A novel compact complementary Colpitts differential CMOS VCO with low phase-noise performance

A low phase-noise Ka-band CMOS voltage-controlled oscillator is proposed in this paper. The CMOS VCO core adopts a new complementary Colpitts structure in a 0.18-μm CMOS technology to achieve the differential-ended outputs with low phase-noise performance, as well as operate at much higher frequency. The VCO oscillates from 29.8 to 30 GHz with 200MHz tuning range. The measured phase-noise at 1-MHz offset is −109 dBc/Hz at 30 GHz and 105.5 dBc/Hz at 29.8 GHz. The power consumption of the VCO core is only 27 mW. To the authors’ knowledge, the proposed CMOS VCO achieves the best figure of merit (FOM) of −185 dB at 29.95-GHz band.