Underwater asymmetric acoustic transmission structure using the medium with gradient change of impedance
Hu Bo1, 2, Shi Jie1, 2, †, 
, Shi Sheng-Guo1, 2, Sun Yu1, 2, Zhu Zhong-Rui1, 2
, Shi Sheng-Guo1, 2, Sun Yu1, 2, Zhu Zhong-Rui1, 2 (a) Prepared media each with a gradient change of impedance. (b) Distributions of acoustic impedance of two prepared media. The dotted–solid line and dashed line refer to the first medium and the second medium as shown in Fig.
