This paper presents a new quadrature voltage-controlled oscillator (QVCO), which consists of two p-core Colpitts cross-coupled voltage-controlled oscillators (VCOs) with an LC ring resonator to provide the quadrature outputs. The proposed CMOS QVCO has been implemented with the TSMC 0.18 μm CMOS technology and the die area is 0.478 x 0.82 mm2. At the supply voltage of 1.5 V, the total power consumption is 20.4 mW. The free-running frequency of the QVCO is tunable from 9.69 GHz to 10.52 GHz as the tuning voltage is varied from 0.0 V to 2 V. The measured phase noise at 1 MHz frequency offset is -122.41 dBc/Hz at the oscillation frequency of 10.52 GHz and the figure of merit (FOM) of the proposed QVCO is -189.7 dBc/Hz.
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