{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,25]],"date-time":"2026-03-25T20:02:06Z","timestamp":1774468926932,"version":"3.50.1"},"reference-count":20,"publisher":"MDPI AG","issue":"15","license":[{"start":{"date-parts":[[2023,8,7]],"date-time":"2023-08-07T00:00:00Z","timestamp":1691366400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Universidad Carlos III de Madrid and the European Union\u2019s Horizon 2020 research and innovation program","award":["801538"],"award-info":[{"award-number":["801538"]}]},{"name":"Universidad Carlos III de Madrid and the European Union\u2019s Horizon 2020 research and innovation program","award":["RSP2023R58"],"award-info":[{"award-number":["RSP2023R58"]}]},{"name":"Universidad Carlos III de Madrid and the European Union\u2019s Horizon 2020 research and innovation program","award":["239858"],"award-info":[{"award-number":["239858"]}]},{"name":"Universidad Carlos III de Madrid and the European Union\u2019s Horizon 2020 research and innovation program","award":["2020\/37\/B\/ST7\/01448"],"award-info":[{"award-number":["2020\/37\/B\/ST7\/01448"]}]},{"name":"King Saud University, Riyadh, Saudi Arabia","award":["801538"],"award-info":[{"award-number":["801538"]}]},{"name":"King Saud University, Riyadh, Saudi Arabia","award":["RSP2023R58"],"award-info":[{"award-number":["RSP2023R58"]}]},{"name":"King Saud University, Riyadh, Saudi Arabia","award":["239858"],"award-info":[{"award-number":["239858"]}]},{"name":"King Saud University, Riyadh, Saudi Arabia","award":["2020\/37\/B\/ST7\/01448"],"award-info":[{"award-number":["2020\/37\/B\/ST7\/01448"]}]},{"name":"Icelandic Centre for Research (RANNIS) Grant","award":["801538"],"award-info":[{"award-number":["801538"]}]},{"name":"Icelandic Centre for Research (RANNIS) Grant","award":["RSP2023R58"],"award-info":[{"award-number":["RSP2023R58"]}]},{"name":"Icelandic Centre for Research (RANNIS) Grant","award":["239858"],"award-info":[{"award-number":["239858"]}]},{"name":"Icelandic Centre for Research (RANNIS) Grant","award":["2020\/37\/B\/ST7\/01448"],"award-info":[{"award-number":["2020\/37\/B\/ST7\/01448"]}]},{"name":"National Science Centre of Poland Grant","award":["801538"],"award-info":[{"award-number":["801538"]}]},{"name":"National Science Centre of Poland Grant","award":["RSP2023R58"],"award-info":[{"award-number":["RSP2023R58"]}]},{"name":"National Science Centre of Poland Grant","award":["239858"],"award-info":[{"award-number":["239858"]}]},{"name":"National Science Centre of Poland Grant","award":["2020\/37\/B\/ST7\/01448"],"award-info":[{"award-number":["2020\/37\/B\/ST7\/01448"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>In this paper, a radiating element consisting of a modified circular patch is proposed for MIMO arrays for 5G millimeter-wave applications. The radiating elements in the proposed 2 \u00d7 2 MIMO antenna array are orthogonally configured relative to each other to mitigate mutual coupling that would otherwise degrade the performance of the MIMO system. The MIMO array was fabricated on Rogers RT\/Duroid high-frequency substrate with a dielectric constant of 2.2, a thickness of 0.8 mm, and a loss tangent of 0.0009. The individual antenna in the array has a measured impedance bandwidth of 1.6 GHz from 27.25 to 28.85 GHz for S11 \u2264 \u221210 dB, and the MIMO array has a gain of 7.2 dBi at 28 GHz with inter radiator isolation greater than 26 dB. The gain of the MIMO array was increased by introducing frequency-selective surface (FSS) consisting of 7 \u00d7 7 array of unit cells comprising rectangular C-shaped resonators, with one embedded inside the other with a central crisscross slotted patch. With the FSS, the gain of the MIMO array increased to 8.6 dBi at 28 GHz. The radiation from the array is directional and perpendicular to the plain of the MIMO array. Owing to the low coupling between the radiating elements in the MIMO array, its Envelope Correlation Coefficient (ECC) is less than 0.002, and its diversity gain (DG) is better than 9.99 dB in the 5G operating band centered at 28 GHz between 26.5 GHz and 29.5 GHz.<\/jats:p>","DOI":"10.3390\/s23157009","type":"journal-article","created":{"date-parts":[[2023,8,8]],"date-time":"2023-08-08T12:45:53Z","timestamp":1691498753000},"page":"7009","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":55,"title":["Frequency-Selective Surface-Based MIMO Antenna Array for 5G Millimeter-Wave Applications"],"prefix":"10.3390","volume":"23","author":[{"given":"Iftikhar","family":"Ud Din","sequence":"first","affiliation":[{"name":"Telecommunication Engineering Department, University of Engineering and Technology, Mardan 23200, Pakistan"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8263-1572","authenticated-orcid":false,"given":"Mohammad","family":"Alibakhshikenari","sequence":"additional","affiliation":[{"name":"Department of Signal Theory and Communications, Universidad Carlos III de Madrid, 28911 Legan\u00e9s, Madrid, Spain"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7203-0039","authenticated-orcid":false,"given":"Bal S.","family":"Virdee","sequence":"additional","affiliation":[{"name":"Center for Communications Technology, London Metropolitan University, London N7 8DB, UK"}]},{"given":"Renu Karthick Rajaguru","family":"Jayanthi","sequence":"additional","affiliation":[{"name":"Center for Communications Technology, London Metropolitan University, London N7 8DB, UK"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5299-1577","authenticated-orcid":false,"given":"Sadiq","family":"Ullah","sequence":"additional","affiliation":[{"name":"Telecommunication Engineering Department, University of Engineering and Technology, Mardan 23200, Pakistan"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6082-3418","authenticated-orcid":false,"given":"Salahuddin","family":"Khan","sequence":"additional","affiliation":[{"name":"College of Engineering, King Saud University, P.O. Box 800, Riyadh 11421, Saudi Arabia"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8439-7321","authenticated-orcid":false,"given":"Chan Hwang","family":"See","sequence":"additional","affiliation":[{"name":"School of Computing, Engineering and the Built Environment, Edinburgh Napier University, 10 Colinton Rd., Edinburgh EH10 5DT, UK"}]},{"given":"Lukasz","family":"Golunski","sequence":"additional","affiliation":[{"name":"Faculty of Electronics, Telecommunications and Informatics, Gdansk University of Technology, 80-233 Gdansk, Poland"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9063-2647","authenticated-orcid":false,"given":"Slawomir","family":"Koziel","sequence":"additional","affiliation":[{"name":"Faculty of Electronics, Telecommunications and Informatics, Gdansk University of Technology, 80-233 Gdansk, Poland"},{"name":"Engineering Optimization & Modeling Center, Reykjavik University, 101 Reykjavik, Iceland"}]}],"member":"1968","published-online":{"date-parts":[[2023,8,7]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Abirami, M. 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