{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,21]],"date-time":"2026-02-21T19:26:03Z","timestamp":1771701963203,"version":"3.50.1"},"reference-count":34,"publisher":"MDPI AG","issue":"18","license":[{"start":{"date-parts":[[2022,9,12]],"date-time":"2022-09-12T00:00:00Z","timestamp":1662940800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"National Research Foundation (NRF) of Korea","award":["NRF-2022R1A2C2008783"],"award-info":[{"award-number":["NRF-2022R1A2C2008783"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Short-range millimeter wave radar sensors provide a reliable, continuous and non-contact solution for vital sign extraction. Off-The-Shelf (OTS) radars often have a directional antenna (beam) pattern. The transmitted wave has a conical main lobe, and power of the received target echoes deteriorate as we move away from the center point of the lobe. While measuring vital signs, the human subject is often located at the center of the antenna lobe. Since beamforming can increase signal quality at the side (azimuth) angles, this paper aims to provide an experimental comparison of vital sign extraction with and without beamforming. The experimental confirmation that beamforming can decrease the error in the vital sign extraction through radar has so far not been performed by researchers. A simple, yet effective receiver beamformer was designed and a concurrent measurement with and without beamforming was made for the comparative analysis. Measurements were made at three different distances and five different arrival angles, and the preliminary results suggest that as the observation angle increases, the effectiveness of beamforming increases. At an extreme angle of 40 degrees, the beamforming showed above 20% improvement in heart rate estimation. Heart rate measurement error was reduced significantly in comparison with the breathing rate.<\/jats:p>","DOI":"10.3390\/s22186877","type":"journal-article","created":{"date-parts":[[2022,9,13]],"date-time":"2022-09-13T04:05:41Z","timestamp":1663041941000},"page":"6877","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":18,"title":["Effects of Receiver Beamforming for Vital Sign Measurements Using FMCW Radar at Various Distances and Angles"],"prefix":"10.3390","volume":"22","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-4661-2956","authenticated-orcid":false,"given":"Shahzad","family":"Ahmed","sequence":"first","affiliation":[{"name":"Department of Electronic Engineering, Hanyang University, Seoul 04763, Korea"}]},{"given":"Junbyung","family":"Park","sequence":"additional","affiliation":[{"name":"Department of Electronic Engineering, Hanyang University, Seoul 04763, Korea"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2393-1428","authenticated-orcid":false,"given":"Sung Ho","family":"Cho","sequence":"additional","affiliation":[{"name":"Department of Electronic Engineering, Hanyang University, Seoul 04763, Korea"}]}],"member":"1968","published-online":{"date-parts":[[2022,9,12]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"7001804","DOI":"10.1109\/LSENS.2018.2882642","article-title":"Robust gesture recognition using millimetric-wave radar system","volume":"2","author":"Hazra","year":"2018","journal-title":"IEEE Sens. Lett."},{"key":"ref_2","doi-asserted-by":"crossref","unstructured":"Ahmed, S., Kim, W., Park, J., and Cho, S.H. (2022). Radar Based Air-Writing Gesture Recognition Using a Novel Multi-Stream CNN Approach. IEEE Internet Things J.","DOI":"10.1109\/JIOT.2022.3189395"},{"key":"ref_3","doi-asserted-by":"crossref","unstructured":"Ahmed, S., Park, J., and Cho, S.H. (2022, January 6\u20139). FMCW Radar Sensor Based Human Activity Recognition using Deep Learning. Proceedings of the 2022 International Conference on Electronics, Information, and Communication (ICEIC), Jeju, Korea.","DOI":"10.1109\/ICEIC54506.2022.9748776"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"292","DOI":"10.1109\/TBCAS.2018.2799322","article-title":"Vital sign monitoring through the back using an UWB impulse radar with body coupled antennas","volume":"12","author":"Schires","year":"2018","journal-title":"IEEE Trans. Biomed. Circuits Syst."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"775","DOI":"10.1109\/JSTARS.2014.2306995","article-title":"Remote detection of human vital sign with stepped-frequency continuous wave radar","volume":"7","author":"Liu","year":"2014","journal-title":"IEEE J. Sel. Top. Appl. Earth Obs. Remote Sens."},{"key":"ref_6","doi-asserted-by":"crossref","unstructured":"Turppa, E., Kortelainen, J.M., Antropov, O., and Kiuru, T. (2020). Vital sign monitoring using FMCW radar in various sleeping scenarios. Sensors, 20.","DOI":"10.3390\/s20226505"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"783","DOI":"10.1109\/JSTARS.2013.2259801","article-title":"Advanced signal processing for vital sign extraction with applications in UWB radar detection of trapped victims in complex environments","volume":"7","author":"Li","year":"2013","journal-title":"IEEE J. Sel. Top. Appl. Earth Obs. Remote Sens."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"115001","DOI":"10.1088\/1361-6579\/ab525c","article-title":"Cardio-respiratory signal extraction from video camera data for continuous non-contact vital sign monitoring using deep learning","volume":"40","author":"Chaichulee","year":"2019","journal-title":"Physiol. Meas."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"11965","DOI":"10.1109\/JSEN.2022.3172559","article-title":"Camera-Augmented Non-Contact Vital Sign Monitoring in Real Time","volume":"22","author":"Shokouhmand","year":"2022","journal-title":"IEEE Sens. J."},{"key":"ref_10","doi-asserted-by":"crossref","unstructured":"Ahmed, S., Kallu, K.D., Ahmed, S., and Cho, S.H. (2021). Hand gestures recognition using radar sensors for human-computer-interaction: A review. Remote Sens., 13.","DOI":"10.3390\/rs13030527"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"138132","DOI":"10.1109\/ACCESS.2021.3117667","article-title":"Ultra-wideband radar-based activity recognition using deep learning","volume":"9","author":"Noori","year":"2021","journal-title":"IEEE Access"},{"key":"ref_12","doi-asserted-by":"crossref","unstructured":"Bordvik, D.A., Hou, J., Noori, F.M., Uddin, M.Z., and Torresen, J. (2022, January 6\u20139). Monitoring In-Home Emergency Situation and Preserve Privacy using Multi-modal Sensing and Deep Learning. Proceedings of the 2022 International Conference on Electronics, Information, and Communication (ICEIC), Jeju, Korea.","DOI":"10.1109\/ICEIC54506.2022.9748829"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"557","DOI":"10.1002\/bem.2250130610","article-title":"Microwave sensing of physiological movement and volume change: A review","volume":"13","author":"Lin","year":"1992","journal-title":"Bioelectromagnetics"},{"key":"ref_14","doi-asserted-by":"crossref","unstructured":"Piuzzi, E., Pisa, S., D\u2019Atanasio, P., and Zambotti, A. (2012, January 13\u201316). Radar cross section measurements of the human body for UWB radar applications. Proceedings of the 2012 IEEE International Instrumentation and Measurement Technology, Graz, Austria.","DOI":"10.1109\/I2MTC.2012.6229134"},{"key":"ref_15","doi-asserted-by":"crossref","unstructured":"Nieh, C.M., and Lin, J. (2014, January 1\u20136). Adaptive beam-steering antenna for improved coverage of non-contact vital sign radar detection. Proceedings of the 2014 IEEE MTT-S International Microwave Symposium (IMS2014), Tampa, FL, USA.","DOI":"10.1109\/MWSYM.2014.6848388"},{"key":"ref_16","doi-asserted-by":"crossref","unstructured":"Yoo, S., Ahmed, S., Kang, S., Hwang, D., Lee, J., Son, J., and Cho, S.H. (2021). Radar recorded child vital sign public dataset and deep learning-based age group classification framework for vehicular application. Sensors, 21.","DOI":"10.3390\/s21072412"},{"key":"ref_17","doi-asserted-by":"crossref","unstructured":"Sacco, G., Piuzzi, E., Pittella, E., and Pisa, S. (2020). An FMCW radar for localization and vital signs measurement for different chest orientations. Sensors, 20.","DOI":"10.3390\/s20123489"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"13367","DOI":"10.1038\/s41598-018-31669-y","article-title":"Ultra-wideband impulse radar through-wall detection of vital signs","volume":"8","author":"Liang","year":"2018","journal-title":"Sci. Rep."},{"key":"ref_19","doi-asserted-by":"crossref","unstructured":"Thi Phuoc Van, N., Tang, L., Demir, V., Hasan, S.F., Duc Minh, N., and Mukhopadhyay, S. (2019). Microwave radar sensing systems for search and rescue purposes. Sensors, 19.","DOI":"10.3390\/s19132879"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"413","DOI":"10.1109\/LMWC.2021.3057867","article-title":"Detection and localization of multiple humans based on curve length of I\/Q signal trajectory using MIMO FMCW radar","volume":"31","author":"Han","year":"2021","journal-title":"IEEE Microw. Wirel. Compon. Lett."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"252","DOI":"10.1038\/s41928-019-0258-6","article-title":"Vital-sign monitoring and spatial tracking of multiple people using a contactless radar-based sensor","volume":"2","author":"Mercuri","year":"2019","journal-title":"Nat. Electron."},{"key":"ref_22","doi-asserted-by":"crossref","unstructured":"Mu\u00f1oz-Ferreras, J.M., Wang, J., Peng, Z., Li, C., and G\u00f3mez-Garc\u00eda, R. (2019, January 6\u20138). Fmcw-radar-based vital-sign monitoring of multiple patients. Proceedings of the 2019 IEEE MTT-S International Microwave Biomedical Conference (IMBioC), Nanjing, China.","DOI":"10.1109\/IMBIOC.2019.8777845"},{"key":"ref_23","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_24","doi-asserted-by":"crossref","unstructured":"Cardillo, E., and Caddemi, A. (2020). A review on biomedical MIMO radars for vital sign detection and human localization. Electronics, 9.","DOI":"10.3390\/electronics9091497"},{"key":"ref_25","doi-asserted-by":"crossref","unstructured":"Walterscheid, I., and Smith, G.E. (2017, January 11\u201315). Respiration and heartbeat monitoring using a distributed pulsed MIMO radar. Proceedings of the 2017 39th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), Jeju, Korea.","DOI":"10.1109\/EMBC.2017.8037598"},{"key":"ref_26","doi-asserted-by":"crossref","unstructured":"Xiong, J., Zhang, H., Hong, H., Zhao, H., Zhu, X., and Li, C. (2020, January 26\u201329). Multi-target vital signs detection using SIMO continuous-wave radar with DBF technique. Proceedings of the 2020 IEEE Radio and Wireless Symposium (RWS), San Antonio, TX, USA.","DOI":"10.1109\/RWS45077.2020.9050054"},{"key":"ref_27","doi-asserted-by":"crossref","unstructured":"Ahmed, S., and Cho, S.H. (2020). Hand gesture recognition using an IR-UWB radar with an inception module-based classifier. Sensors, 20.","DOI":"10.3390\/s20020564"},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"3278","DOI":"10.1109\/JSEN.2018.2808688","article-title":"Latern: Dynamic continuous hand gesture recognition using FMCW radar sensor","volume":"18","author":"Zhang","year":"2018","journal-title":"IEEE Sens. J."},{"key":"ref_29","doi-asserted-by":"crossref","unstructured":"Pirkani, A.A., Pooni, S., and Cherniakov, M. (2019, January 26\u201328). Implementation of mimo beamforming on an OTS FMCW automotive radar. Proceedings of the 2019 20th International Radar Symposium (IRS), Ulm, Germany.","DOI":"10.23919\/IRS.2019.8768103"},{"key":"ref_30","doi-asserted-by":"crossref","unstructured":"Kuptsov, V.D., Ivanov, S.I., Fedotov, A.A., and Badenko, V.L. (2019). Features of multi-target detection algorithm for automotive FMCW radar. Internet of Things, Smart Spaces, and Next Generation Networks and Systems, Proceedings of the 19th International Conference, NEW2AN 2019, and 12th Conference, ruSMART 2019, St. Petersburg, Russia, 26\u201328 August 2019, Springer.","DOI":"10.1007\/978-3-030-30859-9_30"},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"5572","DOI":"10.1109\/JSEN.2016.2567450","article-title":"W-Band multichannel FMCW radar sensor with switching-TX antennas","volume":"16","author":"Lee","year":"2016","journal-title":"IEEE Sens. J."},{"key":"ref_32","unstructured":"(2022, September 01). 60GHz mmWAVE Sensor EVMS (rev. E)\u2014Texas Instruments. (n.d.). Available online: https:\/\/www.ti.com\/lit\/ug\/swru546e\/swru546e.pdf."},{"key":"ref_33","doi-asserted-by":"crossref","unstructured":"Iyer, S., Zhao, L., Mohan, M.P., Jimeno, J., Siyal, M.Y., Alphones, A., and Karim, M.F. (2022). mm-Wave Radar-Based Vital Signs Monitoring and Arrhythmia Detection Using Machine Learning. Sensors, 22.","DOI":"10.3390\/s22093106"},{"key":"ref_34","doi-asserted-by":"crossref","unstructured":"Noori, F.M., Kahlon, S., Lindner, P., Nordgreen, T., Torresen, J., and Riegler, M. (2019, January 4\u20136). Heart rate prediction from head movement during virtual reality treatment for social anxiety. Proceedings of the 2019 International Conference on Content-Based Multimedia Indexing (CBMI), Dublin, Ireland.","DOI":"10.1109\/CBMI.2019.8877454"}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/22\/18\/6877\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T00:29:40Z","timestamp":1760142580000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/22\/18\/6877"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2022,9,12]]},"references-count":34,"journal-issue":{"issue":"18","published-online":{"date-parts":[[2022,9]]}},"alternative-id":["s22186877"],"URL":"https:\/\/doi.org\/10.3390\/s22186877","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2022,9,12]]}}}