Enhanced Carbon Composites via Graphite Exfoliated on Paper for High-Performance Flexible Radar-Absorbing Materials

A novel strategy is proposed using pencil-exfoliated graphite on a paper substrate as a controllable resistive layer for a flexible Salisbury radar-absorbing material (RAM) architecture, governed by the modeling framework introduced. This approach leverages a natural, cost-effective, and environmentally friendly carbon source, avoiding toxic materials such as indium tin oxide (ITO) which is conventionally used for resistive layers. The method is simple, low-cost, and highly reproducible: conductive layers are created by drawing with standard graphite pencils on conventional paper, forming resistive sheets that can be integrated into Salisbury screen-type multilayer composites. By integrating graphite-on-paper layers with graphite-loaded silicone composite slabs on metallic substrates, the system achieves strong microwave reflectivity attenuation (–30 dB) across the C, X, and Ku bands, with a wide –10 dB bandwidth (BW) covering up to 83 % of the X-band. A theoretical model quantifies the effects of surface conductivity and dielectric permittivity, enabling precise tuning of both the absorption amplitude and frequency position. This allows the imaginary part of the permittivity to control attenuation intensity, while the real part determines the resonance frequency. The design offers flexibility, low environmental impact, and precise control of RAM performance.