{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,21]],"date-time":"2026-02-21T19:16:37Z","timestamp":1771701397117,"version":"3.50.1"},"reference-count":41,"publisher":"MDPI AG","issue":"4","license":[{"start":{"date-parts":[[2020,2,20]],"date-time":"2020-02-20T00:00:00Z","timestamp":1582156800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Princess Nourah Bint Abdulrahman University, Riyadh, Saudi Arabia","award":["Fast-Track Research Funding Program"],"award-info":[{"award-number":["Fast-Track Research Funding Program"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>This article presents a compact, planar, quad-port ultra-wideband (UWB) multiple-input\u2013multiple-output (MIMO) antenna with wide axial ratio bandwidth (ARBW). The proposed MIMO design consists of four identical square-shaped antenna elements, where each element is made up of a circular slotted ground plane and feed by a 50 \u2126 microstrip line. The circular polarization is achieved using a protruding hexagonal stub from the ground plane. The four elements of the MIMO antenna are placed orthogonally to each other to obtain high inter-element isolation. FR-4 dielectric substrate of size 45 \u00d7 45 \u00d7 1.6 mm3 is used for the antenna prototype, and a good agreement is noticed among the simulated and experimental results. The proposed MIMO antenna shows 3-dB ARBW of 52% (3.8\u20136.5 GHz) and impedance bandwidth (S11 \u2264 \u221210 dB) of 144% (2.2\u201313.5 GHz).<\/jats:p>","DOI":"10.3390\/s20041174","type":"journal-article","created":{"date-parts":[[2020,2,21]],"date-time":"2020-02-21T10:49:16Z","timestamp":1582282156000},"page":"1174","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":24,"title":["Design of Quad-Port Ultra-Wideband Multiple-Input-Multiple-Output Antenna with Wide Axial-Ratio Bandwidth"],"prefix":"10.3390","volume":"20","author":[{"given":"Pawan","family":"Kumar","sequence":"first","affiliation":[{"name":"Department of Electrical Engineering, School of Engineering, Gautam Buddha University, Greater Noida 201312, India"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1477-8759","authenticated-orcid":false,"given":"Shabana","family":"Urooj","sequence":"additional","affiliation":[{"name":"Department of Electrical Engineering, College of Engineering, Princess Nourah Bint Abdulrahman University, Riyadh 84428, Saudi Arabia"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7123-8548","authenticated-orcid":false,"given":"Areej","family":"Malibari","sequence":"additional","affiliation":[{"name":"Department of Computer Science, Faculty of Computing and IT, King Abdulaziz University, Jeddah 80200, Saudi Arabia"},{"name":"College of Engineering, Princess Nourah Bint Abdulrahman University, Riyadh 84428, Saudi Arabia"}]}],"member":"1968","published-online":{"date-parts":[[2020,2,20]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"3500","DOI":"10.1109\/TAP.2005.858598","article-title":"Study of a printed circular disc monopole antenna for UWB systems","volume":"53","author":"Liang","year":"2005","journal-title":"IEEE Trans. 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