{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,29]],"date-time":"2026-09-29T18:43:57Z","timestamp":1790707437224,"version":"4.1.0"},"reference-count":32,"publisher":"MDPI AG","issue":"5","license":[{"start":{"date-parts":[[2026,5,7]],"date-time":"2026-05-07T00:00:00Z","timestamp":1778112000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"crossref","award":["62101055"],"award-info":[{"award-number":["62101055"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"crossref"}]},{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"crossref","award":["U2006218"],"award-info":[{"award-number":["U2006218"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"crossref"}]},{"award":["62101055"],"award-info":[{"award-number":["62101055"]}],"id":[{"id":"https:\/\/ror.org\/01h0zpd94","id-type":"ROR","asserted-by":"publisher"}]},{"award":["U2006218"],"award-info":[{"award-number":["U2006218"]}],"id":[{"id":"https:\/\/ror.org\/01h0zpd94","id-type":"ROR","asserted-by":"publisher"}]},{"name":"The Youth Beijing Scholars program"},{"name":"Project of Construction and Support for high-level Innovative Teams of Beijing Municipal Institutions","award":["BPHR20220124"],"award-info":[{"award-number":["BPHR20220124"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Micromachines"],"abstract":"<jats:p>In this study, a flexible, lightweight high-frequency underwater transducer (FT) was designed and fabricated. To ensure the flexibility and reliability of the transducer, a flexible piezoelectric composite material with a same-side electrode configuration and a perforated flexible printed circuit (FPC) were designed. First, finite element simulation analysis was performed on the flexible piezoelectric composites to optimize the structural parameters. Next, using a cutting and infusion method combined with reflow soldering, the piezoelectric composites and FPC were integrated to form a flexible sensing element. Finally, a flexible packaging process for the underwater transducer was investigated, resulting in a flexible underwater transducer with a thickness of only 5.3 mm. The results of underwater electroacoustic comparison tests show that the transmission and reception performance of the FT differs by less than 0.5 dB from that of conventional rigid transducers. This demonstrates that the flexible underwater transducer developed in this study not only possesses the advantages of flexibility and can be conformally mounted on curved surfaces but also achieves acoustic performance comparable to that of traditional rigid transducers, thereby providing new insights for the lightweight development of underwater transducers.<\/jats:p>","DOI":"10.3390\/mi17050577","type":"journal-article","created":{"date-parts":[[2026,5,7]],"date-time":"2026-05-07T12:15:07Z","timestamp":1778156107000},"page":"577","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["Flexible High-Frequency Underwater Transducer Based on Piezoelectric Composites"],"prefix":"10.3390","volume":"17","author":[{"ORCID":"https:\/\/orcid.org\/0009-0002-5114-965X","authenticated-orcid":false,"given":"He","family":"Zhou","sequence":"first","affiliation":[{"name":"Beijing Key Laboratory for Sensors, Beijing Information Science & Technology University, Beijing 100192, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Chao","family":"Zhong","sequence":"additional","affiliation":[{"name":"Beijing Key Laboratory for Sensors, Beijing Information Science & Technology University, Beijing 100192, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3975-243X","authenticated-orcid":false,"given":"Lei","family":"Qin","sequence":"additional","affiliation":[{"name":"Beijing Key Laboratory for Sensors, Beijing Information Science & Technology University, Beijing 100192, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,5,7]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"2309","DOI":"10.3390\/s120202309","article-title":"Design and implementation of an omni-directional underwater acoustic micro-modem based on a low-power micro-controller unit","volume":"12","author":"Won","year":"2012","journal-title":"Sensors"},{"key":"ref_2","doi-asserted-by":"crossref","unstructured":"Won, T.-H., Cho, H., and Park, S.-J. (2011). An omni-directional underwater acoustic modem based on cortex-M3. Proceedings of the 2011 IFIP 9th International Conference on Embedded and Ubiquitous Computing, IEEE.","DOI":"10.1109\/EUC.2011.17"},{"key":"ref_3","doi-asserted-by":"crossref","unstructured":"Jeon, J.-H., Hwangbo, S.-H., Peyvandi, H., and Park, S.-J. (2012). Design and implementation of a bidirectional acoustic micro-modem for underwater communication systems. Proceedings of the 2012 Oceans, IEEE.","DOI":"10.1109\/OCEANS.2012.6404886"},{"key":"ref_4","doi-asserted-by":"crossref","unstructured":"Pyun, J.Y., Kim, Y.H., and Park, K.K. (2023). Design of piezoelectric acoustic transducers for underwater applications. Sensors, 23.","DOI":"10.3390\/s23041821"},{"key":"ref_5","doi-asserted-by":"crossref","unstructured":"Wang, J., Zhong, C., Hao, S., Lv, N., and Wang, L. (2021). Design of planar array transducers based on connected 1\u20133 piezoelectric composites. Micromachines, 12.","DOI":"10.3390\/mi12111417"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"108280","DOI":"10.1016\/j.apacoust.2021.108280","article-title":"High-resolution two-dimensional imaging using MIMO sonar with limited physical size","volume":"182","author":"Liu","year":"2021","journal-title":"Appl. Acoust."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"8137","DOI":"10.1021\/acsami.1c21010","article-title":"High-Performance curved piezoelectric Single-Crystal composites via 3D-printing-assisted dice and insert technology for underwater acoustic transducer applications","volume":"14","author":"Jia","year":"2022","journal-title":"ACS Appl. Mater. Interfaces"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"3474","DOI":"10.1121\/10.0006786","article-title":"Ultra-wide operation band of the high-frequency underwater acoustic transducer realized by two-layer 1\u20133 piezoelectric composite","volume":"150","author":"Ji","year":"2021","journal-title":"J. Acoust. Soc. Am."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"106872","DOI":"10.1016\/j.rinp.2023.106872","article-title":"Design, fabrication and testing of a high frequency broadband hydroacoustic transducer for sonar systems","volume":"52","author":"Wu","year":"2023","journal-title":"Results Phys."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"113817","DOI":"10.1016\/j.measurement.2023.113817","article-title":"Hydroacoustic performance analysis and testing of a novel piezoelectric material transducer","volume":"224","author":"Su","year":"2024","journal-title":"Measurement"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"112870","DOI":"10.1016\/j.matdes.2024.112870","article-title":"Research and fabrication of bimetallic plate transducer based on finite element analysis","volume":"240","author":"Lan","year":"2024","journal-title":"Mater. Des."},{"key":"ref_12","doi-asserted-by":"crossref","unstructured":"Zhao, H., Li, H., Wang, Y., Liu, Z., Bian, J., and Chen, J. (2021). A thickness-mode high-frequency underwater acoustic transducer with a low sidelobe level. Actuators, 10.","DOI":"10.3390\/act10090226"},{"key":"ref_13","doi-asserted-by":"crossref","unstructured":"Hao, S., Zhong, C., Wang, L., and Qin, L. (2024). A high-performance flexible hydroacoustic transducer based on 1-3 PZT-5A\/silicone rubber composite. Sensors, 24.","DOI":"10.3390\/s24072081"},{"key":"ref_14","doi-asserted-by":"crossref","unstructured":"Xia, L., Wang, H., and Huang, Q. (2021). Design and fabrication of a stacked three-phase piezoelectric composites ring array underwater ultrasound transducer. Materials, 14.","DOI":"10.3390\/ma14205971"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"114822","DOI":"10.1016\/j.sna.2023.114822","article-title":"Design and analysis of a flexible hydrophone based on PVDF with aluminum film substrate and PDMS encapsulation","volume":"364","author":"Xiao","year":"2023","journal-title":"Sens. Actuators A Phys."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"517","DOI":"10.1126\/science.abo2542","article-title":"Bioadhesive ultrasound for long-term continuous imaging of diverse organs","volume":"377","author":"Wang","year":"2022","journal-title":"Science"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"116130","DOI":"10.1016\/j.trac.2020.116130","article-title":"Multifunctional conductive hydrogel-based flexible wearable sensors","volume":"134","author":"Wang","year":"2021","journal-title":"TrAC Trends Anal. Chem."},{"key":"ref_18","doi-asserted-by":"crossref","unstructured":"AlMohimeed, I., and Ono, Y. (2020). Ultrasound measurement of skeletal muscle contractile parameters using flexible and wearable single-element ultrasonic sensor. Sensors, 20.","DOI":"10.3390\/s20133616"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"58","DOI":"10.1038\/s41528-025-00432-5","article-title":"Flexible piezoelectrics: Integration of sensing, actuating and energy harvesting","volume":"9","author":"Chen","year":"2025","journal-title":"npj Flex. Electron."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"107872","DOI":"10.1016\/j.ultras.2025.107872","article-title":"Wearable flexible ultrasonic transducers: Materials, applications, and challenges","volume":"159","author":"Guo","year":"2025","journal-title":"Ultrasonics"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"20250002","DOI":"10.1360\/nso\/20250002","article-title":"Flexible electronics and micro\/nanomanufacturing","volume":"4","author":"Yin","year":"2025","journal-title":"Natl. Sci. Open"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"eadk8426","DOI":"10.1126\/sciadv.adk8426","article-title":"Wearable bioadhesive ultrasound shear wave elastography","volume":"10","author":"Liu","year":"2024","journal-title":"Sci. Adv."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"eaar3979","DOI":"10.1126\/sciadv.aar3979","article-title":"Stretchable ultrasonic transducer arrays for three-dimensional imaging on complex surfaces","volume":"4","author":"Hu","year":"2018","journal-title":"Sci. Adv."},{"key":"ref_24","doi-asserted-by":"crossref","unstructured":"Qiao, Y., Jin, S., Zhong, C., and Qin, L. (2022). Design and Fabrication of an Underwater Transducer Based on the Shear Vibration Mode and Trapezoid Transition Layer. Micromachines, 13.","DOI":"10.3390\/mi13081320"},{"key":"ref_25","unstructured":"Dow Inc. (2026, April 29). SILASTIC DY 32-7040 U Silicone Rubber. Available online: https:\/\/www.dow.com\/en-us\/pdp.silastic-dy-32-7040-u-silicone-rubber.02518139z.html."},{"key":"ref_26","doi-asserted-by":"crossref","unstructured":"Wang, J., Zhong, C., Hao, S., and Wang, L. (2021). Design and properties analysis of novel modified 1-3 piezoelectric composite. Materials, 14.","DOI":"10.3390\/ma14071749"},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"3565","DOI":"10.1038\/s41467-022-31165-y","article-title":"Near-ideal electromechanical coupling in textured piezoelectric ceramics","volume":"13","author":"Yan","year":"2022","journal-title":"Nat. Commun."},{"key":"ref_28","first-page":"331","article-title":"On the measurement of the electromechanical coupling coefficient kt using different characteristic frequencies","volume":"293","author":"Ramos","year":"2003","journal-title":"Ferroelectrics"},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"97","DOI":"10.1080\/00150193.2022.2115801","article-title":"Characterization for the key parameters of 1-3 piezoelectric composite in thickness vibration mode","volume":"600","author":"Zhong","year":"2022","journal-title":"Ferroelectrics"},{"key":"ref_30","first-page":"326","article-title":"Study on the underwater acoustic properties of polyurethane elastomer","volume":"52","author":"Shin","year":"2017","journal-title":"Elastomers Compos."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"115700","DOI":"10.1016\/j.measurement.2024.115700","article-title":"The calibration methods of hydrophones for underwater environmental sound measurements or biomedical ultrasound measurements: A review","volume":"242","author":"Qin","year":"2025","journal-title":"Measurement"},{"key":"ref_32","doi-asserted-by":"crossref","unstructured":"Huang, Q., Wang, H., Hao, S., Zhong, C., and Wang, L. (2019). Design and fabrication of a high-frequency single-directional planar underwater ultrasound transducer. Sensors, 19.","DOI":"10.3390\/s19194336"}],"container-title":["Micromachines"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2072-666X\/17\/5\/577\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,5,9]],"date-time":"2026-05-09T04:29:18Z","timestamp":1778300958000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2072-666X\/17\/5\/577"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,5,7]]},"references-count":32,"journal-issue":{"issue":"5","published-online":{"date-parts":[[2026,5]]}},"alternative-id":["mi17050577"],"URL":"https:\/\/doi.org\/10.3390\/mi17050577","relation":{},"ISSN":["2072-666X"],"issn-type":[{"value":"2072-666X","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,5,7]]}}}