[1] [1] Shelby R A, Smith D R, et al. Experimental verification of a negative index of refraction ［J］. Science, 2001, 292(4): 77.

[2] [2] Pendry J B, Smith D R, et al. Metamaterial electromagnetic cloak at microwave frequencies ［J］. Science, 2006, 314: 977.

[3] [3] Cui T J, Smith D R, et al. Broadband ground-plane cloak ［J］. Science, 2009, 323: 366.

[4] [4] Caloz C, Itoh T, et al. Planar distributed structures with negative refractive index ［J］. IEEE Trans. Microwave Theory Tech., 2004, 52(4): 1252-1263.

[6] [6] Zhang Zhongxiang, Xu Shanjia. A novel balun structure consisting of composite right-left handed transmission line ［J］. Microwave and Opt. Tech. Lett., 2005, 45(5): 422-424.

[8] [8] Zhang Zhongxiang, et al. A novel two dimensional CRLH-TL structure for double negative materials ［C］. Digest of APS, IEEE, 2006: 4149-4152.