Co-Evaluation of Reflection Loss and Surface Wave Attenuation for Magnetic Absorbing Material

Magnetic absorbing material (MAM) sheet was fabricated by calendaring carbonyl iron flakes into acrylonitrile-butadiene rubber. The complex permittivity and permeability of the sample were measured within 0.3-18 GHz. The calculated reflection loss (RL) and surface wave attenuation constants of the MAM are shown to be effectively manipulated by the layer thickness and electromagnetic (EM) parameters, respectively. It is found that the thickness of MAM should be suitable so as to realize good microwave wave absorption and surface wave attenuation performances in wide frequency range. In view of this goal, there also exist consistency requirements in EM parameters of MAM, i.e., a proper permittivity and high permeability. Furthermore, the measured RL and monostatic radar cross section reduction of a slab coated with the fabricated MAM sheet are in good agreement with the theoretical calculation. The present results provide a pathway to the development of MAM with high-efficiency absorption on both incidence EM waves and surface waves in the gigahertz range.