Multi-frequency acoustic metasurface carpet cloak based on groove structural unit

This paper presents a multi-frequency acoustic metasurface carpet cloak (AMCC) composed of groove-structured units. These structural units function as multi-frequency metasurfaces and operate effectively at both the fundamental and harmonic frequencies. Numerical simulations demonstrate that the proposed AMCC can effectively cloak a triangular object, with a broad operational bandwidth ranging from 3110 to 3750 Hz near the fundamental frequency. Experimental results align well with the numerical simulations, validating the performance of the AMCC under both normally incident plane-wave and cylindrical-wave excitations. In addition, an arc-shaped cloak is designed to demonstrate that the proposed AMCC can also conceal an arc-shaped object. The proposed approach can be extended to arbitrary object geometries, providing a simple configuration and ease of implementation for practical acoustic cloaking applications.