{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,12,30]],"date-time":"2025-12-30T15:39:39Z","timestamp":1767109179660,"version":"build-2065373602"},"reference-count":36,"publisher":"MDPI AG","issue":"1","license":[{"start":{"date-parts":[[2018,1,22]],"date-time":"2018-01-22T00:00:00Z","timestamp":1516579200000},"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>This article deals with the development of a dual channel S-Band frequency-modulated continuous wave (FMCW) system for a through-the-wall imaging (TWRI) system. Most existing TWRI systems using FMCW were developed for synthetic aperture radar (SAR) which has many drawbacks such as the need for several antenna elements and movement of the system. Our implemented TWRI system comprises a transmitting antenna and two receiving antennas, resulting in a significant reduction of the number of antenna elements. Moreover, a proposed algorithm for range-angle-Doppler 3D estimation based on a 3D shift invariant structure is utilized in our implemented dual channel S-band FMCW TWRI system. Indoor and outdoor experiments were conducted to image the scene beyond a wall for water targets and person targets, respectively. The experimental results demonstrate that high-quality imaging can be achieved under both experimental scenarios.<\/jats:p>","DOI":"10.3390\/s18010311","type":"journal-article","created":{"date-parts":[[2018,1,22]],"date-time":"2018-01-22T13:40:39Z","timestamp":1516628439000},"page":"311","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":17,"title":["Dual Channel S-Band Frequency Modulated Continuous Wave Through-Wall Radar Imaging"],"prefix":"10.3390","volume":"18","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-7539-6594","authenticated-orcid":false,"given":"Ying-Chun","family":"Li","sequence":"first","affiliation":[{"name":"Department of Electronic Engineering, Hanyang University, Seoul 04763, Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Daegun","family":"Oh","sequence":"additional","affiliation":[{"name":"Collaborative Robots Research Center, Daegu Gyeongbuk Institute of Science and Technology, Daegu 42988, Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Sunwoo","family":"Kim","sequence":"additional","affiliation":[{"name":"Department of Electronic Engineering, Hanyang University, Seoul 04763, Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Jong-Wha","family":"Chong","sequence":"additional","affiliation":[{"name":"Department of Electronic Engineering, Hanyang University, Seoul 04763, Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2018,1,22]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"2594","DOI":"10.1109\/TAP.2010.2050424","article-title":"A through-dielectric radar imaging system","volume":"58","author":"Charvat","year":"2010","journal-title":"IEEE Trans. Antennas Propag."},{"key":"ref_2","doi-asserted-by":"crossref","unstructured":"Qian, J., Ahmad, F., and Amin, M.G. (2013). Joint localization of stationary and moving targets behind walls using sparse scene recovery. J. Electron. Imaging, 22.","DOI":"10.1117\/1.JEI.22.2.021002"},{"key":"ref_3","unstructured":"Amin, M.G. (2010). Through-The-Wall Radar Imaging, CRC Press."},{"key":"ref_4","doi-asserted-by":"crossref","unstructured":"Gennarelli, G., Ludeno, G., and Soldovieri, F. (2016). Real-Time Through-Wall Situation Awareness Using a Microwave Doppler Radar Sensor. Remote Sens., 8.","DOI":"10.3390\/rs8080621"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"3192","DOI":"10.1109\/TGRS.2009.2019728","article-title":"Spatial Filtering for Wall-Clutter Mitigation in Through-the-Wall Radar Imaging","volume":"47","author":"Yoon","year":"2009","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"943","DOI":"10.1109\/LGRS.2016.2555291","article-title":"Refraction Angle Approximation Algorithm for Wall Compensation in TWRI","volume":"13","author":"Liu","year":"2016","journal-title":"IEEE Geosci. Remote Sens. Lett."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"1968","DOI":"10.1109\/TGRS.2011.2170077","article-title":"Enhanced Detection Using Target Polarization Signatures in Through-the-Wall Radar Imaging","volume":"50","author":"Debes","year":"2012","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_8","unstructured":"Sachs, J., Aftanas, M., Crabbe, S., Drutarovsky, M., Klukas, R., Kocur, D., Nguyen, T.T., Peyerl, P., Rovnakova, J., and Zaikov, E. (2008, January 30\u201331). Detection and tracking of moving or trapped people hidden by obstacles using ultrawideband pseudo-noise radar. Proceedings of the 2008 European Radar Conference (EuRAD), Amsterdam, The Netherlands."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"859","DOI":"10.1109\/TAP.2010.2103015","article-title":"Through-wall opportunistic sensing system utilizing a low-cost flat-panel array","volume":"59","author":"Browne","year":"2011","journal-title":"IEEE Trans. Antennas Propag."},{"key":"ref_10","unstructured":"Biying, L., Song, Q., Zhou, Z., and Wang, H. (2011, January 12\u201314). A SFCW radar for through wall imaging and motion detection. Proceedings of the European Radar Conference (EuRAD), Manchester, UK."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"968","DOI":"10.1109\/LGRS.2012.2187428","article-title":"Detection of human beings in motion behind the wall using SAR interferogram","volume":"9","author":"Biying","year":"2012","journal-title":"IEEE Geosci. Remote Sens. Lett."},{"key":"ref_12","doi-asserted-by":"crossref","unstructured":"Maaref, N., and Millot, P. (2012, January 8\u201314). Array-based UWB FMCW through-the-wall radar. Proceedings of the 2012 IEEE Antennas and Propagation Society International Symposium (APSURSI), Chicago, IL, USA.","DOI":"10.1109\/APS.2012.6347962"},{"key":"ref_13","doi-asserted-by":"crossref","unstructured":"Maaref, N., and Millot, P. (2013). Array-based ultrawideband through-wall radar: Prediction and assessment of real radar abilities. Int. J. Antennas Propag., 2013.","DOI":"10.1155\/2013\/602716"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"5495","DOI":"10.1109\/TAP.2012.2207663","article-title":"A through-dielectric ultrawideband (UWB) switchedantenna-array radar imaging system","volume":"60","author":"Charvat","year":"2012","journal-title":"IEEE Trans. Antennas Propag."},{"key":"ref_15","doi-asserted-by":"crossref","unstructured":"Ralston, T.S., Charvat, G.L., and Peabody, J.E. (2010, January 12\u201315). Real-time through-wall imaging using an ultrawideband multiple-input multiple-output (MIMO) phased array radar system. Proceedings of the IEEE International Symposium on Phased Array Systems and Technology (ARRAY 2010), Waltham, MA, USA.","DOI":"10.1109\/ARRAY.2010.5613314"},{"key":"ref_16","first-page":"62","article-title":"Through-Wall Imaging Radar","volume":"19","author":"Peabody","year":"2012","journal-title":"Linc. Lab. J."},{"key":"ref_17","unstructured":"Ahmad, F., and Amin, M.G. (2007, January 11\u201313). Through-the-wall radar imaging experiments. Proceedings of the IEEE Workshop on Signal Processing Applications for Public Safety and Forensics, Washington, DC, USA."},{"key":"ref_18","doi-asserted-by":"crossref","unstructured":"Hantscher, S., Reisenzahn, A., and Diskus, C.G. (2007, January 3\u20138). An UWB wall scanner based on a shape estimating SAR algorithm. Proceedings of the IEEE\/MTT-S Microwave Symposium, Honolulu, HI, USA.","DOI":"10.1109\/MWSYM.2007.380528"},{"key":"ref_19","doi-asserted-by":"crossref","unstructured":"Hantscher, S., Praher, B., Reisenzahm, A., and Diskus, C.G. (2006, January 18\u201322). 2D imaging algorithm for the evaluation of UWB B-Scans. Proceedings of the IEEE Conference on Ultrawideband and Ultrashort Impulse Signals, Sevastopol, Ukraine.","DOI":"10.1109\/UWBUS.2006.307181"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"1249","DOI":"10.1109\/LAWP.2016.2630006","article-title":"A Hybrid Bistatic\u2013Monostatic Radar Technique for Calibration-Free Estimation of Lossy Wall Parameters","volume":"16","author":"Thajudeen","year":"2017","journal-title":"IEEE Antennas Wirel. Propag. Lett."},{"key":"ref_21","doi-asserted-by":"crossref","unstructured":"Lang, S.A., Demming, M., Jaeschke, T., Noujeim, K.M., Konynenberg, A., and Pohl, N. (2015, January 17\u201322). 3D SAR imaging for dry wall inspection using an 80 GHz FMCW radar with 25 GHz bandwidth. Proceedings of the 2015 IEEE MTT-S International Microwave Symposium, Phoenix, AZ, USA.","DOI":"10.1109\/MWSYM.2015.7166863"},{"key":"ref_22","doi-asserted-by":"crossref","unstructured":"Sevigny, P., DiFilippo, D.J., Laneve, T., and Fournier, J. (2012, January 4). Indoor imagery with a 3D through-wall synthetic aperture radar. Proceedings of the SPIE 8361, Radar Sensor Technology XVI, Baltimore, MD, USA.","DOI":"10.1117\/12.919781"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"110","DOI":"10.1109\/MSP.2008.923510","article-title":"Wideband synthetic aperture beamforming for through-the-wall imaging [Lecture Notes]","volume":"25","author":"Amin","year":"2008","journal-title":"IEEE Signal Process. Mag."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"1869","DOI":"10.1109\/TAES.2013.6558025","article-title":"Image Segmentations for Through-the-Wall Radar Target Detection","volume":"49","author":"Seng","year":"2013","journal-title":"IEEE Trans. Aerosp. Electron. Syst."},{"key":"ref_25","doi-asserted-by":"crossref","unstructured":"Leigsnering, M., Ahmad, F., Amin, M.G., and Zoubir, A.M. (May, January 29). CS based wall ringing and reverberation mitigation for through-the-wall radar imaging. Proceedings of the 2013 IEEE Radar Conference (RadarCon13), Ottawa, ON, USA.","DOI":"10.1109\/RADAR.2013.6586115"},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"920","DOI":"10.1109\/TAES.2013.120528","article-title":"Multipath exploitation in through-the-wall radar imaging using sparse reconstruction","volume":"50","author":"Leigsnering","year":"2014","journal-title":"IEEE Trans. Aerosp. Electron. Syst."},{"key":"ref_27","doi-asserted-by":"crossref","unstructured":"Winkler, V. (2007, January 10\u201312). Range Doppler detection for automotive FMCW radars. Proceedings of the 2007 European Radar Conference, Munich, Germany.","DOI":"10.1109\/EURAD.2007.4404963"},{"key":"ref_28","doi-asserted-by":"crossref","unstructured":"Tivive, F.H.C., and Bouzerdoum, A. (2013, January 16\u201319). An improved SVD-based wall clutter mitigation method for through-the-wall radar imaging. Proceedings of the 2013 IEEE 14th Workshop on Signal Processing Advances in Wireless Communications (SPAWC), Darmstadt, Germany.","DOI":"10.1109\/SPAWC.2013.6612086"},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"2108","DOI":"10.1109\/TGRS.2014.2355211","article-title":"A Subspace Projection Approach for Wall Clutter Mitigation in Through-the-Wall Radar Imaging","volume":"53","author":"Tivive","year":"2015","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_30","unstructured":"Meta, A. (2017, August 10). Signal Processing of FMCW Synthetic Aperture Radar Data. Available online: http:\/\/resolver.tudelft.nl\/uuid:24352ff9-c11a-46c9-87d4-4d9d8968ed81."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"1289","DOI":"10.1109\/TGRS.2008.2010052","article-title":"Through-the-Wall Imaging Using Differential SAR","volume":"47","author":"Dehmollaian","year":"2009","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"1701","DOI":"10.1109\/TAP.2015.2398115","article-title":"Hybrid matching pursuit for distributed through-wall radar imaging","volume":"63","author":"Li","year":"2015","journal-title":"IEEE Trans. Antennas Propag."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"271","DOI":"10.1109\/TAES.2005.1413761","article-title":"Synthetic aperture beamformer for imaging through a dielectric wall","volume":"41","author":"Ahmad","year":"2005","journal-title":"IEEE Trans. Aerosp. Electron. Syst."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"814","DOI":"10.1109\/29.56027","article-title":"Matrix pencil method for estimating parameters of exponentially damped\/undamped sinusoids in noise","volume":"38","author":"Hua","year":"1990","journal-title":"IEEE Trans. Acoust. Speech Signal Process."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"387","DOI":"10.1109\/TASSP.1985.1164557","article-title":"Detection of signals by information theoretic criteria","volume":"ASSP-33","author":"Wax","year":"1985","journal-title":"IEEE Trans. Acoust. Speech Signal Process."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"745","DOI":"10.1109\/LCOMM.2014.030714.132712","article-title":"Robust Super-Resolution TOA Estimation against Doppler Shift for Vehicle Tracking","volume":"18","author":"Oh","year":"2014","journal-title":"IEEE Commun. Lett."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/18\/1\/311\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T14:52:08Z","timestamp":1760194328000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/18\/1\/311"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2018,1,22]]},"references-count":36,"journal-issue":{"issue":"1","published-online":{"date-parts":[[2018,1]]}},"alternative-id":["s18010311"],"URL":"https:\/\/doi.org\/10.3390\/s18010311","relation":{},"ISSN":["1424-8220"],"issn-type":[{"type":"electronic","value":"1424-8220"}],"subject":[],"published":{"date-parts":[[2018,1,22]]}}}