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Shanmugam P, Iglesias L, Michaud JF, Alquier D, Colin L, Dufour I, Certon D. Broad bandwidth air-coupled micromachined ultrasonic transducers for gas sensing. ULTRASONICS 2021; 114:106410. [PMID: 33761341 DOI: 10.1016/j.ultras.2021.106410] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Revised: 02/06/2021] [Accepted: 02/22/2021] [Indexed: 06/12/2023]
Abstract
The present work aims to develop ultra-wide bandwidth air-coupled capacitive micromachined ultrasonic transducers (CMUTs) for binary gas mixture analysis. The detection principle is based on time-of-flight (ToF) measurements, in order to monitor gas ultrasound velocity variations. To perform such measurements, CMUTs were especially designed to work out of resonance mode, like a microphone. The chosen membrane size is 32 × 32 µm2 and gap height is 250 nm. The resonance frequency and collapse voltage were found at 8 MHz and 58 V respectively. As mentioned, the CMUTs were exploited in quasi-static operating mode, in a very low frequency band, from 1 MHz to 1.5 MHz frequencies. The transducer impulse response was characterised, and a -6 dB relative fractional frequency bandwidth (FBW) higher than 100% was measured, enabling to use CMUT for the targeted application. Additionally, a measuring cell has been designed to hold the fabricated CMUT emitter and receiver prototypes facing each other. The volume inside the cell was kept lower than 3 mL and the surface of emitter/receiver was 1.6 × 8 mm2. To validate the general principle of the proposed technique, two binary gas mixtures of CO2/N2 and H2/N2, with varying concentrations, have been tested. The results are very promising with a measured limit of detection (LOD) of 0.3% for CO2 in N2 and 0.15% for H2 in N2.
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Affiliation(s)
- P Shanmugam
- GREMAN Laboratory UMR-CNRS 7347, University of Tours, 16 rue Pierre et Marie Curie, BP 7155, 37071 TOURS Cedex 2, France.
| | - L Iglesias
- IMS Laboratory UMR-CNRS 5218, University of Bordeaux, 351 cours de la libération, 33405 TALENCE Cedex, France.
| | - J F Michaud
- GREMAN Laboratory UMR-CNRS 7347, University of Tours, 16 rue Pierre et Marie Curie, BP 7155, 37071 TOURS Cedex 2, France.
| | - D Alquier
- GREMAN Laboratory UMR-CNRS 7347, University of Tours, 16 rue Pierre et Marie Curie, BP 7155, 37071 TOURS Cedex 2, France.
| | - L Colin
- GREMAN Laboratory UMR-CNRS 7347, University of Tours, 16 rue Pierre et Marie Curie, BP 7155, 37071 TOURS Cedex 2, France.
| | - I Dufour
- IMS Laboratory UMR-CNRS 5218, University of Bordeaux, 351 cours de la libération, 33405 TALENCE Cedex, France.
| | - D Certon
- GREMAN Laboratory UMR-CNRS 7347, University of Tours, 16 rue Pierre et Marie Curie, BP 7155, 37071 TOURS Cedex 2, France.
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Zhang T, Zhang W, Shao X, Yang Y, Wang Z, Wu Y, Pei Y. A Study on Capacitive Micromachined Ultrasonic Transducer Periodic Sparse Array. MICROMACHINES 2021; 12:mi12060684. [PMID: 34208152 PMCID: PMC8230818 DOI: 10.3390/mi12060684] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 06/07/2021] [Accepted: 06/09/2021] [Indexed: 11/18/2022]
Abstract
Capacitive micromachined ultrasonic transducer (CMUT) is an ultrasonic transducer based on the microelectromechanical system (MEMS). CMUT elements are easily made into a high-density array, which will increase the hardware complexity. In order to reduce the number of active channels, this paper studies the grating lobes generated by CMUT periodic sparse array (PSA) pairs. Through the design of active element positions in the transmitting and receiving processes, the simulation results of effective aperture and beam patterns show that the common grating lobes (CGLs) generated by the transmit and receive array are eliminated. On the basis of point targets imaging, a CMUT linear array with 256 elements is used to carry out the PSA pairs experiment. Under the same sparse factor (SF), the optimal sparse array configuration can be selected to reduce the imaging artifacts. This conclusion is of great significance for the application of CMUT in three-dimensional ultrasound imaging.
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Affiliation(s)
- Tian Zhang
- State Key Laboratory of Dynamic Testing Technology, North University of China, Taiyuan 030051, China; (T.Z.); (Y.Y.); (Z.W.); (Y.W.); (Y.P.)
- National Key Laboratory for Electronic Measurement Technology, School of Instrument and Electronics, North University of China, Taiyuan 030051, China
| | - Wendong Zhang
- State Key Laboratory of Dynamic Testing Technology, North University of China, Taiyuan 030051, China; (T.Z.); (Y.Y.); (Z.W.); (Y.W.); (Y.P.)
- National Key Laboratory for Electronic Measurement Technology, School of Instrument and Electronics, North University of China, Taiyuan 030051, China
- Correspondence: (W.Z.); (X.S.)
| | - Xingling Shao
- State Key Laboratory of Dynamic Testing Technology, North University of China, Taiyuan 030051, China; (T.Z.); (Y.Y.); (Z.W.); (Y.W.); (Y.P.)
- National Key Laboratory for Electronic Measurement Technology, School of Instrument and Electronics, North University of China, Taiyuan 030051, China
- Correspondence: (W.Z.); (X.S.)
| | - Yuhua Yang
- State Key Laboratory of Dynamic Testing Technology, North University of China, Taiyuan 030051, China; (T.Z.); (Y.Y.); (Z.W.); (Y.W.); (Y.P.)
- National Key Laboratory for Electronic Measurement Technology, School of Instrument and Electronics, North University of China, Taiyuan 030051, China
| | - Zhihao Wang
- State Key Laboratory of Dynamic Testing Technology, North University of China, Taiyuan 030051, China; (T.Z.); (Y.Y.); (Z.W.); (Y.W.); (Y.P.)
- National Key Laboratory for Electronic Measurement Technology, School of Instrument and Electronics, North University of China, Taiyuan 030051, China
| | - Yang Wu
- State Key Laboratory of Dynamic Testing Technology, North University of China, Taiyuan 030051, China; (T.Z.); (Y.Y.); (Z.W.); (Y.W.); (Y.P.)
- National Key Laboratory for Electronic Measurement Technology, School of Instrument and Electronics, North University of China, Taiyuan 030051, China
| | - Yu Pei
- State Key Laboratory of Dynamic Testing Technology, North University of China, Taiyuan 030051, China; (T.Z.); (Y.Y.); (Z.W.); (Y.W.); (Y.P.)
- National Key Laboratory for Electronic Measurement Technology, School of Instrument and Electronics, North University of China, Taiyuan 030051, China
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