A Novel Shape Memory Alloy Actuator-Based Fluidically Programmable Continuous Frequency Reconfigurable Antenna

A new actuation technique is introduced for overcoming the complexity and radiation performance degradation issues of actuators-based reconfigurable antennas. We employ shape memory alloy (SMAlloy) spring actuators to control the positioning of the fluidic channels, in contrast to the manual filling/loading and evacuating/offloading of dielectric fluids employed in conventional fluidically reconfigurable antennas. To demonstrate this new actuation method, a simple low-cost frequency reconfigurable microstrip patch antenna is fabricated, and two SMAlloy spring actuators are incorporated along the microfluidic channels in the axes of the radiating slots. Electrical control of the pitch of the two SMAlloy springs enables mechanical movement/transformation of the microfluidic channels in two directions along the axes of the radiating slots to attain the required frequency-switching characteristics of the antenna. It should be noted that in contrast to the traditional switching techniques where switches are positioned over the radiating aperture, the proposed method does not deteriorate the performance of the antenna because SMAlloy springs are underneath the radiating patch.