Dual-band quasi-zero refraction and negative refraction in coin-shaped metamaterial

This paper demonstrates a metamaterial capable of realizing a dual-band quasi-zero refractive index and a negative refractive index, which consists of a coin-shaped slice and two parallel planar wires. The zero refractive index is achieved over a very wide frequency range. The bandwidth of the first band of the quasi-zero index can reach up to 3 GHz, and the width of the second band exhibiting low loss is 0.4 GHz. Between these two bands, the negative refractive index band is 9.0–13.9 GHz. The corresponding formulas of electric plasma frequency and magnetic plasma frequency are established, and the theoretical results agree well with the simulated results. The proposed metamaterial may have potential applications in multiband or broadband devices.