{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T00:47:01Z","timestamp":1760143621403,"version":"build-2065373602"},"reference-count":26,"publisher":"MDPI AG","issue":"5","license":[{"start":{"date-parts":[[2024,2,23]],"date-time":"2024-02-23T00:00:00Z","timestamp":1708646400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001840","name":"Icelandic Centre for Research (RANNIS)","doi-asserted-by":"publisher","award":["239858","2020\/37\/B\/ST7\/01448"],"award-info":[{"award-number":["239858","2020\/37\/B\/ST7\/01448"]}],"id":[{"id":"10.13039\/501100001840","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100004281","name":"National Science Centre of Poland","doi-asserted-by":"publisher","award":["239858","2020\/37\/B\/ST7\/01448"],"award-info":[{"award-number":["239858","2020\/37\/B\/ST7\/01448"]}],"id":[{"id":"10.13039\/501100004281","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>In this article, the phenomena of beam deviation in reflectarray is discussed. The radiation pattern of the unit cell, which plays a vital role in shaping the beam of the reflectarray, is analyzed by considering undesired specular and scattered reflections. These unwanted reflections adversely affect the pattern of the single unit cell, thereby reducing the overall performance of the reflectarray. To conduct our investigations, three cases of reflectarray\u2014i.e., (i) a center-fed with broadside beam (Case-I), (ii) a center-fed with the beam at 30\u00b0 (Case-II), and (iii) off-center-fed with the beam at 30\u00b0 reciprocal to feed position with reference to the broadside direction (Case-III)\u2014are simulated. Different degrees of beam deviation are analyzed in each reflectarray by assessing the radiation pattern of a single element. The simulation results shows that maximum of 0\u00b0, 3.4\u00b0, and 0.54\u00b0 beam squint across the bandwidth found in Case-I, Case-II, and Case-III, respectively; this leads to aperture efficiencies of 31.2%, 11.9%, and 31.2%, respectively. The significance of specular reflections is further confirmed by half (left half and right half) aperture analysis of Case-II. This involves simulating the half-plane aperture illuminated by horn antenna, resulting in a distinct beam angle at the same frequency. However, deviations of \u22124.71 to +4.1 for the left half aperture and \u22121.82 to +1.1 for the right half aperture are noticed. Although the analysis specifically focuses on the three cases of the reflectarray, the proposed methodology is applicable to any type of reflectarray. The study presented in this work provides an important insight into the practical aspects of reflectarray operation, particularly in terms of quantifying undesirable effects that are normally overlooked in the design of this class of arrays. To achieve a good performance, a new design of the dielectric loaded horn feed is proposed. This design approach is both simple and applicable to any reflectarray, with the added benefit of maintaining a low profile for the RA. Moreover, this work holds significant potential for remote sensing satellite systems as beam deviation can adversely impact data collection accuracy and compromise observation precision, resulting in distorted images, reduced data quality, and overall hindrance to the system\u2019s performance in capturing reliable information.<\/jats:p>","DOI":"10.3390\/s24051438","type":"journal-article","created":{"date-parts":[[2024,2,23]],"date-time":"2024-02-23T04:31:23Z","timestamp":1708662683000},"page":"1438","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Exploring the Beam Squint Effects on Reflectarray Performance: A Comprehensive Analysis of the Specular and Scattered Reflection of the Unit Cell"],"prefix":"10.3390","volume":"24","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-1049-2606","authenticated-orcid":false,"given":"Manzoor","family":"Elahi","sequence":"first","affiliation":[{"name":"Department of Engineering, Reykjavik University, 102 Reykjavik, Iceland"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5009-9043","authenticated-orcid":false,"given":"Amir","family":"Altaf","sequence":"additional","affiliation":[{"name":"Millibeam, Melbourne, VIC 3053, Australia"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9063-2647","authenticated-orcid":false,"given":"Slawomir","family":"Koziel","sequence":"additional","affiliation":[{"name":"Department of Engineering, Reykjavik University, 102 Reykjavik, Iceland"},{"name":"Faculty of Electronics, Telecommunications and Informatics, Gdansk University of Technology, 80-233 Gdansk, Poland"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2319-6782","authenticated-orcid":false,"given":"Anna","family":"Pietrenko-Dabrowska","sequence":"additional","affiliation":[{"name":"Faculty of Electronics, Telecommunications and Informatics, Gdansk University of Technology, 80-233 Gdansk, Poland"}]}],"member":"1968","published-online":{"date-parts":[[2024,2,23]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"2713","DOI":"10.1109\/TAP.2017.2679493","article-title":"A Broadband Reflectarray Antenna Using Triple Gapped Rings with Attached Phase-Delay Lines","volume":"65","author":"Han","year":"2017","journal-title":"IEEE Trans. Antennas Propagat."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"696","DOI":"10.1109\/LAWP.2016.2600374","article-title":"Design of a Broadband Single-Layer Linearly Polarized Reflectarray Using Four-Arm Spiral Elements","volume":"16","author":"Xue","year":"2016","journal-title":"IEEE Antennas Wirel. Propag. Lett."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"891","DOI":"10.1109\/LAWP.2014.2321035","article-title":"A highefficiency Ku-band reflectarray antenna using single-layer multiresonance elements","volume":"14","author":"Vosoogh","year":"2014","journal-title":"IEEE Antennas Wirel. Propag. Lett."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"378","DOI":"10.1109\/TAP.2015.2502978","article-title":"Broadband reflectarray antenna using subwavelength elements based on double square meander-line rings","volume":"64","author":"Qin","year":"2015","journal-title":"IEEE Trans. Antennas Propagat."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"418","DOI":"10.1002\/mop.28111","article-title":"Bandwidth improvement of reflectarrays using single-layered double concentric circular ring elements on a subwavelength grid","volume":"56","author":"Guo","year":"2014","journal-title":"Microw. Opt. Technol. Lett."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"3132","DOI":"10.1109\/TAP.2019.2900382","article-title":"Broadband Reflectarray Antenna Using Single-Layer Rectangular Patches Embedded with Inverted L-Shaped Slots","volume":"67","author":"Guo","year":"2019","journal-title":"IEEE Trans. Antennas Propagat."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"176197","DOI":"10.1109\/ACCESS.2019.2957840","article-title":"Design of a wideband single-layer reflectarray antenna using slotted rectangular patch with concave arms","volume":"7","author":"Min","year":"2019","journal-title":"IEEE Access"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"172","DOI":"10.1109\/TAP.2017.2775282","article-title":"Wide-angle beam-scanning reflectarray with mechanical steering","volume":"66","author":"Wu","year":"2017","journal-title":"IEEE Trans. Antennas Propag."},{"doi-asserted-by":"crossref","unstructured":"Wu, G.B., Qu, S.W., and Chan, C.H. (2017, January 24\u201326). Wide-angle beam scanning reflectarray antenna design using phase matching method. Proceedings of the 2017 10th Global Symposium on Millimeter-Waves, Hong Kong, China.","key":"ref_9","DOI":"10.1109\/GSMM.2017.7970310"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"4588","DOI":"10.1109\/TAP.2013.2264795","article-title":"Bifocal design and aperture phase optimizations of reflectarray antennas for wide-angle beam scanning performance","volume":"61","author":"Nayeri","year":"2013","journal-title":"IEEE Trans. Antennas Propag."},{"key":"ref_11","first-page":"170","article-title":"Gain and bandwidth limitations of reflectarrays","volume":"26","author":"Devireddy","year":"2011","journal-title":"ACES J.-Appl. Comput. Electromagn. Soc."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"10648","DOI":"10.1109\/TWC.2022.3185713","article-title":"Frequency-invariant sensor selection for MVDR beamforming in wireless acoustic sensor networks","volume":"21","author":"Zhang","year":"2022","journal-title":"IEEE Trans. Wirel. Commun."},{"key":"ref_13","first-page":"1326","article-title":"Minimization of beam squint in microstrip reflectarrays using an offset feed","volume":"2","author":"Targonski","year":"1996","journal-title":"IEEE Antennas Propag. Soc. Int. Symp."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"287","DOI":"10.1109\/8.560348","article-title":"Design of millimeter wave microstrip reflectarrays","volume":"45","author":"Pozar","year":"1997","journal-title":"IEEE Trans. Antennas Propagat."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"937","DOI":"10.1109\/LAWP.2012.2212171","article-title":"On Beam Squint in Offset-Fed Reflectarrays","volume":"11","author":"Almajali","year":"2012","journal-title":"IEEE Antennas Wirel. Propag. Lett."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"3656","DOI":"10.1109\/TAP.2016.2565732","article-title":"Scanning characteristics of metamirror antennas with subwavelength focal distance","volume":"64","author":"Tcvetkova","year":"2016","journal-title":"IEEE Trans. Antennas Propagat."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"1139","DOI":"10.1109\/LAWP.2010.2094178","article-title":"Broadband Reflectarray Antennas Using Double-Layer Subwavelength Patch Elements","volume":"9","author":"Nayeri","year":"2010","journal-title":"IEEE Antennas Wirel. Propag. Lett."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"19","DOI":"10.2528\/PIERC10091505","article-title":"Bandwidth improvement of reflectarray antennas using closely spaced elements","volume":"18","author":"Nayeri","year":"2011","journal-title":"Prog. Electromagn. Res."},{"doi-asserted-by":"crossref","unstructured":"El Hani, R., and Laurin, J.J. (2011, January 3\u20138). Phase analysis for off-specular reflectarray antennas. Proceedings of the IEEE International Symposium on Antennas and Propagation (APSURSI), Washington, DC, USA.","key":"ref_19","DOI":"10.1109\/APS.2011.5996723"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"587","DOI":"10.1109\/LAWP.2013.2260124","article-title":"Beam squint suppression in offset-fed reflectarrays","volume":"12","author":"McNamara","year":"2013","journal-title":"IEEE Antenna Wirel. Propag. Lett."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"45526","DOI":"10.1109\/ACCESS.2019.2909313","article-title":"A reflectarray antenna using hexagonal lattic with ehnanced beam steering capbility","volume":"7","author":"Kiris","year":"2019","journal-title":"IEEE Access"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"1609","DOI":"10.1049\/iet-map.2017.0270","article-title":"Broadband single-layer reflectarray antenna for X-band applications","volume":"12","author":"Bodur","year":"2017","journal-title":"IET Microwaves Antennas Propag."},{"key":"ref_23","first-page":"1230","article-title":"Single layer reflectarray antenna with pie-shaped elements for X-band applications","volume":"33","author":"Shabbir","year":"2018","journal-title":"Appl. Comput. Electromagn. Soc. J. (ACES)"},{"doi-asserted-by":"crossref","unstructured":"Huang, J., and Encinar, J.A. (2008). Reflectarray Antennas, Wiley.","key":"ref_24","DOI":"10.1002\/9780470178775"},{"key":"ref_25","first-page":"1055","article-title":"Mathematical model for progressive phase distribution of ku-band reflectarray antennas","volume":"7","author":"Ismail","year":"2013","journal-title":"Int. J. Commun."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"71","DOI":"10.1109\/MAP.2010.5687509","article-title":"On the scattering analysis methods of and reflection characteristics for an AMC\/AEC surface","volume":"52","author":"Foroozesh","year":"2010","journal-title":"IEEE Antennas Propag. Mag."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/24\/5\/1438\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T14:03:41Z","timestamp":1760105021000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/24\/5\/1438"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2024,2,23]]},"references-count":26,"journal-issue":{"issue":"5","published-online":{"date-parts":[[2024,3]]}},"alternative-id":["s24051438"],"URL":"https:\/\/doi.org\/10.3390\/s24051438","relation":{},"ISSN":["1424-8220"],"issn-type":[{"type":"electronic","value":"1424-8220"}],"subject":[],"published":{"date-parts":[[2024,2,23]]}}}