Millimeter-wave filter using novel micromachined substrate integrated waveguide structure with embedded silicon vias in BCB dilectrics

This paper reports a millimeter-wave bandpass filter (BPF) based on a novel micromachined substrate integrated waveguide (SIW) structure with square complementary split-ring resonators (CSRRs). Four CSRRs are introduced to the SIW as an element providing passband characteristics below a cutoff frequency of the waveguide required for BPF. Unlike usual SIW-BPFs, the proposed BPF can be integrated with silicon-based circuits or RF MEMS devices by micromachining batch process due to its silicon process compatibility. In order to change the propagation mode from TEM to TE₁₀, triangular slots are utilized as a CPW to waveguide transition. The fabricated BPF shows a high selectivity with a minimum insertion loss of 2.27 dB at 14 GHz and a 3-dB bandwidth of 9.3 %. These measured results are in good agreement with the simulation results.