Microwave Absorption Properties of Double-Layer Absorbing Material Based on Carbonyl Iron and Graphene Composites

It is reported that developing microwave absorbers with impedance matching and high efficiency electromagnetic absorbing performance is still extremely challenging. Herein, we report the microwave absorption properties of single-layer and double-layer wave absorbent materials based on hydroxyl iron (CIP) and graphene nanosheets (GNSs) composites. The superior microwave absorption performance of the double-layer absorbers should be attributed to the greater impedance matching characteristic of the GNSs/CIP composite layer and the better dielectric loss ability of graphene layer as well as the increase of magnetic loss of hydroxyl iron (CIP). The results show that the double-layer absorbers, consisting of 35 vol% GNSs/CIP composite as matching layer and GNSs as absorption layer, with total thickness of 2 mm, exhibited a maximum reflection loss (RL) of −23.2 dB at 13.39 GHz, as well as an effective bandwidth below −10 dB of as wide as 5.54 GHz from 11.23 GHz to 16.67 GHz. These double layer structures based on carbonyl-iron (CIP) and graphene nanosheets (GNSs) composites could be helpful for designing new microwave absorbers with high absorption performance.