Six-pole triple mode filters in rectangular waveguide

In this paper we describe tuningless triple mode filters in rectangular waveguide with finite-frequency transmission zeros. The resulting filter structure is very reduced in size so that significant savings are achieved with respect to traditional inductive filter implementations. As an application example, a six pole filter with two transmission zeros is simulated, including the effect of small losses. Comparison between simulation and measurements are also included indicating very good agreement thereby fully validating the proposed triple mode configuration.