A Compact Silicon-Based Millimeter-Wave Bandpass Filter Using DGS Resonators

This paper presents a compact millimeter-wave bandpass filter (BPF) designed on a high-resistivity silicon (HRS) substrate. By etching a defected ground structure (DGS) on the ground plane to form the resonators with feeding lines, the filter only consists of one metal layer on the HRS substrate surface. Accordingly, a very compact size can be achieved. Two spiral-shaped DGS resonators and one U-shaped DGS resonator are utilized to realize a third-order bandpass filtering response. Due to the cross coupling among different resonators and the source-load coupling, three transmission zeros are generated at two sides of the passband, which greatly enhances the skirt selectivity of the proposed filter. For verification, a filter centered at 26.4 GHz with a 1-dB FBW of 29.2 % is designed. Simulated results show good performance, which is attractive to 5 G millimeter-wave applications.