Millimeter-Wave Bandpass Filter Based on Spiral Resonators and DGS Using SiGe BiCMOS Technology

A new ultra-compact millimeter-wave on-chip bandpass filter (BPF) is presented based on two spiral resonators and a defected ground structure (DGS). For investigating the working mechanism of the proposed BPF, an
LC
equivalent circuit is constructed, and then the corresponding transmission zeros (TZs) are calculated in order to make the filter be quickly optimized with the guidance of
LC
equivalent circuit. Finally, the BPF is fabricated using 0.13-
$\mu \text{m}$
SiGe BiCMOS technology for demonstration. The measured results show that the fabricated BPF has a center frequency at 70.65 GHz with a bandwidth of 29.3%. The chip area of the BPF, excluding testing pads, is only 0.0288 mm
²
.