Reconfigurable Metasurfaces for Directional Acoustic Sensing

We design and acoustically simulate additively manufactured, flat acoustic membranes (also called metasurfaces) which can be reconfigured into 3-dimentional solids. Using finite element simulations, we design frequency selective acoustic ` window' membranes. These transmit narrow frequency bands near flexure resonances. The frequency range of coverage was chosen to be in the audible range and spans from 2,500Hz to 10,000Hz with first order resonances only. We demonstrate selective, non-overlapping acoustic transmission through each membrane window in its flat configuration, and directional selectively when the flat metasurface is folded into the truncated-octahedron with an omnidirectional microphone placed on the interior of the solid form. This work was supported by the Office of Naval Research.