Adaptive leakage signal cancellation algorithm in heterodyne FMCW system

Abstract To mitigate the leakage signal that obstructs the target information extraction in miniatured frequency modulated continuous wave (FMCW) radar system, an adaptive leakage signal cancellation algorithm is proposed in this paper. Without any help of the additional auxiliary path, all the processing for the intermediate frequency (IF) signal can be conducted in the digital domain. The basic principle to cancel leakage signal is to produce a cancelling signal, which has the same amplitude and anti-phase with the leakage signal. Differently, in this paper, the input phase parameter of the proposed method can be arbitrary and it can be modified by the corresponding corrected function. Besides, to acquire the phase noise in the leakage signal conveniently when generating cancelling signal, the information geometry theory is applied to transform the complex phase noise model into statistical characteristics calculation of the input signal. The effectiveness of the model and the proposed algorithm is verified by simulated results. Furthermore, a real FMCW system is designed to collect the practice echo signals. The resulting data denotes that the leakage signal in the received signal is greatly suppressed and the leakage signal power drops by −15.92 dB.