Membrane-based acoustic metamaterial with near-zero refractive index
We investigate a one-dimensional acoustic metamaterial with a refractive index of near zero（RINZ） using an array of very thin elastic membranes located along a narrow waveguide pipe. The characteristics of the effective density, refractive index, and phase velocity of the metamaterial indicate that,...
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| Published in | Chinese physics B Vol. 26; no. 1; pp. 237 - 242 |
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| Main Author | |
| Format | Journal Article |
| Language | English |
| Published |
2017
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| Subjects | |
| Online Access | Get full text |
| ISSN | 1674-1056 2058-3834 |
| DOI | 10.1088/1674-1056/26/1/014302 |
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| Summary: | We investigate a one-dimensional acoustic metamaterial with a refractive index of near zero（RINZ） using an array of very thin elastic membranes located along a narrow waveguide pipe. The characteristics of the effective density, refractive index, and phase velocity of the metamaterial indicate that, at the resonant frequency fm, the metamaterial has zero mass density and a phase transmission that is nearly uniform. We present a mechanism for dramatic acoustic energy squeezing and anomalous acoustic transmission by connecting the metamaterial to a normal waveguide with a larger cross-section. It is shown that at a specific frequency f1, transmission enhancement and energy squeezing are achieved despite the strong geometrical mismatch between the metamaterial and the normal waveguide. Moreover, to confirm the energy transfer properties, the acoustic pressure distribution, acoustic wave reflection coefficient, and energy transmission coefficient are also calculated. These results prove that the RINZ metamaterial provides a new design method for acoustic energy squeezing,super coupling, wave front transformation, and acoustic wave filtering. |
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| Bibliography: | Yi-Feng Li1,2,Jun Lan1,Hui-Yang Yu1,Xiao-Zhou Liu3,Jia-Shu Zhang4（1. Department of Computer Science and Technology, Nanjing Technology University, Nanjing 211800, China; 2.Key Laboratory of Modern Acoustics, Ministry of Education, Nanjing University, Nanjing 210093, China; 3. Key Laboratory of Modem Acoustics, Ministry of Education, Institute of Acoustics and School of Physics, Nanjing University, Nanjing 210093, China; 4.Department of Electronic and Electrical Engineering, The University of Sheffield, Sheffield S102TN, UK） We investigate a one-dimensional acoustic metamaterial with a refractive index of near zero（RINZ） using an array of very thin elastic membranes located along a narrow waveguide pipe. The characteristics of the effective density, refractive index, and phase velocity of the metamaterial indicate that, at the resonant frequency fm, the metamaterial has zero mass density and a phase transmission that is nearly uniform. We present a mechanism for dramatic acoustic energy squeezing and anomalous acoustic transmission by connecting the metamaterial to a normal waveguide with a larger cross-section. It is shown that at a specific frequency f1, transmission enhancement and energy squeezing are achieved despite the strong geometrical mismatch between the metamaterial and the normal waveguide. Moreover, to confirm the energy transfer properties, the acoustic pressure distribution, acoustic wave reflection coefficient, and energy transmission coefficient are also calculated. These results prove that the RINZ metamaterial provides a new design method for acoustic energy squeezing,super coupling, wave front transformation, and acoustic wave filtering. 11-5639/O4 acoustic metamaterial; refractive index of near zero（RINZ）; energy squeezing; transmission enhancement |
| ISSN: | 1674-1056 2058-3834 |
| DOI: | 10.1088/1674-1056/26/1/014302 |