Full-wave analysis of coupling between cylindrical combline resonators

The mode-matching method is applied to the analysis of couplings between cy lindrical combline resonators, which are key building elements of combline filters. Finite iris thickness and higher order mode interactions are rigor ously taken into account, thus allowing any size of rectangular coupling ir is to be analyzed, and accurate solutions to be obtained. Validity of the a pproach is verified by checking the field distributions in the resonators a nd comparing the numerical results with HFSS and measurements. As an applic ation of the analysis, a filter design example is demonstrated. Typical cou pling curves of practical importance are presented, which can help in the d esign of combline filters.