High permittivity and microwave absorption of porous graphitic carbons encapsulating Fe nanoparticles

Porous graphitic carbons encapsulating Fe nanoparticles (PGCFs) were fabricated by infiltrating activated carbon (AC) with an iron salt and thereafter heat-treating the products in vacuum, and the electromagnetic parameters of the PGCF were investigated over 2–18 GHz frequency. The results demonstrated that the formation of porous graphitic network encapsulating Fe nanoparticles endowed the composite a very high permittivity and dielectric loss at 2–18 GHz. Return loss (RL) for the PGCF-based absorbers were investigated based on the measured electromagnetic parameters. A typical dual-layer absorber exhibited an excellent microwave absorption with a 43 dB maximum absorption at 10 GHz and a nearly 7 GHz bandwidth for RL < −20 dB.