An E-Band low-noise Transformer-Coupled Quadrature VCO in 40 nm CMOS

This paper presents a Transformer-Coupled Quadrature VCO (TC-QVCO) designed to achieve low-noise performance at millimeter-wave. The VCO core is implemented combining the tuned-input tuned-output (TITO) oscillator and the Colpitts oscillator, while the coupling is realized by means of transformers, resulting in low noise and accurate quadrature phases. Designed in a 40 nm CMOS process, the TC-QVCO operates between 83.7 GHz and 88.7 GHz (i.e, 5.8% tuning range). Dissipating 28.4 mW from a 0.7 V supply, the measured phase noise is -118.8 dBc/Hz at 10 MHz offset from a 88.7 GHz carrier, resulting in a peak phase-noise FoM of -183.2 dBc/Hz. The I/Q phase error is less than 1.2° over the whole tuning range.