A multi-layer square frustum metamaterial for ultra-broadband electromagnetic absorption based on carbonyl iron powder/carbon fiber composites

Ultra-broadband electromagnetic absorption has become a critical issue competing with the advanced broad-band electromagnetic detection systems. In this study, a novel metamaterial with periodic square frustums was designed and prepared, based on the carbonyl iron powder/carbon fiber/Resin composites. The electromagnetic parameters for each component of the meta-structure were determined by the addition content of carbonyl iron powder and carbon fiber, and the prepared metamaterial with optimized electromagnetic and structural parameters realized efficient EM absorption (>90%) in the frequency band of 3.5–40 GHz. Additionally, the electromagnetic absorption mechanism is believed to be attributed to the synergic result of the multiple electromagnetic loss modes and the improved impedance matching caused by the multi-scale structure. Therefore, the proposed metamaterial absorber realizes an ultra-broadband electromagnetic absorption with a coordinated optimization of electromagnetic parameters and meta-structure, which could be served as electromagnetic wave absorbing devices for broadband absorption applications.