Pump using ultrasonic transducer and opposing surface (1st report : observation of pump effect)

Background:: Ultrasound is widely used in the applications of underwater imaging. Capacitive micromachined ultrasonic transducer (CMUT) is a promising candidate to 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 are used to calculate the center frequency in water and the pull-in voltage for determining the operating point of CMUT. 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 can detect the steel wires with the diameter of 100 μm and the axial resolution was 0.582 mm, which is close to one wavelength of ultrasound in 2.6 MHz.

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Design of a hexagonal air-coupled capacitive micromachined ultrasonic transducer for air parametric array

Nanotechnology and Precision Engineering ◽

10.1063/10.0003504 ◽

2021 ◽

Vol 4 (1) ◽

pp. 013004

Author(s):

Xiaoli Zhang ◽

Hui Zhang ◽

Dachao Li

Keyword(s):

Ultrasonic Transducer ◽

Capacitive Micromachined Ultrasonic Transducer ◽

Parametric Array

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Flexible Piezoelectric Micro Ultrasonic Transducer Based on a Laser Processed Substrate

2020 IEEE International Ultrasonics Symposium (IUS) ◽

10.1109/ius46767.2020.9251364 ◽

2020 ◽

Author(s):

Wei Liu ◽

Chunling Zhu ◽

Dawei Wu ◽

Ting Yu

Keyword(s):

Ultrasonic Transducer

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Ultrasonic Transducer from Piezoelectric Polymer Multilayer through Electrophoretic Deposition for Photoacoustic Imaging

IEEE Transactions on Ultrasonics Ferroelectrics and Frequency Control ◽

10.1109/tuffc.2021.3073132 ◽

2021 ◽

pp. 1-1

Author(s):

Weng Heng Liew ◽

Qingqing Ke ◽

Chin Yaw Tan ◽

Shuting Chen ◽

Kui Yao

Keyword(s):

Electrophoretic Deposition ◽

Photoacoustic Imaging ◽

Ultrasonic Transducer ◽

Piezoelectric Polymer

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An Investigation of Silica Aerogel to Reduce Acoustic Crosstalk in CMUT Arrays

Sensors ◽

10.3390/s21041459 ◽

2021 ◽

Vol 21 (4) ◽

pp. 1459

Author(s):

Varshitha Yashvanth ◽

Sazzadur Chowdhury

Keyword(s):

Silica Aerogel ◽

Ultrasonic Transducer ◽

Fluid Interface ◽

Fractional Bandwidth ◽

Neighboring Element ◽

Element Analysis ◽

Average Improvement ◽

Capacitive Micromachined Ultrasonic Transducer ◽

Scholte Wave ◽

Fea Simulation

This paper presents a novel technique to reduce acoustic crosstalk in capacitive micromachined ultrasonic transducer (CMUT) arrays. The technique involves fabricating a thin layer of diisocyanate enhanced silica aerogel on the top surface of a CMUT array. The silica aerogel layer introduces a highly nanoporous permeable layer to reduce the intensity of the Scholte wave at the CMUT-fluid interface. 3D finite element analysis (FEA) simulation in COMSOL shows that the developed technique can provide a 31.5% improvement in crosstalk reduction for the first neighboring element in a 7.5 MHz CMUT array. The average improvement of crosstalk level over the −6 dB fractional bandwidth was 22.1%, which is approximately 5 dB lower than that without an aerogel layer. The results are in excellent agreement with published experimental results to validate the efficacy of the new technique.

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