−188.4-dBc/Hz FoM Complementary VCO Employing Current Harmonic Cancellation Achieving 5-dB Phase Noise Reduction at 1/f ³ Region

A harmonic cancellation technique based on a phase manipulation technique is presented for Ku-band voltage-controlled oscillators (VCO), achieving significant phase noise reduction, especially at the 1/f³ region. The proposed VCO incorporates an auxiliary PMOS transistor with dynamically controlled biasing to generate additional high-order components to compensate for the intrinsic phase difference between the high-order harmonic components of the main PMOS and NMOS cross-coupled transistors, establishing the required 180° phase difference (∆θ) between them. The alignment, facilitated by the proposed technique, significantly suppresses the undesired high-order harmonic components entering the tank’s capacitive path and disturbing its natural frequency. The proposed VCO is fabricated in 65nm CMOS technology, achieving a phase noise of −33.78 dBc/Hz at 1 kHz and -112 dBc/Hz at 1 MHz. The phase noise improvement reaches 5.56 dB at the 1/f³ region compared to a conventional complementary VCO. With a low power consumption of 4.5 mW, the proposed VCO achieves an excellent figure-of-merit (FoM) of −188.4 dBc/Hz with a tuning range of 1.1 GHz (8.1%) operating from 13 GHz to 14.1 GHz.