The Synergistic Effect of Nitrogen-Doped Carbonized Kapok Fiber to Amorphous/Nanocrystalline Fe85SiAl6Cr8 for Broad Effective Absorption Bandwidth Microwave Absorber

With the increasing quantity of intelligent and portable electric devices, a broad effective absorption bandwidth (EAB) microwave absorber (MWA) is required for shielding microwave (MW) interference. An MWA with a magnetic-dielectric synergistic effect is necessary for broadening the EAB of it. The amorphous/nanocrystalline Fe 85 SiAl 6 Cr 8 (FSAC) is a nanolevel high magnetic loss MWA, and the introduction of medium dielectric loss MWA nitrogen-doped carbonized kapok fiber (NCKF) with an appropriate proportion improved the impedance match and damping ability of the composite and broadened the EAB. The results revealed that the minimum reflection loss (RL min ) of FSAC/NCKF was −22.5 dB at 16.8 GHz with a thickness of 1.20 mm, and the EAB was 4.91 GHz with a thickness of 1.30 mm. Besides, the EAB moved to the low-frequency range when the thickness increased. Meanwhile, the RL of the simulation and the experiment were remarkably similar. The strategy offers an approach for developing a MWA with broad EAB.