A 122 GHz FMCW Ranging Radar for Hydraulic Accumulator

In order to solve the problems of high temperature, high pressure and oil pollution in the piston displacement measurement of hydraulic accumulators, a piston displacement measurement scheme is proposed based on 122 GHz FMCW ranging radar. According to the analysis of radar system structure and working principle, the detailed design is carried out from the modulation signal unit, T/ R transceiver unit, conditioning unit and ARM real-time processing unit. On the one hand, the integrated design concept is adopted to reduce the system volume and meet the installation and test requirements in the hydraulic accumulator; on the other hand, it improves the penetration of the 122 GHz millimeter wave inside the hydraulic accumulator by designing a focusing lens. The experimental results show that in the 2 m hydraulic accumulator piston test, the 122 GHz FMCW ranging radar can withstand pressure 30 MPa, and the range error does not exceed 2 cm.