Electromagnetic Wave Absorption of Periodic Cylindrical Structured Gypsum Composites Incorporate With Different Carbonaceous Materials

Abstract In order to improve the impedance matching condition and broaden the effective absorbing bandwidth, a series of cylindrical periodic structured gypsum composites with different kinds of carbonaceous materials as absorbents were fabricated by two-step moulding process. The influences of the mass fraction of helical carbon fiber (HCF), carbon nanotube (CNT), and graphene (GE) on the morphology, permittivity, resistivity, and electromagnetic (EM) wave absorbing properties of the proposed gypsum composites were investigated. The experimental results show that the composite with 2 wt.% HCF exhibits optimum EM wave absorption performance, its reflection loss is lower than -10 dB in 2-18 GHz and bandwidth thickness ratio coefficient reaches 0.8 GHz/mm. The EM wave absorption mechanisms were further explained by the simulation of EM field and power loss distribution. The dielectric loss of carbonaceous absorbents, the destructive interference, and the EM wave diffraction and multiple refractions caused by the periodic cylindrical arrays are the main EM wave attenuation mechanisms of the fabricated composites. This study could provide guidance for the design of broadband EM wave absorbing materials.