High zenithal directivity from a dipole antenna on a photonic crystal

Abstract

A strip dipole on a (111)-oriented face centered cubic photonic crystal is found to have a copolarized directivity and radiative gain of 9.1 and 7.2±1.4, respectively, along the zenith and at a frequency in the first stop band of 18.0 GHz. Under the same conditions, the maximum copolarized directivity and radiative gain were 10.0 and 8.1±1.6, respectively, in the H-plane 5° down from the zenith. The zenithal results correspond to a 5.5-times greater radiation intensity than displayed by the same dipole in free space. From power balance measurements, only 10% of this enhancement is attributed to superior power transfer between the generator and antenna. The remainder is associated with constructive interference between the primary antenna radiation and radiation reflected from the crystal.