Ventilated metamaterials for broadband sound insulation and tunable transmission at low frequency

Metamaterials enabling multifunctional wave control have long attracted great interest, but remain largely unexplored in ventilation-required settings. Using the space-coiling strategy, we design and fabricate a compact acoustic meta-structure consisting of labyrinth resonators arranged around a central air passage. Such meta-structures provide a promising route to design well-ventilated and simultaneously highly-effective sound-proofing barriers allowing broadband (about one octave band) transmission loss up to almost 30 dB in the range of 660-1200 Hz. More interestingly, due to the interferences between the forward propagating waves and those re-radiated by the surrounding resonators, some asymmetric Fano-like resonances are observed appearing in the transmission gap. This Fano-like resonance is very useful to open a high transmission window at frequencies of interest by changing the length of coiled-up channels. Our findings are both numerically and experimentally verified, which may stimulate multifunctional applications, such as broadband sound insulation with high transmission loss and tunable acoustic communication, especially in ventilation-required environments. (C) 2021 Elsevier Ltd. All rights reserved.

Automated summary

Research on acoustical meta-structures made of metamaterials show promising results in sound insulation, with the ability to open high transmission windows at specific frequencies.