A Low-Phase-Noise CMOS Quadrature Voltage-Controlled Oscillator Using a Self-Injection-Coupled Technique

A modified coupled method for multiphase oscillator is proposed and demonstrated in a standard 0.18-μm CMOS technology. A self-injection-coupled (SIC) technique is used to couple two current-reused differential voltage-controlled oscillators (VCOs). Compared with the conventional parallel-coupled quadrature VCO (QVCO), the proposed QVCO using the SIC technique presents low phase noise without increasing dc power consumption. The proposed SIC-QVCO at 16.28 GHz demonstrated a low phase noise of -125 dBc/Hz at 1-MHz offset frequency and a tuning range of 290 MHz. The dc supply voltage and current consumption are 1.8 V and 6 mA, respectively. The chip size of the proposed SIC-QVCO is 0.75 × 0.6 mm
²
.