Journal ArticleDOI
Measurement and Mapping of Elastic Anisotropy of Solids Using a Leaky SAW Excited by an Interdigital Transducer
TLDR
In this paper, the authors proposed a method for focusing the beam from an interdigital transducer and mapping a leaky surface acoustic wave (SAW) velocity on a solid sample surface.Abstract:
Abstmt-Methods of measuring the acoustic properties of solids using acoustic beams in a liquid generated by interdigital transducers (IDT) are described. An IDT can radiate acoustic waves into a liquid in oblique directions with respect to the substrate, and the wave fronts can be arbitrarily controlled by designing the IDT shape. When the acoustic beam is incident on the solid sample-water interface near the Rayleigh angle, the reflection field is equal to the superposed fields of the specular reflection and the reradiation from the leaky surface acoustic wave (SAW) excited on the sample. One normal IDT pair on a piezoelectric substrate is used to measure the acoustic properties of a solid sample. The velocity and the attenuation of the leaky SAW on the sample can be obtained by measuring the trailing field due to the reradiation. A new method for focusing the beam from an IDT and mapping a leaky SAW velocity on a solid sample surface is shown. An interdigital electrode is divided into several sections, each of which is positioned to form a one-dimensional Fresnelphase-plate interdigital transducer (FPP IDT) on a piezoelectric substrate. It has been found that the FPP IDT generates a converging beam onto a focal plane, and the present system is suitable for measuring the two-dimensional variation of the leaky SAW phase velocity on a sample surface. Tread more
Citations
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PatentDOI
Ultrasonic sensors for monitoring the condition of a vascular graft
TL;DR: In this paper, the status of fluid flow is remotely monitored in a vessel, a natural graft, or a synthetic graft by using conformal array transducers (44-46) comprising a plurality of elements that curve around the graft or vessel.
Journal ArticleDOI
Applications of surface acoustic and shallow bulk acoustic wave devices
TL;DR: In this paper, surface acoustic wave (SAW) device coverage includes delay lines and filters operating at selected frequencies in the range from about 10 MHz to 11 GHz; modeling with single-crystal piezoelectrics and layered structures; resonators and low-loss filters; comb filters and multiplexers; antenna duplexers; harmonic devices; chirp filters for pulse compression; coding with fixed and programmable transversal filters; Barker and quadraphase coding; adaptive filters; acoustic and acoustoelectric convolvers and adaptive filters.
Proceedings ArticleDOI
New Sensor in Liquid Using Leaky SAW
TL;DR: In this article, a shear horizontal displacement of a leaky SAW mode is used to realize a SAW sensor to be used in liquid, which is a promising substrate for a biosensor and a viscosity sensor.
Patent
Measurement of physical characsteristics or physical properties of viscous media by means of Rayleigh waves
TL;DR: In this article, the authors proposed a method for measuring physical properties or characteristics of liquids using an acoustic transfer system that utilizes Rayleigh waves, where a wave guide with at least one test section formed from a solid surface made from non-piezo-electric material, contacts the liquid medium to be measured and/or a transfer system.
Patent
Measuring physical or technical parameters of liquids, including highly viscous, doughy or pasty material
TL;DR: In this paper, the authors used an acoustic transfer system with at least one measurement path formed by a solid state surface of non-piezoelectric material which can be at least partially brought into contact with the medium to be measured.
References
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Journal ArticleDOI
Unified theory of Rayleigh-angle phenomena for acoustic beams at liquid-solid interfaces
Henry L. Bertoni,Theodor Tamir +1 more
TL;DR: In this paper, a model of the reflection process is developed that explains all of the observed phenomena, including a shift of the reflected beam from the position predicted by geometrical acoustics, a null or minimum of intensity within the reflected beacon, a 180° phase reversal of the field on either side of the null, a weak trailing field on only one side of a reflected beam and a frequency of least reflection when the solid is lossy.
Journal ArticleDOI
Acoustic focusing device with an interdigital transducer
Kohji Toda,Yohji Murata +1 more
TL;DR: In this paper, a simple acoustic focusing device with an interdigital transducer was proposed, in which all radiation from each section of the transducers constructively interferes at a focal point in water.
Journal ArticleDOI
Longitudinal acoustic wave radiated from an arched interdigital transducer
TL;DR: In this article, an arched interdigital transducer was devised for acoustic imaging uses, where two kinds of acoustic beams are radiated into water from the transducers, one of which is radiated at a constant angle independent of the frequency change.
Journal ArticleDOI
Measurement of Rayleigh phase velocity and estimates of shear speed by schlieren visualization
TL;DR: In this article, a schlieren technique is used to give a direct accurate measurement of Rayleigh phase velocity on various materials, and the measured Rayleigh velocities are used to estimate estimates of shear velocity, and these estimates are compared with direct velocity measurements.
Proceedings ArticleDOI
Microscope Lens Using Conversion of Rayleigh to Compressional Waves
G.W. Farnell,C.K. Jen +1 more
TL;DR: In this paper, a planar a coustic microscope lens is demonstrated which produces an almost aberration-free focal spot in a liquid mediuc, where a circular interdigital transducer generates converging acoustic surface waves on the interface between the piezoelectric solid and the liquid.