Comment on "Superwide-band negative refraction of a symmetrical E-shaped metamaterial with two electromagnetic resonances".
The superwide-band negative refraction of the symmetrical E-shaped structure designed by Yan [Phys. Rev. E 77, 056604 (2008)] may not exist. While we accepted the validity of scattering parameter simulations completely, the process of retrieving material parameters could not be justified.
Gu
Chao
C
The College of Science, Air Force University of Engineering, Xi'an 710051, People's Republic of China. guchao123abc@sina.com
Pei
Zhibing
Z
Qu
Shaobo
S
Wang
Jiafu
J
Ma
Hua
H
Xu
Zhuo
Z