Directivity enhancement based on anisotropic zero refraction index metamaterials

In this paper, we have reviewed some recent works about the anisotropic zero refraction index metamaterials, which has been proved to be helpful to enhance the directivity of microwave antennas. An improved Vivaldi antenna with metamaterial loadings has been discussed and simulated. Simulation results show that anisotropic zero refraction index metamaterials can be utilized to improve the antenna performance efficiently, which is important for practical antenna designs.