A V-Band CMOS Sextuple Sub-Harmonically Injection-Locked VCO Using Transformer and Cascade-Series Coupling with FTL

In this paper, a V-band sextuple sub-harmonically injection-locked voltage-controlled oscillator (SILVCO) with frequency-tracking loop (FTL) is proposed using a 90-nm CMOS process. To achieve high power with good efficient, a current-reused transformer-coupled topology is utilized. An innovative cascade-series coupling is proposed to employ in the oscillator core to highly widen locking range with a sub-harmonic injection number of up to 6. The control voltage of the SILVCO is adaptively aligned using FTL to resist the variations. The measured locking range is from 50.8 to 53.4 GHz with an output power of 0 dBm. The measured phase noise at 1-MHz offset and the rms jitter integrated from 1 kHz to 10 MHz are -109.6 dBc/Hz and 43 fs, respectively. This work features high-order sub-harmonic injection, compact size, and low phase noise.