Department of Mechanical Engineering, Tufts University, Medford, Massachusetts 02155, USA.
J Acoust Soc Am. 2013 Aug;134(2):1011-20. doi: 10.1121/1.4812249.
This paper describes the design, fabrication, modeling, and characterization of a small (1 cm(2) transducer chip) acoustic Doppler velocity measurement system using microelectromechanical systems capacitive micromachined ultrasound transducer (cMUT) array technology. The cMUT sensor has a 185 kHz resonant frequency to achieve a 13° beam width for a 1 cm aperture. A model for the cMUT and the acoustic system which includes electrical, mechanical, and acoustic components is provided. Furthermore, this paper shows characterization of the cMUT sensor with a variety of testing procedures including Laser Doppler Vibrometry (LDV), beampattern measurement, reflection testing, and velocity testing. LDV measurements demonstrate that the membrane displacement at the center point is 0.4 nm/V(2) at 185 kHz. The maximum range of the sensor is 60 cm (30 cm out and 30 cm back). A velocity sled was constructed and used to demonstrate measureable Doppler shifts at velocities from 0.2 to 1.0 m/s. The Doppler shifts agree well with the expected frequency shifts over this range.
本文描述了一种使用微机电系统电容式微加工超声换能器 (cMUT) 阵列技术的小尺寸（1 cm² 换能器芯片）声学多普勒速度测量系统的设计、制造、建模和特性分析。cMUT 传感器的谐振频率为 185 kHz，实现了 1 cm 孔径下 13°的波束宽度。提供了一个包括电气、机械和声学组件的 cMUT 和声学系统模型。此外，本文通过各种测试程序（包括激光多普勒测振仪 (LDV)、波束图测量、反射测试和速度测试）展示了 cMUT 传感器的特性。LDV 测量表明，在 185 kHz 时中心点的膜片位移为 0.4 nm/V²。传感器的最大测量范围为 60 cm（30 cm 外和 30 cm 内）。构建了一个速度滑台，并用于演示在 0.2 至 1.0 m/s 的速度下可测量的多普勒频移。在这个范围内，多普勒频移与预期的频率偏移吻合较好。
