Absorption–diffusion integrated acoustic metasurface for scattering reduction

Abstract

Absorption and diffusion are expected to reduce the energy intensity of reflected waves, while combining the advantages of both can further disperse incoming energy and improve acoustic stealth performances. In the paper, an absorption-diffusion integrated acoustic metasurface (ADM) is proposed, achieving high-performance acoustic backward scattering reduction in the operating bandwidth ranging from 6550 Hz to 6950 Hz. In order to obtain the proposed ADM, two kinds of subwavelength dual-layer unit cells with phase differences of 180° and low amplitudes (<0.4) are introduced. The highly efficient absorption of acoustic waves is achieved by extending the acoustic wave propagation path of the proposed unit cells. Meanwhile, the destructive interference between the pre-designed unit cells also contributes to diffusion-like scattering, which contributes to further suppression of specular reflection. Both simulated and experimental results demonstrate that the proposed ADM can achieve excellent acoustic backward scattering reduction. The proposed integrated mechanism can provide a method for achieving high-performance acoustic wavefront manipulation, which has potential applications in stealth technology, camouflage, noise control, and other relevant applications.