Low Profile Multi-Frequency Dipole Antenna Array Based on Planar Meta-Surfaces

In this paper, the radiation performance of a low profile multi-frequency dipole antenna array with a planar meta-surface is presented. The meta-surface consists of two closely located parallel grids of short dipoles and one grid of continuous wires in between. By tuning a dipole to the pass band of the superstrate and due to the magnetic dipole moments induced in the unit cells, a uniform illumination is achieved and therefore an enhancement of the directivity. Placing a second meta-surface under the dipole with the stop-band tuned to the working frequency, the back radiation is reduced. By combining low and high resonant-frequency unit cells and tuning dipoles to these frequencies, a double-frequency array is formed.