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 ( R L ) value and effective bandwidth of BGHSA can reach −51 dB and 15.4 GHz, respectively, exhibiting a distinct improvement ( R L 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 .