3V 4GHz nMOS voltage-controlled oscillator with integrated resonator

Fully monolithic voltage-controlled oscillators (VCOs) presents many challenges to any technology since they require low-parasitic high-quality passives for acceptable tuning range and phase noise levels, and low-power active devices at microwave frequencies. A 1.8GHz CMOS VCO with a 4.5% tuning range is not fully monolithic as it requires bonding wires as inductive elements in the tank circuit. A fully-monolithic VCO based on an nMOS gain stage and an integrated tunable resonator operates at 4GHz with a 9% tuning range.