Negative refraction in a dielectric rod superlattice

We studied microwave transmission, reflection, and refraction from a planar superlattice consisting of dielectric rods with two different diameters. This structural modulation results in a narrow transmission band inside the first photonic stopband. Band structure simulations indicate that this transmission band exhibits a negative phase velocity. We performed electric field mapping inside our superlattice, which revealed a negative phase velocity. In another setup we built a prism and studied transmission through it. We observed negative refraction, as expected for material with a negative refraction index.