A low-power low-phase-noise wide-tuning-range 60-GHz voltage-controlled oscillator in 0.18-µm CMOS

A low-power low-phase-noise wide-tuning-range 60-GHz push-push voltage-controlled oscillator (VCO) is presented in this paper. To eliminate the required λ/4 micropstrip or coplanar waveguide (CPW) line of the conventional push-push VCO, the enhanced second-harmonic output signal (2f_o) is extracted at middle of the varactors, leading to a minimized chip area. By employing MOS varactors deposited between the drain and source terminations of the cross-coupled pair, the tuning range is effectively boosted, and the phase noise is improved. According to these techniques, the fabricated 0.18-μm CMOS VCO exhibits a measured 8.3% tuning range. Operating at 1.2-V supply voltage, the VCO dissipates 7.7-mW dc power excluding the testing buffers. The measured phase noise at 1-MHz offset from 61.5-GHz oscillation frequency is -91.5 dBc/Hz. Compared to recently published 60-GHz VCOs in 0.13-μm CMOS, this work can simultaneously achieve low phase noise, wide tuning range, and low dc power, resulting in the better figure of merit (FOM) and figure of merit considering the tuning range (FOM_T).