A 60 GHz low phase noise VCO with second harmonic tail extraction in 40-nm CMOS

This work presents a 60 GHz continuously adjustable mm-wave cross-coupled voltage − controlled oscillator (VCO) utilizing an innovative frequency doubling technique in 40 nm CMOS technology. The extraction of the second harmonic is performed through a transformer from the tail of the 30 GHz fundamental VCO. The primary side of the transformer serves a dual purpose, functioning both as a filter for the second harmonic and as a balun simultaneously. The circuit incorporates a MOS varactor along with a four-bit binary weighed capacitor bank to achieve coarse and fine frequency tuning respectively. Post Layout simulation results indicate that the VCO spans a broad tuning range of 12.3 GHz, covering frequencies from 52.7 to 64.98 GHz. Phase noise (PN) remains below −96.3 dBc/Hz at a 1 MHz frequency offset within all bands Power consumption, including the output stage, is 21.8 mW from a 1.1-Volt supply. The VCO provides more than −13 dBm output power in all frequency bands and occupies a chip area of 0.53 $m{m}^2$.