Unusual Wave Phenomena in a Guiding/Radiating Clustered Dielectric Particle Metamaterial (CDP-MTM)

A novel clustered dielectric particle (CDP) metamaterial (MTM), constituted by the periodic repetition of a molecule-like cluster of dielectric atom-like particles, is explored. Both a closed-guiding and an open-radiating structure are presented, with conical-beam leaky-wave radiation in the second case. Three interesting and unusual effects are observed: negative refractive index (NRI) like (inhomogeneous) focusing, artificial homogeneity in a higher (than the dominant) order band and, most importantly, a true (i.e. homogeneous) negative refraction in a high-order band. It seems to be the first time that true negative refraction is reported for such a purely dielectric periodic structure. This effect has a significant potential for THz and optical MTM applications