Design Guidelines for Microwave Filters in Gap Waveguide Technology

In this paper, the effects of each physical parameter of a gap waveguide structure on the key factors for the design and realization of gap waveguide bandpass filters (BPFs) are discussed and a set of design guidelines is presented. Based on the proposed design guidelines, a third-order differential bandpass filter with intrinsic common-mode suppression is designed, fabricated, and measured for demonstration. Practical considerations regarding the EM power leak from the gap waveguide cavities are also highlighted.