BZN varactor -based VCO phase noise and phase-locked technology research
|School||University of Electronic Science and Technology|
|Course||Electronic Science and Technology|
|Keywords||BZN capacitor phase noise VCO PLL high frequency measurement|
VCOs (voltage controlled oscillators), for carrier generating and mixing, are widely used in wireless communication and radar system. Phase noise is the key parameter of VCOs. The most effective noise reduction method is to introduce resonators with high Q factor. In microwave frequency band, the most popular device for oscillator tuning is semiconductor varactor, whose loss reduces total Q factor of the resonator. At present, in microwave frequency band, the BZN (bismuth zinc niobate) capacitor’s Q factor is larger then varactor. So, we could estimate the BZN capacitor’s performance may exceed varactor and optimize the phase noise of VCOs.The dissertation includes four key technologies.Firstly, the measurement methods of BZN capacitor are researched, the calibration theory and fixture design are studied.Secondly, the relative theory of VCOs and PLLs design and noise modeling are presented. A VCO is designed with the ADS.Thirdly, the jointing technology of chip transistors and circuit is studied, and the Influence of the additional parameters of relative devices is analyzed.To sum up, the dissertation finished the test method and platform for BZN capacitor. The finished VCO has good electrical character, The phase noise is–92.8dBc/Hz@100kHz. The PLL based on ADF4112 further improves the near carrier phase noise. The phase noise of the PLL is–85.4dBc/Hz@100KHz.