Realization of an absorptive bandpass filter based on groove gap waveguide technology

Abstract

This article introduces a novel Absorptive Bandpass Filter (BPF) based on Groove Gap Waveguide (GGW) technology. Absorption is achieved by coupling waves from a GGW filter to an auxiliary waveguide including an absorptive sheet through transversal resonant slots at specific frequency bands. The slot positions are determined based on the distribution of the standing wave electric field in the stop-band of the filter. Since filtering and absorption occur together along the wave path without using a T-junction, the filter will be compact and simple. Measurement results of the filter at the central frequency of 14.93 GHz show a minimum insertion loss (IL) of 0.96 dB with a 1.5-dB Fractional Bandwidth (FBW) of 1.74 % and the absorption bandwidth with a minimum return loss of 10 dB in the lower and upper stop-bands is 240 MHz and 1.97 GHz, respectively.