Vibrating Clutter Interference Removal Technique in FMCW Radar for Mechanical Vibration and Vital Sign Detection

Based on the phase evaluation method, frequency modulated continuous wave (FMCW) radar has been used for non-contact range tracking with a high accuracy. However, due to the finite range resolution, FMCW radar is still vulnerable to the target’s adjacent clutters which would distort the phase history. Especially, when the clutters are no longer stationary, which is common in biological heartbeat detection scenario, general stationary clutter removal methods may not work properly. In this paper, a novel method is proposed to reduce the vibrating clutter by subtraction of frames with a proper time interval. Based on this method, the beat frequency of a metal reflector interfered by an adjacent vibrating clutter is recovered accurately. Moreover, in human vital sign detection scenario, experiment shows that the impact of human respiration, which usually acts as a natural adjacent clutter for the heartbeat, could be deeply reduced and the signal quality of the heartbeat is improved significantly.