Electromagnetic Wave Absorption Performances of Metal Alloy/Spinel Ferrite/Polymer Composites

High-frequency electromagnetic wave (EM-wave) absorbing characteristics of metal alloy/spinel ferrite/polymer composite materials with various metal alloy particle contents were evaluated from measurements of complex permeability
$\mu=\mu^{\prime}-{\rm j}\mu^{\prime\prime}$
by the coaxial reflection method in the frequency interval from 1 MHz to 3 GHz. We varied the volume content of metal alloy in composites from 0 to 60 vol% at fixed 40 vol% content of polymer matrix. The increasing metal alloy content in composites resulted in a smaller matching thickness and larger matching frequency than that of spinel ferrite/polymer composite. The return loss calculations showed that prepared composites are good EM-wave absorbers in the quasi-microwave band (100 MHz–3 GHz) and thus suitable for electromagnetic interference noise suppression in electronic communication systems.