A 219-GHz fundamental oscillator with 0.5 mW peak output power and 2.08% DC-to-RF efficiency in a 65 nm CMOS

This paper presents a 219 GHz fundamental CMOS oscillator with a 2.08% DC-to-RF efficiency. The proposed structure oscillates at a high fundamental frequency by adopting a capacitive-load reduction technique. In addition, a differential-to-single (DTS) transformer increases the output power by combing the differential signals. The proposed oscillator is fabricated in a 65 nm CMOS process. The measurements show an output power of 0.5 mW at the fundamental oscillation frequency of 219 GHz, while consuming 24 mA from a 1 V supply voltage. This work presents a fundamental oscillator with a higher DC-to-RF efficiency compared to previous state-of-the-art generators between the 200 and 300 GHz frequency range.