An Enhanced Noise-Performing 77GHz FMCW Radar with Low Cost Practical Implementation

Abstract

A low cost practical 77 GHz frequency modulated continuous wave (FMCW) radar with enhanced noise performance is presented. Conventional FMCW radar suffers from unwanted direct coupled signal at Rx path caused by structural limitations. Moreover, Tx leakages degrade the sensitivity of the receiver. In this work, enhanced Tx-to-Rx isolation is achieved with physically separated Tx and Rx ports. In addition, Tx leakage is further suppressed by 5dB up to 15dB at the receiver with the introduction of hybrid ring coupler into the design. To reduce the manufacturing cost, a soft Teflon substrate of RT/Duroid 5880 with permittivity 2.2 is used. As a result, measured receiver dynamic range is from -97 dBm ~ -20 dBm. Maximum detection range is 104 meters according to the field test. Operating temperature is -40 °C ~ +85 °C considering the severe outdoor environment for vehicle by using all filed proven automotive industrial devices.