Double-layer structural design of dielectric ordered mesoporous carbon/paraffin composites for microwave absorption

Microwave absorbing materials composed of ordered mesoporous carbon (OMC) as absorbent and paraffin as matrix were prepared, and their electromagnetic and microwave absorbing properties could be tuned by changing the weight fraction of OMC at 2-18 GHz. The minimum reflection loss (RL) value reached -9.3 dB at 8.0 GHz and the absorption range with RL lower than -5 dB was obtained at 5.8-14.4 GHz for a single-layer absorber filled with 1.98 wt.% OMC at 3.0 mm. If a double-layer structure was adopted, the total thickness of the absorber could be reduced below 2.0 mm and the effective absorption range (RL <-10 dB) could be obtained at 8.9-14.3 GHz with a minimal RL of -28.5 dB at 10.6 GHz. This work demonstrated that dielectric composites could be used as excellent absorbers by adopting reasonable multilayer structures.