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 degrees to 50 degrees. Furthermore, the manufacturing process of the absorber is simple, efficient, and inexpensive, which presents considerable potential for its widespread implementation in practical engineering applications.