Liquid-Crystal-Based Beam-Steering Guided-Wave Metasurface Antenna at Millimeter-Wave Band

In this letter, we present the design and fabrication of a liquid crystal (LC)-based metasurface antenna for millimeter-wave beam-steering applications. Unlike the conventional beamforming systems that rely on phase shifters, our approach harnesses the electrical tunability of LCs. We target a frequency of 34.5 GHz, taking advantage of the pronounced low dielectric loss characteristics exhibited by LCs. The proposed antenna uses a substrate-integrated waveguide (SIW) to feed millimeter-wave to metasurface unit cells, and each cell's radiation is controlled through dc voltage biasing of the. The measurement results demonstrate a beam-steering range of 120° with a maximum gain of 10.754 dBi and a sidelobe level (SLL) of −11.562 dBc at the boresight.