{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,25]],"date-time":"2026-04-25T14:47:45Z","timestamp":1777128465536,"version":"3.51.4"},"reference-count":30,"publisher":"MDPI AG","issue":"9","license":[{"start":{"date-parts":[[2021,5,4]],"date-time":"2021-05-04T00:00:00Z","timestamp":1620086400000},"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>This work presents methods for miniaturizing and characterizing a modified dipole antenna dedicated to the implementation of wireless power transmission systems. The antenna size should respect the planar dimensions of 60 mm \u00d7 30 mm to be integrated with small IoT devices such as a Bluetooth Lower Energy Sensing Node. The provided design is based on a folded short-circuited dipole antenna, also named a T-match antenna. Faced with the difficulty of reducing the physical dimensions of the antenna, we propose a 3D configuration by adding vertical metallic arms on the edges of the antenna. The adopted 3D design has an overall size of 56 mm \u00d7 32 mm \u00d7 10 mm at 868 MHz. Three antenna-feeding techniques were evaluated to characterize this antenna. They consist of soldering a U.FL connector on the input port; vertically connecting a tapered balun to the antenna; and integrating a microstrip transition to the layer of the antenna. The experimental results of the selected feeding techniques show good agreements and the antenna has a maximum gain of +1.54 dBi in the elevation plane (E-plane). In addition, a final modification was operated to the designed antenna to have a more compact structure with a size of 40 mm \u00d7 30 mm \u00d7 10 mm at 868 MHz. Such modification reduces the radiation surface of the antenna and so the antenna gain and bandwidth. This antenna can achieve a maximum gain of +1.1 dBi in the E-plane. The two antennas proposed in this paper were then associated with a rectifier to perform energy harvesting for powering Bluetooth Low Energy wireless sensors. The measured RF-DC (radiofrequency to direct current) conversion efficiency is 73.88% (first design) and 60.21% (second design) with an illuminating power density of 3.1 \u00b5W\/cm2 at 868 MHz with a 10 k\u03a9 load resistor.<\/jats:p>","DOI":"10.3390\/s21093193","type":"journal-article","created":{"date-parts":[[2021,5,5]],"date-time":"2021-05-05T22:51:42Z","timestamp":1620255102000},"page":"3193","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":15,"title":["Compact Antenna in 3D Configuration for Rectenna Wireless Power Transmission Applications"],"prefix":"10.3390","volume":"21","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-4123-7349","authenticated-orcid":false,"given":"Alassane","family":"Sidibe","sequence":"first","affiliation":[{"name":"Laboratoire d\u2019Analyse et d\u2019Architecture des Syst\u00e8mes du Centre National de la Recherche Scientifique (LAAS-CNRS), Universit\u00e9 de Toulouse, Centre National de la Recherche Scientifique (CNRS), Institut National des Sciences Appliqu\u00e9s de Toulouse (INSA), Universit\u00e9 Paul Sabatier, Toulouse III (UPS), 31400 Toulouse, France"},{"name":"Uwinloc, 9 Rue Humbert Tomatis, 31200 Toulouse, France"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Alexandru","family":"Takacs","sequence":"additional","affiliation":[{"name":"Laboratoire d\u2019Analyse et d\u2019Architecture des Syst\u00e8mes du Centre National de la Recherche Scientifique (LAAS-CNRS), Universit\u00e9 de Toulouse, Centre National de la Recherche Scientifique (CNRS), Institut National des Sciences Appliqu\u00e9s de Toulouse (INSA), Universit\u00e9 Paul Sabatier, Toulouse III (UPS), 31400 Toulouse, France"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3347-0036","authenticated-orcid":false,"given":"Ga\u00ebl","family":"Loubet","sequence":"additional","affiliation":[{"name":"Laboratoire d\u2019Analyse et d\u2019Architecture des Syst\u00e8mes du Centre National de la Recherche Scientifique (LAAS-CNRS), Universit\u00e9 de Toulouse, Centre National de la Recherche Scientifique (CNRS), Institut National des Sciences Appliqu\u00e9s de Toulouse (INSA), Universit\u00e9 Paul Sabatier, Toulouse III (UPS), 31400 Toulouse, France"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8589-6093","authenticated-orcid":false,"given":"Daniela","family":"Dragomirescu","sequence":"additional","affiliation":[{"name":"Laboratoire d\u2019Analyse et d\u2019Architecture des Syst\u00e8mes du Centre National de la Recherche Scientifique (LAAS-CNRS), Universit\u00e9 de Toulouse, Centre National de la Recherche Scientifique (CNRS), Institut National des Sciences Appliqu\u00e9s de Toulouse (INSA), Universit\u00e9 Paul Sabatier, Toulouse III (UPS), 31400 Toulouse, France"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2021,5,4]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"146","DOI":"10.3390\/smartcities4010008","article-title":"Miniaturized Pervasive Sensors for Indoor Health Monitoring in Smart Cities","volume":"4","author":"Carminati","year":"2021","journal-title":"Smart Cities"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"E1","DOI":"10.1557\/mre.2014.6","article-title":"The rectenna device: From theory to practice (a review)","volume":"1","author":"Donchev","year":"2014","journal-title":"MRS Energy Sustain."},{"key":"ref_3","unstructured":"Lin, L.C., Chiu, C., and Gong, J. 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