Parametric interpolation of the moment matrix in surface integral equationformulation

In the analysis of electromagnetic scattering and radiation from objects of arbitrary shape using the method of moments (MoM), it is desirable to fill the impedance (or moment) matrix efficiently so that larger size problems can be solved. This article describes a general MoM technique in which the matrix is filled by spatial interpolation with respect to a parametrized el ectrical separation between source and test elements. The parametrization i s accomplished such that the same algorithm also provides frequency interpo lation, thus facilitating efficient computations over a wide frequency band . The spatial interpolation method is illustrated by application to the ana lysis of radiation from tunable microstrip patch antennas over multiple fre quency bands. By specializing the interpolation scheme to a surface integra l equation formulation that employs rooftop basis functions on a grid of re ctangular cells, it is shown that the interpolation method results in consi derable reduction of the storage and CPU time requirements. (C) 1999 John W iley & Sons, Inc.