A feasible approach to achieve acoustic carpet cloak in air

A type of acoustic carpet cloak has been theoretically designed and numerically implemented in air using steel/air composites. By using the effective medium theory, the effective density and bulk modulus of the composite material are designed to agree with the spatially variant parameters calculated from the coordinate transformation approach. Great cloaking performance is achieved as an object is well hidden under a sound reflective surface in a wide frequency range. It has also been shown that sound can be effectively manipulated using the proposed composite materials because of its low complexity.