Target Detection With Short-Range FMCW Radar Based on Time–Frequency Characteristic-Based Leakage Cancellation Technique

Frequency-modulated continuous-wave (FMCW) radar is commonly employed for target detection. Nevertheless, leakage often occurs between the transmitter (Tx) and the receiver (Rx), leading to degrade the detection of targets in short range. It happens because the Tx–Rx leakage introduces a time delay that is comparable with that of the backscattered reflections from the target, which worsens the signal-to-noise ratio (SNR) and the signal-to-interference ratio (SIR). This article proposes a novel and versatile time–frequency characteristic-based leakage cancellation technique (TFCBLC). By cleverly exploiting the frequency-domain features of the intermediate frequency (IF) signal, the leakage is mitigated through the IF compensation with an antileakage signal. Moreover, the multichirps convolution technique (MCCT) based on the equivalent FMCW radar has been developed to address the problems associated with challenging detection caused by residual leakage and inherent noise. The proposed technique effectively suppresses the Tx–Rx leakage and attenuates noise, enhancing the system’s ability for short-range target detection. A series of simulations and experiments were conducted to demonstrate the effectiveness of the proposed technique for short-range detection with strong leakage and significant noise environments. The results indicate that the SIR and SNR have been improved by around 30 and 17 dB, respectively.