Acoustic external cloak with only spatially varying bulk modulus

School of Information Science and Engineering, Yunnan University, Kunming 650091, P.R. China

^a huangming@ynu.edu.cn

Received: 17 July 2011
Revised: 27 October 2011
Accepted: 4 November 2011
Published online: 23 December 2011

Abstract

Acoustic external cloak is an important device, which can cloak an object without encircling it but allows the object to exchange information with the outer region. By choosing appropriate spatial transformation, we design a cylindrical acoustic external cloak with only spatially varying bulk modulus in this paper. The general expressions of material parameters are derived, and then the performance of the external cloak is simulated based on full-wave simulations. The advantage of the cloak is that mass density elements are constants, and only bulk modulus is a function of radius, which make it easier to realize in practice. Besides, the effects of perturbations of parameters on the performance of the cloak are also investigated. This work provides a feasible way for the fabrication of the metamaterial-assisted acoustic external cloak.