Manipulating the directivity of antennas with metamaterial.

In this paper we use spatially variant metamaterial substrate to manipulate the directivity of antennas. We show theoretically that by embedding a dipole at different locations inside this substrate, the emitted rays can be directed to different orientations as required. As a result, spatial multiplexing can be realized by carefully selecting proper parameters of this substrate. It can also be observed that the electric field received in this antenna system is enhanced when it is used for reception. Simulations based on finite element method are used to validate our theoretical analysis, showing a controllable high directive property. In order to simplify the physical realization process, we propose the reduced parameters for practical design and also study it with numerical simulations.