A 31.8–40.8GHz Continuously Wide-Tuning VCO Based on Class-B Oscillator using Single Varactor and Inductor

A 31.8-40.8GHz continuously voltage-tuning LC-tank CMOS differential VCO is presented that has been designed by using only a pair of varactors and single symmetric inductor available from library, and adopting class-B oscillator. The push-pull complementary class-B oscillator is applied in the VCO to isolate LC-tank resonator from external and internal loads, and to produce more negative resistance, and thus resulting in wide frequency tuning range. The VCO shows 24.8% tuning range, -93.5dBc/Hz phase noise at 1MHz offset, and -14dBm output power with 50Ω load. The VCO is manufactured using 40nm CMOS process with consuming 20mW in oscillator circuit.