Second harmonic power combining technique for low phase noise cross-coupled push-push VCO

An even-mode power combining technique was developed for a high-performance K-band push-push voltage control oscillator (VCO) in standard 0.18 μm CMOS technology. The VCO was designed based on linear time variant (LTV) phase noise model. The obtained frequency tuning range and maximum output power were 1.95 GHz and -9.68 dBm with core power consumption of 3.6 mW at maximum oscillation frequency of 26.7 GHz. The push-push VCO demonstrated a phase noise of -117.5 dBc/Hz at 1 MHz offset, which resulted in an excellent FoM of -199.82 dBc/Hz.