In:
The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 126, No. 4_Supplement ( 2009-10-01), p. 2197-2197
Abstract:
The piezoelectric transducer bonded to a thick plate resonator wholly vibrates as a single transducer. Since the distribution of stress in the thickness direction is asymmetric, the transducer resonates at even order harmonic frequencies as well as odd order ones. The back of the resonator is bonded to a quarter-wavelength matching layer to transmit backward the fundamental frequency wave through the layer. The front of piezoelectric transducer is bonded to another matching layer to transmit forward the ultrasonic wave of higher order frequencies. If both the piezoelectric transducer and the resonator are made of low Q materials, the admittance curve including troughs among resonance peaks is flattened and shows broadband characteristics. Such broadband characteristic transducers made of one to three composite piezoelectric materials were experimentally studied. The thickness of the piezoelectric transducer and the resonator were designed for resonance frequencies of 7 and 1 MHz, respectively. The back of matching layer was bonded to the absorbing material not to reflect forward the ultrasonic waves of 1 MHz. As a result, the ultrasound of center frequency of 5 MHz and fractional bandwidth of 100% were transmitted from the transducer driven by an impulsive signal.
Type of Medium:
Online Resource
ISSN:
0001-4966
,
1520-8524
Language:
English
Publisher:
Acoustical Society of America (ASA)
Publication Date:
2009
detail.hit.zdb_id:
1461063-2
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