{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T01:24:25Z","timestamp":1760145865185,"version":"build-2065373602"},"reference-count":23,"publisher":"MDPI AG","issue":"17","license":[{"start":{"date-parts":[[2024,8,28]],"date-time":"2024-08-28T00:00:00Z","timestamp":1724803200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"National Science and Technology Council, R.O.C","award":["NSTC 112-2221-E-224-008","NSTC 112-2622-E-224-017"],"award-info":[{"award-number":["NSTC 112-2221-E-224-008","NSTC 112-2622-E-224-017"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>This paper presents a real-time and non-contact dual-mode embedded impulse-radio (IR) ultra-wideband (UWB) radar system designed for microwave imaging and vital sign applications. The system is fully customized and composed of three main components, an RF front-end transmission block, an analog signal processing (ASP) block, and a digital processing block, which are integrated in an embedded system. The ASP block enables dual-path receiving for image construction and vital sign detection, while the digital part deals with the inverse scattering and direct current (DC) offset issues. The self-calibration technique is also incorporated into the algorithm to adjust the DC level of each antenna for DC offset compensation. The experimental results demonstrate that the IR-UWB radar, based on the proposed algorithm, successfully detected the 2D image profile of the object as confirmed by numerical derivation. In addition, the radar can wirelessly monitor vital sign behavior such as respiration and heartbeat information.<\/jats:p>","DOI":"10.3390\/s24175555","type":"journal-article","created":{"date-parts":[[2024,8,28]],"date-time":"2024-08-28T03:57:06Z","timestamp":1724817426000},"page":"5555","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":3,"title":["Dual-Mode Embedded Impulse-Radio Ultra-Wideband Radar System for Biomedical Applications"],"prefix":"10.3390","volume":"24","author":[{"given":"Wei-Ping","family":"Hung","sequence":"first","affiliation":[{"name":"Department of Computer Science and Information Engineering, National United University, Miaoli 306301, Taiwan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4700-9902","authenticated-orcid":false,"given":"Chia-Hung","family":"Chang","sequence":"additional","affiliation":[{"name":"Department of Electrical Engineering, National Yunlin University of Science and Technology, Yunlin County 64002, Taiwan"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2024,8,28]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"594","DOI":"10.1587\/transcom.E97.B.594","article-title":"Fundamental study on UWB radar for respiration and heartbeat detection","volume":"97","author":"Li","year":"2014","journal-title":"IEICE Trans. Commun."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"2076","DOI":"10.1109\/TMTT.2013.2252185","article-title":"IR-UWB Radar Demonstrator for Ultra-Fine Movement Detection and Vital-Sign Monitoring","volume":"61","author":"Schleicher","year":"2013","journal-title":"IEEE Trans. Microw. Theory Tech."},{"key":"ref_3","doi-asserted-by":"crossref","unstructured":"Dang, X., Zhang, J., and Hao, Z. (2022). A Non-Contact Detection Method for Multi-Person Vital Signs Based on IR-UWB Radar. Sensors, 22.","DOI":"10.3390\/s22166116"},{"key":"ref_4","doi-asserted-by":"crossref","unstructured":"Zhang, X., Yang, X., Ding, Y., Wang, Y., Zhou, J., and Zhang, L. (2021). Contactless Simultaneous Breathing and Heart Rate Detections in Physical Activity Using IR-UWB Radars. Sensors, 21.","DOI":"10.3390\/s21165503"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"137","DOI":"10.1109\/22.265541","article-title":"Microwave inverse scattering\/spl minus\/ local shape function imaging for improved resolution of strong scatterers","volume":"42","author":"Otto","year":"1994","journal-title":"IEEE Trans. Microw. Theory Tech."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"339","DOI":"10.1109\/36.905242","article-title":"Inverse scattering of two-dimensional dielectric objects buried in a lossy earth using the distorted Born iterative method","volume":"39","author":"Cui","year":"2001","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_7","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_8","doi-asserted-by":"crossref","first-page":"1018","DOI":"10.1109\/TMTT.2016.2536600","article-title":"A Fully Integrated 60-GHz CMOS Direct-Conversion Doppler Radar RF Sensor with Clutter Canceller for Single-Antenna Noncontact Human Vital-Signs Detection","volume":"64","author":"Kuo","year":"2016","journal-title":"IEEE Trans. Microw. Theory Tech."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"88","DOI":"10.1109\/LMWC.2017.2775143","article-title":"Vital Signal Radar with Adaptive Compensation Circuits to Effectively Eliminate DC Offsets","volume":"28","author":"Yang","year":"2018","journal-title":"IEEE Microw. Wirel. Compon. Lett."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"292","DOI":"10.1109\/TVLSI.2019.2940035","article-title":"Vital-Sign Processing Receiver with Clutter Elimination Using Servo Feedback Loop for UWB Pulse Radar System","volume":"28","author":"Chang","year":"2020","journal-title":"IEEE Trans. Very Large Scale Integr. Syst."},{"key":"ref_11","doi-asserted-by":"crossref","unstructured":"Ko, G.-H., Moon, S.-J., Kim, S.-H., Kim, J.-G., and Baek, D. (2024). Fully Integrated 24-GHz 1TX-2RX Transceiver for Compact FMCW Radar Applications. Sensors, 24.","DOI":"10.3390\/s24051460"},{"key":"ref_12","doi-asserted-by":"crossref","unstructured":"Mercuri, M., Torfs, T., Rykunov, M., Laureti, S., Ricci, M., and Crupi, F. (2022). Analysis of Signal Processing Methods to Reject the DC Offset Contribution of Static Reflectors in FMCW Radar-Based Vital Signs Monitoring. Sensors, 22.","DOI":"10.3390\/s22249697"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"20190672","DOI":"10.1587\/elex.16.20190672","article-title":"A 100-M\/s 2.6-pJ\/pulse compact UWB impulse transmitter based on antenna-and-pulse-generator codesign","volume":"16","author":"Lyu","year":"2019","journal-title":"IEICE Electron. Express"},{"key":"ref_14","doi-asserted-by":"crossref","unstructured":"Ghavami, M., Michael, L.B., and Kohno, R. (2007). Ultra Wideband Signals and Systems in Communication Engineering, John Wiley & Sons. [2nd ed.].","DOI":"10.1002\/9780470060490"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"20170787","DOI":"10.1587\/elex.14.20170787","article-title":"Miniaturization of rectangular microstrip patch antenna using topology optimized metamaterial","volume":"19","author":"Mahdi","year":"2017","journal-title":"IEICE Electron. Express"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"20190672","DOI":"10.1587\/elex.16.20190242","article-title":"A miniaturized planar antenna with defective ground structure for UWB applications","volume":"16","author":"Venkatachalam","year":"2019","journal-title":"IEICE Electron. Express"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"1328","DOI":"10.1002\/cta.2470","article-title":"A programmable analog baseband filter with DC offset reduction using servo loop feedback","volume":"46","author":"Chang","year":"2018","journal-title":"Int. J. Circuit Theory Appl."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"20200062","DOI":"10.1587\/elex.17.20200062","article-title":"Accurate Doppler radar-based heart rate measurement using matched filter","volume":"17","author":"Kai","year":"2020","journal-title":"IEICE Electron. Express"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"150","DOI":"10.1109\/LES.2020.3039898","article-title":"Design and Implementation of an Embedded Cardio-Respiratory Monitoring System for Wheelchair Users","volume":"13","author":"Chang","year":"2021","journal-title":"IEEE Embedded Syst. Lett."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"121","DOI":"10.1109\/LES.2022.3198666","article-title":"New Paradigm for Contactless Vital-Sign Sensing Using UWB Radar and Hybrid Optical Wireless Communication","volume":"15","author":"Hu","year":"2023","journal-title":"IEEE Embed. Syst. Lett."},{"key":"ref_21","doi-asserted-by":"crossref","unstructured":"Henault, S., and Antar, Y.M.M. (2009, January 20\u201323). Accurate evaluation of mutual coupling for array calibration. Proceedings of the Computational Electromagnetics International Workshop, Izmir, Turkey.","DOI":"10.1109\/CEM.2009.5228109"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"53","DOI":"10.1109\/78.815478","article-title":"Array calibration in the presence of multipath","volume":"48","author":"Leshem","year":"2000","journal-title":"IEEE Trans. Signal Process."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"20190318","DOI":"10.1587\/elex.16.20190318","article-title":"An impulse radio duty-cycled radar with ultra-wideband VCO using frequency hopping technique","volume":"16","author":"Chang","year":"2019","journal-title":"IEICE Electron. Express"}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/24\/17\/5555\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T15:44:00Z","timestamp":1760111040000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/24\/17\/5555"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2024,8,28]]},"references-count":23,"journal-issue":{"issue":"17","published-online":{"date-parts":[[2024,9]]}},"alternative-id":["s24175555"],"URL":"https:\/\/doi.org\/10.3390\/s24175555","relation":{},"ISSN":["1424-8220"],"issn-type":[{"type":"electronic","value":"1424-8220"}],"subject":[],"published":{"date-parts":[[2024,8,28]]}}}