Multi-mode wideband bandpass filters using waveguide cavities (invited)

A novel class of miniaturized multi-mode wideband bandpass filters (BPFs) is introduced this paper, includes four multiple-mode filters. Two of them are realized using metal cavity and two of them are realized using substrate integrated waveguide (SIW). These filters have significant advantages in size reduction which can reduce 2.5-4 times compared with traditional single-mode cavity filter. The fractional bandwidth of three filters achieves 30%, 31% and 42%, respectively. All three BPFs are analyzed and experimentally demonstrated. Comparisons of the measured and simulated results are presented and in good agreements with each other.