Design and numerical demonstration of a 2D millimeter-wave beam-scanning reflectarray based on liquid crystals and a static driving technique

In this paper, the design method for a two-dimensional (2D) beam-scanning reflectarray based on liquid crystals (LCs) and static driving technique in the millimeter-wave band is proposed. The reflectarray is composed of multi-resonant elements which obtain the phase shift by applying the driving voltage on the LC. The LC elements of the reflectarray are controlled by static driving method. In order to reduce the negative impact of the densely distributed LC driving lines on the performance of the reflectarray, a novel LC driving strategy is presented to further reduce the number of driving lines. Subarray partition is employed, and more importantly, the ground plane of the reflectarray is divided into several segments so that about one third part of the driving lines can be transferred from the patch layer to the ground plane layer. A 32 × 30 reflectarray is designed and taken for an example to demonstrate the proposed method. Full wave numerical simulations are conducted, and the results show large beam scanning ranges of the reflectarray over 50° in the plane containing the offset feed and over 40° in the plane perpendicular to the feed plane.