Title :
A measurement system of SAW velocity distribution using a layer-structure transducer for a leaky SAW
Author :
Toda, K. ; Sawaguchi, A.
Author_Institution :
Dept. of Electron. Eng., Nat. Defense Acad., Yokosuka, Japan
Abstract :
An ultrasonic system in which a leaky surface acoustic wave (SAW) transducer is composed of a piezoelectric ceramic thin plate, an interdigital transducer (IDT), and a fused quartz plate for measuring the distribution of leaky SAW velocity on a test sample is described. A compression wave reradiated into a water layer from the surface of the test sample is detected as electrical signals with different delay times at receiving IDTs. The phase difference between the two delayed signals is dependent on the leaky SAW velocity on the test sample. This method, which uses a layer-structure leaky SAW transducer, has the advantage of a wide measurable region of SAW velocity, unlike the normal kind of leaky SAW transducer, because of plural dispersive leaky SAW modes. Experimental results for a LiNbO3 wafer and a glass substrate were obtained using three dispersive leaky modes
Keywords :
surface acoustic wave devices; ultrasonic materials testing; LiNbO3 wafer; SAW velocity; compression wave; delay times; electrical signals; fused quartz plate; glass substrate; interdigital transducer; layer-structure transducer; leaky SAW velocity; leaky surface acoustic wave transducer; nondestructive evaluation; phase difference; piezoelectric ceramic thin plate; plural dispersive leaky SAW modes; test sample; ultrasonic system; water layer; Acoustic measurements; Acoustic testing; Acoustic transducers; Acoustic waves; Dispersion; Piezoelectric transducers; Surface acoustic waves; Ultrasonic transducers; Ultrasonic variables measurement; Velocity measurement;
Conference_Titel :
Ultrasonics Symposium, 1990. Proceedings., IEEE 1990
Conference_Location :
Honolulu, HI
DOI :
10.1109/ULTSYM.1990.171516