Liquid-Based Reconfigurable Fabry–Pérot Cavity Antenna for Beam-Steering Applications

This letter presents a liquid-based reconfigurable Fabry–Pérot cavity antenna (FPCA) for beam-steerable applications. The proposed antenna system consists of a patch antenna resonating at 10 GHz and a tri-layer partially reflective surface (PRS) with a 2 × 2 3-D printed liquid chamber inside a polylactic acid (PLA) substrate acting as a phase gradient PRS. Together with the patch antenna, the PRS forms an FPCA. Phase gradient is created by filling different chambers of the PRS with distilled water. Eight different steering angles are realized by filling different chambers of the PRS. A scan range of more than ±30° is achieved in both E- and H-plane, with a gain of more than 7.5 dBi, whereas steering of ±17° is achieved in the EH-plane with a gain of more than 6.5 dBi. The proposed concept is validated by fabricating a prototype antenna where good agreement is found between the simulation and measurement results. The proposed antenna can be useful in low-cost applications requiring some degree of beam steering.