▎ 摘　　要

Impedance matching and enhanced microwave attenuation have been proven to be effective strategies for improving reflection loss (RL) and widening of the effective absorption (RL <-10 dB) bandwidth of absorbers. Herein, we present novel multimaterial bilayer absorbing composites consisting of graphene/Li0.35Zn0.3Fe2.35O4/polymethyl methacrylate (GFP) as the matching layer and graphene/carbonyl iron powder/polymethyl methacrylate (GIP) as the absorption layer via our multimaterial digital light processing (DLP) 3D printing method. Through numerical calculations, microwave absorption performance of the bilayer absorber is found to be greatly enhanced as compared to its constituents. In addition, the effective absorption bandwidth can be also tuned via differing ratios of the GFP/GIP layer thicknesses under a fixed total thickness. A GFP/GIP bilayer of 1.4/2.6 mm was optimized based on RL. Experimented maximum RL peaks of -46.1 and -17.9 dB were revealed at frequencies of 4.7 and 15.7 GHz, respectively, with effective absorption bandwidth up to 3.5 GHz (4.15-5.35, 14.7-17.0 GHz). The microwave absorption performance of the GFP thorn GIP bilayer absorber is significantly improved by proper impedance matching and multiple-type loss forms. Overall this work provides a new strategy to manufacture efficient, broadband, and adjustable microwave absorbers by 3D printing. (C) 2020 Elsevier Ltd. All rights reserved.