Comparison between the Kummer's transformation and Ewald method for the evaluation of the parallel plate Green's functions

In this paper, we present a convergence and efficiency study of two different acceleration techniques for the evaluation of the parallel plate Green's functions. The first technique is based on the extraction of the asymptotic terms of the spectral representation of the parallel plate Green's functions by applying the Kummer's transformation. The second technique is a straightforward reformulation of the 2-D Green's functions for 1-D periodic structures to the parallel plate case. The PPW Green's functions calculated by the two methods have been successfully applied to the analysis of a practical inductive microwave filter containing metallic and dielectric posts. The filter analysis technique is based on solving a surface integral equation by the MoM. The convenience of using one of the proposed acceleration technique or the other for the evaluation of each Green's function components and its derivatives, necessary to solve the MoM problem, is properly justified.