Edge selectively oxidized graphene on carbonyl iron composites for microwave absorption and radar cross-section performance at X- and Ku-band

Abstract This study examined the microwave absorption properties of graphene oxide-carbonyl iron particle (GOCIP) composites and edge selectively oxidized graphene-CIP (EOGCIP) composites with a variation of graphene contents. Due to the addition of selectively oxidized graphene (EOG) to CIP, the resultant EOGCIP composites revealed excellent electromagnetic (EM) absorption properties. Significantly, the minimum reflection loss (RLmin) of −45.37 dB at 10 GHz with a bandwidth (BW@−10 dB) of 4.08 GHz with a thickness of 1.52 mm observed for EOG (5.0 wt%)CIP (72 wt%) composite. Moreover, the highest value of RLmin reached −69.27 dB at 15 GHz with BW@−10 dB beyond 6.47 GHz with a thickness of only 1.33 mm for EOG (0.5 wt%)CIP (72 wt%) composite. In addition, the EOGCIP composites revealed the most robust reduction in the radar cross-section value of approximately 35 dBsm against that of Al flat plate with the same physical area. The EM absorption properties of EOGCIP composites were enhanced compared to those of GOCIP and CIP composites. The increasing content of EOG tunes the dielectric properties of EOGCIP composites to attain proper impedance matching. Moreover, the unique structure of EOG can induce dipolar and interfacial polarization, which increases the dielectric loss in synchronization with magnetic loss resulting in enhanced EM absorption properties. This study suggests a new approach for controlling the EM absorption properties, essentially in the X-band region, which is worthwhile for radar absorption materials (RAM) applications.