Enhancement and concealment of broadband acoustic transmission through the coupling of monopole resonances in meta-structures

Abstract

Broadband acoustic transmission enhancement is crucial in practical applications. Here, we propose a meta-structure composed of a central cavity, a middle cavity, eight zigzag channels and eight straight channels, which can improve the acoustic emission and reception efficiency in the broadband range by coupling the first and second monopole resonances, respectively. An acoustic transmission system is constructed by placing the meta-structures at the emitting and receiving end. After parameter optimization, simulation and experiments show that the system achieves an efficiently enhanced broadband acoustic transmission through the cascade process of broadband emission and reception enhancement with a maximum sound pressure level (SPL) gain of 36.5 dB and a -3 dB bandwidth of 797Hz-1187Hz. Furthermore, while maintaining the same SPL at the receiving end, the system can reduce the SPL in other areas by 20 dB to achieve acoustic concealed transmission. The proposed system shows significant potential in acoustic communication.