Design of a compact 77-GHz CMOS on-chip bandpass filter using U-type dual-spiral resonators

A first reported ultra-compact 77-GHz CMOS on-chip bandpass filter (BPF) fabricated in TSMC 0.18-μm standard CMOS process is presented. The U-type dual-spiral resonators are utilized to reduce the size of the filter. The extra transmission zero is generated by the tapped-line input/output feed structure. The transmission zero at the lower stopband is located at 57 GHz. The selectivity of the proposed filter is much enhanced. The ultra-compact chip size of the proposed filter is 0.17 × 0.405 mm². The good agreement between simulation and measurement is obtained.