{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,24]],"date-time":"2025-10-24T08:17:07Z","timestamp":1761293827053,"version":"build-2065373602"},"reference-count":23,"publisher":"MDPI AG","issue":"10","license":[{"start":{"date-parts":[[2018,10,18]],"date-time":"2018-10-18T00:00:00Z","timestamp":1539820800000},"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>The vortex electromagnetic (EM) wave with orbital angular momentum (OAM) brings a new degree of freedom for synthetic aperture radar (SAR) imaging, although to date, its application to multi-input multi-output (MIMO) SAR has not yet been widely reported. In this paper, an orbital angular momentum (OAM)-based MIMO-SAR system is proposed. The rotational Doppler Effect (RDE) of vortex EM waves offers a novel scheme for an OAM-based MIMO-SAR system. By transmitting the rotational vortex EM waves, echoes of different OAM modes can be discriminated by a bandpass filter in the range-Doppler domain. The performance of the proposed scheme is independent of the time-variant channel responses, and the wider beam width of the vortex EM waves delivers, for the same antenna aperture size, better performance in terms of swath width and azimuth resolution, in contrast to the plane EM waves. Moreover, the spatial diversity of vortex EM waves shows great potential to enhance the MIMO-SAR system applications, which involve high-resolution wide-swath remote sensing, 3-D imaging, and radar-communication integration. The proposed scheme is verified by proof-of-concept experiments. This work presents a new application of vortex EM waves, which facilitates the development of new-generation and forthcoming SAR systems.<\/jats:p>","DOI":"10.3390\/s18103511","type":"journal-article","created":{"date-parts":[[2018,10,18]],"date-time":"2018-10-18T10:55:41Z","timestamp":1539860141000},"page":"3511","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":16,"title":["A Novel Scheme for MIMO-SAR Systems Using Rotational Orbital Angular Momentum"],"prefix":"10.3390","volume":"18","author":[{"given":"Xiangxi","family":"Bu","sequence":"first","affiliation":[{"name":"Science and Technology on Microwave Imaging Laboratory, Institute of Electronics, Chinese Academy of Sciences, Beijing 100190, China"},{"name":"School of Electronics, Electrical and Communication Engineering, University of Chinese Academy of Sciences, Beijing 100049, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Zhuo","family":"Zhang","sequence":"additional","affiliation":[{"name":"Science and Technology on Microwave Imaging Laboratory, Institute of Electronics, Chinese Academy of Sciences, Beijing 100190, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Xingdong","family":"Liang","sequence":"additional","affiliation":[{"name":"Science and Technology on Microwave Imaging Laboratory, Institute of Electronics, Chinese Academy of Sciences, Beijing 100190, China"},{"name":"School of Electronics, Electrical and Communication Engineering, University of Chinese Academy of Sciences, Beijing 100049, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Longyong","family":"Chen","sequence":"additional","affiliation":[{"name":"Science and Technology on Microwave Imaging Laboratory, Institute of Electronics, Chinese Academy of Sciences, Beijing 100190, China"},{"name":"School of Electronics, Electrical and Communication Engineering, University of Chinese Academy of Sciences, Beijing 100049, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Haibo","family":"Tang","sequence":"additional","affiliation":[{"name":"Science and Technology on Microwave Imaging Laboratory, Institute of Electronics, Chinese Academy of Sciences, Beijing 100190, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Zheng","family":"Zeng","sequence":"additional","affiliation":[{"name":"Science and Technology on Microwave Imaging Laboratory, Institute of Electronics, Chinese Academy of Sciences, Beijing 100190, China"},{"name":"School of Electronics, Electrical and Communication Engineering, University of Chinese Academy of Sciences, Beijing 100049, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Jie","family":"Wang","sequence":"additional","affiliation":[{"name":"School of Electronic &amp; Information Engineering, Nanjing University of Information Science &amp; Technology, Nanjing 210044, China"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2018,10,18]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"31","DOI":"10.1109\/TGRS.2007.905974","article-title":"Multidimensional waveform encoding, a new digital beamforming technique for synthetic aperture radar remote sensing","volume":"46","author":"Krieger","year":"2008","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"2628","DOI":"10.1109\/TGRS.2013.2263934","article-title":"MIMO-SAR: Opportunities and pitfalls","volume":"52","author":"Krieger","year":"2014","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_3","unstructured":"Krieger, G., Gebert, N., and Moreira, A. (2006, January 16\u201318). Digital beamforming techniques for spaceborne radar remote sensing. Proceedings of the 6th European Conference on Synthetic Aperture Radar, Dresden, Germany."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"38","DOI":"10.1109\/TGRS.2010.2053715","article-title":"Exploiting MIMO SAR potentialities with efficient cross-track constellation configurations for improved range resolution","volume":"49","author":"Cristallini","year":"2011","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_5","unstructured":"Kim, J., Younis, M., Moreira, A., and Wiesbeck, W. (2010, January 7\u201310). A novel OFDM waveform for fully polarimetric SAR data acquisition. Proceedings of the 8th European Conference on Synthetic Aperture Radar, Aachen, Germany."},{"key":"ref_6","doi-asserted-by":"crossref","unstructured":"Krieger, G., Younis, M., Huber, S., Bordoni, F., Patyuchenko, A., Kim, J., Laskowski, P., Villano, M., Romme, T., and L\u00f3pez-Dekker, P. (2012, January 22\u201327). MIMO-SAR and the orthogonality confusion. Proceedings of the 2012 IEEE International Geoscience and Remote Sensing Symposium, Munich, Germany.","DOI":"10.1109\/IGARSS.2012.6351242"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"1556","DOI":"10.1109\/LGRS.2015.2412961","article-title":"A Novel Space\u2013Time Coding Scheme Used for MIMO-SAR Systems","volume":"12","author":"Wang","year":"2015","journal-title":"IEEE Geosci. Remote Sens. Lett."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"5218","DOI":"10.1109\/TGRS.2015.2419271","article-title":"Implementation of the OFDM chirp waveform on MIMO SAR systems","volume":"53","author":"Wang","year":"2015","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"033001","DOI":"10.1088\/1367-2630\/14\/3\/033001","article-title":"Encoding many channels on the same frequency through radio vorticity: First experimental test","volume":"14","author":"Tamburini","year":"2012","journal-title":"New J. Phys."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"15412","DOI":"10.1038\/s41598-017-15250-7","article-title":"RCS Diversity of Electromagnetic Wave Carrying Orbital Angular Momentum","volume":"7","author":"Zhang","year":"2017","journal-title":"Sci. Rep."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"164102","DOI":"10.1063\/1.4981253","article-title":"Super-resolution radar imaging based on experimental OAM beams","volume":"110","author":"Liu","year":"2017","journal-title":"Appl. Phys. Lett."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"764","DOI":"10.1109\/LAWP.2018.2814980","article-title":"Implementation of Vortex Electromagnetic Waves High-Resolution Synthetic Aperture Radar Imaging","volume":"17","author":"Bu","year":"2018","journal-title":"IEEE Antennas Wirel. Propag. Lett."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"4828","DOI":"10.1103\/PhysRevLett.81.4828","article-title":"Rotational frequency shift of a light beam","volume":"81","author":"Courtial","year":"1998","journal-title":"Phys. Rev. Lett."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"537","DOI":"10.1126\/science.1239936","article-title":"Detection of a spinning object using light\u2019s orbital angular momentum","volume":"341","author":"Lavery","year":"2013","journal-title":"Science"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"31921","DOI":"10.1038\/srep31921","article-title":"Millimetre wave with rotational orbital angular momentum","volume":"6","author":"Zhang","year":"2016","journal-title":"Sci. Rep."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"4585","DOI":"10.1038\/s41598-017-04313-4","article-title":"Detecting the Orbital Angular Momentum of Electro-Magnetic Waves Using Virtual Rotational Antenna","volume":"7","author":"Zhang","year":"2017","journal-title":"Sci. Rep."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"343","DOI":"10.1080\/2150704X.2017.1421791","article-title":"Three dimensional SAR imaging based on vortex electromagnetic waves","volume":"9","author":"Yang","year":"2018","journal-title":"Remote Sens. Lett."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"3504","DOI":"10.1109\/TSP.2018.2831624","article-title":"Joint System Design for Co-Existence of MIMO Radar and MIMO Communication","volume":"66","author":"Qian","year":"2018","journal-title":"IEEE Trans. Signal Process."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"565","DOI":"10.1109\/TAP.2009.2037701","article-title":"Orbital angular momentum in radio\u2014A system study","volume":"58","author":"Mohammadi","year":"2010","journal-title":"IEEE Trans. Antennas Propag."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"3217","DOI":"10.1103\/PhysRevLett.80.3217","article-title":"Measurement of the rotational frequency shift imparted to a rotating light beam possessing orbital angular momentum","volume":"80","author":"Courtial","year":"1998","journal-title":"Phys. Rev. Lett."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"757","DOI":"10.1109\/LMWC.2017.2723719","article-title":"Experimental Demonstration of the Capacity Gain of Plane Spiral OAM-Based MIMO System","volume":"27","author":"Zhang","year":"2017","journal-title":"IEEE Microw. Wirel. Compon. Lett."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"183","DOI":"10.1016\/0030-4018(96)00070-3","article-title":"The generation of free-space Laguerre-Gaussian modes at millimetre-wave frequencies by use of a spiral phase plate","volume":"127","author":"Turnbull","year":"1996","journal-title":"Opt. Commun."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"1308","DOI":"10.1109\/TWC.2016.2645199","article-title":"Mode Division Multiplexing Communication Using Microwave Orbital Angular Momentum: An Experimental Study","volume":"16","author":"Zhang","year":"2017","journal-title":"IEEE Trans. Wirel. Commun."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/18\/10\/3511\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T15:26:26Z","timestamp":1760196386000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/18\/10\/3511"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2018,10,18]]},"references-count":23,"journal-issue":{"issue":"10","published-online":{"date-parts":[[2018,10]]}},"alternative-id":["s18103511"],"URL":"https:\/\/doi.org\/10.3390\/s18103511","relation":{},"ISSN":["1424-8220"],"issn-type":[{"type":"electronic","value":"1424-8220"}],"subject":[],"published":{"date-parts":[[2018,10,18]]}}}