Constructing honeycomb structured metastructure absorber based on FeSiAl@CeO2 flakes for ultra-broadband microwave absorption

Due to the limitations of the Kramers-Kronig relationship, how to achieve ultra-wide effective absorption bandwidth remains a challenge for typical magnetic-dielectric absorbers. In the present work, we have explored the possibility of obtaining ultra-wide absorption bandwidth in FeSiAl composites with help of efficient electromagnetic (EM) simulation software-Computer Simulation Technology (CST). Flaky FeSiAl powders covered by CeO2 have been prepared, in which EM parameters can be tuned by filling ratio of FeSiAl/CeO2 in FeSiAl/CeO2-paraffin composites. The filling ratio has an effect on impedance matching and EM parameters by the arrangement of particles in the paraffin. The composite with 30 wt% flaky FeSiAl/CeO2 achieves an effective absorption bandwidth (EAB) of 6.48 GHz and the optimal microwave absorption efficiency of 1499.3 dB GHz/(wt%& sdot;m) at 1.9 mm. Integrated with a macroscale honeycomb structural design, the FeSiAl/CeO2 composites based metastructure exhibits broadband microwave absorption with an EAB of 14.224 GHz covering from 3.776 GHz to 18 GHz and reflection loss of-65.61 dB at 8.5 GHz. The excellent performances of the designed absorber are ascribed to multiple loss by integrating EM parameters of flaky FeSiAl/CeO2 and the geometry parameters of honeycomb metasrtucture. The present work makes flaky FeSiAl/CeO2 composites possible to achieve broadband microwave absorption.