3D printed labyrinth multiresonant composite metastructure for broadband and strong microwave absorption

Microwave absorbers (MAs) with broadband and strong microwave absorption capacities are urgently required to meet the demands of complex electromagnetic (EM) environments. Herein, a novel labyrinth multiresonant metastructure composed of a polyether-ether-ketone/flaky carbonyl iron (PEEK/CIP) magnetic composite was proposed and fabricated via 3D printing technology. A complex multiresonant cavity design was introduced, and the resonant loss area was significantly improved. Both broadband and high-efficiency microwave absorption performances were achieved. The multilayer labyrinth multiresonant metastructure was designed with gradient impedance. The effects of structural parameters on the absorbing properties were investigated and optimized. Experiments and simulations demonstrated the effectiveness of the design strategy. The designed metastructure with a 10 mm thickness exhibited a -10 dB absorption bandwidth at a frequency of 3.78-40 GHz and an absorption bandwidth below -15 dB at 7.5-36.5 GHz. Moreover, an excellent wide-angle absorption performance was observed for different polarization states, including transverse electric (TE) and transverse magnetic (TM) modes. The combination of a complex multiresonant metastructure design and 3D printing fabrication provides a facile route to considerably extend the absorption bandwidth and strength of electromagnetic absorbers. This work is expected to provide a promising strategy for further enhancing microwave absorption performance, and the designed metastructure possesses great application potential in stealth and electromagnetic compatibility technologies.