  We show that, under appropriate oblique-incidence and polarization
conditions, the inherent opaqueness of a homogeneous, isotropic single-negative
slab may be perfectly compensated (in the ideal lossless case) by a homogenous,
anisotropic (uniaxial) double-positive slab, so that complete tunneling (with
total transmission and zero phase delay) occurs. We present an analytical and
numerical study aimed at deriving the basic design rules, elucidating the
underlying physical mechanisms, and exploring the role of the various involved
parameters.
