Overview of Wide-Stopband Substrate-Integrated Waveguide Bandpass Filters and Multiplexers

The overview of wide-stopband substrate-integrated waveguide (SIW) bandpass filters (BPFs) and multiplexers are presented, the realization schemes with respect to the merits and drawbacks are summarized and classified into following types, i.e., introducing lowpass filters (LPFs), producing transmission zeros (TZs), staggering higher-order mode resonances, controlling couplings, and pushing higher-order mode resonances. Current research status is summarized and the future development vision is also proposed, including the promising outlooks and study obstacles pertaining the progress of wide-stopband SIW filtering devices.