On the Impact of Idle-Time Reduction on FMCW Radar Phase Noise Performance

This brief theoretically investigates the impact of reducing idle time—the dead time between consecutive chirps—on the performance of frequency-modulated continuous-wave (FMCW) radar systems. The results show that reducing idle time while maintaining the chirp bandwidth helps lower the chirp slope, offering several key advantages. First, it alleviates the effects of reciprocal mixing caused by system phase noise (PN), thereby improving the signal-to-noise ratio in multi-target scenarios. Second, it enhances the range correlation effect, further mitigating phase noise and improving target detection capabilities. Third, this adjustment relaxes the requirements for the analog-to-digital converter. Finally, it improves chirp linearity and range resolution by enabling the use of an FMCW signal with a lower chirp slope. These findings are supported by theoretical analysis and validated through simulation results.