A 253–280 GHz Wide Tuning Range VCO with -3.5 dBm Peak Output Power in 40-nm CMOS

This paper presents a wide tuning range push-push voltage-controlled oscillator (VCO) at the sub-THz frequency bands. With the introduction of a novel capacitive splitting feedback (CSF) technique and tunable source degeneration (TSD) network, the proposed VCO can simultaneously archive a wide tuning range while maintaining a high output power. The CSF technique improves the oscillation frequency by reducing the effective transistor capacitances, and a wide tuning range is achieved through the TSD network without employing varactors. The proposed VCO is fabricated in a 40-nm digital CMOS process. It shows a -3.5 dBm peak output power with 1.35% DC-to-RF efficiency and a wide tuning range of 10.16% at a center frequency of 267.2 GHz.