A High-Efficiency and Broadband Folded Reflectarray Based on an Anisotropic Metasurface for Generating Orbital Angular Momentum Vortex Beams

In this paper, a low-profile folded reflectarray (FRA) assembled by an anisotropic metasurface is proposed to generate high-efficiency and broadband orbital angular momentum (OAM) vortex waves in the Ka band. order suppress mutual coupling increase polarization conversion efficiency, dual-polarization phase matching method (DPPMM) for helical wavefront construction developed achieve minimum compensation error orthogonal direction. A compact subwavelength meta-atom with || |-shaped structure designed flexible manipulation high-resolution x y-polarization incident waves. After optimization design, nearly 100% cross-polarization efficiency can be achieved at working frequency of 12 GHz. To validate design method, OAM FRA 24×24 meta-atoms fabricated measured. The measurement results show that aperture carried mode l = 1 significantly improved reaches 20.2%. Moreover, bandwidth 3-dB gain reach 22.5% 25%, respectively.