Acoustic emission enhancement and self-centering effect via an extreme anisotropic metamaterial

Abstract

An extreme anisotropic metamaterial consisting of one central cavity, eight zigzag and straight channels is proposed, aiming to achieve acoustic emission enhancement and self-centering effect. By placing a monopole source in the center of the metamaterial, acoustic emission enhancement can be achieved through the resonance in the zigzag channels and the monopole resonances. Theory and simulation confirm the self-centering effect of the proposed metamaterial, that is, when monopole sources are placed away from the center of the metamaterial, the external sound field can still be regarded as a uniform sound field generated by a monopole source placed in the center.