Multimode moment method formulation for waveguide discontinuities

A computationally efficient method for analyzing waveguide discontinuities is presented. The method is based on Galerkin´s moment method formulation. The generalized scattering matrix of a waveguide discontinuity is derived. A generalized equivalent circuit is constructed which gives physical insight to the problem. The method is found to be several times faster than the well-known mode matching technique. The accuracy of the proposed method is demonstrated by comparing the numerical result with the measured return loss of a multisection iris-coupled filter