A novel millimeter wave filter based on a thin-film IPD process

In this letter, a millimeter dual-band bandpass SIW filter using thin-film IPD process is proposed. The filter adopts a single SIW cavity, uses mode coupling and CSRR resonator coupling to realize the passband of third-order and second-order filters respectively, and has four zeros at the same time. Under the condition of ensuring good performance, the miniaturization of SIW millimeter wave filter is realized. In addition, the introduction of slot perturbations in the cavity allows flexible adjustment of the bandwidth and center frequencies (CFs) of both passbands. The millimeter dual-band bandpass filter designed in this paper has center frequencies of 29.8 and 42.25 GHz, 3-dB bandwidths of 10% and 6.8%, and insertion losses of 2.11 and 2.72 dB, respectively.