A flat transducer was constructed, using a 9-μm-thick PVDF (polyvinylidene fluoride) film for generation and detection of high-frequency ultrasonic waves, and used for measurements of the phase velocity of longitudinal waves traveling along the thickness direction in a very thin material. The transducer has a useful wideband frequency characteristic extending from 10 MHz to over 150 MHz. Measurements of the phase velocity of the longitudinal waves are carried out using a 0.212-mm-thick glass slide and a 0.102-mm-thick stainless-steel shim, using water as a coupling medium. The thickness limit for this measurement appears to be approximately 20 μm. The phase velocity of the longitudinal mode is obtained as a function of frequency in the frequency domain by using a modified sampled continuous wave (cw) technique. It can also be measured in the time domain by using a broadband pulse of short duration.

Topics
Ultrasound, Wave mechanics, Polymers
1.
Bolef, D. I., and Miller, J. G. (1971). “High Frequency Continuous Wave Ultrasonics”, in Physical Acoustics, edited by W. P. Mason and R. N. Thurston (Academic, New York), Vol. 8, pp. 95–201.
2.
McSkimin
,
H. J.
(
1961
). “
Pulse Superposition Method for Measuring Ultrasonic Wave Velocities in Solids”
,
J. Acoust. Soc. Am.
33
, pp.
12
–
16
.
Google Scholar
Crossref
Search ADS
 
3.
McSkimin
,
H. J.
, and
Andreatch
,
P.
(
1962
). “
Analysis of the Pulse Superposition Method for Measuring Ultrasonic Wave Velocities as a Function of Temperature and Pressure
”,
J. Acoust. Soc. Am.
34
, pp.
609
–
615
.
Google Scholar
Crossref
Search ADS
 
4.
Papadakis, E. P. (1976). “Ultrasonic Velocity and Attenuation: Measurement Methods with Scientific and Industrial Applications”, in Physical Acoustics, edited by W. P. Mason and R. N. Thurston (Academic, New York), Vol. 12, pp. 277–374.
5.
Smolorz
,
S.
, and
Grill
,
W.
(
1996
), “
Focusing PVDF transducers for acoustic microscopy
”,
Res. Nondestruct. Eval.
7
, pp.
195
–
201
.
Google Scholar
Crossref
Search ADS
 
6.
Williams
,
J.
, and
Lamb
,
J.
(
1958
).
J. Acoust. Soc. Am.
30
,
308
.
Google Scholar
Crossref
Search ADS
 
7.
Zou
,
W.
,
Holland
,
S.
,
Kim
,
K. Y.
, and
Sachse
,
W
. (
2003
). “
Wideband high-frequency line-focus PVDF transducer for materials characterization
”,
Ultrasonics
41
, pp.
157
–
161
.
Google Scholar
Crossref
Search ADS
PubMed
 
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2003
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