Development of backing piezoelectric micromachined ultrasonic transducer (B-PMUT) 2D array

Author(s):  
Xu-Bo Wang ◽  
You-Cao Ma ◽  
Le-Ming He ◽  
Yan Wang ◽  
Wei-Jiang Xu ◽  
...  
2006 ◽  
Vol 321-323 ◽  
pp. 132-135
Author(s):  
Bong Young Ahn ◽  
Ki Bok Kim ◽  
Hae Won Park ◽  
Young Joo Kim ◽  
Yong Seok Kwak

As cMUTs (capacitive Micromachined Ultrasonic Transducer) offer numerous advantages over traditional transducers in terms of efficiency, bandwidth, and cost, they are expected to replace piezoelectric transducers in many applications. In particular, 2D-array cMUTs have aroused great interest in the medical engineering society because of their ability to materialize a true volumetric ultrasonic image. In this study, single element cMUTs with 32 x 32 and 64 x 64 cells were successfully fabricated. The diameter and thickness of the membrane are 35 and 1000 nm, respectively, with a sacrificial layer thickness of 600 nm. The electric characteristics of the fabricated cMUT were measured. Tests on the efficiencies of the cMUT in terms of wave generation and in terms of detection according to the bias and pulse voltage were performed in an air atmosphere.


Sensors ◽  
2021 ◽  
Vol 21 (5) ◽  
pp. 1823
Author(s):  
Xu-Bo Wang ◽  
Le-Ming He ◽  
You-Cao Ma ◽  
Wen-Juan Liu ◽  
Wei-Jiang Xu ◽  
...  

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 (λ) pitch. We implement this backing on a 16 × 8 array with 75 µm pitch (3λ/4) with a 15 MHz working frequency. Adding the backing nearly doubles the bandwidth to 92% (−6 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.


2020 ◽  
Vol 140 (2) ◽  
pp. 37-42
Author(s):  
Nozomu Fujimoto ◽  
Takefumi Kanda ◽  
Masaya Katsuta ◽  
Yusaku Sakata ◽  
Yoshiaki Yamada ◽  
...  

Author(s):  
P. Maréchal ◽  
L. Haumesser ◽  
G. Feuillard ◽  
L.P. Tran-Huu-Hue ◽  
J. Holc ◽  
...  

Author(s):  
Yuanyu Yu ◽  
Jiujiang Wang ◽  
Xin Liu ◽  
Sio Hang Pun ◽  
Weibao Qiu ◽  
...  

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.


2018 ◽  
Vol 49 (2) ◽  
pp. 477-484
Author(s):  
Ismail E. Mohamed ◽  
Ayman G. Ibrahim ◽  
Hamdy M. Zidan ◽  
Hesham S. El-Bahkiry ◽  
Adel Y. El-sahragti

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