A Novel Trisection for Implementing Below-Passband Transmission Zeros in Evanescent-Mode Waveguide Filters

This paper addresses the design and development of a novel trisection topology in evanescent-mode waveguide technology providing one below-passband transmission zero. The innovative proposal achieves significant improvement in simplicity as compared to alternative solutions where other elements, like cross-coupling probes, are required. As a result, the resulting structure is suitable for tuning-less implementations. A prototype synthesizing a third order filtering function has been designed and manufactured. Measured results fully validate the proposed trisection topology.