4D Vital Sign Detection Based on a 24GHz 2T4R MIMO Radar System

A 4D vital sign detection technique is proposed in this paper. This method leverages the angle detection capabilities of MIMO radar and the distance sensing capabilities of FMCW radar. It tracks detailed heart and chest movements in time domain by assessing cardiac signals, thus completing the task of 3D spatial and 1D temporal vital sign detection. The proposed technique can acquire targets within a very narrow distance range and accurately locate the heart position. Additionally, a FMCW 2T4R MIMO radar prototype was designed and fabricated for experimental validation. Overnight experiments demonstrated that this method effectively locates the heart in various sleep postures, including supine, lateral, and prone positions. The effective overnight heart rate detection time exceeded $92 \%$, with an average detection error of 1.5 bpm. Compared to traditional beamforming methods, this approach accurately locates the heart while achieving medical-grade precision in heart rate detection, offering significant potential for further cardiopulmonary chronic disease analysis.