Dipole Antenna Directivity Modification by All-Dielectric Quasiperiodic Structure

Inverse space design method enables the engineering of all-dielectric quasiperiodic photonic structures with the desired electromagnetic properties. We demonstrate in the article that a quasiperiodic structure with special-defined reciprocal space can be engineered to modify the radiation pattern of a dipole embedded inside such a structure. The numerical analysis of the properties of the structure has proven the high directivity of the dipole antenna inside the structure. The numerical calculations show the possibility of achieving the effective enhanced emission up to 10 dB in a narrow frequency range in desired direction and at a dielectric contrast of two materials of 1.55. The emission enhancement effect is observed at the frequencies of the edge of the bandgap, where the local density of states increases, which is also illustrated by numerical results. The antenna gain is also strongly dependent on the size of the quasiperiodic structure. We find the most optimal sample size to maximize gain.