Novel planar negative refractive index metamaterials

Planar periodic arrays of metallic elements printed on grounded dielectric substrates are presented to exhibit first-order left-handed modes with an equivalent negative refractive index (NRI). The proposed structures dispense with the need for grounding vias and ease the implementation of completely planar (also called uniplanar) NRI metamaterials at higher frequencies. Full wave dispersion curves are presented. A verification of the left-handedness is presented by means of full wave simulation of finite uniplanar arrays using commercial software (HFSS). The cell dimensions are a small fraction of the wavelength (about λ/24) so that the structures can be considered as a homogeneous effective medium. The structures are simple, readily scalable to higher frequencies and compatible with low-cost fabrication techniques.