Radiation from a short vertical dipole in a disk-type PBG material

A photonic crystal has in general directional band-gaps where the propagation of electromagnetic waves is inhibited. An antenna in a photonic crystal cannot radiate energy into the directions of space in the band-gap regime. Consequently, the radiation into the other directions can be greatly enhanced and the gain can be very high. Several antenna applications have been proposed in the recent years that explore this concept. In this paper, we calculate the far field from a short electric dipole in a disk-type medium. We discuss the physics of the radiation process in the periodic structure. The motivation for the study is to enlighten the physics of the radiation mechanism in metallic crystals, and assess the effect of the metallic crystal on the radiation characteristic for long wavelengths.