Terahertz narrow bandstop, broad bandpass filter using double-layer S-shaped metamaterials. - Lanju Liang; Biaobing Jin; Jingbo Wu; Gaochao Zhou; Yonggang Zhang; Xuecou Tu; Tao Jia; Xiaoqing Jia; Chunhai Cao; Lin Kang; Weiwei Xu; Jian Chen (Sci. China Inf. Sci., 2013)