Design and Experiment of Capacitive Micromachined Ultrasonic Transducer Array for High-frequency Underwater Imaging

Author(s): Yuanyu Yu, Jiujiang Wang*, Xin Liu, Sio H. Pun, Weibao Qiu, Shuang Zhang, Ching H. Cheng, Kin F. Lei, Mang I. Vai, Peng U. Mak

Journal Name: Recent Advances in Electrical & Electronic Engineering
Formerly Recent Patents on Electrical & Electronic Engineering

Volume 14 , Issue 2 , 2021

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Graphical Abstract:


Background: Ultrasound is widely used in the applications of underwater imaging. Capacitive micromachined ultrasonic transducer (CMUT) is a promising candidate for the traditional piezoelectric ultrasonic transducer. In underwater ultrasound imaging, better resolutions can be achieved with a higher frequency ultrasound. Therefore, a CMUT array for high-frequency ultrasound imaging is proposed in this work.

Methods: Analytical methods were used to calculate the center frequency in water and the pull-in voltage for determining the operating point of CMUT. A finite element method model was developed to finalize the design parameters. The CMUT array was fabricated with a five-mask sacrificial release process.

Results: The CMUT array owned an immersed center frequency of 2.6 MHz with a 6 dB fractional bandwidth of 123 %. The pull-in voltage of the CMUT array was 85 V. An underwater imaging experiment was carried out with the target of three steel wires.

Conclusion: In this study, we have developed CMUT for high-frequency underwater imaging. The experiment showed that the CMUT could detect the steel wires with a diameter of 100 μm and the axial resolution was 0.582 mm, which was close to one wavelength of ultrasound in 2.6 MHz.

Keywords: Capacitive micromachined ultrasonic transducer, underwater imaging, sacrificial release process, Zirconate Titanate, device design, Capacitive micromachined ultrasonic transducer (CMUT).

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Article Details

Year: 2021
Published on: 18 February, 2021
Page: [233 - 240]
Pages: 8
DOI: 10.2174/2352096513999201026225123
Price: $25

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