Complex band structures and effective medium descriptions of periodic acoustic composite systems

Xianyu Ao, C. T. Chan
2009 Physical Review B  
We examine the complex band structures and effective medium descriptions of a periodic acoustic composite system. It is shown that if the system exhibits a negative velocity band, the assignment of the system as a phononic crystal or as a "double negative" metamaterial is unambiguous only in some cases. An example is given where the system properties can be tuned gradually and continuously from an acoustic metamaterial to a phononic crystal, and there is no sharp dividing line between these two
more » ... e between these two regimes. e 0 k 0 K e J m ͑K e r 0 ͒ J m Ј ͑K e r 0 ͒ = J m ͑k 0 r 0 ͒ + D m H m ͑1͒ ͑k 0 r 0 ͒ J m Ј ͑k 0 r 0 ͒ + D m H m ͑1͒Ј ͑k 0 r 0 ͒ , m = 0,1, PHYSICAL REVIEW B 80, 235118 ͑2009͒
doi:10.1103/physrevb.80.235118 fatcat:3y5gycsetzf5tlbqi6dlpy22ee