A Superharmonic Injection Based G-Band Quadrature VCO in CMOS

This paper presents a G-band quadrature voltage-controlled oscillator (QVCO) enabled by a superharmonic injection technique. This technique ensures differential phases at the common mode tail current source nodes of two differential oscillators, which are then enforced to generate quadrature outputs. It achieves a maximum output power of -1.54 dBm with the efficiency of 3.2% and the tuning range (TR) from 149.3 GHz to 152.4 GHz. The measured phase noise (PN) is -91.9 dBc/Hz at 1 MHz offset. The IQ outputs are down-converted by an on-chip mixer for phase and amplitude accuracy measurement. The measured I/Q phase mismatch is less than 1.5° and amplitude mismatch of less than 0.33 dB over the operating frequency range. The QVCO is implemented in a 28 nm CMOS process, occupying 0.028 mm² chip area.