{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,12]],"date-time":"2025-10-12T03:39:08Z","timestamp":1760240348765,"version":"build-2065373602"},"reference-count":37,"publisher":"MDPI AG","issue":"10","license":[{"start":{"date-parts":[[2019,5,20]],"date-time":"2019-05-20T00:00:00Z","timestamp":1558310400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"National Nature Science Foundation of China","award":["61871386"],"award-info":[{"award-number":["61871386"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>The all solid-state terahertz (THz) radar has obvious miniaturized integration and high resolution imaging advantages compared with conventional microwave radar. In this paper, a 0.22 THz active frequency-modulated pulse radar system with one transmission channel and four receiving channels is presented, and interferometric inverse synthetic aperture radar (InISAR) imaging experiments, which can acquire altitude information of objects, are carried out. In order to acquire high-quality InISAR images, a calibration method is presented to solve the nonlinearity of wideband signal frequency and phase inconsistency of different receiving channels together. Furthermore, to deal with the phase wrapping in InISAR imaging of objects with large scale, a novel method based on the dominant scatterers to estimate the objects rotation rate is presented. Finally, to show more information of objects in the InISAR images, the imaging results with a large rotation angle by the convolutional back-projection algorithm are obtained. The imaging results verify the superior performance of the multi-channel THz radar system and the imaging processing method, which can provide support for further research on InISAR imaging in the THz band.<\/jats:p>","DOI":"10.3390\/s19102330","type":"journal-article","created":{"date-parts":[[2019,5,20]],"date-time":"2019-05-20T11:05:07Z","timestamp":1558350307000},"page":"2330","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":16,"title":["Experimental Research on Interferometric Inverse Synthetic Aperture Radar Imaging with Multi-Channel Terahertz Radar System"],"prefix":"10.3390","volume":"19","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-3503-1187","authenticated-orcid":false,"given":"Ye","family":"Zhang","sequence":"first","affiliation":[{"name":"College of Electronic Science and Technology, National University of Defense Technology, Changsha 410073, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3637-6232","authenticated-orcid":false,"given":"Qi","family":"Yang","sequence":"additional","affiliation":[{"name":"College of Electronic Science and Technology, National University of Defense Technology, Changsha 410073, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Bin","family":"Deng","sequence":"additional","affiliation":[{"name":"College of Electronic Science and Technology, National University of Defense Technology, Changsha 410073, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Yuliang","family":"Qin","sequence":"additional","affiliation":[{"name":"College of Electronic Science and Technology, National University of Defense Technology, Changsha 410073, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Hongqiang","family":"Wang","sequence":"additional","affiliation":[{"name":"College of Electronic Science and Technology, National University of Defense Technology, Changsha 410073, China"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2019,5,20]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"293","DOI":"10.1109\/TTHZ.2011.2159562","article-title":"THz chemical imaging for biological applications","volume":"1","author":"Ajito","year":"2011","journal-title":"IEEE Trans. Terahertz Sci. Technol."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"169","DOI":"10.1109\/TTHZ.2011.2159556","article-title":"THz imaging radar for standoff personnel screening","volume":"1","author":"Cooper","year":"2011","journal-title":"IEEE Trans. Terahertz Sci. Technol."},{"key":"ref_3","doi-asserted-by":"crossref","unstructured":"Sheen, D.M., Hall, T.E., and Severtsen, R.H. (2009, January 13\u201317). Active wideband 350 GHz imaging system for concealed-weapon detection. Proceedings of the Passive Millimeter-Wave Imaging Technology XII, Orlando, FL, USA.","DOI":"10.1117\/12.817927"},{"key":"ref_4","doi-asserted-by":"crossref","unstructured":"Caris, M., Stanko, S., and Palm, S. (2015, January 24\u201326). 300 GHz radar for high resolution SAR and ISAR applications. Proceedings of the 16th International Radar Symposium, Dresden, Germany.","DOI":"10.1109\/IRS.2015.7226313"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"594","DOI":"10.1109\/TTHZ.2013.2268317","article-title":"Real-time imaging with a 140 GHz inverse synthetic aperture radar","volume":"3","author":"Cheng","year":"2013","journal-title":"IEEE Trans. Terahertz Sci. Technol."},{"key":"ref_6","doi-asserted-by":"crossref","unstructured":"Dengler, R.J., Cooper, K.B., and Chattopadhyay, G. (2007, January 3\u20138). 600 GHz imaging radar with 2 cm range resolution. Proceedings of the IEEE\/MTT-S International Microwave Symposium, Honolulu, HI, USA.","DOI":"10.1109\/MWSYM.2007.380468"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"64","DOI":"10.1109\/LMWC.2007.912049","article-title":"A high-resolution imaging radar at 580 GHz","volume":"18","author":"Cooper","year":"2008","journal-title":"IEEE Microw. Wirel. Compon. Lett."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"2771","DOI":"10.1109\/TMTT.2008.2007081","article-title":"Penetrating 3-D imaging at 4 and 25 m range using a submillimeter-wave radar","volume":"56","author":"Cooper","year":"2008","journal-title":"IEEE Trans. Microw. Theory Tech."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"1999","DOI":"10.1109\/TMTT.2010.2050106","article-title":"Time-delay multiplexing of two beams in a terahertz imaging radar","volume":"58","author":"Llombart","year":"2010","journal-title":"IEEE Trans. Microw. Theory Tech."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"232","DOI":"10.1109\/TTHZ.2013.2296146","article-title":"Time-delay multiplexing with linear arrays of THz radar transceivers","volume":"4","author":"Blazquez","year":"2014","journal-title":"IEEE Trans. Terahertz Sci. Technol."},{"key":"ref_11","doi-asserted-by":"crossref","unstructured":"Sheen, D.M., Mcmakin, D.L., and Thomas, E.H. (2009, January 11\u201312). Active millimeter-wave standoff and portal imaging techniques for personnel screening. Proceedings of the IEEE Conference on Technologies for Homeland Security, Waltham, MA, USA.","DOI":"10.1109\/THS.2009.5168070"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"3877","DOI":"10.1109\/TMTT.2012.2221738","article-title":"Terahertz aperture synthesized imaging with fan-beam scanning for personnel screening","volume":"60","author":"Gu","year":"2012","journal-title":"IEEE Trans. Microw. Theory Tech."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"1314","DOI":"10.1007\/s10762-011-9825-2","article-title":"Design, Analysis and Measurement of a Millimeter Wave Antenna Suitable for Stand off Imaging at Checkpoints","volume":"32","author":"Gao","year":"2011","journal-title":"J. Infrared Millim. Terahertz Waves"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"479","DOI":"10.1109\/TTHZ.2014.2326004","article-title":"Fast Three-Dimensional Image Reconstruction of Targets Under the Illumination of Terahertz Gaussian Beams with Enhanced Phase-Shift Migration to Improve Computation Efficiency","volume":"4","author":"Sun","year":"2014","journal-title":"IEEE Trans. Terahertz Sci. Technol."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"509","DOI":"10.1109\/TTHZ.2018.2853551","article-title":"340 GHz 3-D imaging radar with 4Tx-16Rx MIMO array","volume":"5","author":"Cheng","year":"2018","journal-title":"IEEE Trans. Terahertz Sci. Technol."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"38","DOI":"10.1109\/TTHZ.2017.2764383","article-title":"Fast Three-Dimensional Image Reconstruction of a Standoff Screening System in the Terahertz Regime","volume":"4","author":"Gao","year":"2018","journal-title":"IEEE Trans. Terahertz Sci. Technol."},{"key":"ref_17","unstructured":"Soumekh, M. (1999). Synthetic Aperture Radar Signal Processing with MATLAB Algorithms, Wiley. [1st ed.]."},{"key":"ref_18","doi-asserted-by":"crossref","unstructured":"\u00d6zdemir, C. (2012). Inverse Synthetic Aperture Radar Imaging with MATLAB Algorithms, Wiley.","DOI":"10.1002\/9781118178072"},{"key":"ref_19","unstructured":"Cumming, I.G., and Wong, F.H. (2005). Digital Processing of Synthetic Aperture Radar Data: Algorithms and Implementation, Artech House."},{"key":"ref_20","unstructured":"Bao, Z., and Xing, M. (2005). Technology of Radar Imaging, Publishing House of Electronics Industry."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"1114","DOI":"10.1049\/el:20071865","article-title":"High-Bandwidth 220 GHz Experimental Radar","volume":"43","author":"Essen","year":"2007","journal-title":"Electron. Lett."},{"key":"ref_22","unstructured":"Stanko, S., Caris, M., and Wahlen, A. (2013, January 19\u201321). Millimeter Resolution with Radar at Lower Terahertz. Proceedings of the IEEE International Radar Symposium, Dresden, Germany."},{"key":"ref_23","doi-asserted-by":"crossref","unstructured":"Kim, S., Fan, R., and Dominski, F. (2018, January 13\u201327). A 235 GHz radar for airborne applications. Proceedings of the IEEE Radar Conference, Oklahoma City, OK, USA.","DOI":"10.1109\/RADAR.2018.8378797"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"606","DOI":"10.1109\/TTHZ.2013.2271298","article-title":"THz 3-D image formation using SAR techniques: Simulation, processing and experimental results","volume":"3","author":"Ding","year":"2013","journal-title":"IEEE Trans. Terahertz Sci. Technol."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"16264","DOI":"10.1364\/OE.18.016264","article-title":"Terahertz Inverse Synthetic Aperture Radar (ISAR) Imaging with a Quantum Cascade Laser Transmitter","volume":"18","author":"Danylov","year":"2010","journal-title":"Opt. Express"},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"290","DOI":"10.1109\/JSEN.2014.2342495","article-title":"Terahertz Imaging Radar with Inverse Aperture Synthesis Techniques: System Structure, Signal Processing, and Experiment Results","volume":"15","author":"Zhang","year":"2015","journal-title":"IEEE Sens. J."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"780","DOI":"10.1007\/s10762-014-0079-7","article-title":"Experimental 0.22 THz Stepped Frequency Radar System for ISAR Imaging","volume":"35","author":"Liang","year":"2014","journal-title":"J. Infrared Millim. Terahertz Waves"},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"2048","DOI":"10.1002\/mop.30668","article-title":"Experimental research on vehicle-borne SAR imaging with THz radar","volume":"59","author":"Yang","year":"2017","journal-title":"Microw. Opt. Technol. Lett."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"627","DOI":"10.1109\/TGRS.1990.572968","article-title":"Seismic migration for SAR focusing: Interferometric application","volume":"28","author":"Prati","year":"1990","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"436","DOI":"10.1109\/83.908519","article-title":"Three-dimensional ISAR imaging of maneuvering targets using three receivers","volume":"10","author":"Wang","year":"2001","journal-title":"IEEE Trans. Image Process."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"1792","DOI":"10.1109\/TIP.2005.857285","article-title":"Generalized ISAR\u2014Part II: Interferometric techniques for three-dimensional location of scatterers","volume":"14","author":"Given","year":"2005","journal-title":"IEEE Trans. Image Process."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"2487","DOI":"10.1109\/36.789644","article-title":"Weighted least square estimation of phase errors for SAR\/ISAR autofocus","volume":"37","author":"Ye","year":"1999","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"205","DOI":"10.1109\/LGRS.2009.2031658","article-title":"Minimum Entropy via Subspace for ISAR Autofocus","volume":"7","author":"Cao","year":"2010","journal-title":"IEEE Geosci. Remote Sens. Lett."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"124","DOI":"10.1109\/36.739143","article-title":"A region-growing algorithm for InSAR phase unwrapping","volume":"37","author":"Xu","year":"1999","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"107","DOI":"10.1364\/JOSAA.11.000107","article-title":"Robust two-dimensional weighted and unweighted phase unwrapping that uses fast transforms and iterative methods","volume":"11","author":"Ghiglia","year":"1994","journal-title":"J. Opt. Soc. Am. A"},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"1709","DOI":"10.1109\/TGRS.2002.802453","article-title":"Phase unwrapping for large SAR interferograms: Statistical segmentation and generalized network models","volume":"40","author":"Chen","year":"2002","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"730","DOI":"10.1109\/8.668918","article-title":"Spherical wave near-field imaging and radar cross-section measurement","volume":"46","author":"Broquetas","year":"1998","journal-title":"IEEE Trans. Antennas Propag."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/19\/10\/2330\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T12:53:45Z","timestamp":1760187225000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/19\/10\/2330"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2019,5,20]]},"references-count":37,"journal-issue":{"issue":"10","published-online":{"date-parts":[[2019,5]]}},"alternative-id":["s19102330"],"URL":"https:\/\/doi.org\/10.3390\/s19102330","relation":{},"ISSN":["1424-8220"],"issn-type":[{"type":"electronic","value":"1424-8220"}],"subject":[],"published":{"date-parts":[[2019,5,20]]}}}