Multiband quasi-perfect low-frequency sound absorber based on double-channel Mie resonator

Abstract

Metamaterial absorbers have recently been developed to act as efficient sound absorption components of subwavelength dimensions. However, the working frequency has so far been mainly limited to a single narrow band. Here, we demonstrate a multiband quasi-perfect absorber constructed by a double-channel Mie resonator (DMR) in a unique configuration. By attentively tuning the leakage factor to match the loss factor at multi-order monopolar and dipolar resonances of DMR simultaneously, a series of absorptive peaks with near-unity absorptances have been achieved in both numerical simulation and the experimental measurement. Our approach gives a simple platform for extending the response of metamaterial devices from the single band to the multiband without superimposing resonant elements in multiple configurations, which allows us to envision acoustic devices with versatile applications.

Low-frequency perfect sound absorption achieved by a modulus-near-zero metamaterial

“…In contrast, the geometric parameters of the Mie resonator in ref. 38 are fixed (with fixed loss factor) and the near critical coupling condition is satisfied by tuning the periods of Mie resonators (changing leakage factor). Our theory can also be applied in explaining the mechanism of the absorption of the double-channel Mie resonator (DMR).…”

“…In contrast to the previous work by Long et al . 38 , which focused on multiband quasi-perfect absorption by satisfying near critical coupling condition, here we develop a general theory to get PA with the MNZ MAs at designed working frequency. In addition, we would like to note that by using two critically coupled Mie resonators to achieve monopolar and dipolar resonances respectively in the same frequency window, double-zero parameter for the design of the perfect absorber can be envisioned, which may provide a ventilated absorption system.…”

Damped resonance for broadband acoustic absorption in one-port and two-port systems

“…Thus, minimizing the number of resonators in a unit cell is practically desired for constructing compact broadband absorbers. One approach implements multi-order resonances of one resonator in the unit cell, simultaneously satisfying critical coupling conditions at these multi-order resonances 15 . In this device, the spacing between the individual resonances is restricted by the fundamental frequency and its higher harmonics.…”

Reconfigurable sound anomalous absorptions in transparent waveguide with modularized multi-order Helmholtz resonator

“…We also note that the design and fabrication of advanced sound absorbers, which exhibits superior characteristics than conventional sound absorber such as acoustic porous materials 24 , has attracted considerable interest recently. To efficiently absorb the low-frequency sound energy with (deep−) subwavelength structure, a significant number of resonators have been employed to build up sound absorbers spanning from acoustic membrane 17 , 25 , 26 , acoustic metasurface 27 , 28 , acoustic split-ring resonator 29 , 30 , Mie resonator 31 , to labyrinthine Fabry-Perot resonator 32 , 33 , et al . However, most absorbers are based on single-port systems which need a rigid-backed wall to block the sound energy.…”