Design and Fabrication of Reflective Phase Shifter for Two-Dimensional Terahertz Beam-Scanning Reflectarray

A reflective phase shifter is proposed to realize the two-dimensional beam-scanning reflectarray. The reflectarray is composed of double-dipole resonant elements in which the phase shift is implemented by applying a driving voltage to the liquid crystal (LC). A 30 × 30 phase shifter sample is fabricated on a quartz substrate with a 480 μ m thickness and a 4 cm × 4 cm area. According to the experimental results, 0 to 360° phase shift can be achieved within the bandwidth of 5 GHz. In order to accomplish two-dimensional beam-scanning and reduce the negative impact of driving lines on the reflectarray, a new LC driving method is developed. To verify the accuracy of the proposed approach, three samples of different driving line numbers are designed using the above-mentioned phase shifter, which all have achieved a 0−360° phase shift in the bandwidth of 4 GHz. Considering the influence of LC anisotropy and inhomogeneity, an improved calculation result is obtained and compared with experimental data.