A 76–82 GHz VCO in 65 nm CMOS With 189.3 dBc/Hz PN FOM and −0.6 dBm Harmonic Power for mm-Wave FMCW Applications

We present a mm-wave low-phase-noise (PN) and power-efficient super-harmonic voltage controlled oscillator (VCO) based on a new PN and harmonic power manipulation technique by shaping voltage waveforms. By observing the effect of relative amplitude and phase of fundamental and second harmonic voltage components across the transistor terminals, it is shown how the impulse sensitivity function (ISF) associated with the noise of transistor as well as generated harmonic power by the active device are inter-related. By systematically choosing the passive embedding of the transistor inside the proposed VCO, it is shown how the circuit can achieve a very low PN while maintaining a high harmonic power generation efficiency. The proposed VCO is fabricated in 65-nm Bulk CMOS technology and achieves a measured frequency tuning range (FTR) of 76–82 GHz with a PN of -109.8 dBc/Hz at 1MHz offset frequency, and a peak figure-of-merit (FoM) of 189.3 dBc/Hz. The proposed VCO demonstrates a 4.6% DC-to-RF efficiency and a peak output power of -0.6 dBm. To the best of our knowledge, This work demonstrates the highest FOM among Si/SiGe varactor-based oscillators operating at this frequency band, to date.