Full Wave Analysis of Composite Absorbing Layers

A two layer absorbing structure is investigated. It is built from small lossy dielectric spheres. Their density is adjusted such that the wave impedance increases linearly. The different layers are further loaded with metallic helices. These give high losses at resonance. A scattering approach based on the dipole-polarizabilities of the helices and the Mie-solution of the dielectric spheres is compared to the Maxwell-Garnett theory. It is shown that due to strong mutual coupling some differences arise. These are assessed in view of design considerations for such materials