Research On Key Technology Of W-band FMCW Transceiver Front-end

Millimeter Wave frequency modulated continuous wave(FMCW)transceiver frontend is a key component of millimeter wave FMCW radar,and its performance has an important influence on the overall performance of the radar.Thus,the research of FMCW Transceiver Front-End is of great significance.Based on the characteristics and application background of millimeter wave,this paper introduces the application of millimeter wave in communication and radar.The W-Band is one of the four atmospheric windows with relatively low transmission loss in millimeter wave band,which is widely used.This paper introduces a frequency modulated continuous wave(FMCW)transceiver front-end which works in W band.Firstly,some common radar front-end transceiver architectures and FMCW signal implementation methods are analyzed,and their advantages and disadvantages are compared.According to the subject index,the overall design scheme of the front end of the system is proposed,and the system is divided into three modules: Microwave FMCW modulation source module,W frequency transmitting module and W band receiving module.The transmitting Signal Center frequency is 93.3GHz,the saw-tooth wave modulation is used and has three kinds of switchable waveform forms,and the modulation bandwidth and cycle are 600MHz/2.5ms,300MHz/0.25 ms and 150MHz/0.25 ms respectively.The receiver module uses two times down frequency conversion structure,the first local oscillator LO is a frequency modulated(FM)signal which center frequency is 95.7GHz,and the waveform form is same with the launch branch signal.After I/Q mixing,getting the 2.4GHz first intermediate frequency(IF)signal,which realizes demodulation directly in the W frequency band.Then the first IF signal is processed by the Medium frequency processing module,and after mixing with the second LO which frequency is 2.34 GHz,obtaining the 60 MHz second-IF signal,and the final output is sent to the baseband signal processing.In this paper,the circuit of each part is analyzed,fabricated and tested.The test results show that the transmitter power is larger than 400 mW,the spurious rejection is better than 56 dBc in the whole working frequency band,and the phase noise is better than-81dBc/Hz@1kHz,-80dBc/Hz@10kHz,-95dBc/Hz@200kHz and-124dBc/Hz@10MHz.The gain and dynamic range of receiver are both greater than 60 dB,and the noise figure is lower than 7d B.The developed front-end provides an effective RF front-end solution for W-band FMCW radar.