Current Distribution in Microstrip Planar Antennas

The accurate determination of surface currents in microstrip planar antennas requires the solution of a two-dimensional singular integral equation. The first problem encountered when solving this equation numerically, is the obtention of a fast and accurate algorithm for evaluating its kernel, which cannot be calculated by standard computer integration methods. A second problem is the implementation of an efficient moment method. This task is very delicate because the kernel is singular. In particular, the diagonal or self terms in the moment matrix must be carefully evaluated. This paper discusses both problems and presents some new techniques for their resolution.