An Efficient Technique for Computing the Potential Green´s Functions for a Thin, Periodically Excited Parallel-Plate Waveguide Bounded by Electric and Magnetic Walls

An efficient formulation is described for calculating all vector and scalar potential Green´s functions for a thin, infinitely long waveguide with periodic excitation. The Green´s functions are represented by the first few terms of the modal expansion plus a quasi-static correction. This allows one to compute the Green´s functions over a wide band of frequencies with little additional effort over that required for a single frequency. An attractive feature of the method is that the l/R free-space singularity exhibited by the potentials is explicitly extracted in the lowest order quasi-static term. Tfris is convenient for evaluating method-of-moments self-term contributions in closed form. The Green´s functions have application for problems involving stripline structures such as Rotman lenses.