Investigation of multiple rectangular aperture irises in rectangular waveguide using TE_mn^x-modes

With the use of proper aperture basis functions in conjunction with the moment method and TE_mn^x-modal expansion, the coupling effect of transverse irises with multiple rectangular coupling apertures in a rectangular waveguide has been investigated. Numerical studies carried out for twin- and triple-aperture coupling irises have been confirmed by the experiments. The simulation result for a Ka-band bandpass filter realized with triple-aperture irises gives a higher stop-band attenuation than that of a filter with single-aperture irises. The use of TE_mn^x-modal expansion is characterized by the reduction of both computer memory and CPU time requirements during the numerical study as compared with the commonly used TE_mn-TM_mn modal approach