Frequency response of waveguide filters with thick diaphragms†

Abstract

Abstract The solution for tho far field diffraction by a slit in a thick conducting screen is utilized to find the scattering coefficients of a symmetric inductive waveguide diaphragm of finite thickness. The resulting equivalent circuit is employed to design a three cavity 0.5 dB pasaband ripple Tehebyseheff filter using thick waveguide diaphragms. The analytical results for the diaphragm and filter are shown to be in good agreement with numerical and experimental data. It is also shown that the diaphragm thickness can be effectively used as an additional design parameter and, with all other parameters fixed, the bandwidth decreases with increasing diaphragm thickness.