Multi-Functional Antennas Based on Meta-Surfaces

The design of a multi-functional antenna based on meta-surfaces is investigated. The proposed structure consists of a wideband dipole antenna located between two meta-surfaces working in different frequency bands. The result is an antenna with enhanced gain that radiates in a different half-space at each frequency band. A prototype composed of an elliptical dipole and two meta-surfaces formed by grids of cut and continuous wires demonstrates that the proposed antenna discriminates the radiation in different half-spaces, as well as increases the gain of a nearly omnidirectional dipole to values 8.9 dBi and 7.7 dBi for the top and bottom half-spaces, respectively. Moreover, the antenna remains planar with total thickness of 0.13λ at the lowest resonant frequency.