Direct-Coupled Cavity Filter in Ridge Gap Waveguide

This paper describes a novel design for a direct-coupled cavity filter realization using a ridge gap waveguide technology. A ridge gap waveguide transmission line with two coaxial feed connectors is designed and operated within the frequency band of 10-13 GHz. A cavity is coupled to the transmission line to achieve bandstop filter characteristic. Then, the structure of the filter is modified in a way to generate a bandpass feature. The final manufactured prototype is a fourth-order bandpass filter, operating at the center frequency of 11.59 GHz with a bandwidth of 72 MHz. The proposed design has potential applications in channeling filters for telecommunication satellites.