Design of Reconfigurable Reflectarray Antenna Based on Liquid Crystal

This paper introduces an electronically scanned reflectarray antenna based on liquid crystal with a thickness of 40 μ m. The proposed liquid crystal-based reflectarray element consists of three main materials: glass, metal, and liquid crystal. In this work, the metals distributed on the upper and lower layers of the liquid crystal form a capacitive cavity, with the liquid crystal functioning as a varactor. When the relative permittivity of the liquid crystal is varied from 2.65 to 3.45, the antenna unit achieves relative phase shifts of more than 237°. The reflection loss of the reflectarray cell is less than 3.5 dB in the whole frequency band of 26-30 GHz. The performance of the proposed reflectarray is validated by constructing a 20 × 20 reflectarray and using a horn antenna as the feed. The simulation results indicate that the proposed liquid crystal-based reflectarray antenna can achieve ± 60° scanning at 28 GHz. Specifically, it can reach a main lobe gain of 24.3 dBi and a peak aperture efficiency of 30.1% when the scanning angle is 0°.