A Beam-Steering Antenna With a Fluidically Programmable Metasurface

In this paper, we demonstrate a beam-steering antenna using a fluidically programmable metasurface (FPMS). The proposed FPMS-based antenna consists of a source antenna and a bilayered programmable metasurface as a superstrate. The metasurface is composed of a 4 × 4 square-ring element array on the top side of a thin dielectric substrate and 3-D-printed fluidic channels for fluid movement as the bottom layer. The switchable phase of the metasurface was obtained by realizing air holes of equal dimensions inside the dielectric polylactic acid (PLA) substrate using 3-D-printing technology. The simplicity of the approach is acquired from the beam-steering properties through programmable water injection in different channels. Beam steering of ± 20° in the elevation plane with a 10 dB impedance bandwidth of 2.57-2.64 GHz was achieved. A stable radiation gain of more than 6 dBi was demonstrated across the operating bandwidth. To validate the concept, an antenna prototype was fabricated, and far-field measurements were performed. The simulation and measurement results showed good agreement and confirmed the proposed concept. The proposed antenna has a low profile and was fabricated at low cost and thus is a cheap and accessible way to control the electromagnetic waves in the microwave region using water.