Design of multi-beam antennas based on Epsilon-Near-Zero metamaterials

A novel Epsilon-Near-Zero (ENZ) metamaterial-assisted multi-beam antenna is presented. Simulation results show that the cylindrical wave emitted from a line source can be transformed to narrow beams through an ENZ metamaterial layer with a circular inner contour and a polygonal outer contour. The number of beams of the antenna can be controlled by adjusting the number of sidelines and the shape of the polygonal ENZ metamaterial layer. The 3 dB bandwidth of the designed multi-beam antenna is 218 MHz. Due to ENZ metamaterials may be found naturally at infrared and optical frequency band, comparing with optical transformation approach, by which space variant media is applied to the design of high-performance antenna, the ENZ metamaterial-assisted approach is more preferable.