Inverse Design of Perfectly-Matched Metamaterials

In this work, inverse design is used to develop inhomogeneous, anisotropic 2D metamaterials (electrical networks) that perform specified electromagnetic field transformations. The unique feature of the proposed metamaterials is that all their unit cells are impedance matched to each other, as well as to the surrounding space. These perfectly-matched metamaterials, unlike absorptive perfectly matched layers (PMLs), are lossless and passive. As an example, a 2D metamaterial that collimates the field of a point source excitation is reported.