{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,2]],"date-time":"2026-06-02T09:25:22Z","timestamp":1780392322451,"version":"3.54.1"},"reference-count":26,"publisher":"MDPI AG","issue":"3","license":[{"start":{"date-parts":[[2019,1,23]],"date-time":"2019-01-23T00:00:00Z","timestamp":1548201600000},"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>In this study, we propose a design of a multi-band slot antenna array applicable for fourth-generation (4G) and fifth-generation (5G) smartphones. The design is composed of double-element square-ring slot radiators fed by microstrip-line structures for easy integration with radio frequency (RF)\/microwave circuitry. The slot radiators are located on the corners of the smartphone printed circuit board (PCB) with an overall dimension of 75 \u00d7 150 mm2. The proposed multiple-input multiple-output (MIMO) antenna is designed to meet the requirements of 4G and 5G mobile terminals with essential bandwidth for higher data rate applications. For \u221210 dB impedance bandwidth, each single-element of the proposed MIMO design can cover the frequency ranges of 2.5\u20132.7 GHz (long-term evolution (LTE) 2600), 3.45\u20133.8 GHz (LTE bands 42\/43), and 5.00\u20135.45 GHz (LTE band 46). However, for \u22126 dB impedance bandwidth, the radiation elements cover the frequency ranges of 2.45\u20132.82 GHz, 3.35\u20134.00 GHz, and 4.93\u20135.73 GHz. By employing the microstrip feed lines at the four different sides of smartphone PCB, the isolation of the radiators has been enhanced and shows better than 17 dB isolation levels over all operational bands. The MIMO antenna is implemented on an FR-4 dielectric and provides good properties including S-parameters, efficiency, and radiation pattern coverage. The performance of the antenna is validated by measurements of the prototype. The simulation results for user-hand\/user-head impacts and specific absorption rate (SAR) levels of the antenna are discussed, and good results are achieved. In addition, the antenna elements have the potential to be used as 8-element\/dual-polarized resonators.<\/jats:p>","DOI":"10.3390\/s19030456","type":"journal-article","created":{"date-parts":[[2019,1,24]],"date-time":"2019-01-24T03:52:32Z","timestamp":1548301952000},"page":"456","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":69,"title":["Multi-Band MIMO Antenna Design with User-Impact Investigation for 4G and 5G Mobile Terminals"],"prefix":"10.3390","volume":"19","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-8375-0269","authenticated-orcid":false,"given":"Naser","family":"Ojaroudi Parchin","sequence":"first","affiliation":[{"name":"Faculty of Engineering and Informatics, School of Electrical Engineering and Computer Science, University of Bradford, Bradford BD7 1DP, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Haleh","family":"Jahanbakhsh Basherlou","sequence":"additional","affiliation":[{"name":"Microwave Technology Company, Ardabil 56158-46984, Iran"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7859-3550","authenticated-orcid":false,"given":"Yasir I. A.","family":"Al-Yasir","sequence":"additional","affiliation":[{"name":"Faculty of Engineering and Informatics, School of Electrical Engineering and Computer Science, University of Bradford, Bradford BD7 1DP, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Atta","family":"Ullah","sequence":"additional","affiliation":[{"name":"Faculty of Engineering and Informatics, School of Electrical Engineering and Computer Science, University of Bradford, Bradford BD7 1DP, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2972-9965","authenticated-orcid":false,"given":"Raed A.","family":"Abd-Alhameed","sequence":"additional","affiliation":[{"name":"Faculty of Engineering and Informatics, School of Electrical Engineering and Computer Science, University of Bradford, Bradford BD7 1DP, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"James M.","family":"Noras","sequence":"additional","affiliation":[{"name":"Faculty of Engineering and Informatics, School of Electrical Engineering and Computer Science, University of Bradford, Bradford BD7 1DP, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2019,1,23]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"726","DOI":"10.1109\/TCOMM.2017.2762685","article-title":"Design of 5G full dimension massive MIMO systems","volume":"66","author":"Nadeem","year":"2018","journal-title":"IEEE Trans. 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