Double-layer microwave absorbers based on materials with large magnetic and dielectric losses

The present paper deals with double-layer absorbers consisting of an absorbing (upper) layer with values of losses exceeding their optimum values for single-layer absorbers and a lossless (inner) layer under the normal incidence. The calculations were done at 10 GHz as a function of the material parameters of upper and inner layers in order to obtain a benchmark between optimum thicknesses--material properties--zero-reflection. It is shown that double-layer absorbers with only or dominantly magnetic losses, although have thicker absorbing layer, give thinner total absorber thickness than those with only or dominantly dielectric losses for the same values of the material parameters