A Warning About Metamaterials for Users of Frequency-Domain Numerical Simulators

It is shown that users of frequency-domain numerical simulators should be warned of the danger of using models with adjacent complementary media since such a configuration of materials can be a cause of a numerical instability which cannot be overcome by the presence of other lossy media or absorbing boundary conditions. The physical realizability at any frequency of models considering complementary media with sharp interfaces is then questioned by the contradiction between the deduced result and the one which holds true when the actual dielectric structure of metamaterials is considered.