Numerical study on a three-dimensional broadband isotropic left-handed metamaterial based on closed rings

In this paper, a three-dimensional (3D) broadband isotropic left-handed metamaterial (LHM) is proposed and investigated numerically. The 3D unit cell is composed of a dielectric cube with metallic closed rings (CRs) printed on all its six sides. Simulations of the electric field and surface current distributions, the effective electromagnetic (EM) parameter retrieval and a refraction phenomenon based on a wedge-shaped model were carried out to further verify the LH properties of the proposed 3D CRs structure model. The results show that the relative bandwidth is more than 6 GHz, and the LH band is polarization independent and almost unchanged for different incident angles. Moreover, the EM parameters of the unit cell with different geometrical parameters are also explored in order to obtain an optimized design for 3D LHM. (paper)