The electromagnetic characteristics and design of mechanically alloyed Fe–Co particles for electromagnetic-wave absorber

The electromagnetic and microwave-absorbing properties of mechanically alloyed Fe–Co particles were studied in this work. Their complex permeability and permittivity were measured over a frequency range of 2 – 4 GHz. It is found that the permeability of the Fe–Co particles–epoxy composites decreases with the Co content and is two to three times larger than that of spinel-type ferrite particles. The permittivity is tunable with varying the Co content. It results in the variation of the normalized input impedance and thus affects the absorbing properties. The numerical calculations indicate that the Fe–Co particles have potential application for thin quasi-microwave absorbers.