Beam-forming of a Linear Antenna Array Using Reconfigurable Frequency Selective Surface

In this article, a 4-element linearly polarized antenna array incorporated with a reconfigurable frequency selective surface is proposed for the beam-forming applications. The antenna structure comprises $1 \times 4$ linearly polarized radiating elements, which is fed by a power dividing circuit and a coaxial fed connector. A reconfigurable FSS superstrate is mounted on the top of the antenna array to exploit the beam-forming capability of the proposed design. The reconfigurable FSS embodies $6 \times 6$ unit cells arrangement, each having dimension of $0.36 \lambda_{0} \times 0.36 \lambda_{0}$. The reconfigurable FSS superstrate layer is again splitted into two segments to obtain the desired beam-forming. The unit cell is made reconfigurable by employing PIN diodes in its vertical arms. The over all dimension of the antenna structure is $2.4 \lambda_{0} \times 2.4 \lambda_{0} \times 0.47 \lambda_{0}$. The proposed structure can generate three radiating beams, when the reconfigurable FSS is illuminated by the electromagnetic radiation generated by the antenna array. The reconfigurable FSS superstrate is biased accordingly to obtain all three radiation beams. The proposed design provide a maximum realized gain of 10.7dBi and beam tilt of ± 48° at the operating frequency of 5.5 GHz.