Oblique response of a split-ring-resonator-based left-handed metamaterial slab

We experimentally studied the transmission response of a one-dimensional rectangle-prism-shaped metamaterial slab for oblique incidence angles. The electrical size of the split-ring resonators was 1 order of magnitude smaller than the operation wavelength ~8.5 cm. We demonstrated that the left-handed transmission peak preserved up to an angle of incidence 45 degrees . The angular measurements were performed with respect to two lateral directions. The confirmed insensitivity of split-ring-resonator-based metamaterials to the angle of incidence makes them a good candidate for superlens applications.