Acoustic Doppler velocity measurement system using capacitive micromachined ultrasound transducer array technology.
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.
Department of Mechanical Engineering, Tufts University, Medford, Massachusetts 02155, USA.
Minchul
M
Shin
Joshua S
JS
Krause
Paul
P
DeBitetto
Robert D
RD
White
D004301:Doppler Effect; D004867:Equipment Design; D008567:Membranes, Artificial; D055616:Microtechnology / Q000295:instrumentation* / Q000379:methods; D008904:Miniaturization; D008962:Models, Theoretical; D009038:Motion; D011312:Pressure; D012815:Signal Processing, Computer-Assisted; D013016:Sound; D013018:Sound Spectrography; D013997:Time Factors; D014160:Transducers, Pressure; D014465:Ultrasonics / Q000295:instrumentation* / Q000379:methods; D014732:Vibration
D008567:Membranes, Artificial