Alternate lamination of high-permittivity dielectric materials for super thin wave absorber

In this paper, alternate lamination of highper-permittivity dielectric materials for super thin wave absorber is presented. The material had anisotropic relative permittivity values due to an array direction of the compounded graphite. Equivalent relative permittivities were calculated for various number of laminated layers. It was found that the equivalent relative permittivity was came close to arithmetic average values. Then the absorber was designed with the matching frequency of 2.0 GHz and a guaranteed absorption for the number of layers was studied. These results showed that more than 20 dB guaranteed absorption was achieved with six or more layers. Measured results of absorption characteristics agreed well with the simulated ones. The thickness of the fabricated absorber was very thin as 4.52 mm (d/λ=0.029).