Fractal Spheres as Molecules for Artificial Dielectric Metamaterials

The most common types of molecule geometries that have been considered in the past for artificial dielectric materials include simple dipoles and spheres. In this article we consider a fractal approach, combining aspects of both the dipole and sphere, resulting in an inclusion with a greater number of resonances as well as resonant behavior at lower frequencies than either their dipole or sphere counterparts of the same size. The results of this investigation suggest that the fractal sphere molecules allow an extension of the lower frequency band of artificial dielectric metamaterials and in some instances also provide multi-band response.