  We study metamaterials with an anisotropic effective permittivity tensor in
which one component is near zero. We find that such an anisotropic metamaterial
can be used to control wave propagation and construct almost perfect bending
waveguides with a high transmission rate (>95%). This interesting effect
originates in the power flow redistribution by the surface waves on the input
and output interfaces, which smoothly matches with the propagating modes inside
the metamaterial waveguide. We also find that waves in such anisotropic
epsilon-near-zero materials can be reflected by small-sized perfect magnetic
conductor defects. Numerical calculations have been performed to confirm the
above effects.
