A Mixed Cross Coupling Gap Waveguide Bandpass Filter with Asymmetric Transmission Zeros

This paper presents a novel mixed cross coupling bandpass filter based on groove gap waveguide technology. A fifth-order cross-coupled bandpass filter centered at 15.07 GHz is designed. A pair of asymmetric transmission zeros are introduced by mixed cross coupling between nonadjacent resonators, which improves the filter selectivity. A wide coupling window is designed to get a wider passband. The designed filter works at Ku band with a 4% relative bandwidth and 0.4 dB insertion loss.