Thin metamaterial Luneburg lens for surface waves

By suitably patterning a metasurface, the phase velocity of surface waves may be manipulated. Here, a low-loss, thin (1/14th of the free-space wavelength), omnidirectional Luneburg lens, based upon a Sievenpiper "mushroom" array [Sievenpiper et al., IEEE Trans. Microwave Theory Tech. 47, 2059 (1999) (http://dx.doi.org/10.1109/22.798001)]. is fabricated and characterized at microwave frequencies. Surface waves excited using a near-field point source on the perimeter of the lens, exit the opposite side of the lens as planar wave fronts. The electric field of the surface wave is mapped out experimentally and compared to numerical simulations.