Thin electromagnetic wave absorber containing Fe-Co alloy for quasi-microwave band

The need for effective thin-layer electromagnetic wave absorbers for operation in quasi-microwave band has fueled to much research on both the materials and design methods. Magnetic absorbing materials are one of the popular absorbers because they have lower work frequencies and are relatively thinner. Many attentions are paid to the improvements of the complex permeability and most of them are focus on the amorphous ferromagnetic materials. It was reported that the reflection loss maps are constructed as functions of d (thickness) and the material parameters such as the dielectric loss tangen tg ε, the magnetic loss tangen tg μ and the ratio of ε_r/μ_r. Thus, performances of the absorbers should be adjusted from the panoramic view. In our work, Fe-Co alloy with suitable electromagnetic characteristics was fabricated by mechanical alloying (MA) and was design for absorbers in the quasi-microwave band. Compared with amorphous alloy-ferrite-epoxy composite, it is thinner (about 2.5 mm thick) and easier to be prepared.