Radar absorbing and shielding characteristics in ferrite-polymer composites Mn-Zn ferrite/P (TFE-VDF)

Abstract

The article discusses the electromagnetic absorbing and shieldingproperties of ferrite-polymer composites of the composition Mn-Znferrite/fluoroplast-42, obtained by pressing a mixture of powders withheating. The measurement of the complex magnetic and dielectricpermittivity spectra, as well as the reflection coefficient spectra wascarried out in the frequency range 0.1-7 GHz. Using the obtained spectra,a comprehensive analysis of the absorbing characteristics of the compositeswas carried out, and the factors responsible for the absorption weredetermined. Fitting of the composites magnetic permeability spectra showthat the process of natural ferromagnetic resonance prevails over theresonance of domain walls, and a decrease in the concentration of ferriteinclusions leads to a significant shift in the frequency of naturalferromagnetic resonance to high frequencies. It was found that forcomposites with a thickness of 5-10 mm, compositions with a mass fractionof ferrite ≤0.4 show radio-absorbing properties, while compositions with afraction of ≥0.6 show shielding properties. Keywords: polymer composite, magnetic properties, radio absorption, feromagnetic resonance, polyvinylidene fluoride, manganese-zinc ferrite.\