  We investigate the emission of electromagnetic waves from biaxial
subwavelength metamaterials. For tunable anisotropic structures that exhibit a
vanishing dielectric response along a given axis, we find remarkable variation
in the launch angles of energy associated with the emission of leaky wave
radiation. We write closed form expressions for the energy transport velocity
and corresponding radiation angle $\phi$, defining the cone of radiation
emission, both as a functions of frequency, and material and geometrical
parameters. Full wave simulations exemplify the broad range of directivity that
can be achieved in these structures.
