Wide-angle microwave absorption properties of multilayer metamaterial fabricated by 3D printing

Conventional absorbing materials have always been challenged by the technical difficulty of effectively absorbing (<−10 dB) oblique incident electromagnetic waves in a wide frequency domain. In this study, 3D printing technology was used to combine metamaterials with multilevel gradient absorbing materials. To provide good impedance matching, the multilayer structure absorber was designed with a gradient index of characteristic impedance by adjusting the geometric parameters of the unit cell and the distribution of spherical carbonyl iron powder enhanced polyether ether ketone (CI-PEEK). The results show that the prepared 3D-printed multilayer metamaterial effectively absorbed electromagnetic waves across a wide range of incident angles (0°–50°) in the bandwidth of 8–18 GHz. Compared with the current technology on wave absorbing materials, this work showed a considerable improvement in the effective absorption of wide-angle electromagnetic waves and the integrated manufacturing of absorption composite materials with the desired characteristics. Thus, this study has important research significance and engineering value.