Multilayer metamaterial absorbers inspired by perfectly matched layers

We derive periodic multilayer absorbers with effective uniaxial properties similar to perfectly matched layers (PML). This approximate representation of PML is based on the effective medium theory and we call it an effective medium PML (EM-PML). We compare the spatial reflection spectrum of the layered absorbers to that of a PML material and demonstrate that after neglecting gain and magnetic properties, the absorber remains functional. This opens a route to create electromagnetic absorbers for real and not only numerical applications and as an example we introduce a layered absorber for the wavelength of $8$~$\mu$m made of SiO$_2$ and NaCl. We also show that similar cylindrical core-shell nanostructures derived from flat multilayers also exhibit very good absorptive and reflective properties despite the different geometry

On the feasibility of using ferromagnetic materials for thin EM absorbers

In this paper the magnetization of a ferro-or ferri-magnetic material has been modeled with the Landau-Lifshitz-Gilbert (LLG) equation. We show that with the aid of a static magnetic bias field the material can be switched between a Lorentz-like material with a resonance frequency and a material exhibiting a magnetic conductivity. The reflection from a magnetic material backed by a perfect electrical conductor (PEC) is then analyzed. It is found that one can achieve low reflection (around -20 dB) for a quite large bandwidth (more than two decades)