All-angle blockage of sound by an acoustic double-fishnet metamaterial

In this paper we design an acoustic metamaterial for broadband sound blockage that is easy to fabricate and presents tunable capabilities. Two adjacent holey plates are predicted to support a gap mode which is responsible of a forbidden band, displaying a negative effective bulk modulus. This acoustic metamaterial exhibits a weak dispersion with parallel momentum implying that strong attenuation appears for a broad range of angles of incident sound. Its bandwidth can be tailored at will by varying the separation between the two holey plates. (C) 2010 American Institute of Physics. [doi:10.1063/1.3491289]