{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,7]],"date-time":"2026-04-07T20:11:57Z","timestamp":1775592717718,"version":"3.50.1"},"reference-count":35,"publisher":"MDPI AG","issue":"7","license":[{"start":{"date-parts":[[2022,3,29]],"date-time":"2022-03-29T00:00:00Z","timestamp":1648512000000},"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>A compact flexible multi-frequency antenna for smart portable and flexible devices is presented. The antenna consists of a coplanar waveguide-fed slotted circular patch connected to a rectangular secondary resonator (stub). A thin low-loss substrate is used for flexibility, and a rectangular stub in the feedline is deployed to attain wide operational bandwidth. A rectangular slot is etched in the middle of the circular patch, and a p-i-n diode is placed at its center. The frequency reconfigurability is achieved through switching the diode that distributes the current by changing the antenna\u2019s electrical length. For the ON state, the antenna operates in the UWB region for \u221210 dB impedance bandwidth from 2.76 to 8.21 GHz. For the OFF state of the diode, the antenna operates at the ISM band (2.45\/5.8 GHz), WLAN band (5.2 GHz), and lower X-band (8 GHz) with a minimum gain of 2.49 dBi and a maximum gain of 5.8 dBi at the 8 GHz band. Moreover, the antenna retains its performance in various bending conditions. The proposed antenna is suitable for modern miniaturized wireless electronic devices such as wearables, health monitoring sensors, mobile Internet devices, and laptops that operate at multiple frequency bands.<\/jats:p>","DOI":"10.3390\/s22072601","type":"journal-article","created":{"date-parts":[[2022,3,29]],"date-time":"2022-03-29T21:45:51Z","timestamp":1648590351000},"page":"2601","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":44,"title":["A Conformal Frequency Reconfigurable Antenna with Multiband and Wideband Characteristics"],"prefix":"10.3390","volume":"22","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-9730-4622","authenticated-orcid":false,"given":"Niamat","family":"Hussain","sequence":"first","affiliation":[{"name":"Department of Smart Device Engineering, School of Intelligent Mechatronics Engineering, Sejong University, Seoul 05006, Korea"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4548-9765","authenticated-orcid":false,"given":"Adnan","family":"Ghaffar","sequence":"additional","affiliation":[{"name":"Department of Electrical and Electronics Engineering, Auckland University of Technology, Auckland 1010, New Zealand"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9709-0433","authenticated-orcid":false,"given":"Syeda Iffat","family":"Naqvi","sequence":"additional","affiliation":[{"name":"Telecommunication Engineering Department, University of Engineering & Technology Taxila (UET Taxila), Taxila 47050, Pakistan"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8694-5341","authenticated-orcid":false,"given":"Adnan","family":"Iftikhar","sequence":"additional","affiliation":[{"name":"Department of Electrical and Computer Engineering, COMSATS University Islamabad, Islamabad 45550, Pakistan"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4266-0309","authenticated-orcid":false,"given":"Dimitris E.","family":"Anagnostou","sequence":"additional","affiliation":[{"name":"Institute of Signals, Sensors and Systems, Heriot Watt University, Edinburgh EH14 4AS, UK"}]},{"given":"Huy H.","family":"Tran","sequence":"additional","affiliation":[{"name":"Faculty of Electrical and Electronic Engineering, PHENIKAA University, Hanoi 12116, Vietnam"}]}],"member":"1968","published-online":{"date-parts":[[2022,3,29]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Anagnostou, D.E., Chryssomallis, M.T., and Goudos, S. 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