Computation of Green´s Functions for the Problem of a Dielectric Covered Aperture

Four computation methods for Green´s functions arising in the problem of electromagnetic transmission through an aperture in a planar infinite perfectly conducting screen, covered with a dielectric layer are presented and compared. The mixed-potential integral equation (MPIE) usually applied in such a situation, comprises so-called Sommerfeld integrals which must be computed numerically when the method-of-moments (MoM) computational scheme is used. In this work we use four versions of the algorithm resulting from application of the Discrete Complex Images Method (DCIM). The results are compared with those obtained by a direct numerical integration of Sommerfeld integrals.