Self-collimation of Ultrasound in a Two-dimensional Phononic Crystal with a Square Lattice Immersed in Water

초록

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. © 2019 The Korean Physical Society. All rights reserved.

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