95/190 GHz push-push VCO in 90 nm CMOS

A 95/190 GHz voltage-controlled oscillator (VCO) using gain-enhanced frequency doubler is demonstrated in 90 nm CMOS. Compared with the traditional push-push architecture, the proposed one can significantly increase the second-harmonic output signal due to the inductive series-peaking gain-enhancement of the full-wave-rectifier-based frequency doubler. In addition, low power dissipation is achieved because the bias current of the frequency doubler is reused by the transistors of the VCO. The VCO consumes 12 mW. At the fundamental port, the VCO achieves a tuning range of 92.6∼95 GHz, and a low phase-noise of −88.2 dBc/Hz at 1 MHz offset from the center frequency. The corresponding FOM is −177 dBc/Hz. At the push-push port, the VCO achieves a tuning range of 185.2∼190 GHz, and a low phase-noise of −82.5 dBc/Hz at 1 MHz offset from the center frequency. The corresponding FOM is −177.3 dBc/Hz. To the authors' knowledge, the phase noise and FOM performances of the VCO are one of the best results ever reported for a W-band or G-band CMOS VCO.