Abstract: It is a challenge to design an absorber which can simultaneously satisfy comprehensive demands of broad absorption band, wide incident angle range, and low-profile. In this work, we designed a metamaterial absorber (MMA) based on the antenna reciprocity theory to achieve the above goals. Firstly, a three-dimensional (3D) propeller-like structure with reference to a typical magneto-electric dipole (MED) antenna was proposed and analyzed by the characteristic mode (CM) theory to realize near-omnidirectional radiation. Then, the radiation-absorption conversion was realized by introducing lossy materials into this structure, and the absorption performance was further improved by optimizing the dispersion feature of the lossy materials. Finally, the propeller-like metamaterial absorber with a thickness of 0.113λ_L was manufactured efficiently and integrally through 3D printing technology. Simulation results showed that the proposed absorber can achieve broadband absorption with the efficiency more than 90% in the frequency band of 3.4-10 GHz. It also has excellent wide-angle absorption capacity, with Transverse Electric (TE) polarization of 0° to 50° and Transverse Magnetic (TM) polarization of 0° to 80°. With the increase of incident angle, the upper limit of absorption bandwidth can be gradually extended to 18 GHz. Moreover, the effectiveness in the range of 0° to 60° incident angle is verified by measuring the reflectivity of the 3D printed absorber.

Key words: 3D printing, Metamaterial, Microwave absorption, Antenna reciprocity