We report the results of a Snell's law experiment on a negative index of refraction material in free space from 12.6 to 13.2 GHz. Numerical simulations using Maxwell's equations solvers show good agreement with the experimental results, confirming the existence of negative index of refraction materials. The index of refraction is a function of frequency. At 12.6 GHz we measure and compute the real part of the index of refraction to be -1.05. The measurements and simulations of the electromagnetic field profiles were performed at distances of 14lambda and 28lambda from the sample; the fields were also computed at 100lambda.

This work investigates the gains realisable through the use of artificially structured materials, otherwise known as metamaterials, in the wide angle impedance matching (WAIM) of waveguide-fed phased-array antennas. The authors propose that the anisotropic properties of a metamaterial layer, when designed appropriately, can be employed to achieve impedance matching at a wide contiguous range of phased-array antenna transmission angles. Simulation and numerical results show that an optimised impedance match over a broad angular range can be readily achieved using a doubly uniaxial (magnetic and electric) anisotropic layer, an outcome not found accomplishable when an optimised isotropic dielectric layer is used. The authors propose the possibility of using metamaterials to achieve anisotropic WAIM layer configurations, and the authors show, using two simple uniaxial designs, that a metamaterial layer over the phased-array gives performance characteristics similar to its homogeneous anisotropic effective medium counterpart.