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.