Study of Radar Absorbing Characteristics of Polymer Composites with Ferrite Fillers

The search for effective radio-absorbing materials is an urgent task in solving the problems of electromagnetic compatibility, electromagnetic pollution, as well as stealth and stealth technologies. We present the results of studying the electrophysical and radio-absorbing characteristics of ferrite-polymer composites depending on the structure and magnetic properties of the ferrite filler, as well as the dielectric properties of the polymer matrix. The radio absorbing characteristics of composites F-42/Mn-Zn-ferrite, F-42/Ni-Zn-ferrite, F-42/yttrium iron garnet, F-42/BaFe12O19, F2M/LiMnZn-spinel, PS525/Mn-Zn -ferrite, PVA/Mn-Zn ferrite, and PVA/Ni-Zn ferrite have been studied. Experimental data on the reflection coefficient, determined on a metal plate in a frequency range of 0.1 – 7 GHz showed that spinel ferrites and composites containing them are effective radio absorbing materials. Analysis of the spectra of complex dielectric and magnetic permeability revealed that composites with spinel ferrites and yttrium iron garnet are characterized by a dispersion of the magnetic permeability, which arises as a result of resonance processes of the motion of domain boundaries and natural ferromagnetic resonance. Moreover, the electrical properties of ferrites can affect the high-frequency spectra of the permittivity and permeability. It is shown that the use of electroactive polymers as matrices makes it possible to increase dielectric losses in the high-frequency range and obtain the maximum attenuation of electromagnetic radiation within 25 – 40 dB with a width of 10 dB up to 2.5 GHz in 2 – 7 GHz range. The results obtained can be used in further study of the functional properties of radio-absorbing materials in the high-frequency range.