An Image-Reused Phase-Tuning mm-Wave QVCO with a FoM_T of -204 dBc/Hz

This paper presents an image-reused phase tuning technique (IPTT) for millimeter-wave (mm-wave) quadrature voltage-controlled oscillators (QVCOs). The phase shifter addresses the -45°-45° phase rotation limitation, extending it to 135°-225°. This enhancement extends the QVCO tuning range without deteriorating phase noise. To facilitate the expanded phase tuning range, a transformer-based fourth-order resonator providing bimodal impedance is employed in the proposed QVCO. The bimodal impedance ensures intra-band monotonicity and inter-band continuity, optimizing the overall tuning range. Mismatch mitigation and PLL integration of the proposed QVCO are also discussed. A prototype QVCO, operating from 31.6 to 49.2 GHz, is fabricated in a 40-nm CMOS process. Measurement results show that the QVCO consumes 10 mW of power and achieves a tuning range of 44% and phase noise of -129 dBc / Hz at 10-MHz offset. This leads to a figure of merit (FoM_T) of -204 dBc / Hz at a 10-MHz offset.