Shape Memory Alloy-Based Fluidically Reconfigurable Metasurfaced Beam Steering Antenna

Abstract

A low-cost actuator-based fluidically programmable metasurface (FPMS) antenna is proposed to solve the slow tuning speed problem of the manually fluidic based reconfigurable antennas. The FPMS-based antenna is probe-fed and comprises a $4\times4$ square ring metasurface as a superstrate. Moreover, two shape memory alloy (SMA)-based electrically-controlled actuators are employed in the design for controlling the position of the 3D-printed fluidic channels beneath the metasurface along the axes of the radiating slots of the patch antenna. This results in beam-steering of over ±20° in the elevation plane, with a peak gain of 9.1 dBi. It is worth mentioning that compared to conventional electronic tuning technologies where the switches are employed on the top of the radiating aperture of the antenna, which usually deteriorate the antenna performance, the SMA spring actuators do not deteriorate the performance as these are not interacting with the radiating aperture. The proposed antenna was designed and simulated using CST MWS, and the prototype was fabricated and measured. The simulated and measured results are in good agreement, which corroborates the adequacy of the proposed concept. By incorporating the SMA-based fluidic actuators, the proposed antenna is simple and highly efficient as compared to metasurface-based beam-steering antennas reported in the literature thus far.