Electronically Reconfigurable Reflectarray Antenna Based on Single-Layer Liquid Crystal With Independent Dual-Polarization Control

This article introduces a low-cost, easy-to-manufacture, dual polarization reconfigurable reflectarray antenna based on liquid crystal (LC) that operates at W-band. The antenna is electrically large and is capable of independently steering the beam of two orthogonal polarizations. Two different implementations of single-layer unit cells (single resonant and multiresonant) capable of providing suitable phase range to independently control the two radiofrequency (RF) polarizations with enough isolation have been investigated. The single resonant cell was finally used to design, manufacture, and test a complete reflectarray antenna made of
$55\times 55$
elements, for which an accurate and efficient modeling of the cells was implemented. The effect of the LC bias lines is minimized by following a thorough impact study. At a cell level, the measurements validate both the modeling and the capability of the LC to be locally biased at the same cell provided that the biasing network and the resonators of each polarization are properly distributed. At an antenna level, the measurements are predicted by simulations with excellent accuracy, which validates the design and modeling process. The measured antenna shows 35° of 1-D scanning range with 25 dBi gain and a maximum SLL of −9 dB in the entire range for both polarizations at 98 GHz.