An acoustic metasurface for perfect absorption: optimal design and experimental validation

Abstract

An acoustic metasurface perfectly absorbing sound at a desired low frequency is designed by using optimization method and validated via experiments. We propose an acoustic metasurface composed of a periodic array of four Helmholtz resonators in subwavelength scale. We use the theoretical model in our recent work, which is based on visco-thermal effects considering frequency dependence. As a practical application of the theoretical model, we design the metasurface perfectly absorbing sound at a target frequency by using optimization method. The reflection and absorption coefficients obtained from the theoretical model are compared with FEM simulation and experiment. The proposed metasurface yields high absorption coefficients for a wide range of incidence angles in the range of 0°≤θ≤60°.