Research And Design Of X Band Low Phase Noise And Low Spurious Frequency Source

As one of the key components in electronic systems such as radar,communication and navigation,the performance of frequency source directly affects the overall performance of electronic systems.With the rapid development of electronic information field,various communication systems have higher requirements for the performance index of frequency source.Low phase noise,high frequency,wide bandwidth,high power,low spurious,agile frequency conversion,small step and miniaturization are ideal targets for frequency source design.In order to realize the portable W-band solid-state cloud detection radar,this thesis designed a miniaturized X-band low-phase-noise and low-spurious frequency source as the "heart" of the radar according to requirements of the radar.Firstly,the research status and development of frequency sources of x-band and other bands at home and abroad were studied,and the functional applications of frequency sources were briefly analyzed.The various implementation methods of frequency synthesis,the main performance indexes of frequency source and their effects on the radar system were studied.The key parts and the advantages and disadvantages of the implementation methods were analyzed in detail.Secondly,combined with the application background and index requirements of frequency source,the mixed structure of DS,DDS and PLL and their respective advantages and disadvantages were analyzed.The scheme of using DDS excitation PLL to realize miniaturization,broadband,low phase noise and low spurious frequency source was determined,and the feasibility of the overall design scheme including structure,chip,phase noise and spurious was demonstrated,and whether the scheme meets the overall design index was analyzed.Then the function module area division and cavity design were performed on the whole system.This thesis briefly introduced the application method of key chips of each functional module,and designed PCB board reasonably considering the problems of size,cost and electromagnetic compatibility.Finally,the performance of each functional module and the whole frequency source was tested,and the measured results were analyzed in detail.At the same time,the problems encountered in the design process were evaluated and analyzed,and the improvement of the subsequent test scheme was also proposed.Through final test of the frequency source,the output signal of 8.5~9.5GHz was realized,the output power is greater than 10 dBm,and at 9.5GHz the phase noise is-110.86dBc/Hz@10kHz.The spur suppression is greater than 50 dBc and the frequency resolution is less than 10 Hz.The research and design of miniaturization,wideband,low phase noise and low spurious frequency sources were realized.