Single-layer broadband planar antenna using ultrathin high-efficiency focusing metasurfaces
Hou Hai-Sheng, Wang Guang-Ming, Li Hai-Peng, Guo Wen-Long, Li Tang-jing, Cai Tong
       

(color online) (a) Phase response on the cut line along the x direction. (b) Relative reflection phase distribution in the xoy plane.