Absorption Characterization of Mn-Zr-Substituted La-Sr Hexaferrite Using Open-Circuit and Short-Circuit Approaches in 8.2–18 GHz Frequency Range

Abstract

The present study reports on the microwave absorption characterization of Mn2+-Zr4+ substituted lanthanum strontium ferrites, Sr0.85La0.15(MnZr) x Fe12−2x O19, where x = 0.0, 0.25, 0.50, 0.75 and 1.0 in the X- and Ku-band. The synthesized ferrites are characterized with regard to their electromagnetic properties such as complex permittivity \( \left( {\varepsilon^{\prime} - j\varepsilon^{\prime\prime}} \right) \) and complex permeability \( \left( {\mu^{\prime} - j\mu^{\prime\prime}} \right) \) using vector network analysis in the 8.2–18 GHz frequency range. Real and imaginary parts of permittivity decrease with the increase in Mn-Zr concentration due to a reduction in electron hopping conduction and eddy current losses, respectively. Microwave permeability spectra are also affected by the doping. The amplitude of magnetic loss peak increases with the increase in doping except for the x = 1.0 composition. Two commonly used approaches, open-circuit and short-circuit, have been employed for the absorption analysis. The difference in the results of these two techniques is justified on the basis of the reflection mechanism. The presented experimental findings underline the potential of the synthesized compositions with Mn-Zr concentrations x = 0.25, 0.5 and 0.75 in the suppression of electromagnetic reflections and radar signatures.