{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,23]],"date-time":"2026-04-23T02:00:50Z","timestamp":1776909650260,"version":"3.51.2"},"reference-count":41,"publisher":"MDPI AG","issue":"10","license":[{"start":{"date-parts":[[2020,5,25]],"date-time":"2020-05-25T00:00:00Z","timestamp":1590364800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["61771083"],"award-info":[{"award-number":["61771083"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["61901076"],"award-info":[{"award-number":["61901076"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["61704015"],"award-info":[{"award-number":["61704015"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100013048","name":"Fundamental and Frontier Research Project of Chongqing","doi-asserted-by":"publisher","award":["cstc2017jcyjAX0380"],"award-info":[{"award-number":["cstc2017jcyjAX0380"]}],"id":[{"id":"10.13039\/501100013048","id-type":"DOI","asserted-by":"publisher"}]},{"name":"Young project of science and technology research program of Chongqing Education Commission of China","award":["KJQN201900603"],"award-info":[{"award-number":["KJQN201900603"]}]},{"name":"University Outstanding Achievement Transformation Project of Chongqing","award":["KJZH17117"],"award-info":[{"award-number":["KJZH17117"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>In recent years, non-contact radar detection technology has been able to achieve long-term and long-range detection for the breathing and heartbeat signals. Compared with contact-based detection methods, it brings a more comfortable and a faster experience to the human body, and it has gradually received attention in the field of radar sensing. Therefore, this paper extends the application of millimeter-wave radar to the field of health care. The millimeter-wave radar first transmits the frequency-modulated continuous wave (FMCW) and collects the echo signals of the human body. Then, the phase information of the intermediate frequency (IF) signals including the breathing and heartbeat signals are extracted, and the Direct Current (DC) offset of the phase information is corrected using the circle center dynamic tracking algorithm. The extended differential and cross-multiply (DACM) is further applied for phase unwrapping. We propose two algorithms, namely the compressive sensing based on orthogonal matching pursuit (CS-OMP) algorithm and rigrsure adaptive soft threshold noise reduction based on discrete wavelet transform (RA-DWT) algorithm, to separate and reconstruct the breathing and heartbeat signals. Then, a frequency-domain fast Fourier transform and a time-domain autocorrelation estimation algorithm are proposed to calculate the respiratory and heartbeat rates. The proposed algorithms are compared with the contact-based detection ones. The results demonstrate that the proposed algorithms effectively suppress the noise and harmonic interference, and the accuracies of the proposed algorithms for both respiratory rate and heartbeat rate reach about 93%.<\/jats:p>","DOI":"10.3390\/s20102999","type":"journal-article","created":{"date-parts":[[2020,5,26]],"date-time":"2020-05-26T03:29:10Z","timestamp":1590463750000},"page":"2999","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":211,"title":["Remote Monitoring of Human Vital Signs Based on 77-GHz mm-Wave FMCW Radar"],"prefix":"10.3390","volume":"20","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-5061-8173","authenticated-orcid":false,"given":"Yong","family":"Wang","sequence":"first","affiliation":[{"name":"School of Communication and Information Engineering, Chongqing University of Posts and Telecommunications, Chongqing 400065, China"}]},{"given":"Wen","family":"Wang","sequence":"additional","affiliation":[{"name":"School of Communication and Information Engineering, Chongqing University of Posts and Telecommunications, Chongqing 400065, China"}]},{"given":"Mu","family":"Zhou","sequence":"additional","affiliation":[{"name":"School of Communication and Information Engineering, Chongqing University of Posts and Telecommunications, Chongqing 400065, China"}]},{"given":"Aihu","family":"Ren","sequence":"additional","affiliation":[{"name":"School of Communication and Information Engineering, Chongqing University of Posts and Telecommunications, Chongqing 400065, China"}]},{"given":"Zengshan","family":"Tian","sequence":"additional","affiliation":[{"name":"School of Communication and Information Engineering, Chongqing University of Posts and Telecommunications, Chongqing 400065, China"}]}],"member":"1968","published-online":{"date-parts":[[2020,5,25]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"5093","DOI":"10.1038\/srep05093","article-title":"Surface chest motion decomposition for cardiovascular monitoring","volume":"4","author":"Shafiq","year":"2014","journal-title":"Sci. Rep."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"250","DOI":"10.1016\/j.bios.2017.03.016","article-title":"Flexible heartbeat sensor for wearable device","volume":"94","author":"Kwak","year":"2017","journal-title":"Biosens. Bioelectron."},{"key":"ref_3","unstructured":"Yamashita, S. (2013). Biological Signal Detection Electrode and Biological Signal Detection Apparatus. (8,620,401), U.S. Patent."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"105","DOI":"10.1109\/10.817625","article-title":"Microwave life-detection systems for searching human subjects under earthquake rubble or behind barrier","volume":"47","author":"Chen","year":"2000","journal-title":"IEEE Trans. Biomed. Eng."},{"key":"ref_5","doi-asserted-by":"crossref","unstructured":"Li, C., Lin, J., and Xiao, Y. (September, January 30). Robust overnight monitoring of human vital signs by a non-contact respiration and heartbeat detector. Proceedings of the 2006 International Conference of the IEEE Engineering in Medicine and Biology Society, New York, NY, USA.","DOI":"10.1109\/IEMBS.2006.260148"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"1363","DOI":"10.1175\/JTECH-D-13-00107.1","article-title":"Assessment of CODAR Seasonde and WERA HF Radars in Mapping Surface Currents on the West Florida Shelf","volume":"31","author":"Liu","year":"2014","journal-title":"J. Atmos. Ocean. Technol."},{"key":"ref_7","doi-asserted-by":"crossref","unstructured":"Zhao, C., Zezong, C., He, C., Xie, F., Chen, X., and Mou, C. (2018). Validation of Sensing Ocean Surface Currents Using Multi-Frequency HF Radar Based on a Circular Receiving Array. Remote. Sens., 10.","DOI":"10.3390\/rs10020184"},{"key":"ref_8","doi-asserted-by":"crossref","unstructured":"Wyatt, L.R. (2012, January 21\u201324). Use of HF radar for marine renewable applications. Proceedings of the 2012 Oceans\u2014Yeosu, Yeosu, Korea.","DOI":"10.1109\/OCEANS-Yeosu.2012.6263439"},{"key":"ref_9","doi-asserted-by":"crossref","unstructured":"Yavari, E., Jou, H., Lubecke, V., and Boric-Lubecke, O. (2013, January 20). Doppler radar sensor for occupancy monitoring. Proceedings of the 2013 IEEE Topical Conference on Power Amplifiers for Wireless and Radio Applications, Santa Clara, CA, USA.","DOI":"10.1109\/PAWR.2013.6490217"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"57","DOI":"10.1109\/MMM.2013.2296210","article-title":"Is there anybody in there?: Intelligent radar occupancy sensors","volume":"15","author":"Yavari","year":"2014","journal-title":"IEEE Microw. Mag."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"4592","DOI":"10.1109\/TMTT.2015.2495298","article-title":"Gesture sensing using retransmitted wireless communication signals based on Doppler radar technology","volume":"63","author":"Wang","year":"2015","journal-title":"IEEE Trans. Microw. Theory Tech."},{"key":"ref_12","doi-asserted-by":"crossref","unstructured":"Liu, C., Gu, C., and Li, C. (2015, January 25\u201328). Non-contact hand interaction with smart phones using the wireless power transfer features. Proceedings of the 2015 IEEE Radio and Wireless Symposium (RWS), San Diego, CA, USA.","DOI":"10.1109\/RWS.2015.7129750"},{"key":"ref_13","unstructured":"Hosseini, S.A.T., and Amindavar, H. (2017, January 5\u20139). UWB radar signal processing in measurement of heartbeat features. Proceedings of the 2017 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP), New Orleans, LA, USA."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"1079","DOI":"10.1109\/LGRS.2012.2190707","article-title":"Through-Wall Detection of Human Being\u2019s Movement by UWB Radar","volume":"9","author":"Li","year":"2012","journal-title":"IEEE Geosci. Remote. Sens. Lett."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"2046","DOI":"10.1109\/TMTT.2013.2256924","article-title":"A review on recent advances in Doppler radar sensors for noncontact healthcare monitoring","volume":"61","author":"Li","year":"2013","journal-title":"IEEE Trans. Microw. Theory Tech."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"1132","DOI":"10.1109\/TMTT.2019.2948844","article-title":"Doppler Cardiogram: A Remote Detection of Human Heart Activities","volume":"68","author":"Dong","year":"2019","journal-title":"IEEE Trans. Microw. Theory Tech."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"5633","DOI":"10.1109\/TGRS.2013.2291573","article-title":"Short-range wideband FMCW radar for millimetric displacement measurements","volume":"52","author":"Anghel","year":"2014","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"933","DOI":"10.1049\/el.2015.0309","article-title":"Method of doubling range resolution without increasing bandwidth in FMCW radar","volume":"51","author":"Li","year":"2015","journal-title":"Electron. Lett."},{"key":"ref_19","unstructured":"Sharpe, S.M., Seals, J., MacDonald, A.H., and Crowgey, S.R. (1990). Non-Contact Vital Signs Monitor. (4,958,638), U.S. Patent."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"571986","DOI":"10.1155\/2013\/571986","article-title":"FMCW radar for small displacement detection of vital signal using projection matrix method","volume":"2013","author":"Zhang","year":"2013","journal-title":"Int. J. Antennas Propag."},{"key":"ref_21","doi-asserted-by":"crossref","unstructured":"Lee, H., Kim, B.H., Park, J.K., and Yook, J.G. (2019). A Novel Vital-Sign Sensing Algorithm for Multiple Subjects Based on 24-GHz FMCW Doppler Radar. Remote Sens., 11.","DOI":"10.3390\/rs11101237"},{"key":"ref_22","doi-asserted-by":"crossref","unstructured":"Anitori, L., de Jong, A., and Nennie, F. (2009, January 4\u20138). FMCW radar for life-sign detection. Proceedings of the 2009 IEEE Radar Conference, Pasadena, CA, USA.","DOI":"10.1109\/RADAR.2009.4976934"},{"key":"ref_23","doi-asserted-by":"crossref","unstructured":"Gu, C., Wang, G., Inoue, T., and Li, C. (2013, January 2\u20137). Doppler radar vital sign detection with random body movement cancellation based on adaptive phase compensation. Proceedings of the 2013 IEEE MTT-S International Microwave Symposium Digest (MTT), Seattle, WA, USA.","DOI":"10.1109\/MWSYM.2013.6697618"},{"key":"ref_24","doi-asserted-by":"crossref","unstructured":"Ahmad, A., Roh, J.C., Wang, D., and Dubey, A. (2018, January 23\u201327). Vital signs monitoring of multiple people using a FMCW millimeter-wave sensor. Proceedings of the 2018 IEEE Radar Conference (RadarConf18), Oklahoma City, OK, USA.","DOI":"10.1109\/RADAR.2018.8378778"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"54958","DOI":"10.1109\/ACCESS.2019.2912956","article-title":"Remote monitoring of human vital signs using mm-wave FMCW radar","volume":"7","author":"Alizadeh","year":"2019","journal-title":"IEEE Access"},{"key":"ref_26","unstructured":"Brooker, G.M. (2005, January 21\u201323). Understanding millimetre wave FMCW radars. Proceedings of the 1st International Conference on Sensing Technology, Palmerston North, New Zealand."},{"key":"ref_27","unstructured":"Budge, M.C., and Burt, M.P. (1993, January 20\u201322). Range correlation effects in radars. Proceedings of the Record of the 1993 IEEE National Radar Conference, Lynnfield, MA, USA."},{"key":"ref_28","unstructured":"Barrick, D.E. (2020, May 20). FM\/CW Radar Signals and Digital Processing. Available online: http:\/\/www.codar.com\/images\/about\/1973Barrick_FMCW.pdf."},{"key":"ref_29","doi-asserted-by":"crossref","unstructured":"Ding, L., Ali, M., Patole, S., and Dabak, A. (2016, January 20\u201325). Vibration parameter estimation using FMCW radar. Proceedings of the 2016 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP), Shanghai, China.","DOI":"10.1109\/ICASSP.2016.7472072"},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"4261","DOI":"10.1109\/TMTT.2018.2852625","article-title":"Doppler Vital Signs Detection in the Presence of Large-Scale Random Body Movements","volume":"66","author":"Lv","year":"2018","journal-title":"IEEE Trans. Microw. Theory Tech."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"1073","DOI":"10.1109\/TMTT.2007.895653","article-title":"Arctangent demodulation with DC offset compensation in quadrature Doppler radar receiver systems","volume":"55","author":"Park","year":"2007","journal-title":"IEEE Trans. Microw. Theory Tech."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"1837","DOI":"10.1109\/TMTT.2014.2342663","article-title":"High dynamic-range motion imaging based on linearized Doppler radar sensor","volume":"62","author":"Lv","year":"2014","journal-title":"IEEE Trans. Microw. Theory Tech."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"489","DOI":"10.1109\/TIT.2005.862083","article-title":"Robust uncertainty principles: Exact signal reconstruction from highly incomplete frequency information","volume":"52","author":"Romberg","year":"2006","journal-title":"IEEE Trans. Inf. Theory."},{"key":"ref_34","unstructured":"Chen, W., and Wassell, I. (2011, January 23\u201325). Energy efficient signal acquisition via compressive sensing in wireless sensor networks. Proceedings of the 2011 6th International Symposium on Wireless and Pervasive Computing (ISWPC), Hong Kong, China."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"549","DOI":"10.1016\/j.sigpro.2005.05.029","article-title":"Extensions of compressed sensing","volume":"86","author":"Tsaig","year":"2006","journal-title":"Signal Process."},{"key":"ref_36","doi-asserted-by":"crossref","unstructured":"Sun, H., and Ni, L. (2013, January 12\u201313). Compressed sensing data reconstruction using adaptive generalized orthogonal matching pursuit algorithm. Proceedings of the 2013 3rd International Conference on Computer Science and Network Technology, Dalian, China.","DOI":"10.1109\/ICCSNT.2013.6967295"},{"key":"ref_37","unstructured":"Soman, K. (2010). Insight into Wavelets: From Theory to Practice, PHI Learning Pvt. Ltd."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"1792","DOI":"10.1002\/mop.31823","article-title":"Heartbeat detection using a Doppler radar sensor based on the scaling function of wavelet transform","volume":"61","author":"Choi","year":"2019","journal-title":"Microw. Opt. Technol. Lett."},{"key":"ref_39","doi-asserted-by":"crossref","unstructured":"Valencia, D., Orejuela, D., Salazar, J., and Valencia, J. (September, January 31). Comparison analysis between rigrsure, sqtwolog, heursure and minimaxi techniques using hard and soft thresholding methods. Proceedings of the 2016 XXI Symposium on Signal Processing, Images and Artificial Vision (STSIVA), Bucaramanga, Colombia.","DOI":"10.1109\/STSIVA.2016.7743309"},{"key":"ref_40","unstructured":"(2020, January 15). AWR1642 Single-Chip 76-GHz to 81-GHz Automotive Radar Sensor Evaluation Module. Available online: http:\/\/www.ti.com\/tool\/AWR1642BOOST."},{"key":"ref_41","unstructured":"(2020, January 15). DCA1000EVM Real-time Data-capture Adapter For Radar Sensing Evaluation Module. Available online: http:\/\/www.ti.com\/tool\/DCA1000EVM."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/20\/10\/2999\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T09:32:26Z","timestamp":1760175146000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/20\/10\/2999"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2020,5,25]]},"references-count":41,"journal-issue":{"issue":"10","published-online":{"date-parts":[[2020,5]]}},"alternative-id":["s20102999"],"URL":"https:\/\/doi.org\/10.3390\/s20102999","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2020,5,25]]}}}