an incident plane wave is parallel to the fibers. Results of this approximation are compared with the field scattered by a homogeneous hypothetical layer. Thus, its relative effective permittivity (εe), permeability (µe), refractive index (ηe), and impedance (ze) are determined. It has been shown that such an equivalent material is sometimes characterized by negative values of either Im(εe) or Im(µe) (with the time dependence e−iωt), and may be interpreted as a medium with an internal generation.

ISSN:0272-6343    

DOI:10.1080/02726349408908376

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Field integral equations of various forms governing the scattering of an incident EM wave by a finite heterogeneous body with arbitrary electrical and magnetic parameters are investigated and presented in this paper. Either dyadic or scalar Green's function is used to expressed the kernels of the integral equations. Numerical solutions of these integral equations are compared and advantages and disadvantages of various equations are discussed. The effect on the induced electric field in the body due to magnetic materials is also investigated.

ISSN:0272-6343    

DOI:10.1080/02726349408908377

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

We investigate the stability and accuracy of a time dependent, surface integral equation method to calculate the scattering from a dielectric body subjected to a transient incident electromagnetic field. The integral equation is solved using time marching, and an averaging method is used to ensure the numerical stability of the solution. The accuracy of the method as the dielectric parameters and pulse width are varied is discussed.

ISSN:0272-6343    

DOI:10.1080/02726349408908378

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Analytical expressions for the resonant frequencies in an electromagnetic cylindrical/spherical cavity with an off-axis inner electrically small dielectric sphere are derived, for both magnetic and electric modes. The walls of the cylindrical/spherical cavity are perfectly conducting. Cylindrical/spherical vector wave functions and related addition theorems, as well as expansion of cylindrical wave functions in terms of spherical ones, are used. Our results are useful in problems connected with resonant cavities containing small inhomogeneities, as well as in cases that we want to determine the permittivities or magnetic permeabilities of various materials, by measuring the resonant frequency shifts caused by the introduction of small samples of them, inside cavities. Graphical results for some of the lower order modes are given, for various values of the parameters and for both kinds of modes.

ISSN:0272-6343    

DOI:10.1080/02726349408908379

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

The locus of an impedance or admittance function for a lossy transmission line when plotted on a Smith chart is a spiral. In this paper, an alternative presentation is given by means of a new chart, designated as the A-B/R-X chart. The spiral is then replaced by a circular path and one linear path to relate the input impedance and the load impedance of a lossy line.

ISSN:0272-6343    

DOI:10.1080/02726349408908380

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

A formulation that combines the scalar Helmholtz equation with an integral equation radiation boundary condition is developed for electromagnetic scattering from heterogeneous geometries exhibiting one-dimensional periodicity. A finite element discretization is implemented using piecewise-linear interpolation functions. Numerical results are presented for the reflection and transmission coefficients associated with several diffraction gratings.

ISSN:0272-6343    

DOI:10.1080/02726349408908381

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

In this article, a full-wave moment method solution for probe-fed circular microstrip patch antennas backed by circular cavities is presented. The antenna performance in both scattering and radiation cases is considered. Results are compared to those of conventional probe-fed circular patch antennas.

ISSN:0272-6343    

DOI:10.1080/02726349408908382

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor