A Shared Aperture 1 Bit Metasurface for Orbital Angular Momentum Multiplexing

In this letter, a shared aperture 1 bit metasurface for orbital angular momentum (OAM) multiplexing is studied. A phased array antenna fed by the phase shift network is embedded on the reflective aperture of the 1 bit metasurface. The proposed device can work on reflectarray mode and phased array mode from 7.1 to 7.5 GHz and 7 to 7.5 GHz, respectively. Correspondingly, OAM vortex beam with topological charge l = -1 and 1 can be generated. The transmission coefficient between the two working modes is below -30 dB, and the envelope correlation coefficient is quite close to 0, which reveals the excellent isolation and diversity performance. A prototype of the proposed device is fabricated and tested. The measured S-parameters and radiation patterns agree well with the simulation results.