On the Sensitivity Degradation Caused by Short-Range Leakage in FMCW Radar Systems

Frequency modulated continuous wave (FMCW) radar systems suffer from permanent leakage due to their continuous operation. Especially in integrated circuits this leads to the well known issue of on-chip leakage due to limited isolation between transmit and receive circuitry. In addition, we investigate short-range (SR) leakage resulting from signal reflections of an unwanted close object located a few centimeters distant from the antennas. We carry out an in-depth analysis of the SR leakage and show that its residual phase noise in the intermediate frequency signal exceeds the total noise floor of the system, hence degrading the target detection sensitivity. We prove our analytical derivations with a complete FMCW radar system simulation.