Graphene oxide obtained by Hummer's method is used to synthesize reduced graphene oxide (RGO) using chemical and thermal treatment method. Flexible composites of RGO-Silicon carbide (SiC)-Low density polyethylene (LLDPE) in different wt.% ratios of fillers are characterized for complex permittivity and permeability in X-band. A metamaterial design of ring shaped with four stripe structure is designed on developed substrate as well as standard FR4 substrate and simulated using EM simulator, CST Microwave Studio. Simulated results showed shifting of resonant peak frequency from C-band frequency for FR4 substrate to X-band for developed substrates signifying a role of microwave constitutive properties of the dielectric spacer. The fabricated metamaterial structure on RGO-SiC-LLDPE composite of thickness 0.7 mm shows a S11 ∼ −25 dB at 10.7 GHz with maximum absorption of 96.7%. Thus, the developed meta-material design showing a potential application in microwave applications.

The present work investigate the microwave absorption properties of reduced graphene oxide (RGO)-Silicon carbide (SiC)-Linear low-density polyethylene (LLDPE) composites prepared in different concentration of fillers(10, 20, 30, 40 wt. %) with LLDPE matrix. Synthesis of RGO is confirmed from XRD analysis and SiC is used as received from supplier. Complex permittivity of the composites is measured using Nicolson Ross method showing an increasing trend with increasing filler concentrations with maximum and for 40 wt. % composite sample. Based on transmission line theory and using measured value of complex permittivity, conductor backed single and double layer absorber is designed by thickness optimization. The calculated reflection loss (RLc) value of ~-71 dB at 11.23 GHz is observed for 40 wt. % composite sample of 7 mm thickness with -10 dB absorption bandwidth of 1.48 GHz and -20 dB bandwidth of 0.64 GHz.