Planar Via-Free Medium with 2-D Negative Refractive Index Properties

A novel planar medium with 2-D negative refractive indices is proposed. The medium consists of a two-dimensional array of Jerusalem cross like metallic pattern on a dielectric substrate without using vertical vias for easy fabrication in high frequency applications above millimeter-wave frequencies. Dispersion characteristics are theoretically analyzed based on an equivalent circuit, and it is shown that the structure fundamentally exhibits 2-D negative refractive indices with the composite right/left-handed mode in one direction and the photonic-crystal oriented space harmonic mode in the perpendicular direction. In addition, a via-free medium operating at the Ka-band is designed by full-wave simulations. Dispersion characteristics are obtained for the implemented medium and it is confirmed by full-wave simulation that the implemented medium exhibits 2-D negative refractive indices.