Membrane-based acoustic metamaterial with near-zero refractive index
Li Yi-Feng1, 2, †, Lan Jun1, Yu Hui-Yang1, Liu Xiao-Zhou3, Zhang Jia-Shu4
       

(color online) Acoustic pressure distributions along the RINZ acoustic metamaterial and normal material with respect to frequency (a) below , (b) equal to , (c) equal to f 1, and (d) above f 1.