A transformer-based current-reuse QVCO with a capacitor coupling technique in 180 nm CMOS

This paper proposes a low-power and low phase-noise current-reuse quadrature VCO using a combination of capacitor coupling and transformer feedback technique. Compared with conventional active coupled QVCO, the proposed QVCO can achieve a low phase noise characteristics with low power consumption. The proposed QVCO was fabricated in 180nm CMOS process technology and showed a 1MHz offset phase noise of −127 dBc/Hz at 3.97 GHz. The power consumption was 6.26mW with 1.0V supply voltage and a figure of merit (FOM) of the proposed QVCO was −191 dBc/Hz.