All-Metal Perfectly-Matched Metamaterials

This work introduces a method for designing all-metallic metamaterials that perform a prescribed field transfor-mation in a reflectionless manner. First, Perfectly-Matched Meta-materials (PMMs) are reviewed. PMMs consist of subwavelength unit cells that remain impedance-matched to each other and the surrounding medium under any excitation. It is shown that for a given field transformation, the constitutive parameters of a PMM's unit cells can be analytically calculated. Using homogenization, the PMM's constitutive parameters are then realized as elliptical metallic pins in a parallel-plate waveguide environment. An all-metal perfectly-matched collimator is designed to validate the proposed design technique.