Wide-angle broadband metamaterial absorber with carbon black-carbonyl iron/polylactic acid composites fabricated by fused filament fabrication

A complex composite structure comprising periodic stepped square hole (SSH) units was designed to achieve wide-angle broadband microwave absorption. The SSH structure serves as a metamaterial absorber and was fabricated with carbon black, carbonyl iron powder, and polylactic acid composite by fused filament fabrication 3D printing. Only 50 wt% addition of loss material was required in the composite filament. Electromagnetic simulation was developed to investigate the effect of geometric parameters of the SSH structure on the microwave absorption performance, using the measured complex permittivity and permeability of the composite as the input. The geometric parameters were optimized for absorption reflection loss and bandwidth in the electromagnetic simulation. The simulation revealed that the optimal SSH structure with a height of 18 mm can achieve a –10 dB absorption bandwidth of 14.032 GHz in the frequency range of 2 – 18 GHz with a reflectivity peak (−45.74 dB) at 15.056 GHz. The optimal structure can sustain strong absorption and broadband performance with incident angles of 0 – 50° for both transverse electric polarization and transverse magnetic polarization. The simulation results were verified by reflectivity experiments on the SSH structure with optimal geometric parameters. This work provides an effective and promising approach for the practical application of strong broadband and wide-angle microwave absorption.