Scanning-Angle Expansion of Phased Array Antenna Based on Transmissive Metasurface

A "four-leaf clover" shaped transmissive phase-controlling metasurface structure is proposed, which can regulate the phase of transmitted electromagnetic waves from 0° to 360° at 10 GHz while maintaining a transmission amplitude better than 0.8. This paper derives the equivalent circuit structure of this structure based on the surface-induced electric field and current distribution. A comparative analysis is conducted between the equivalent circuit method and the results obtained from three-dimensional electromagnetic simulation software. Furthermore, the generalized Snell′s law is employed to verify the metasurface′s capability in controlling the transmitted phase. Based on this law and the angular deflection phenomenon of transmitted electromagnetic waves, a method is proposed to enhance the beam scanning range of a phased array antenna. Finally, a 4×4 phased array prototype is designed, and the metasurface is integrated in a loading manner to achieve a beam scanning range of ±75° in the xoz plane and ±71° in the yoz plane.