Structural design of a coding absorber filled with graphene/carbonyl iron powder composite microspheres

Abstract

Electromagnetic stealth technology played a crucial role in national defense. Encoded metasurfaces and metamaterials had been widely applied in the fields of radar and electromagnetic stealth. In this study, a filled absorber based on scattering enhancement was investigated. Graphene/iron carbonyl composite microspheres were filled into a 3D-printed shell as the absorbing material. The scattering characteristics were controlled by adjusting the absorption gradient, reflection amplitude, and reflection phase of each basic unit. The filled absorber allowed for control of the reflection amplitude through phase modulation, achieving a combined effect of electromagnetic loss and scattering characteristics, resulting in the reduction of radar cross-section. The study also examined the effect of the area fraction of the two cells on the performance of the reduced RCS. The best performance is achieved when the area fraction of cell 0 is 0.5. Simulation results show that the filled absorber effectively reduces the radar cross section in the frequency range of 9.92 GHz to 18 GHz with a minimum value of −34.58 dB. Compared with the simulation results, the measured data show that it effectively reduces the radar cross section in the frequency range of 8.32 GHz to 16.03 GHz with a minimum value of −25.08 dB. This study provided a novel approach for designing high-performance absorbers based on scattering enhancement, which held significant potential in the fields of electromagnetic wave absorption and stealth technology.