A K-Band Voltage-Controlled Oscillator with Gate-Drain Phase Shift Achieving 110 kHz 1/f3 Corner

Abstract—This work presents a K-band low flicker phase noise (1/f3) corner voltage-controlled oscillator (VCO) utilizing gate-drain phase shift. It incorporates two auxiliary LC tanks to shift the relative phase of the fundamental harmonic between the gate-drain and attenuate the second harmonic components at the output waveform. This design effectively suppresses phase noise caused by flicker noise upconversion without compromising the desired 1/f2 phase noise (PN) performance. By utilizing gate-drain phase shift to symmetrize effective impulse sensitivity function (ISF), the proposed VCO achieves a 1/f3 PN corner of 110kHz while consuming only 4.18mW at 19.64GHz. The design is implemented in a 65nm technology with an active area of 0.1mm2. The measured phase noise at a 1MHz offset frequency is -113.21dBc/Hz, yielding a peak Figure-of-Merit (FoM) of 186.84dBc/Hz at 19.64GHz.