Multifunctional carbon fiber reinforced multilayered metastructure with broadband microwave absorption and effective mechanical resistance

Metastructure is an innovative structure form to improve broadband microwave absorption. However, without reliable mechanical properties, it is difficult to apply metastructure absorbers in realistic application scenarios. Herein, a multifunctional carbon fiber reinforced multilayered metastructure (CFRMM) is proposed and fabricated through the principles of multiscale design, gradient structure design, and metastructure design. The multiwall carbon nanotube (MWCNT)/carbonyl iron (CI)/epoxy resin(EP) nano lossy composite was integrated with the patterned resistive films (PRF) to form a gradient metastructure. Carbon fiber (CF) cloth was incorporated into the structure to enhance mechanical resistance. The CFRMM achieves −10 dB absorption bandwidth in frequency bands of 2-4.3 GHz and 7.02-18 GHz with maximum absorption of −17.4 dB. The −9 dB absorption bandwidth was covered in the full band 2-18 GHz. The CFRMM exhibits excellent mechanical properties with equivalent tensile strength and flexural strength of 75.77 and 408.43 MPa, respectively. The large tensile fracture strain of 24% reveals the good toughness of the metastructure. Broadband microwave absorption and effective load bearing integrated in one structure make the CFRMM more promising for applications in the future.