Analysis of High-Efficiency Cross-Polarized Converter at Oblique Incidence

In this letter, we present a theoretical study on a cross-polarized converter based on the reflective metasurface that is composed of slanted metallic cut-lines on a perfect electrical conductor backed substrate. According to the model, although reflection and refraction laws are still applicable in the interface between the air and the substrate, the metallic cut-lines break the original boundary condition. In order to describe the broken boundary condition, the generalized Fresnel's formulas are established based on the traditional Fresnel's formulas and the induced radiation of the metallic cut-lines. Finally, multiple reflections and refractions are resulted from the back metallic sheet in the interface of metallic cut-lines, and the total reflected wave is obtained by summing all waves except the incident wave in air. The theoretical results agree well with the simulated and measured results at the oblique incidence. When incidence angle varies from 0° to 25°, the metasurface can convert more than 99% incident wave into its cross-polarized reflected wave within a relative bandwidth of 22%.