Acoustic Metasurfaces for Sound Control

Metamaterials are artificial materials properly engineered to obtain properties and characteristics that are not possible to find in natural materials. Theory and applications of metamaterials, already consolidated in electromagnetism, have been extended to acoustics, in particular, they can be applied to improve properties of acoustical panels and absorbers. In this frame, acoustic cloaking technique is an actively investigated subject given its wide-ranging possible applications. In this contribution we investigate the application of the so-called mantle cloaking technique to the environmental acoustical problems. We propose an innovative way to achieve the acoustical insulation of a confined environment, aiming to lower noise pollution, by designing a subwavelength-thick surface with proper surface acoustic impedance. This solution would require panels with lower mass and thickness compared with the conventional ones. We present a few models of simple structures designed to obtain sound control and test their behavior by means of full-wave simulations.