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https://doi.org/10.3938/NPSM.69.673
Self-collimation of Ultrasound in a Two-dimensional Phononic Crystal with a Square Lattice Immersed in Water
New Phys.: Sae Mulli 2019; 69: 673~678
Published online June 28, 2019;  https://doi.org/10.3938/NPSM.69.673
© 2019 New Physics: Sae Mulli.

Hwi Suk KANG, Kang Il LEE*

Department of Physics, Kangwon National University, Chuncheon 24341, Korea
Correspondence to: acustica@kangwon.ac.kr
Received April 22, 2019; Revised May 14, 2019; Accepted May 21, 2019.
cc This is an open-access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
Abstract
In the present study, the self-collimation of ultrasound was theoretically and experimentally investigated in a two-dimensional phononic crystal with a square lattice immersed in water. The acoustic band structure of the phononic crystal was calculated by using the finite element method, and the acoustic pressure fields at the frequencies of each band were calculated with and without the phononic crystal in the acoustic path. Ultrasonic waves were theoretically found not to be allowed at the frequencies of the bandgaps and were self-collimated at the frequencies of the second transmission band due to the negative refraction. The self-collimation of ultrasound was experimentally observed in the same two-dimensional phononic crystal as with the theoretical modeling. In conclusion, we theoretically and experimentally verified the self-collimation and the directivity enhancement of ultrasound in a two-dimensional phononic crystal immersed in water.
PACS numbers: 43.20.Bi, 43.20.El, 43.20.Fn
Keywords: Acoustic metamaterial, Phononic crystal, Band structure, Negative refraction, Self-collimation


June 2019, 69 (6)
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