Design And Realization Of Millimetre-wave Frequency Synthesizer Applied In FMCW Automotive Collision Avoidance

In recent years, as science is developing rapidly, automobiles are taken full use of by human in varieties of aspects. Automobiles cause more accidents while providing convenience. Research of Automotive Radar becomes significant. FMCW radar is the most popular way in use among various sorts of safety systems.This article studies on working principles of FMCW radars and phase locked loop s. A Millimetre-wave Frequency Synthesizer is proposed with its simulation and measure results.The paper commences a brief review of present research status and a general introduction of automobile safety radar. Then theoretical analysis on FMCW radar with frequency triangle wave is presented. Working principle of phase locked loop is also reviewed with emphasis on designing of loop filter. Simulation results of system p hase noise with different loop filter parameters are given to verify how diverse parameters influence system phase noise. On the basis of FMCW radar and phase locked loop theories, this paper concludes with a design of frequency synthesizer which is capable producing linear frequency signal via rapidly changing its frequency dividing ratio. Fractional-N synthesizer ADF4159 produced by Analog Devices is used in this design.The designed synthesizer is fabricated finally. Measurement results meet design requirement.