Characterization of metamaterials made of stacked layers of dogbone conductor pairs

The metamaterials composed of planar arrays of tightly coupled dogbone-shaped conductors have recently attracted considerable interest owing to their potential of supporting backward wave propagation [l]-[3]. The detailed study of the plane wave interaction with a layer of dogbone pairs has been performed in [3], [4] along with the eigenwave analysis of an infinite stack of array layers. In particular, it has been found that such metamaterial may exhibit negative effective refractive index near the transmission resonances. In this paper we present the results of the theoretical and experimental studies of the stacked arrays of the dogbone shaped conductor pairs. The obtained results demonstrate for the first time that in the stacks of finite thickness, strong coupling between the closely spaced arrays causes the additional transmittance resonances. The comprehensive interpretation of the observed transmission resonances and underlying physical mechanisms is proposed on the basis of the simulated current distributions in the dogbone conductors.