Underwater acoustic metamaterial based on double Dirac cone characteristics in rectangular phononic crystals Project supported by the National Natural Science Foundation of China (Grant Nos. 11602269, 11972034, and 11802213), the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No. XDB22040301), and the Research Program of Beijing, China (Grant Nos. Z161100002616034 and Z171100000817010). |
(a) PC consisting of rectangular scatterers surrounded by water positioned in a rectangular lattice. (b) Cell of a rectangular PC. (c) Irreducible Brillouin zone of a cell. |