Mixed-resonance compact in-line pseudo-elliptic filters

The paper presents a new class of compact in-line pseudo-elliptic filters which are based on combining waveguide cavities and resonant irises. Two different configurations, which allow precise control of the direct couplings between the different resonator types, are introduced. Two different 3-pole filters have been designed to demonstrate the feasibility of the principle. The first filter combines a resonant iris and two TE/sub 101/ mode cavities while the second one utilizes two TM/sub 110/ mode cavities and one resonant iris. The latter has been realized and its response measured. Excellent agreement between computed and measured responses is achieved.