A 18.7-to-31.8GHz Wideband Low-Phase-Noise Hybrid-Coupled Quad-Core Millimeter-Wave VCO with 200.5dBc/Hz of FoM_T

This paper proposes a quad-core, quad-mode millimeter-wave (mmWave) voltage-controlled oscillator (VCO) utilizing electromagnetic hybrid coupling. This design achieves a wide frequency tuning range and low phase noise, fulfilling the needs of integrated sensing and communication (ISAC) systems. The oscillator addresses the challenge of concurrent oscillations in multi-mode switching oscillators by implementing a switched transconductance network. The VCO also employs a controllable tail transistor array to suppress flicker noise up-conversion across a wide bandwidth, effectively reducing the 1/f ³ corner frequency and enhancing the phase noise performance. The VCO is fabricated in a 55-nm CMOS process occupying a core area of 0.08 mm². Measurement results show that the VCO achieves a tuning range of 51.9% spanning from 18.7 to 31.8 GHz, and a phase noise of -110.0 dBc/Hz at 1 MHz offset while consuming 8.4 mW of power, leading to a figure of merit (FoM) of 186.2 dBc/Hz and FoM_T of 200.5 dBc/Hz at 1 MHz offset.