Substrate integrated waveguide quasi-elliptic bandpass filter with meander-slot coupling structures

This paper presents a novel cross-coupled bandpass filter using substrate integrated waveguide (SIW) cavity resonators. A special negative coupling scheme with symmetrical meander slots on the top and bottom metal planes is applied. The design strategies and performances are introduced and discussed in detail. The proposed fourth-order filter shows a fractional bandwidth of 8.2% at 15.24 GHz with a return loss of better than -17.25 dB, an insertion loss of less than -1.8 dB, and excellent frequency selectivity.