EaZE: Flexible Wideband Time-Delay Beamforming using Passive, 3D Reconfigurable, Wideband Metasurfaces

Abstract

Enhanced acoustic zones that emphasize acoustic information in desired 3D spatial regions in a contactless manner, are integral to the vision of immersive spaces. Yet, realizing such zones in practice requires catering to wideband audio signals and 3D spatial selectivity in a cost-effective, deployment-friendly manner, which has been challenging for existing approaches that employ active speaker arrays or metasurfaces. We propose EaZE, a novel, passive, composable metasurface system that enables (i) time-delay beamforming through a principled design of labyrinth-based structures that enable beamforming over a wide 10 kHz lower acoustic band; and (ii) 3D reconfigurability through a composition of modular metasurfaces, whose additional rotation-based degree of freedom, allows composing new beamforming directions passively based on the constituting metasurfaces. EaZE can be easily 3D-printed and deployed with commodity speakers. Comprehensive evaluations highlight its ability to create 3D acoustic zones with enhanced spatial selectivity (10-15 dB) and improved user experience in indoor and outdoor environments for various audio (music, speech) signals.