Two-Dimensional Distributed Transmission-Line Models for Broadband Full-Tensor Anisotropic Acoustic Metamaterials Based on Transformation Acoustics

Abstract

We propose the design method for broadband acoustic metamaterials based on the concept of transformation acoustics. Two-dimensional distributed transmission-line (TL) models for full-tensor anisotropic electromagnetic metamaterials are applied to full-tensor anisotropic acoustic metamaterials and the design formulas are shown to uniquely determine the structural parameters of the unit cells. Two-dimensional acoustic waveguide unit cell structures for realizing the TL models are proposed and an acoustic carpet cloak and an acoustic illusion medium are designed according to the introduced theory. The complex sound pressure distributions in the acoustic waveguides of the unit cells are calculated by full-wave simulations to verify the validity of the proposed method, and the broadband operations of the designed carpet cloak and illusion medium are confirmed from the results.

Keywords

• transformation acoustics
• acoustic carpet cloaks
• acoustic illusions
• full-tensor anisotropic acoustic metamaterials
• transmission-line approach