{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,19]],"date-time":"2026-03-19T07:03:51Z","timestamp":1773903831413,"version":"3.50.1"},"reference-count":16,"publisher":"MDPI AG","issue":"8","license":[{"start":{"date-parts":[[2024,4,17]],"date-time":"2024-04-17T00:00:00Z","timestamp":1713312000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Constanta Maritime University"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Remote Sensing"],"abstract":"<jats:p>Many fields of human activity benefit from the ability to create images of obscured objects placed behind walls and to map their displacement in a noninvasive way. Usually, imaging devices like Synthetic Aperture Radars (SARs) and Ground-Penetrating Radars (GPRs) use expensive dedicated electronics which results in prohibitive prices. This paper presents the experimental implementation and the results obtained from an imaging system capable of performing SAR imaging and interferometric displacement mapping of targets located behind walls, as well as 3D GPR imaging using a low-cost general-purpose radar sensor. The proposed solution uses for the RF section of the system a K-band microwave radar sensor module implementing Frequency-Modulated Continuous Wave (FMCW) operation. The low-cost sensor was originally intended for simple presence detection and ranging for domestic applications. The proposed system was tested in several scenarios and proved to operate as intended for a fraction of the cost of a commercial imaging device. In one scenario, it was able to detect and locate a 15 cm-diameter fire-extinguisher located at a distance of 3.5 m from the scanning system and 1.6 m behind a 3 cm-thick MDF (medium-density fiberboard) wall with cm-level accuracy. In a second test, the proposed system was used to perform interferometric displacement measurements, and it was capable of determining the displacement of a metal case with sub-millimeter accuracy. In a third experiment, the system was used to construct a 3D image of the inside of a wood table with cm-level resolution.<\/jats:p>","DOI":"10.3390\/rs16081426","type":"journal-article","created":{"date-parts":[[2024,4,17]],"date-time":"2024-04-17T10:52:37Z","timestamp":1713351157000},"page":"1426","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":10,"title":["Through-Wall Imaging Using Low-Cost Frequency-Modulated Continuous Wave Radar Sensors"],"prefix":"10.3390","volume":"16","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-0851-8296","authenticated-orcid":false,"given":"Mirel","family":"Paun","sequence":"first","affiliation":[{"name":"Department of Electronics and Telecommunications, Constanta Maritime University, 900663 Constanta, Romania"}]}],"member":"1968","published-online":{"date-parts":[[2024,4,17]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"103886","DOI":"10.1016\/j.dsp.2022.103886","article-title":"MIMO through-wall-radar down-view imaging for moving target with ground ghost suppression","volume":"134","author":"Zhang","year":"2023","journal-title":"Digit. Signal Process."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"e5510","DOI":"10.1002\/dac.5510","article-title":"An efficient FPGA-based implementation of UWB radar system for through-wall imaging","volume":"36","author":"Saad","year":"2023","journal-title":"Int. J. Commun. Syst."},{"key":"ref_3","unstructured":"Jol, H.M. (2009). Ground Penetrating Radar: Theory and Applications, Elsevier Science. [1st ed.]."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"531","DOI":"10.1111\/j.1365-2478.1989.tb02221.x","article-title":"Ground-Penetrating Radar for High-Resolution Mapping of Soil and Rock Stratigraphy","volume":"37","author":"Davis","year":"1989","journal-title":"Geophys. Prospect."},{"key":"ref_5","doi-asserted-by":"crossref","unstructured":"Kirsch, R. (2006). 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Proceedings of the IEEE MTT-S International Conference on Microwaves for Intelligent Mobility (ICMIM), Munich, Germany.","DOI":"10.1109\/ICMIM.2018.8443526"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"58","DOI":"10.1016\/j.ndteint.2017.04.002","article-title":"A review of Ground Penetrating Radar application in civil engineering: A 30-year journey from Locating and Testing to Imaging and Diagnosis","volume":"96","author":"Derobert","year":"2018","journal-title":"NDT E Int."},{"key":"ref_9","doi-asserted-by":"crossref","unstructured":"Yigit, E., Demirci, S., and Ozdemir, C. (2007, January 17\u201321). Ground Penetrating Radar Image Focusing using Frequency-Wavenumber based Synthetic Aperture Radar Technique. 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GPR Image Focusing Using Matched Filter Algorithm. Proceedings of the 2018 XXIIIrd International Seminar\/Workshop on Direct and Inverse Problems of Electromagnetic and Acoustic Wave Theory (DIPED), Tbilisi, Georgia.","DOI":"10.1109\/DIPED.2018.8543133"},{"key":"ref_13","unstructured":"(2024, March 29). Walabot Tech Brief. Available online: https:\/\/site.walabot.com\/docs\/walabot-tech-brief-416\/."},{"key":"ref_14","doi-asserted-by":"crossref","unstructured":"Koul, S.K., and Bharadwaj, R. (2021). Wearable Antennas and Body Centric Communication, Springer. Lecture Notes in Electrical Engineering.","DOI":"10.1007\/978-981-16-3973-9"},{"key":"ref_15","doi-asserted-by":"crossref","unstructured":"Gorham, L.A., and Moore, L.J. (2010, January 5\u20139). SAR image formation toolbox for MATLAB. 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Available online: https:\/\/hforsten.com\/backprojection-backpropagation.html."}],"container-title":["Remote Sensing"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2072-4292\/16\/8\/1426\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T14:29:33Z","timestamp":1760106573000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2072-4292\/16\/8\/1426"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2024,4,17]]},"references-count":16,"journal-issue":{"issue":"8","published-online":{"date-parts":[[2024,4]]}},"alternative-id":["rs16081426"],"URL":"https:\/\/doi.org\/10.3390\/rs16081426","relation":{},"ISSN":["2072-4292"],"issn-type":[{"value":"2072-4292","type":"electronic"}],"subject":[],"published":{"date-parts":[[2024,4,17]]}}}