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Article dans une revue

Metadiffusers: Deep-subwavelength sound diffusers

Abstract : We present deep-subwavelength diffusing surfaces based on acoustic metamaterials, namely metadiffusers. These sound diffusers are rigidly backed slotted panels, with each slit being loaded by an array of Helmholtz resonators. Strong dispersion is produced in the slits and slow sound conditions are induced. Thus, the effective thickness of the panel is lengthened introducing its quarter wavelength resonance in the deep-subwavelength regime. By tuning the geometry of the metamaterial, the reflection coefficient of the panel can be tailored to obtain either a custom reflection phase, moderate or even perfect absorption. Using these concepts, we present ultra-thin diffusers where the geometry of the metadiffuser has been tuned to obtain surfaces with spatially dependent reflection coefficients having uniform magnitude Fourier transforms. Various designs are presented where, quadratic residue, primitive root and ternary sequence diffusers are mimicked by metadiffusers whose thickness are 1/46 to 1/20 times the design wavelength, i.e., between about a twentieth and a tenth of the thickness of traditional designs. Finally, a broadband metadiffuser panel of 3 cm thick was designed using optimization methods for frequencies ranging from 250 Hz to 2 kHz.
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https://hal.archives-ouvertes.fr/hal-02511767
Contributeur : Jean-Philippe Groby <>
Soumis le : jeudi 19 mars 2020 - 09:28:10
Dernière modification le : mercredi 14 octobre 2020 - 04:16:11

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Noé Jiménez, Trevor Cox, Vicent Romero-Garcia, Jean-Philippe Groby. Metadiffusers: Deep-subwavelength sound diffusers. Scientific Reports, Nature Publishing Group, 2017, 7 (1), ⟨10.1038/s41598-017-05710-5⟩. ⟨hal-02511767⟩

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