{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,11]],"date-time":"2026-02-11T20:19:09Z","timestamp":1770841149675,"version":"3.50.1"},"reference-count":19,"publisher":"MDPI AG","issue":"11","license":[{"start":{"date-parts":[[2017,11,15]],"date-time":"2017-11-15T00:00:00Z","timestamp":1510704000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>It has been the dream of many scientists and engineers to realize a non-contact remote sensing system that can perform continuous, accurate and long-term monitoring of human vital signs as we have seen in many Sci-Fi movies. Having an intelligible sensor system that can measure and record key vital signs (such as heart rates and respiration rates) remotely and continuously without touching the patients, for example, can be an invaluable tool for physicians who need to make rapid life-and-death decisions. Such a sensor system can also effectively help physicians and patients making better informed decisions when patients\u2019 long-term vital signs data is available. Therefore, there has been a lot of research activities on developing a non-contact sensor system that can monitor a patient\u2019s vital signs and quickly transmit the information to healthcare professionals. Doppler-based radio-frequency (RF) non-contact vital signs (NCVS) monitoring system are particularly attractive for long term vital signs monitoring because there are no wires, electrodes, wearable devices, nor any contact-based sensors involved so the subjects may not be even aware of the ubiquitous monitoring. In this paper, we will provide a brief review on some latest development on NCVS sensors and compare them against a few novel and intelligent phased-array Doppler-based RF NCVS biosensors we have built in our labs. Some of our NCVS sensor tests were performed within a clutter-free anechoic chamber to mitigate the environmental clutters, while most tests were conducted within the typical Herman-Miller type office cubicle setting to mimic a more practical monitoring environment. Additionally, we will show the measurement data to demonstrate the feasibility of long-term NCVS monitoring. The measured data strongly suggests that our latest phased array NCVS system should be able to perform long-term vital signs monitoring intelligently and robustly, especially for situations where the subject is sleeping without hectic movements nearby.<\/jats:p>","DOI":"10.3390\/s17112632","type":"journal-article","created":{"date-parts":[[2017,11,15]],"date-time":"2017-11-15T11:13:35Z","timestamp":1510744415000},"page":"2632","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":72,"title":["Non-Contact Sensor for Long-Term Continuous Vital Signs Monitoring: A Review on Intelligent Phased-Array Doppler Sensor Design"],"prefix":"10.3390","volume":"17","author":[{"given":"Travis","family":"Hall","sequence":"first","affiliation":[{"name":"Department of Electrical and Computer Engineering, Texas Tech University, Lubbock, TX 79409-3102, USA"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1788-8910","authenticated-orcid":false,"given":"Donald","family":"Lie","sequence":"additional","affiliation":[{"name":"Department of Electrical and Computer Engineering, Texas Tech University, Lubbock, TX 79409-3102, USA"},{"name":"Texas Tech University Health Sciences Center, Texas Tech University, Lubbock, TX 79430, USA"}]},{"given":"Tam","family":"Nguyen","sequence":"additional","affiliation":[{"name":"Department of Electrical and Computer Engineering, Texas Tech University, Lubbock, TX 79409-3102, USA"},{"name":"Texas Tech University Health Sciences Center, Texas Tech University, Lubbock, TX 79430, USA"}]},{"given":"Jill","family":"Mayeda","sequence":"additional","affiliation":[{"name":"Department of Electrical and Computer Engineering, Texas Tech University, Lubbock, TX 79409-3102, USA"}]},{"given":"Paul","family":"Lie","sequence":"additional","affiliation":[{"name":"Texas Tech University Health Sciences Center, Texas Tech University, Lubbock, TX 79430, USA"}]},{"given":"Jerry","family":"Lopez","sequence":"additional","affiliation":[{"name":"Department of Electrical and Computer Engineering, Texas Tech University, Lubbock, TX 79409-3102, USA"}]},{"given":"Ron","family":"Banister","sequence":"additional","affiliation":[{"name":"Texas Tech University Health Sciences Center, Texas Tech University, Lubbock, TX 79430, USA"}]}],"member":"1968","published-online":{"date-parts":[[2017,11,15]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Boric-Lubecke, O., Lubecke, V.M., Droitcour, A.D., Park, B.K., and Singh, A. (2016). Doppler Radar Physiological Sensing, Wiley.","DOI":"10.1002\/9781119078418"},{"key":"ref_2","unstructured":"(2017, November 15). Murata\u2019s Contactless Bed Sensors. Available online: http:\/\/www.murata.com\/en-us\/products\/sensor\/accel\/sca10h_11h."},{"key":"ref_3","unstructured":"Emfit, Corp (2017, November 15). Movement Monitor. Available online: http:\/\/www.emfitcorp.com\/index.php?page=movement-monitor."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"704","DOI":"10.4236\/jbise.2013.67086","article-title":"An approach to a non-contact vital sign monitoring using dual-frequency microwave radars for elderly care","volume":"6","author":"Satoshi","year":"2013","journal-title":"J. Biomed. Sci. Eng."},{"key":"ref_5","unstructured":"Microsoft (2017, November 15). Kinect for Xbox One. Available online: http:\/\/www.xbox.com\/en-US\/xbox-one\/accessories\/kinect-for-xbox-one."},{"key":"ref_6","unstructured":"Woollaston, V. (2017, November 15). 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Available online: https:\/\/www.youtube.com\/watch?v=El88VU6dYdo."},{"key":"ref_14","doi-asserted-by":"crossref","unstructured":"Hall, T., Nukala, B., Stout, C., Brewer, N., Tsay, J., Lopez, J., Banister, R.E., Nguyen, T., and Lie, D.Y.C. (2015, January 17\u201322). A Phased Array Non-Contact Vital Signs Sensor with Automatic Beam Steering. Proceedings of the IEEE International Microwave Symposium (IMS2015), Phoenix, Arizona.","DOI":"10.1109\/MWSYM.2015.7166973"},{"key":"ref_15","doi-asserted-by":"crossref","unstructured":"Hall, T., Stout, C., Brewer, N., Dominguez, G., Tsay, J., Boothby, A., Das, V., Lopez, J., Nguyen, T., and Banister, R.E. (2014, January 7\u20138). Extending the Range of Phased Array Non-Contact Vital Signs Monitoring in an Office Cubicle Setting. Proceedings of the IEEE Texas Symposium on Wireless and Microwave Circuits and Systems (TSWMCS), Waco, TX, USA.","DOI":"10.1109\/WMCaS.2014.7015870"},{"key":"ref_16","doi-asserted-by":"crossref","unstructured":"Hall, T., Dominguez, G., Tsay, J., Boothby, A., Lopez, J., Nguyen, T., and Lie, D.Y.C. (2014, January 23\u201325). Robust Phased Array Non-Contact Vital Signs Monitoring in an Office Cubicle Setting. Proceedings of the 1st International Conference on Intelligent Green Building and Smart Grid (IGBSG), Taipei, Taiwan.","DOI":"10.1109\/IGBSG.2014.6835224"},{"key":"ref_17","unstructured":"Graschew, G. (2011). A 2.4GHz Non-Contact Biosensor System for Continuous Monitoring of Vital-Signs, Telemedicine Techniques and Applications, InTech. Available online: http:\/\/www.intechopen.com\/books\/telemedicine-techniques-and-applications\/a-2-4ghz-non-contact-biosensor-system-for-continuous-monitoring-of-vital-signs."},{"key":"ref_18","unstructured":"Boothby, A. (2012). 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Proceedings of the 38th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC\u201916), Orlando, FL, USA."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/17\/11\/2632\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T18:49:36Z","timestamp":1760208576000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/17\/11\/2632"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2017,11,15]]},"references-count":19,"journal-issue":{"issue":"11","published-online":{"date-parts":[[2017,11]]}},"alternative-id":["s17112632"],"URL":"https:\/\/doi.org\/10.3390\/s17112632","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2017,11,15]]}}}