Title :
Applications of micromachined capacitance transducers in air-coupled ultrasonics and nondestructive evaluation
Author :
Schindel, D.W. ; Hutchins, D.A.
Author_Institution :
Dept. of Phys., Queen´´s Univ., Kingston, Ont., Canada
Abstract :
Micromachined capacitance transducers have been investigated in practical situations where air-coupled ultrasound has current application. Their /spl sim/2 MHz bandwidths lead to good performance in pulse-echo and through transmission operation at solid surfaces. Applications in surface profiling and distance measurement have been investigated. For the transduction of waves within solid media, the devices are shown to be capable of detecting longitudinal and shear waves at solid surfaces, as well as Rayleigh and Lamb waves. Examples are also given of fully noncontact, through transmission of carbon fibre reinforced polymer plates.<>
Keywords :
Rayleigh waves; acoustic transducers; capacitance measurement; distance measurement; micromachining; microsensors; surface acoustic waves; surface topography measurement; ultrasonic materials testing; ultrasonic transducers; ultrasonic waves; 2 MHz; Lamb waves; Rayleigh waves; air-coupled ultrasonics; carbon fibre reinforced polymer plates; distance measurement; longitudinal waves; micromachined capacitance transducers; nondestructive evaluation; pulse-echo operation; shear waves; solid surfaces; surface profiling; through transmission operation; Absorption; Capacitance; Inspection; Manufacturing automation; Polymers; Solids; Surface waves; Ultrasonic imaging; Ultrasonic transducers; Ultrasonic variables measurement;
Journal_Title :
Ultrasonics, Ferroelectrics, and Frequency Control, IEEE Transactions on
