High-efficiency Ventilated Metamaterial Absorber at Low Frequency

TL;DR

This paper introduces a low-frequency ventilated metamaterial absorber that achieves over 90% efficiency with only two layers, leveraging hybridized eigenmodes to surpass traditional absorption limits, suitable for noise reduction and ventilation.

Contribution

The study presents a novel low-frequency ventilated metamaterial absorber with high efficiency, utilizing weak coupling of split tube resonators to break conventional absorption limits.

Findings

Achieves >90% absorption efficiency at <500 Hz

Operates effectively with only two layers of absorption units

Can be extended to array configurations for free space applications

Abstract

We demonstrate a ventilated metamaterial absorber operating at low frequency (< 500 Hz).With only two layers of the absorption units, high-efficiency absorption (> 90%) has been achieved in both simulations and experiments. This high-efficiency absorption under ventilation condition is originated from the weak coupling of the two identical split tube resonators constituting the absorber, which leads to the hybridization of the degenerate eigenmodes and breaks the absorption upper limit of 50% for conventional transmissive symmetric acoustic absorbers. The absorber can also be extended to an array and work in free space. The absorber should have potential applications in acoustic engineering where both noise reduction and ventilation are required.