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Piezoelectric MEMS Acoustic Transducer with Electrically-Tunable Resonant Frequency

The paper presents a technique to obtain an electrically-tunable matching between the series and parallel resonant frequencies of a piezoelectric MEMS acoustic transducer to increase the effectiveness of acoustic emission/detection in voltage-mode driving and sensing. The piezoelectric MEMS transduc...

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Autores principales: Nastro, Alessandro, Ferrari, Marco, Rufer, Libor, Basrour, Skandar, Ferrari, Vittorio
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2022
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8779133/
https://www.ncbi.nlm.nih.gov/pubmed/35056264
http://dx.doi.org/10.3390/mi13010096
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author Nastro, Alessandro
Ferrari, Marco
Rufer, Libor
Basrour, Skandar
Ferrari, Vittorio
author_facet Nastro, Alessandro
Ferrari, Marco
Rufer, Libor
Basrour, Skandar
Ferrari, Vittorio
author_sort Nastro, Alessandro
collection PubMed
description The paper presents a technique to obtain an electrically-tunable matching between the series and parallel resonant frequencies of a piezoelectric MEMS acoustic transducer to increase the effectiveness of acoustic emission/detection in voltage-mode driving and sensing. The piezoelectric MEMS transducer has been fabricated using the PiezoMUMPs technology, and it operates in a plate flexural mode exploiting a 6 mm × 6 mm doped silicon diaphragm with an aluminum nitride (AlN) piezoelectric layer deposited on top. The piezoelectric layer can be actuated by means of electrodes placed at the edges of the diaphragm above the AlN film. By applying an adjustable bias voltage V(b) between two properly-connected electrodes and the doped silicon, the d31 mode in the AlN film has been exploited to electrically induce a planar static compressive or tensile stress in the diaphragm, depending on the sign of V(b), thus shifting its resonant frequency. The working principle has been first validated through an eigenfrequency analysis with an electrically induced prestress by means of 3D finite element modelling in COMSOL Multiphysics(®). The first flexural mode of the unstressed diaphragm results at around 5.1 kHz. Then, the piezoelectric MEMS transducer has been experimentally tested in both receiver and transmitter modes. Experimental results have shown that the resonance can be electrically tuned in the range V(b) = ±8 V with estimated tuning sensitivities of 8.7 ± 0.5 Hz/V and 7.8 ± 0.9 Hz/V in transmitter and receiver modes, respectively. A matching of the series and parallel resonant frequencies has been experimentally demonstrated in voltage-mode driving and sensing by applying V(b) = 0 in transmission and V(b) = −1.9 V in receiving, respectively, thereby obtaining the optimal acoustic emission and detection effectiveness at the same operating frequency.
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spelling pubmed-87791332022-01-22 Piezoelectric MEMS Acoustic Transducer with Electrically-Tunable Resonant Frequency Nastro, Alessandro Ferrari, Marco Rufer, Libor Basrour, Skandar Ferrari, Vittorio Micromachines (Basel) Article The paper presents a technique to obtain an electrically-tunable matching between the series and parallel resonant frequencies of a piezoelectric MEMS acoustic transducer to increase the effectiveness of acoustic emission/detection in voltage-mode driving and sensing. The piezoelectric MEMS transducer has been fabricated using the PiezoMUMPs technology, and it operates in a plate flexural mode exploiting a 6 mm × 6 mm doped silicon diaphragm with an aluminum nitride (AlN) piezoelectric layer deposited on top. The piezoelectric layer can be actuated by means of electrodes placed at the edges of the diaphragm above the AlN film. By applying an adjustable bias voltage V(b) between two properly-connected electrodes and the doped silicon, the d31 mode in the AlN film has been exploited to electrically induce a planar static compressive or tensile stress in the diaphragm, depending on the sign of V(b), thus shifting its resonant frequency. The working principle has been first validated through an eigenfrequency analysis with an electrically induced prestress by means of 3D finite element modelling in COMSOL Multiphysics(®). The first flexural mode of the unstressed diaphragm results at around 5.1 kHz. Then, the piezoelectric MEMS transducer has been experimentally tested in both receiver and transmitter modes. Experimental results have shown that the resonance can be electrically tuned in the range V(b) = ±8 V with estimated tuning sensitivities of 8.7 ± 0.5 Hz/V and 7.8 ± 0.9 Hz/V in transmitter and receiver modes, respectively. A matching of the series and parallel resonant frequencies has been experimentally demonstrated in voltage-mode driving and sensing by applying V(b) = 0 in transmission and V(b) = −1.9 V in receiving, respectively, thereby obtaining the optimal acoustic emission and detection effectiveness at the same operating frequency. MDPI 2022-01-08 /pmc/articles/PMC8779133/ /pubmed/35056264 http://dx.doi.org/10.3390/mi13010096 Text en © 2022 by the authors. https://creativecommons.org/licenses/by/4.0/Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Nastro, Alessandro
Ferrari, Marco
Rufer, Libor
Basrour, Skandar
Ferrari, Vittorio
Piezoelectric MEMS Acoustic Transducer with Electrically-Tunable Resonant Frequency
title Piezoelectric MEMS Acoustic Transducer with Electrically-Tunable Resonant Frequency
title_full Piezoelectric MEMS Acoustic Transducer with Electrically-Tunable Resonant Frequency
title_fullStr Piezoelectric MEMS Acoustic Transducer with Electrically-Tunable Resonant Frequency
title_full_unstemmed Piezoelectric MEMS Acoustic Transducer with Electrically-Tunable Resonant Frequency
title_short Piezoelectric MEMS Acoustic Transducer with Electrically-Tunable Resonant Frequency
title_sort piezoelectric mems acoustic transducer with electrically-tunable resonant frequency
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8779133/
https://www.ncbi.nlm.nih.gov/pubmed/35056264
http://dx.doi.org/10.3390/mi13010096
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