Hyperbolic Metamaterial Near-field Coupler

We propose a metamaterial waveguide having an annular region made up with a material having relative permittivity ε
_r
<; 0, ε
_φ
> 0 & ε
_z
> 0 and relative permeability μ
_r
<; 0, μ
_φ
> 0 & μ
_z
> 0. This medium has a radial negative index material with hyperbolic dispersion. Such a waveguide has lower no cut-off frequency for transverse electric and transverse magnetic modes. We can achieve a better impedance match between waveguide material to a free space. This can be used to enhance the out-coupled power from the near-field of small radiating sources. Numerical simulations show the seven orders of enhancement in the magnitude of the out-coupled power compared to the conventional isotropic waveguide. This waveguide can be used as a near-field coupler and imaging probes.