Multimaterial 3D-printing barium titanate/carbonyl iron composites with bilayer-gradient honeycomb structure for adjustable broadband microwave absorption

An effective method to fabricate barium titanate (BTO)/carbonyl iron powder (CIP) composites with enhanced microwave absorption (MA) performance was prepared via multimaterial digital optical processing (DLP) 3D printing technique. The bilayer-gradient honeycomb structural absorber (BGHSA) with adjustable broadband can be obtained by leveraging of varying compositional and structural design (layered thickness ratios, and gradient structures). The optimal reflection loss (RL) value and effective bandwidth of BGHSA can reach −51 dB and 15.4 GHz, respectively, exhibiting a distinct improvement (RL increased by 32.4% and effective bandwidth by 42.9%) compared with the reference. The highly improved performances especially in the broadband absorption (15.4 GHz) were mainly attributed to the better impedance matching and waves multi-reflections. This work provides a promising strategy to fabricate functionally graded materials for potential application in the absorption of electromagnetic waves.