Dual-Band Substrate Integrated Waveguide Filters Based on Multi-Mode Resonator Overlapping Mode Control

In this brief, a multi-mode resonator (MMR) overlapping mode control technique is proposed to realize dual-band substrate-integrated waveguide (SIW) bandpass filters (BPFs). A pair of via perturbations and two kinds of slotlines are introduced to control the overlapping modes. Five resonant modes TM110 (a pair of degenerate modes), TM210 (a pair of degenerate modes) and TM020 are perturbed to realize the dual-band filters. The degenerate modes can be rearrange by the via perturbations, and the overlapping modes can be adjusted by the slotlines. Thus, two kinds of dual-band filters can be realized in a single resonant cavity. Then a two-cavity dual-band filter is proposed to realize better out-band suppression and return loss performance. The proposed two-cavity dual-band BPF is synthesized, designed, fabricated, and measured, realizing the 3-dB fractional bandwidth (FBW) of 6.1% and 7.7% at Q-band and V-band, respectively.