A novel 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. A new complementary Colpitts structure was adopted in a 0.18-μm CMOS process to achieve differential-ended outputs, low phase-noise performance, and low-power consumption. The designed VCO oscillates from 29.8 to 30 GHz with 200 MHz 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 VCO is only 27 mW. In addition, compared with the published papers, the proposed CMOS VCO achieves the best figure of merit (FOM) of −185 dB at 29.95-GHz band.