Phase Method: A More Precise Beam Steering Model For Phase-Delay Metasurface based Risley Antenna

A phase method is proposed specially for metasurface based Risley antennas, with which analytical solutions are obtained for both beam direction prediction and deflector orientation retrieval. The new method is compared with traditional paraxial approximation method to reveal their connections and differences. A phase-delay metasurface is simulated to verify the theoretical model. The prediction error of the phase method is only 1.2° at a large steering angle of 56°, and an improvement of 5.0° is achieved comparing with paraxial method. It is demonstrated that phase method is a more precise and appropriate method when phase-delay metasurfaces are utilized as deflectors in Risley antennas.