A 0.18 $\mu$ m CMOS Quadrature VCO Using the Quadruple Push-Push Technique

This letter presents a new quadrature voltage-controlled oscillator (QVCO), which consists of two complementary cross-coupled voltage-controlled oscillators (VCOs) with two tail inductors. The two differential VCOs are coupled via two tail inductors to form a quadrature VCO. The proposed CMOS QVCO has been implemented with the TSMC 0.18 μm CMOS technology and the die area is 0.83 × 0.96 mm
²
. At the supply voltage of 1.45 V, the free-running frequency of the QVCO is tunable from 4.94 to 5.22 GHz as the tuning voltage is varied from 0.0 to 1.0 V. The total power consumption is 8.7 mW and the measured phase noise at 1 MHz frequency offset is -124.58 dBc/Hz at the oscillation frequency of 5.15 GHz and the figure of merit (FOM) of the proposed QVCO is -189.42 dBc/Hz.