An arbitrarily curved acoustic metasurface for three-dimensional reflected wave-front modulation

Abstract Acoustic metasurfaces are attractive due to the feasibility of unprecedented modulation for reflected or refracted waves. However, most proposed acoustic metasurfaces are planar, which limits the application of metasurfaces. An acoustic metasurface with a curved surface shape is rarely reported, especially for the three-dimensional case. In this paper, the three-dimensional generalized Snell’s law for reflection at an arbitrarily curved surface is derived. Then tunable curved metasurfaces composed of the corrugated holes unit-cells are designed. And anomalous reflection, focusing and ground illusion are numerically demonstrated. The design methodology proposed in this paper expands the application range of acoustic metasurfaces and paves the way to some special application realms, such as wearable acoustic devices and acoustic devices with curved surfaces.