A Two-Dimensional Beam-Steering Partially Reflective Surface (PRS) Antenna Using a Reconfigurable FSS Structure

Abstract

A two-dimensional (2-D) (azimuth and elevation) beam-steering partially reflective surface (PRS) antenna is proposed in this letter. It consists of a probe-fed square patch antenna acting as the radiator and a reconfigurable PRS structure serving as the beam-steering superstrate. The reconfigurable superstrate employs 6 × 6 reconfigurable unit cells and is equally divided into four sections. By controlling the states of the PIN diodes inserted in each unit cell, four sections have diverse biasing combinations, which can generate ten different radiation models. As a result, the proposed antenna can radiate a boresight beam or a ±22° tilted beam in the plane of ϕ = 0°, 45°, 90°, and 135°. To verify the design feasibility, an antenna prototype operating at 5.5 GHz is fabricated and measured. The simulated and measured results for the input reflection coefficients and radiation patterns are in good agreement. The measured realized gains are around 10 dBi for all states. Moreover, the gain variation from the broadside direction to the tilted direction (22°) is less than 0.8 dBi. Compared with some reported 2-D beam-steering PRS antennas, the proposed design can achieve a much wider beam-tilting range with a more stable radiation performance and fewer tunable diodes.