Interference Mitigation of 24-GHz FMCW Sensor Using IQ -Channel Projection Method

This paper presents a projection-based interference suppression method for FMCW radar sensors under single-tone continuous wave jamming. The proposed approach operates in the baseband domain by exploiting the orthogonality of I and Q channels. First, a CFAR-based thresholding process localizes jamming-contaminated segments, from which the dominant phase trajectory is estimated in the IQ polar domain. Leveraging this trajectory, the signal is phase-rotated to concentrate the jamming energy into a single channel (I or Q). Subsequently, variance analysis identifies the interference-minimized “optimum channel”, to which FFT processing is exclusively applied. Experimental validation using a 24.6 GHz jamming source demonstrates that the proposed method reduces the noise floor by up to 16 dB, effectively recovering target detectability degraded by interference. These results confirm the method’s computational efficiency and robustness, thereby improving detection reliability in spectrally congested environments.