摘要:

Two powerful direct singular integral equation techniques (DSIET) are applied to the analytical solution of TM/TE scattering by dielectric cylinders loaded with flat or curved strips. In all cases characteristic-currents-theory is also applied as an alternative method of solution. The emphasis here is on demonstrating the high accuracy and efficiency of the proposed algorithms by detailed numerical examples and by comparisons with available results.

ISSN:0920-5071    

DOI:10.1163/156939396X00117

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

In this summary paper we will outline a new approximate method for solving large scale two-dimensional electromagnetic boundary value problems over perfect electric conductors PEC. Specifically, we will expand the Green's function in the kernel of the electric field integral equation EFIE [1] as a perturbation series with respect to the arc length variable s . The series is restricted by demanding that the first term is Toeplitz [2] with respect to s . The approximation is achieved by using the series form of the Green's function, truncated after Toeplitz term, in the EFIE. The reasoning behind such a scheme lies in the computational efficiency of inverting Toeplitz operators. In particular, Toeplitz operators can be inverted, using the fast Fourier transform FFT [3] thus reducing an O(N3) operation, where N is the number of discretizations along the scatterer, to an O(N log N) operation. There is also a saving in core storage from O(N2) to O(N).

ISSN:0920-5071    

DOI:10.1163/156939396X00126

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

It has been proposed in the literature that a uniaxial bianisotropic chiral medium can be manufactured by aligning helices in a host material such that their axes are parallel to each other. In this paper, such a uniaxial bianisotropic material is fully characterized for the first time in a purely numerical environment and its effective constitutive parameters are obtained via a combination of numerical and analytical techniques. This new materials characterization methodology completely accounts for all self- and mutual-coupling between the particles. Data confirming the accuracy of this methodology is presented for rod-shaped particles and arrays of helices at oblique angles of illumination. During the course of this work, it was found that certain restrictions must be imposed on the dimensions of the helical inclusions so that they scatter as uniaxial objects.

ISSN:0920-5071    

DOI:10.1163/156939396X00135

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Propagational characteristics of hybrid modes in circular Faraday chirowaveguides (FCW) are examined in this communication, and the theoretical treatment is based on the method of separation variables combined with the technique of Muller's calculating roots. Numerical results are given to show the effects of constitutive parameters on the bifurcation and attenuation of hybrid modes.

ISSN:0920-5071    

DOI:10.1163/156939396X00144

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The Maliuzhinets function appears in the important problem of diffraction by an impedance wedge. A more convenient normalized Maliuzhinets function is introduced and new methods of approximating this function are proposed. The Osipov's algorithm is adapted to this normalized function, which provides more accuracy, an extension of the validity domain of the approximation, and more efficiency in computation times. Alternate new methods which permit significant saving computation times are then developed.

ISSN:0920-5071    

DOI:10.1163/156939396X00153

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

An approximate expression of the scattering coefficient, for electromagnetic waves scattering from a random rough surface, is used in order to show in a simple way how multicovariance functions, and their Fourier transforms or multispectra, are naturally introduced. In fact, particular combinations of the moments are required that depend only on the separation distance between two points of the surface. The functions of lowest order are the correlation function, the skewness function and the peakedness function. Some properties of these functions are discussed. The particular case of a normal surface is briefly considered. Examples of skewness and peakedness functions, depending on characteristic distances, are discussed, and relationships are established between these distances and the wind speed for the ocean surface.

ISSN:0920-5071    

DOI:10.1163/156939396X00162

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

ISSN:0920-5071    

DOI:10.1163/156939396X00171

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor