Design of W-band Fin-Line Bandpass Filter With Broadband And Low-Insertion Loss Performance

In this paper, a broadband waveguide bandpass filter (BPF) is proposed using E-plane insert fin-line structure. The design principle is detailed. The characteristics of inductive coupling cell is investigated using the equivalent T-type network and K inverter. Moreover, the relationship between the bandwidth and gap width b
₁
is numerically studied. It is clear that when the gap width is enhanced, both the bandwidth and the selectivity are improved. As demonstration, a wideband BPF with central frequency 94 GHz and bandwidth 11 GHz (FBW 11.7%) is designed, fabricated and measured. The measured results agree well with the simulated ones.