{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,16]],"date-time":"2026-06-16T14:56:19Z","timestamp":1781621779418,"version":"3.54.5"},"reference-count":22,"publisher":"MDPI AG","issue":"5","license":[{"start":{"date-parts":[[2021,3,5]],"date-time":"2021-03-05T00:00:00Z","timestamp":1614902400000},"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":"publisher","award":["61674043, 12004078, 51950410582"],"award-info":[{"award-number":["61674043, 12004078, 51950410582"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Piezoelectric micromachined ultrasonic transducers (PMUT) are promising elements to fabricate a two-dimensional (2D) array with a pitch small enough (approximately half wavelength) to form and receive arbitrary acoustic beams for medical imaging. However, PMUT arrays have so far failed to combine the wide, high-frequency bandwidth needed to achieve a high axial resolution. In this paper, a polydimethylsiloxane (PDMS) backing structure is introduced into the PMUTs to improve the device bandwidth while keeping a sub-wavelength (\u03bb) pitch. We implement this backing on a 16 \u00d7 8 array with 75 \u00b5m pitch (3\u03bb\/4) with a 15 MHz working frequency. Adding the backing nearly doubles the bandwidth to 92% (\u22126 dB) and has little influence on the impulse response sensitivity. By widening the transducer bandwidth, this backing may enable using PMUT ultrasonic arrays for high-resolution 3D imaging.<\/jats:p>","DOI":"10.3390\/s21051823","type":"journal-article","created":{"date-parts":[[2021,3,5]],"date-time":"2021-03-05T11:46:09Z","timestamp":1614944769000},"page":"1823","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":34,"title":["Development of Broadband High-Frequency Piezoelectric Micromachined Ultrasonic Transducer Array"],"prefix":"10.3390","volume":"21","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-9014-6158","authenticated-orcid":false,"given":"Xu-Bo","family":"Wang","sequence":"first","affiliation":[{"name":"State Key Laboratory of ASIC and System, School of Microelectronics, Fudan University, Shanghai 201203, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4131-3508","authenticated-orcid":false,"given":"Le-Ming","family":"He","sequence":"additional","affiliation":[{"name":"State Key Laboratory of ASIC and System, School of Microelectronics, Fudan University, Shanghai 201203, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9537-7198","authenticated-orcid":false,"given":"You-Cao","family":"Ma","sequence":"additional","affiliation":[{"name":"State Key Laboratory of ASIC and System, School of Microelectronics, Fudan University, Shanghai 201203, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Wen-Juan","family":"Liu","sequence":"additional","affiliation":[{"name":"State Key Laboratory of ASIC and System, School of Microelectronics, Fudan University, Shanghai 201203, China"},{"name":"Univ. Polytechnique Hauts-de-France, CNRS, Univ. Lille, Centrale Lille, UMR 8520-IEMN, DOAE, F-59313 Valenciennes, France"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7309-2343","authenticated-orcid":false,"given":"Wei-Jiang","family":"Xu","sequence":"additional","affiliation":[{"name":"Univ. Polytechnique Hauts-de-France, CNRS, Univ. Lille, Centrale Lille, UMR 8520-IEMN, DOAE, F-59313 Valenciennes, France"},{"name":"INSA Hauts-de-France, Le Mont Houy, F-59313 Valenciennes, France"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jun-Yan","family":"Ren","sequence":"additional","affiliation":[{"name":"State Key Laboratory of ASIC and System, School of Microelectronics, Fudan University, Shanghai 201203, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Antoine","family":"Riaud","sequence":"additional","affiliation":[{"name":"State Key Laboratory of ASIC and System, School of Microelectronics, Fudan University, Shanghai 201203, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9098-5661","authenticated-orcid":false,"given":"Jia","family":"Zhou","sequence":"additional","affiliation":[{"name":"State Key Laboratory of ASIC and System, School of Microelectronics, Fudan University, Shanghai 201203, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2021,3,5]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"338","DOI":"10.1109\/58.660144","article-title":"Two-dimensional arrays for medical ultrasound using multilayer flexible circuit interconnection","volume":"45","author":"Davidsen","year":"1998","journal-title":"IEEE Trans. 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