Ultrabroadband and Reconfigurable Transmissive Acoustic Metascreen

Passive acoustic wave manipulations are severely constrained by the narrow frequency bandwidth of acoustic metastructures. In this research, an unprecedented type of reconfigurable acoustic metascreen is proposed for broadband manipulations of transmitted acoustic waves. The conceived structure is composed of uniquely designed unit cells producing the modulation of the transmitted phase shift within the full 2 pi range with an excellent impedance matching with the background medium. By rationally arranging the reconfigurable elements within the metascreen based on the corresponding parameter profile, different phenomena and functionalities can be easily realized. As examples, acoustic focusing and acoustic bending are presented to showcase the performance of the proposed metascreen. We indeed numerically and experimentally demonstrate the ultra-broadband and reconfigurable features of our concept over an astonishing frequency range extending from 3 to 17 kHz, which covers the majority spectrum of the audible range of human hearing. Our work provides a unique and remarkable conceptual design of acoustic metascreen opening a promising and pragmatic route to conceive compact broadband acoustic devices, where wavefront manipulations on broadband sound signals or pulsed signals are required.