Noncontact Vibration and Deformation Detection based on Low Complexity CW Radar

Abstract

A low-cost and high-precision CW radar system is proposed for non-contact detection of the target’s tiny vibration. The radar system can obtain the vibration frequency and amplitude of the target by extracting the phase change of the reflected signal caused by the target’s vibrations. The proposed radar system uses a combination of the phase shifter and the hardware-based phase comparator, which has the advantages of high detection accuracy and low system complexity. Besides, the combination establishes a linear relationship between the phase change caused by vibration and the output signal of the phase comparator, providing the system with the ability to detect the vibration amplitude. Experimental validations show that the radar system can accurately detect the vibration frequency and amplitude of the loudspeaker and monitor human respiration in real-time at a distance of 2 m. For the amplitude experimental, the absolute error of the vibration amplitude measured by the radar system within 30 cm is less than 0.1 mm.