An acoustic Maxwell's fish-eye lens based on gradient-index metamaterials
Bao-guo Yuan(袁保国), Ye Tian(田野), Ying Cheng(程营), Xiao-jun Liu(刘晓峻)
Chin. Phys. B . 2016, (10): 104301 -104301 .  DOI: 10.1088/1674-1056/25/10/104301