Research And Design Of L-band LC VCO And High-speed Divider-2Circuits

As one of the key modules, Local Oscillator has great influence on the RFFront-end Receiver System. In order to better suppress image signal and improve theperformance of RF Front-end Receiver System, it requires Local Oscillator module canprovide fine full-differential quadrature signals.A complementary LC VCO and a high-speed div-2circuit were designed by theTSMC0.18μm RF CMOS Process for obtaining good performance of quadraturesignals. Firstly, the principle of VCO and the key components with their basic propertieswere described in this thesis. Compared with several other VCO structures andcombined with the design requires, the structure of complementary LC VCO is adopted.Secondly, the phase noise was analyzed and several models commonly used were given.Some actions to reduce the phase noise were introduced to provide theoretical supportfor designing a high-performance LC VCO. Then, the method for detailed realization ofLC VCO and the advice on the choice of inductors, capacitors in the actual circuitdesign were provided. The structure of analog tuning capacitor array and the digitalswitch capacitor array was given as well.In order to better suppress image signal, the system requires the Local Oscillatorcan provide full-differential quadrature signals. Compared with several methods thatcan provide quadrature signals, the div-2circuit with stable performance which takes upsmall area was adopted. The steps to design the div-2circuit were given as well. Thetapeout test results show that the frequency tuning range completely covers the requiredfrequency points and the phase noise is up to-98.53dBc/Hz@100kHz,-121.84dBc/Hz@1MHz.