A Low Phase Noise and Ultra-Wideband Voltage-Controlled Oscillator Based on 65nm CMOS

This paper presents a novel approach to realize a low phase noise ultra-wideband Voltage-Controlled Oscillator (VCO) using 65nm CMOS technology. The core circuit of the oscillator employs PMOS cross-coupled pairs to generate second harmonic signals, constituting the push-push structure. Transformer coupling technique is utilized for single-ended to differential signal conversion, and a 3-bit switched capacitor array is designed for wide-range frequency modulation, thereby broadening the operational frequency band of the oscillator. The fundamental oscillation frequency of the proposed VCO is from 3GHz to 5GHz, thus generates a frequency tuning range of 5.7GHz to 10.2GHz for the second harmonic signal. The measured phase noise at a 1MHz offset from the center frequency at room temperature (25°C) is -122.4dBc/Hz. Under a 2.5V power supply, the VCO’s overall power consumption typically ranges around 12.35mW.