Broadband Frequency Selective Directing on Interface Between Isotropic and Anisotropic Unloaded Transmission Line Metamaterials

Abstract

—In this paper, we study the unusual properties of electromagnetic waves on the interface between anisotropic metamaterials and conventional materials based on two dimensional periodic unloaded transmission lines. In a certain frequency region, the dispersion relation of the anisotropic metamaterials shows different behaviors separated by resonance frequency, while the shapes of wavevector surfaces are hyperbolic. The asymptotes of these hyperbolic surfaces are in the same directions as the wavevector surfaces in the resonance frequency. Therefore, with careful designing, the interface consisting of the anisotropic and the isotropic grids realizes the frequency selection of the microwave beams' direction. These phenomena can occur in a broad frequency range which is verified by the results of the simulations and experiments.