Application of Linear-Frequency-Modulated Continuous-Wave (LFMCW) Radars for Tracking of Vital Signs

• Published in: IEEE transactions on microwave theory and techniques Vol. 62; no. 6; pp. 1387 - 1399
• Main Authors: Wang, Guochao, Munoz-Ferreras, Jose-Maria, Gu, Changzhan, Li, Changzhi, Gomez-Garcia, Roberto
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.06.2014; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Algorithms; Applied sciences; Architecture; Biomedical applications; Clutter; Computer simulation; Doppler radar; Exact sciences and technology; Exploitation; History; linear-frequency-modulated continuous-wave (LFMCW) radars; Maintenance; Mathematical analysis; Monitoring; Radar; Radar tracking; Radiolocalization and radionavigation; range tracking; short-range radars; Telecommunications; Telecommunications and information theory; Tracking; vital signs; wireless sensors; Parameter estimation; Frequency modulation; Prototype; Wireless telecommunication; Clutter; Implementation; Remote sensing; Mathematical analysis; linear-frequency-modulated continuous-wave (LFMCW) radars; Robustness; Monitoring; Biomedical engineering; Target tracking; vital signs; Biomedical applications; CW radar; Multiple scattering; short-range radars; Algorithm; wireless sensors; Simulation; Phase estimation; Coherence; range tracking; Biomedical electronics; Non contact measurement; Short range radar
• ISSN: 0018-9480; 1557-9670
• DOI: 10.1109/TMTT.2014.2320464

This paper focuses on the exploitation of linear-frequency-modulated continuous-wave (LFMCW) radars for noncontact range tracking of vital signs, e.g., respiration. Such short-range system combines hardware simplicity and tracking precision, thus outperforming other remote-sensing approaches in the addressed biomedical scenario. A rigorous mathematical analysis of the operating principle of the LFMCW radar in the context of vital-sign monitoring, which includes the explanation of key aspects for the maintenance of coherence, is detailed. A precise phase-based range-tracking algorithm is also presented. Exhaustive simulations are carried out to confirm the suitability and robustness against clutter, noise, and multiple scatterers of the proposed radar architecture, which is subsequently implemented at the prototype level. Moreover, live data from real experiments associated to a metal plate and breathing subjects are obtained and studied.