Reflected continuously tunable acoustic metasurface with rotatable space coiling-up structure

In this paper, we propose a continuously tunable acoustic metasurface composed of identical anisotropic resonant units, each of which contains a rigid pedestal and a rotatable inclusion with space coiling-up structure. The metasurface can manipulate the reflected phase by adjusting the rotational angle of inclusion. The theoretical analysis shows that the polarization-dependent phase change can be induced by the even-order standing wave modes inside inclusion. By utilizing the rotatable inclusion, we design a tunable acoustic carpet cloaking device, which works with a wide range for the incident angle. When incident waves come from different directions, the cloaking effect can be obtained by arranging the rotational angle of each inclusion.