A Compact 240 GHz Differential Fundamental Oscillator with -94.2dBc/Hz Phase Noise and 5.4% DC-to-RF Efficiency in 22nm FDSOI

This paper presents a 240-GHz differential fundamental oscillator. With a novel differential π-type topology, the oscillator achieves a compact area, while naturally separating the gate and drain of the transistor to realize biasing flexibility and enhance performance. Thanks to the co-design of the large-signal behavior of transistors and the losses of embedding and matching networks, the DC-to-RF efficiency is optimized. Fabricated in 22nm FDSOI process, the oscillator generates 0.63-mW output power with a 0.5-V gate bias voltage and 1-V power supply, corresponding to a 5.4% DC-to-R$\Gamma$ efficiency. The measured tuning range is 1.47%. To the best of the author’s knowledge, this oscillator has a minimal core area of only 0.003 m$\mathrm{m}^{2}$ and the lowest phase noise of -94.2dBc/Hz at 1 MHz offset among single-core fundamental oscillators with high efficiency.