3D Printed Bioinspired Flexible Absorber: Toward High-Performance Electromagnetic Absorption at 75–110 GHz

Although various bioinspired devices designed to increase absorption and minimize reflection have been developed, there is no research focusing on wideband electromagnetic (EM) absorbers at 75-110 GHz, which is not conducive to the advancement of millimeter wave technology. Herein, inspired by the ultrablack butterfly scale nanostructure, an innovative flexible multistage honeycomb structure absorber (FMHSA) of carbonyl iron (CIP)/multiwalled carbon nanotubes (MWCNTs)/flexible photopolymer resin (FPR) composite is successfully prepared by digital light processing (DLP) 3D printing. FMHSA exhibits excellent EM wave absorption performance with full band absorption at 75-110 GHz under different bending states. At the bending angle of 150°, The effective absorption bandwidth of FMHSA is 35 GHz, covering the whole W-band, and its minimum reflection loss (RL) value is -37.04 dB. Moreover, integrated functionalities are revealed in the FMHSA, including superior flexibility, recoverability, and lightweight feature. Such findings may prove to be useful for the design of flexible absorbers with potential EM absorption and improved wearability.