NUMERICAL-ANALYSIS OF DISCONTINUITIES IN A RECTANGULAR WAVE-GUIDE LOADED WITH ISOTROPIC OR ANISOTROPIC OBSTACLES BY MEANS OF THE COUPLED-MODE METHOD AND THE MODE-MATCHING METHOD

A hybrid method obtained as a combination of the coupled-mode method (CMM) and the mode-matching method (MMM) is developed and applied in the analysis of multiple dielectric and magnetic discontinuities in rectangular waveguides. As both are moment methods, some kind of truncation has to be carried out in the computer implementation. It is shown that selection of a different number of modes in the two methods is not necessary, unless low-permittivity media inside the waveguide are considered. As a consequence, the procedure for selecting the number of basis functions is only done in one of the methods. Numerical examples are presented showing the behaviour of the method and the proofs of convergence. Examples are included illustrating the power of this hybrid technique, especially in relation to non-reciprocal structures containing magnetized ferrites.