Promoting the microwave absorption characteristics in the X band using core-shell structures of Cu metal particles/PPy and hexaferrite/PPy

Abstract

Abstract Multifunctional microwave absorber materials exhibit promising characteristics, since they combine the diverse properties of their components. More precisely, by precipitating polypyrrole (PPy) on a mixture soundly chosen of copper and two different hexaferrites, the dielectric, plasmonic and ferrimagnetic properties can be combined in a beneficial way to tune the absorption characteristics. Beyond the multifunctionality of this absorber, several properties may emerge from intrinsic factors, such as: morphology and/or interfacial polarization linked to the core-shell structure. The absorber has been structurally characterized by XRD, FTIR and UV–vis spectroscopy. The magnetic properties and the microwave reflection loss (RL) have been investigated using a VSM and VNA, respectively. The results indicate that the presence of copper metal boosts the reflection loss of the absorber, widen the bandwidth and shifts the matching frequency towards higher values. The core-shell structure formed by coating PPy on the copper and hexaferrites mixture enhances the RL and lower both absorber thickness and loading percentage required to achieve comparable absorption performance to that of an absorber prepared by simple mixture of the components. The current optimized absorber exhibits a minimum RL of −22 dB at a matching frequency around 10.8 GHz and a thickness of 2 mm. The bandwidth under −10 dB covers all the X band starting from 9.6 GHz and continues into the Ku band.