Multitarget Vital Signs Measurement With Chest Motion Imaging Based on MIMO Radar

• Published in: IEEE transactions on microwave theory and techniques Vol. 69; no. 11; pp. 4735 - 4747
• Main Authors: Feng, Chen, Jiang, Xiaonan, Jeong, Min-Gyo, Hong, Hong, Fu, Chang-Hong, Yang, Xiaohui, Wang, E., Zhu, Xiaohua, Liu, Xiaoguang
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.11.2021; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: 2-D digital beamforming (DBF); Antenna measurements; Beamforming; Chest; Continuous radiation; Continuous wave (CW); Flicker; Frequency measurement; Heart beat; Imaging radar; Intermediate frequencies; MIMO communication; MIMO radar; multiple targets; multiple-input–multiple-output (MIMO); Radar; Radar equipment; Radar imaging; Radar measurements; Radar systems; vital signs
• ISSN: 0018-9480; 1557-9670
• DOI: 10.1109/TMTT.2021.3076239

Simultaneous multitarget vital signs measurement has become a hot issue for noncontact vital signs perception. However, there is still challenge in the multitarget heartbeat measurement due to the weakness of heartbeat signal and interference from complex environment. In this article, a new multiple-input-multiple-output (MIMO) continuous-wave (CW) radar system equipped with 2-D digital beamforming (DBF) is presented to measure the respiration and heartbeat of multiple human subjects at unknown positions simultaneously. Through 2-D beam scanning of the whole scene, a 2-D radar image is generated. From the image, the chest motion of multiple targets is accurately located. Then, the vital signs of targets are obtained through forming individual beams focusing on the chests of targets. Moreover, the low intermediate frequency (low-IF) architecture is adopted to minimize the impact of flicker noise in low-frequency amplifier stages. The experimental results demonstrate that the proposed MIMO 2-D imaging radar system can locate chest areas of multiple targets, suppress the clutters, and make vital signs measurement, heartbeat measurement in particular, more robust compared with single-input-multiple-output (SIMO) radar system in complex environment.