Chiang, P.-H.P.-H.ChiangCheng, J.-H.J.-H.ChengWu, Y.-C.Y.-C.WuChiong, C.-C.C.-C.ChiongLiu, W.-D.W.-D.LiuHuang, G.-W.G.-W.HuangHuang, T.-W.T.-W.HuangHUEI WANGTIAN-WEI HUANG2020-06-042020-06-042015https://scholars.lib.ntu.edu.tw/handle/123456789/497540A 206 ∼ 220 GHz varactor-free voltage-controlled oscillator (VCO) is proposed to improve the output power and tuning range. The topology of the VCO is push-push crosscoupled pair. By using body-bias technique, the parasitic capacitor of the cross-coupled pair can be adjusted, and the varactors in the conventional VCO design can be removed. The proposed VCO was designed and implemented in TSMC 65-nm CMOS technology with a chip size of 0.25 × 0.25 mm2. The tuning range is 6.6% (from 206.2 to 220 GHz). The measured phase noise is -66 dBc/Hz at 1 MHz offset frequency. The output power is 1.3 dBm at 216 GHz with 54-mW dc power consumption and its maximum dc-to-RF efficiency is 2.1%. To the best of our knowledge, this varactor-free VCO achieves the highest dc-to-RF efficiency among published CMOS VCOs around 200 GHz. © 2015 IEEE.[SDGs]SDG7Bias voltage; Circuit oscillations; CMOS integrated circuits; Energy efficiency; Oscillistors; Phase noise; Varactors; Body bias; CMOS technology; Cross-coupled; DC power consumption; Frequency-tuning; Offset frequencies; Parasitic capacitors; Tuning ranges; Variable frequency oscillatorsconference paper10.1109/MWSYM.2015.71668532-s2.0-84946058835https://www.scopus.com/inward/record.uri?eid=2-s2.0-84946058835&doi=10.1109%2fMWSYM.2015.7166853&partnerID=40&md5=4dddeb7b7a881a80d3b703789a7cb3e8