Design And Implementation Of The Ku-band Frequency Synthesizer

In this paper, based on the research of the working principle of the frequency synthesizer, we analyse the characteristics of stray and loop noise source; Three implementation schemes of frequency synthesizer have been carried on the comprehensive comparison.Using DDS incentive PLL scheme to realize frequency sweep source, and through the point frequency source mixing designed a Ku-band band frequency synthesizer. Software and hardware design of frequency synthesizer are given, and we use ADIsimPLL software simulate various properties of PLL circuit.We developed working range17.4-17.5GHz Ku-band frequency sweep source. And the final machining test result matches simulation results. Phase noise:-89dBc/Hz@10kHz、-112dBc/Hz@lMHz、Basicly achieving the technical indicators.In order to further make the frequency of the output more pure,we use the microstrip structure to design Ku-band narrow bandpass filter.We use Ansoft HFSS12.0to achieve circuit modeling and simulation, and machining and testing. Controling the test and the simulation results, the cause of the differences are analyzed.Controling its test and simulation results, analysing the causes of differences, final we design a center frequency17.46GHz, the bandwidth of120MHz Ku-band narrow bandpass filter.