Flexible Metamaterial Absorbers Based on Fe₃O₄-Doped Laser-Induced Graphene with Tunable Absorption Bands

Due to widespread applications of electromagnetic waves (EMWs) in radar and communication systems, there is an urgent need for developing EMW absorbers capable of working efficiently at multiple frequency points. In this work, flexible metamaterial absorbers (MAs) based on Fe₃O₄-doped laser-induced graphene (LIG/Fe₃O₄) are large-scale fabricated with the absorption bands tunable by regulating ferric chloride concentration and laser path of the LIG/Fe₃O₄ meta-surface. The as-prepared triple band LIG/Fe₃O₄ MA demonstrates superior S₁₁ values of -15.0 dB (9.0 GHz), -40.7 dB (12.2 GHz), and -23.2 dB (16.8 GHz), respectively, attributed to subwavelength units of LIG/Fe₃O₄, synergistically combining dielectric and magnetic loss. Moreover, LIG/Fe₃O₄ MAs exhibit commendable corrosion resistance and radar cross-section reduction characteristics, showing promising potential in electromagnetic protection fields.