Material realizations of extreme electromagnetic boundary conditions and metasurfaces

The paper discusses the correspondence between electromagnetic boundary conditions and interface conditions. In particular, the focus is on the synthetic approach where the interest is in finding material realizations for given boundary conditions. Material realizations are approximative but not unique because, especially if anisotropic and bianisotropic materials are allowed, there are different material classes with which any given boundary condition can be mimicked. As examples, the PEC, PMC, PEMC, and DB boundary conditions are discussed. By comparing the scattering characteristics, it is demonstrated how well certain extreme-parameter material realizations are able to simulate the boundary effect.