Backward waves in uniaxial materials and subwavelength waveguides formed by resonant scatterers

Abstract

Three-dimensional electromagnetic crystals formed by resonant uniaxial scatterers are considered. Dispersion equation is obtained with help of dynamic interaction constant method. Comparison with properties of uniaxial media is made. Existence of negative refraction and backward waves with respect to interface is demonstrated. An eigenmode problem for waveguide which is periodically loaded by uniaxial structures is considered. It is transformed to the lattice problem with help ofimage theory. The backward wave effect is observed for both magnetic and electric dipolar scatterers. In this paper the electromagnetic properties of regular three-dimensional structures formed by resonant uniaxial magnetic (split ring resonators) and electric (short loaded wires) scatterers are studied. An analytical dynamic interaction constant method based on local field approach and dipole approximation is presented. It is similar to the methods used in (l,2). The effects of negative refraction and backward waves with respect to interface, predicted in (3), are demonstrated.