Title :
Asymmetric iris coupled cavity filters with stopband poles
Author :
Arndt, F. ; Duschak, T. ; Papziner, U. ; Rolappe, P.
Author_Institution :
Microwave Dept., Bremen Univ., West Germany
Abstract :
An improved type of asymmetric-iris coupled-cavity filters is introduced which utilizes the dual mode resonance and interference characteristics of the fundamental mode and the next-higher-order odd mode in suitably optimized resonators. This design achieves additional stopband poles which may advantageously be used to improve the edge steepness and the rejection characteristic in the second stopband. Based on the modal scattering matrix method. The rigorous design takes into account both the finite iris thickness and the higher-order mode interaction at all step discontinuities. Computer-optimized design examples of asymmetric inductive and resonant iris coupled resonator filters for the waveguide Ku-band (12-18 GHz) and W-band (75-110 GHz), respectively, demonstrate the improved stopband behavior. The theory is verified by available measured results.<>
Keywords :
band-stop filters; cavity resonators; microwave filters; passive filters; waveguide couplers; waveguide theory; 12 to 18 GHz; 75 to 110 GHz; EHF; Ku-band; SHF; W-band; all step discontinuities; asymmetric-iris coupled-cavity filters; computer optimised design; dual mode resonance; edge steepness; finite iris thickness; fundamental mode; higher-order mode interaction; inductive iris coupled resonant filters; interference characteristics; measured results; modal scattering matrix method; next-higher-order odd mode; optimized resonators; rejection characteristic; resonant iris coupled resonator filters; rigorous design; second stopband; stopband behavior; stopband poles; Attenuation; Frequency; Iris; Microwave filters; Resonance; Resonator filters; Scattering; Transmission line matrix methods; Waveguide discontinuities; Waveguide junctions;
Conference_Titel :
Microwave Symposium Digest, 1990., IEEE MTT-S International
Conference_Location :
Dallas, TX
DOI :
10.1109/MWSYM.1990.99559
