Design And Study Of Broadband Left-handed Electromagnetic Materials Based On The Fishnet Structure

In recent years, there are many studies about an artificial material that is called left-handed materials, and their relative permittivity and permeability are simultaneously negative, and in some frequency bands the refraction index is negative.The fishnet structure is a new type of left-handed materials, this paper analyzes the fishnet sturcture theoretically using the simulation result in detail. The main contents and contribution of the paper as follows:Firstly, describe the basic theory of the left-handed materials, and analysis the method that exports the effective electromagnetic parameters(permittivity, permeability and refractive index) based on the S parameter. Study various left-handed materials, but focuses on the fishnet structure, and introduce the design principle and the equivalent circuit, through the use of the software CST, study the transmission characteristics of the fishnet sturcture, and extract the material parameters, and at the same time study some modified fishnet stuctures;Secondly, modify the basic fishnet structure, it is found that the moidified fishnet structure maintains good characteristics of the traditional fishnet structure, and the bandwidth of negative refraction and the bandwidth in which the relative permittivity and permeability are simultaneously negative is about twice than the traditional fishnet structure; And based on the modified fishnet structure proposes an isotropic-like fishnet structrue; Finally, analysis the left-handed performance of the traditional fishnet structure and the modified fishnet structure when the incident wave is oblique, and the frequency range in which the relative permittivity and permeability are simultaneously negative will shift when the angle of the incident wave changes.