Microwave absorption properties of double-layer absorbers based on Co0.2Ni0.4Zn0.4Fe2O4 ferrite and reduced graphene oxide composites

In this work, microwave absorption properties of single-layer and double-layer absorbers based on Co0.2Ni0.4Zn0.4Fe2O4 (CNZF) ferrite and reduced graphene oxide (rGO) composites were investigated. The CNZF was prepared by using a sol-gel autoignition method and the rGO was prepared by using a thermal reduction process. Paraffin composites were synthesized by using a facile hot-press method. Their electromagnetic parameters were measured by using coaxial line method. The double-layer absorbers, consisting of 30 wt% CNZF composite as matching layer and 30 wt% rGO composite as absorption layer, with total thickness of 2.5 mm, exhibited a maximum reflection loss (R-L) of -49.5 dB at 16.9 GHz, as well as an effective bandwidth below -10 dB of as wide as 6.0 GHz from 12.0 GHz to 18.0 GHz. The greater microwave absorption performance of the double-layer absorbers should be attributed to the better impedance matching characteristic of the CNZF layer and the greater dielectric loss ability of rGO layer. It is expected that our double-layer structures can be used as a reference to design new microwave absorbers with high absorption performances. (C) 2017 Elsevier B.V. All rights reserved.