A Reflectarray for Generating Wideband Orbital Angular Momentum Vortex Wave

In this paper, a wideband vortex beam reflectarray for generating l=±2 modes orbital angular momentum (OAM) waves is proposed. The unit cell of the reflectarray consists of double cross loops and four square patches. This multi-resonance structure provides 4300 smooth phase curves. The required phase shift in the reflective metasurface is realized by adjusting the length of double cross loops. The simulated results indicate the peak gain of 19.1 dBi at 12.5 GHz with 27.5% 1-dB gain bandwidth.