Research And Implementation Of High Resolution MIMO Millimeter Wave Radar Imaging Front End System

With the continuous development of intelligent sensors,the development of millimeter wave imaging radar with small size,low power consumption and easy integration has become the mainstream development direction of millimeter wave radar,and has also become a research focus of scholars and related enterprises at home and abroad.MIMO millimeter wave FM continuous wave imaging radar can greatly improve the angular resolution of radar and achieve high resolution point cloud imaging while taking into account the above advantages,and will undoubtedly become the mainstream of radar application in the future.In this context,a high resolution MIMO millimeter wave imaging radar front-end system working in 77 GHz band is designed and implemented in this paper,which provides implementation scheme for miniaturization and intelligent radar applications.Firstly,according to the requirements of high resolution imaging of millimeter wave radar sensor,an imaging radar front-end structure containing the whole RF front end,echo data capture and transmission to PC is proposed.It includes the RF part based on 12Tx×16Rx MIMO architecture and the signal processing part of data capture and transmission using FPGA with expanded DDR RAM,which can complete the whole process of transmitting radar signal,receiving echo signal,transmitting and uploading signal to PC.According to the basic structure and parameter design of the system,the realization scheme of radar front-end system is designed.The link budget of local oscillator signal cascade is made for four 3Tx×4Rx MMIC chip cascade systems,and design the cascade structure of reference clock signal and synchronous trigger signal,then complete the 12Tx×16Rx multi-channel synchronization design of the system.A bisector Wilkinson power divider operating in the frequency band 19 GHz to 19.5GHz is designed and implemented,and a coaxial type via is designed to reduce parasitic inductance and parasitic capacitance of PCB via of RF signal,thus increasing the link allowance of the system.In the signal transmission part,Zynq Ultra Scale+MPSoc XCZU15 EG with DDR4 memory expansion of 8Gbit memory is used to complete the acquisition and transmission of radar echo signal,and the data upload is completed by gigabit Ethernet interface.Finally,the high resolution MIMO millimeter wave radar imaging front-end system is implemented,and the RF part and signal transmission part are fixed on the structure shell.The phase noise of the RF front-end signal transmitted at 1MHz is below-96 DBC /Hz,and the linearity of FM is below 0.1%,the transmitted signal power meets the design specifications.After testing,the azimuth resolution of the designed millimeter-wave MIMO radar imaging front-end system is up to 0.55°,the signal-to-noise ratio of a single image is nearly 2dB higher than the design index,and the target imaging of 100 meters can be achieved.Finally,the test results are compared with the design indexes,and the rationality of the existing errors is analyzed.The test results show that the high resolution MIMO millimeter wave radar imaging front-end system can meet the design requirements.