For my undergraduate senior project, I designed a half maxwell fish-eye lens antenna by using inhomogeneous metamaterial. In this project, I validated the concept in simulation, designed a IML (impedance matching layer) to improve performance, then built the antenna and measured it in anechoic chamber. It shows how metamaterials can manipulate electromagnetic waves spatially.
Hui Feng Ma, Ben Geng Cai, Teng Xiang Zhang, Yan Yang, Wei Xiang Jiang and Tie Jun Cui
Three-Dimensional Gradient-Index Materials and Their Applications in Microwave Lens Antennas, IEEE Transactions on Antennas & Propagation, Volume 61, Issue 5, May 2013