Abstract
Metamaterials allow the accurate control of the acoustic scattering using subwavelength thickness panels. In this work, we report the scattering of spiral-shaped metasurfaces with practical application to sound diffusers. We analytically, numerically and experimentally show that bipolar spiral-shaped metasurfaces produce broadband non-specular reflection. We observe that the reflected energy can be scattered at higher diffraction orders and, due to the spiral geometry, the phase of the scattering field rotates producing a vortex in the near field. Thus, the specular component at normal incidence vanish. This produces a perfect correlationscattering coefficient when comparing to a rigid flat reflector of same dimensions. In particular, the scattering of an Archimedes spiral metasurface is presented. We show that the scattering pattern corresponds to a high-order Bessel beam. The use of binary locally reacting surfaces with chiral geometry produce non-specular reflected patterns, allowing the use of these structures use as sound diffusers.
BibTeX citation
@inproceedings{JimenezMETA2018difusoresvortice,
author = {Noé Jiménez and Jean Philippe Groby and Vicent Romero-García},
booktitle = {METAMATERIALS 2018: 12th International Congress on Artificial Materials for Novel Wave Phenomena. Espoo, Finland. Aug. 27th - Sept. 1st},
doi = {https://doi.org/10.1109/MetaMaterials.2018.8534047},
editor = {Conference proceedings},
isbn = {ISBN: 978-1-5386-4702-8},
month = {9},
organization = {Metamaterials Conferences},
pages = {194-196},
publisher = {IEEE},
series = {Oral},
title = {Vortex-sound diffusers using spiral metasurfaces},
url = {https://ieeexplore.ieee.org/document/8534047},
year = {2018}
}