Experimental verification of apparent negative refraction in low-epsilon material in the microwave regime

摘要

We analyze the effect of negative refraction in dielectric photonic crystals with almost circular equifrequency surfaces experimentally and theoretically. We found experimental evidence for negative refraction in the microwave regime in low-epsilon material and suggest an improved interpretation. The apparent negative refraction originates from Bragg refraction and its combination with noncoupling bands.