A reflectarray is a type of antenna system that employs an array of reflecting elements to redirect and focus electromagnetic waves in a desired direction. This type of antenna is typically flat and consists of a planar reflecting surface with a dense array of elements arranged in a pattern that allows for control and manipulation of the reflected waves. Reflectarrays are commonly used in radar systems, satellite communications, and other applications where high-gain and beam-steering capabilities are required. Research in reflectarrays focuses on improving the design, efficiency, and performance of these antennas through the use of advanced materials, signal processing techniques, and optimization algorithms.