Sound attenuation enhancement of acoustic meta-atoms via coupling

Arrangements of acoustic meta-atoms, better known as acoustic metamaterials, are commonly applied in acoustic cloaking, for the attenuation of acoustic fields or for acoustic focusing. A precise design of single meta-atoms is required for these purposes. Understanding the details of their interaction allows improvement of the collective performance of the meta-atoms as a system, for example, in sound attenuation. Destructive interference of their scattered fields, for example, can be mitigated by adjusting the coupling or tuning of individual meta-atoms. Comprehensive numerical studies of various configurations of a resonator pair show that the coupling can lead to degenerate modes at periodic distances between the resonators. We show how the resonators' separation and relative orientation influence the coupling and thereby tunes the sound attenuation. The simulation results are supported by experiments using a two-dimensional parallel-plate waveguide. It is shown that coupling parameters like distance, orientation, detuning, and radiation loss provide additional degrees of freedom for efficient acoustic meta-atom tuning to achieve unprecedented interactions with excellent sound attenuation properties.

Automated summary

Arrangements of acoustic meta-atoms, known as acoustic metamaterials, are widely used for acoustic cloaking, field attenuation, and focusing. Understanding the interaction between individual meta-atoms is crucial for improving their collective performance. Numerical studies and experiments reveal that adjusting the coupling and tuning of meta-atoms can mitigate destructive interference, leading to efficient sound attenuation properties.