A Multimodal Variational Approach for the Characterization of Waveguide Discontinuities for Microwave Filter Design

A multimodal variational method for analyzing waveguide discontinuities is developed. It combines the accuracy of the theory with a fast computation, thanks to the use of the "coupled" and "uncoupled" modes notions. Some waveguide discontinuities are studied in order to design dual-mode cavity filters and evanescent-mode ridged waveguide filters. Experimental prototypes have been realized and the expected theoretical performances are in good agreement with the measured data.