Guided mode propagations of grounded double-positive and double-negative metamaterial slabs with arbitrary material indexes

The guided dispersion characteristics of grounded slab waveguides whose permittivities and permeabilities are simultaneously negative are numerically investigated. Several different sets of materials with simultaneously negative permittivities and permeabilities are chosen in order to clarify the effects of the material constants on the guided dispersion characteristics. The dispersion characteristics of grounded double-negative slab waveguides are also compared with those of their double-positive counterparts. For the grounded double-negative metamaterial slab waveguides, superslow waves, backward waves, and mode suppressions are observed in certain circumstances, which cannot occur in conventional grounded dielectric slab waveguides. The present results may find applications in the areas of compact waveguiding structures using subwavelength guidance.