Millimeter-wave bandpass filter using high-Q conical inductors and MOM capacitors

This paper describes an efficient implementation of a lumped millimeter(mm)-wave narrow bandpass filter at 60 GHz. The mm-wave filter uses layout optimized conical spiral inductors which are shown to have higher quality factor (Q) and self resonant frequency values than standard spiral inductors. The filter also uses interdigital metal-oxide-metal capacitors which are shown to have Q values than nitride metal-insulator-metal (MIM) capacitors at these high frequencies. The filter is fabricated in 0.18 μm high resistivity RF silicon-on-insulator CMOS technology. The filter has a center frequency of 60 GHz and 3 dB bandwidth of 8 GHz, with a fractional bandwidth of 13.3% and a loaded Q of 7.5 occupying an area of (150×215)μm2. Monte-carlo simulations of the filter demonstrate excellent robustness against process variations due to usage of only two top thick metals and exclusion of MIM capacitors.