An RF analog of ENZ dielectric waveguide

Recently, there have been several studies on potential application of the ENZ (plasmonic) metamaterials in dielectric waveguides and similar structures at optical frequencies. It was shown possible to tunnel the flow of EM energy trough a slab (or a rod) made out of an ENZ material, transversal dimension of which can be arbitrarily smaller than a wavelength. In addition, one could think of a complementary structure that comprises a dielectric slab embedded within an ENZ metamaterial. Such a structure (a simple air slab with a subwavelength thickness, embedded within an anisotropic ENZ metamaterial) is analyzed in this paper. Numerical results revealed behavior similar to the behavior of an ordinary dielectric waveguide, but with considerably longer guiding wavelength (for a fixed width of a core slab). Numerical results were verified by the measurements on the RF scaled replica of an ENZ waveguide, operating in 4 GHz frequency band.