Quad-OAM-beam based on a coding transmissive metasurface

A coding transmissive metasurface is presented for −1 mode quad-OAM-beam generation in 9.2–9.4 GHz. The 3bit metasurface is designed based on Pancharatnam−Berry (PB) phase principle, which is fed by a linear horn antenna. To satisfy the phase requirement of quad-OAM-beam, the phase compensation is introduced in the design for transmitting spherical waves into plane waves and promoting the directionality of incidence. The prototype of the metasurface is fabricated and measured. The experimental results coincide with theoretical analysis. Additionally, the OAM efficiency and purity are calculated to reveal the perfect performance of the metasurface. The proposed method has potential application in multi-channel wireless communication systems.