Subwavelength focusing and resolution with hyperbolic transmission line metamaterial

We show the potential of using two dimensional hyperbolic metamaterials (HMs) made of microstrip transmission line (TL) grids loaded by lumped components for achieving subwavelength focusing and resolution at microwave frequencies. The designed planar HM exhibits a very flat wavevector-dispersion diagram over a wide frequency range, signature of the so-called canalization regime. The canalization regime allows us to transfer the field profile of a single point source at the interface through the HM, with full width half maximum of λ_g / 69, where λ_g is the guided wavelength in the isotropic TL grid at 200 MHz. We also report the ability to resolve two point sources with subwavelength distance of λ_g / 15.