Yihang Ding, Eleftherios Christos Statharas, Kui Yao, and Minghui Hong, “Broadband Acoustic Metamaterial with Impedance Matching Layer of Gradient Index,” Applied Physics Letters, Vol. 110, No. 24, 241903, 2017. (DOI: 10.1063/1.4986472)
Narrowband transmission of some acoustic metamaterial limits their device applications. Here, we propose and demonstrate a broadband acoustic metamaterial comprising a space coiling structure by introducing an impedance-matching layer (IML) between air and the metamaterial. The impedance-matching layer is achieved by specially designing the parameters of the space coiling structure to form gradient index (GRIN). It is found that the metamaterial with the impedance matching layers substantially improves energy transmission in the frequency range of 2 ~ 6 kHz. We also show the capability of such metamaterial to modulate the phase of acoustic waves with high energy transmission up to 60% at least.
This research is supported by the Singapore Maritime Institute research project (SMI-2015-OF-10) and the National Research Foundation, Prime Minister’s Office, Singapore under its Competitive Research Programme (CRP Award No. NRF-CRP15-2015-04). The authors at IMRE acknowledge the support in part by National Research Foundation under L2NIC Award No. L2NICCFP1-2013-9, with project code of IMRE/14-9P1112.
This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in Appl. Phys. Lett. 110, 241903 (2017) and may be found at https://doi.org/10.1063/1.4986472