Novel Solution for the Coaxial Excitation of Inductive Rectangular Waveguide Filters

In this work, a novel topology for the coaxial excitation of band-pass inductive waveguide filters is presented. The proposed solution, which is based on the use of a new dual-mode resonator, provides us with a very compact design compared to the classical topology of this type of filters. Furthermore, this novel resonator produces a transmission zero in the upper side of the filter pass-band, thus improving the response selectivity. For verification purposes, a compact 5-pole band-pass filter has been successfully designed using a systematic procedure. An equivalent circuit model, based on lumped and distributed elements, is also derived in order to ensure a rigorous design process of the considered filter topology.