Ultra‐Broadband and Wide‐Angle Metamaterial Absorber with Carbon Black/Carbonyl Iron Composites Fabricated by Direct‐Ink‐Write 3D Printing

This study proposes the fabrication of an asymmetric woodpile metamaterial absorber using direct‐ink‐writing 3D printing technology. The prepared inks are compounded using two loss fillers: carbon black and carbonyl iron powder. The synergistic effect enhances the electromagnetic loss performance and the synergistic mechanism is analyzed. The designed asymmetric woodpile absorber has a wider bandwidth than a simple tetragonal woodpile, and the advantage presented by the asymmetric woodpile arrangement overcomes the local impedance mismatch. A simulation is then performed, which demonstrates that the designed asymmetric woodpile metamaterial with a thickness of 8.6 mm can achieve a −10 dB absorbing bandwidth in the frequency range of 3.9–18 GHz, and the maximum reflection loss reaches up to −39 dB. Additionally, the absorber exhibits excellent angular performance and the absorption bandwidth of the transverse electric polarization or transverse magnetic polarization waves can reach more than 10 GHz with incident angles from 0° to 50°. Furthermore, the manufacturing process of the absorber is simple, efficient, and inexpensive, which presents considerable potential for its widespread implementation in practical engineering applications.