The Research Of Low Phase Noise Techniques For Microwave Oscillator

Oscillator is a major part of modern communication circuit.With the rapid progress of wireless communication technology, the performance of signal source was required higher,which primarily focused on improving the stability of the frequency of the signal source,in other words,reducing its phase noise performance.Therefore,this dissertation discussed the design theory and the actual circuit to reduce the oscillator phase noise.Through in-depth understanding of the oscillator principle and oscillator phase noise model,an overall knowledge of the oscillator phase noise was acquired.Based on these knowledge,a detailed analysis and summary method to reduce the circuit of the oscillator phase noise were carried out.Finally,a1.2GHz phase-locked loop(PLL) was designed,simulated and implemented.phase-locked technology was drew into the circuit to further improve the VCO output signal phase noise performance.The simulation of PLL circuit verified its function to improve the phase noise near central oscillation frequency.The phase noise of VCO output signal was reduced from-73.34dBc/Hz@10kHz to-84.4dBc/Hz@10kHz.