To date, a number of interesting applications have been proposed and experimentally verified, such as the gradient index lens
, invisible cloak and sub-wavelength imaging [8-16].
Worth noting is that, thanks to the good transmission characteristics of the ZIML as shown in Figure 2, the distance d between the ZIML and the antenna will not to be a vital parameter affecting the gain enhancement ability of the detached ZIML, distinct from lenses based on Fabry-Perot resonance and gradient index lens
. One can predict that the gain of the antenna will not vary markedly with the change of the distance d.
De Leon, "Planar photonic crystal gradient index lens
, simulated with a finite difference time domain method," Phys.