108 and 124 GHz Fundamental VCOs with 21% and 7% DC-to-RF Efficiency in 22nm CMOS FDSOI

This paper presents the design of two high efficiency fundamental voltage controlled oscillators (VCO) for sub-THz applications. The design optimizes the transistor for voltage gain, swing and PAE at the operating frequency to achieve 21% and 7% DC-to-RF efficiencies. The varactor and back-gate voltages are utilized for tuning control. The back-gate controls improves the relative tuning range of the VCOs by $\sim$ 50%. Layout techniques are employed in the transistor and inductor to improve the VCO frequency. The two VCOs are implemented in 22nm CMOS FDSOI, oscillate at 108.7 GHz and 124 GHz having an output power of 3.41 and -1.45 dBm with a tuning range of 3.4% and 3.7%, respectively. The chip operates at a supply voltage of 0.7V and an $I_{BIAS}$ of 1.4mA with a core power consumption of 10.2mW and 9.9mW, respectively. The active area is 0.095x0.087 $mm^{2}$ .