Subwavelength broadband sound absorber based on a composite metasurface.

Publisher:
Springer Science and Business Media LLC
Publication Type:
Journal Article
Citation:
Scientific reports, 2020, 10, (1), pp. 13823
Issue Date:
2020-08-14
Full metadata record
Suppressing broadband low-frequency sound has great scientific and engineering significance. However, normal porous acoustic materials backed by a rigid wall cannot really play its deserved role on low-frequency sound absorption. Here, we demonstrate that an ultrathin sponge coating can achieve high-efficiency absorptions if backed by a metasurface with moderate surface impedance. Such a metasurface is constructed in a wide frequency range by integrating three types of coiled space resonators. By coupling an ultrathin sponge coating with the designed metasurface, a deep-subwavelength broadband absorber with high absorptivity ([Formula: see text]) exceeding one octave from  185 Hz to  385 Hz (with wavelength [Formula: see text] from 17.7 to 8.5 times of thickness of the absorber) has been demonstrated theoretically and experimentally. The construction mechanism is analyzed via coupled mode theory. The study provides a practical way in constructing broadband low-frequency sound absorber.
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