{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,17]],"date-time":"2026-06-17T21:04:46Z","timestamp":1781730286610,"version":"3.54.5"},"reference-count":27,"publisher":"MDPI AG","issue":"13","license":[{"start":{"date-parts":[[2024,6,23]],"date-time":"2024-06-23T00:00:00Z","timestamp":1719100800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"National Natural Science Foundation of China","award":["52205564"],"award-info":[{"award-number":["52205564"]}]},{"name":"National Natural Science Foundation of China","award":["2022CFB898"],"award-info":[{"award-number":["2022CFB898"]}]},{"name":"Natural Science Foundation of Hubei Province","award":["52205564"],"award-info":[{"award-number":["52205564"]}]},{"name":"Natural Science Foundation of Hubei Province","award":["2022CFB898"],"award-info":[{"award-number":["2022CFB898"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Ultrasonic focusing transducers have broad prospects in advanced ultrasonic non-destructive testing fields. However, conventional focusing methods that use acoustic concave lenses can disrupt the acoustic impedance matching condition, thereby adversely affecting the sensitivity of the transducers. In this paper, an active focusing planar ultrasonic transducer is designed and presented to achieve a focusing effect with a higher sensitivity. An electrode pattern consisting of multiple concentric rings is designed, which is inspired by the structure of Fresnel Zone Plates (FZP). The structural parameters are optimized using finite element simulation methods. A prototype of the transducer is manufactured with electrode patterns made of conductive silver paste using silk screen-printing technology. Conventional focusing transducers using an acoustic lens and an FZP baffle are also manufactured, and their focusing performances are comparatively tested. The experimental results show that our novel transducer has a focal length of 16 mm and a center frequency of 1.16 MHz, and that the sensitivity is improved by 23.3% compared with the conventional focusing transducers. This research provides a new approach for the design of focusing transducers.<\/jats:p>","DOI":"10.3390\/s24134082","type":"journal-article","created":{"date-parts":[[2024,6,24]],"date-time":"2024-06-24T06:59:58Z","timestamp":1719212398000},"page":"4082","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":5,"title":["Investigation of an Active Focusing Planar Piezoelectric Ultrasonic Transducer"],"prefix":"10.3390","volume":"24","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-8777-4778","authenticated-orcid":false,"given":"Qiao","family":"Wu","sequence":"first","affiliation":[{"name":"School of Mechanical Engineering, Hubei University of Technology, Wuhan 430068, China"},{"name":"Key Lab of Modern Manufacture Quality Engineering, Hubei University of Technology, Wuhan 430068, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Bin","family":"You","sequence":"additional","affiliation":[{"name":"School of Mechanical Engineering, Hubei University of Technology, Wuhan 430068, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Xu","family":"Zhang","sequence":"additional","affiliation":[{"name":"School of Mechanical Engineering, Hubei University of Technology, Wuhan 430068, China"},{"name":"Key Lab of Modern Manufacture Quality Engineering, Hubei University of Technology, Wuhan 430068, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4974-9077","authenticated-orcid":false,"given":"Jun","family":"Tu","sequence":"additional","affiliation":[{"name":"School of Mechanical Engineering, Hubei University of Technology, Wuhan 430068, China"},{"name":"Key Lab of Modern Manufacture Quality Engineering, Hubei University of Technology, Wuhan 430068, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2024,6,23]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Dong, Z., Zhao, P., Ji, K., Chen, Y., Gao, S., and Fu, J. 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