Abstract
In resent years，wireless communication systems developed rapidly. In the RF front-end circuit，there are some essential component，like LNA、Mixer、and VCO. In the thesis，we would discuss how to minimize the phase noise. We simulate with H-spice and use the model of TSMC 0.25 CMOS process. The tuning range of VCO is from 2.44GHz to 2.77GHz by sweeping control voltage from 0.8V to 1.6V. The phase noise is –107dBc/Hz at 600kHz frequency offset. The power supply voltage is 1.8V and bias current is about 1.2~1.5mA.