Terahertz, Infrared, and Optical Reflectarray Antennas

This chapter presents some of the latest progress in terahertz (THz), infrared, and optical reflectarray antennas. Most reflectarray antenna research in the recent years has been in the microwave and sub‐millimeter range, and while microwave concepts can generally be extended to higher frequencies, several factors come into play that complicate the antenna design. The chapter discusses some basic material characteristics and design challenges, and then reviews several THz, infrared, and optical reflectarray antennas that have been developed over the years. The region of frequency spectrum between microwave frequencies and visible light consists of THz and infrared bands. At microwave frequencies, since a high conductivity is obtained for conductors and a low‐loss tangent can be achieved for substrates, the gain loss of a reflectarray due to the materials is relatively small. In traditional reflectarray antennas, both conductors and dielectrics are used in element designs.