Anisotropic metamaterial lens with a monopole feed for high-gain multi-beam radiation

In this paper, we present both the theory and design of an anisotropic metamaterial lens for antenna applications. This type of lens requires simple effective medium tensor parameters to achieve highly-directive radiated beams, which differs from more conventional isotropic zero-index metamaterial lenses. Making use of the less dispersive low permittivity and/or permeability band, the lens is promising for wideband applications. A specific metamaterial lens with permeability tensor parameter values that are less than unity was designed to tailor the radiation pattern of a monopole antenna. Full-wave simulations show that the lens achieves a high-gain quad-beam radiation pattern over a 20% bandwidth and also improves the return loss with a 50% -10dB bandwidth broadening. This device enables highly-directive emission and beam shaping with potential application in wireless communication systems.