摘要:

The 5:1 dipole benchmark case has been analyzed extensively by many researchers using different codes based on various numerical techniques. In this paper this benchmark case is solved by the current-model method in which the fulfillment of the boundary condition is improved using the singular value decomposition (SVD) of the moment matrix. The SVD is the most informative general representation of a matrix and its use in the current-model method improves the stability as well as the accuracy of the numerical solution. Its application results in a considerable reduction of the boundary condition errors between the matching points. Obviously, the boundary condition errors at the matching points are no longer strictly zero, but acceptably low values are retained. Comparisons between the results obtained using the various techniques are presented. It is shown that the difference between Ludwig's results, which are based on a spherical-wave expansion approach, and ours is within the error estimate characterizing the former results accuracy.

ISSN:0920-5071    

DOI:10.1163/156939393X00011

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Scattering of electromagnetic waves from periodic surfaces is considered in time-domain for an oblique angle of incidence. The finite-difference time-domain (FDTD) method is used to obtain numerical solutions without resorting to frequency-domain analysis and Fourier transformation. For the application of FDTD method to the oblique incidence case, Maxwell's equations are transformed such that the computational domain can be truncated by using periodic boundary conditions. The FDTD method is then used to solve the transformed equations. In solving the transformed equations by the FDTD method, the absorbing boundary conditions are modified and the eigenvalues of the system are determined for the stability analysis. The final results are obtained by using the inverse transformation. Since the transformation is very simple, the computational time is primarily determined by the FDTD solution of the transformed equations. The theoretical results are illustrated by calculating the scattered fields in the computational domain as a function of time for a pulse incident at an oblique angle. The time domain results are also transformed into frequency domain and compared with the results obtained using a standard frequency domain technique.

ISSN:0920-5071    

DOI:10.1163/156939393X00020

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

The coupling between parallel identical chiral slabs has been evaluated. The perturbation formula used involves a line integral along a contour situated between the guides. The coupling coefficient has been derived in the general case. It has been analysed for symmetrical fields and the conditions for which it vanishes have been established. Graphs of the normalized coupling coefficient have been given as a function of the normalized frequency and of the chirality admittance. In general, for a given normalized frequency, the coupling diminishes when the chirality admittance grows.

ISSN:0920-5071    

DOI:10.1163/156939393X00039

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

The diffraction of a high-frequency electromagnetic wave by a smooth convex perfectly conducting surface is analyzed in terms of physical optics (PO) and physical theory of diffraction (PTD). The contributions of the PO current and the correction current to the surface-diffracted field near the shadow boundary away from the surface are described, respectively, by the Fresnel function and the non-singular Pekeris functions.

ISSN:0920-5071    

DOI:10.1163/156939393X00048

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

The problem of determining the complex natural frequencies of closed objects with arbitrary shape is considered. The surface of the complex body, which is supposed to have an infinite conductivity, is divided into a large number of plane patches (finite elements) where the current is assumed to be constant. The appropriate boundary condition for the electric field on the surface of the complex body is imposed, yielding a homogeneous system of equations for the current coefficients. The regions of resonance (natural frequencies) of the complex object are determined as those where the determinant of this system is close to zero. As an example, the complex natural frequencies of a rectangular parallelpiped (or a cube) are calculated.

ISSN:0920-5071    

DOI:10.1163/156939393X00057

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

The point of departure of the present paper is the observation that the strong fluctuation theory for statistically layered media needs not only the coordinate-acting effective permittivity operator (EPO) but also its spectral representation in the specific basis set of waves associated with this class of random media. Extending the author's previous work for isotropic and uniaxial media, the paper treats the EPO and its proper spectral counterpart for a statistically layered medium with arbitrary permeability and random permittivity dyads. These results have been obtained by exploiting a new recipe for regularizing the Green's dyad for the background medium. As compared with other approaches, the proposed one has the advantage of removing secular terms simultaneously in the expressions for the EPO and its spectral representation in the aforementioned basis set. In addition to the general case, the examples of gyrotropic random media and statistically rough interfaces separating deterministic layered media are considered.

ISSN:0920-5071    

DOI:10.1163/156939393X00066

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

ISSN:0920-5071    

DOI:10.1163/156939393X00075

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

ISSN:0920-5071    

DOI:10.1163/156939393X00084

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

ISSN:0920-5071    

DOI:10.1163/156939393X00093

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor