Design of an Optically Transparent Reflectarray for Solar Applications Using Indium Tin Oxide

Optically transparent planar antennas made of transparent conductive oxide (TCO) have attracted considerable attention in research over the years, particularly for solar panel applications. However, their design has proved difficult due to their inherent conductor losses. This paper focuses on the design of an optically transparent reflectarray using indium tin oxide, which is a type of TCO. The design is composed of subwavelength rectangular patch elements that exhibit 272° of phase range and mitigate conductor losses in reflectarray operation. This paper examines the behavior and response of lossy reflectarray unit cells and investigates different techniques to reduce the impact of loss in TCO reflectarray designs, primarily using different patch geometries and subwavelength elements. The proposed element design is simulated and experimentally characterized. A full reflectarray prototype operating at 26 GHz is successfully demonstrated and fabricated, with the simulated and experimental results in good agreement.