Hybrid Mode Matching Method for the Efficient Analysis of Metal and Dielectric Rods in H Plane Rectangular Waveguide Devices

The paper presents a new accurate and efficient technique for the analysis of H-plane single or multiple rods in rectangular waveguides. The new method is based on a mode matching procedure that matches open space and guided modes along a circular boundary that encloses the rods. Since the EM fields around the obstacles are expanded using open space cylindrical modes, a full analytical (and highly efficient) solution can be obtained for dielectric or metallic circular posts. However, this technique can also cope with any arbitrary geometry of the H plane obstacles. In such a case, a numerical method should be used to characterize geometries other than circular in terms of cylindrical modes, and therefore the efficiency would be reduced. The method has been successfully applied to the analysis and design of several H plane filters with different topologies involving single centered and off-centered posts, as well as double post geometries.