Impact of Circuit Nonlinearities on the Performance of Millimeter-Wave FMCW Radar-on-Chip Systems

In this paper, we present a nonlinear system model to evaluate the impact of circuit nonlinearities on the performance of millimeter-wave frequency-modulated continuous-wave (FMCW) radar-on-chip systems. The developed model can be used to derive frequency and amplitude of spurs in the radar IF spectrum. The major new insights about the impact of different nonlinearities as well as their interactions are as follows. 1) The harmonics of the frequency multiplier appear as spurs close to the target echo in the radar IF spectrum. 2) The PA can be operated in its nonlinear region to mitigate the harmonics generated by the frequency multiplier. 3) The interaction between the TX-to-RX leakage signal and the LNA nonlinearity can lead to spurs close to the target echo in the IF spectrum. 4) The leakage signal can generate spurs very close to the target echo when the delay of the leakage signal is comparable to the radar signal time-of-flight.