Design of the Broadband Metamaterial Absorber Based on Dispersed Carbon Fibers in Oblique Incidence

In this paper, a broadband double-layer metamaterial absorber (MMA) based on carbon fibers (CFs) is proposed, which consists of three basic elements. Firstly, the reflectivity of CFs double-layer MMA in normal incidence is analyzed, and compared to the copper double-layer MMA with same size, the simulated results show that it obtains better absorbing effect. With the increase of incident angle, the multi-frequency resonance is activated, leading to larger effective bandwidth. Moreover, when incident angle is between 55 and 70 degrees, the continuous absorption band above 85% can totally cover X and Ku microwave band. Meanwhile, when the EM frequency is at 6-7.5GHz, the change of incident angle hardly affects the absorbing performances of CFs double-layer MMA. A specimen of the CFs double-layer MMA was fabricated by the vacuum bag molding process to verify its effectiveness and the measured results fitted well with the simulated results. In order to discuss the mechanism of EM absorption, the distribution of E-fields and power loss density were monitored. The results indicate that incident angle effects the distribution of E-fields and the way of absorption to change the absorbing performances. The proposed MMA has potential application prospects in the structural and functional integration design of CFs.