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TitleA taper microstructure for impedance matching
Publication TypeConference Paper
Year of Publication2010
AuthorsWu, D., Harris P.D., and Young R.
Conference NameProceedings - IEEE Ultrasonics Symposium
Date Published2010
KeywordsAcoustic impedance, Acoustic matching, Broad frequency range, Finite element modeling, microrod, Microrods, Quarter-wave matching, Reflection properties, Single mode, tapered, Ultrasonic transducers, Ultrasonics, Wave propagation, Wave scattering
AbstractThe object of this work is to present the concept of a composite materialwhich consists of many closely packed tapered microrods. The material isintended to be used for ultrasonic transducer matching and fabricated usingphotolithographic methods. We find that for appropriate microrod diameter andtaper, relative to the wavelength, the tapered microrod has a smooth continuoustransition in its acoustic impedance. Further for the structures that seem mosteasily fabricated importantly this includes impedance in the range 3 to 10MRayl, where there is no useful alternative solid. Wave propagation in themicrostructure has been studied with PZFlex finite element modeling and thiswork shows that when an appropriate taper has been selected that energytransferred is dominated by a single mode. The reflection property of thecomposite has also been investigated and this data is compared with that forsingle and dual conventional quarter wave matching layers. It is found that thetapered microrod can provide matching over a very broad frequency range. Unlikeloaded epoxy implicitly there is no wave scattering. © 2010 IEEE.

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