A 4.9 GHz low phase noise QVCO using ring coupling technique and used for wireless band application

This letter presents a 8.12mW Quadrature phase Voltage Control Oscillator (VCO) which designed and implemented in tsmc 0.18 um CMOS 1P6M process. This circuit using NMOS coupling circuit to injected into each VCO cross-couple MOS gate. Another key circuit for low power is Class C circuits which lower dc voltage of VCO cross-couple gate side that can reduce power consumption. At the supply voltage 1V, the output frequency is 4.482GHz and the phase noise is - 120.94dBc/Hz at 1MHz offset. Excluding output buffers, the VCO consumes the power 8.12mW under a standard supply of 1 V and Current 8.12mA. The FOM of this VCO is -184.85dBc/Hz.