Mode matching analysis of multiple offset coaxial irises in circular waveguide

The step junction between a circular and an eccentric coaxial waveguide is analysed using a rigorous mode matching technique along with the Graffʹs addition theorem for cylindrical functions. The necessary expressions including the coupling integrals are considered analytically. Based on this analysis the off-centred coaxial iris in a circular waveguide is studied. Its properties are pointed out and the single and dual irises on the same diaphragm features are exploited for the design of bandpass filters.