Resonance Phase And Geometric Phase Integrated Diffusion Metasurface For Broadband Scattering Control

In this paper, we demonstrate a binary diffusion metasurface with a broadband radar cross section (RCS) reduction performance based on the integration of resonance and geometric phase manipulation. The working principle of such a metasurface was investigated and the general criterion for the electromagnetic (EM) responses of the meta-atom was derived. In particular, we deployed a split metallic ellipse ring with a beam along the short axis and its counterpart with a 90 degrees inclined angle as the binary elements to construct the diffusion metasurface. EM responses of the proposed anisotropic meta-atom were explored in the framework of the equivalent circuit model. The inherent resonance phases of the meta-atom along its two symmetric axes were adjusted by changing its structural parameters. Then, we integrated the manipulation of the resonance phase and geometric phase together and designed a metasurface that can achieve broadband specular RCS reduction (more than -10 dB) from 4.3 GHz to 16.5 GHz. The RCS reduction performance of the metasurface is polarization-independent and shows a certain degree of stability under oblique incidence. For verification, a prototype with optimized structural parameters was fabricated and the measured results coincide well with the simulated results. Our work provides a convenient approach to realize a binary diffusion metasurface for the purpose of broadband RCS reduction.