<scp>Dual‐band polarization‐insensitive</scp> orbital angular momentum beam generation based on <scp>1‐bit polarization‐converting</scp> transmitting coding metasurface

This article presents a polarization-insensitive 1-bit coding metasurface (CM) for dual-band orbital angular momentum (OAM) beam generation. The metasurface unit cell is composed of two symmetric metal layers, which are separated by a dielectric substrate. Each metal layer consists of an outer square ring, a middle square ring, and an inner rhombus patch. By rotating the direction of the inner rhombus patch to 0° and 90°, two states with out-of-phase transmitting responses for both bands are achieved. An equivalent circuit is proposed to analyze the design. The OAM beams are then realized by properly distributing the two states on the metasurface aperture. A metasurface with 30 × 30 elements is designed, simulated, and experimentally demonstrated. The experimental results agree well…