Suppressing Coupling and Stationary Clutters in FMCW Radars with Temporal Filtering

In this paper, a novel signal processing technique based on temporal filtering is proposed to alleviate the coupling between the transmitting (TX) and receiving (RX) channels in frequency-modulated continuous-wave (FMCW) radars. It works by subtracting the target beat signal with the reference beat signal in the absence of the target being detected. Moreover, the proposed temporal filtering technique is also promising to eliminate static clutters. A spectrum-based alignment algorithm was developed to align the target beat signal with the reference signal. The working principle and theory were introduced in details. The gesture sensing experiments are carried out to validate the proposed technique. The experimental results show that the TX-RX coupling was suppressed by about 20 dB. With the proposed technique, the ranging accuracy is also significantly improved by suppressing the mean square error (MSE) by 12.5 dB.