Reflectarrays and Other Aperture Antennas

There are a variety of other aperture antennas which find use in specialized applications that have not yet been considered. This chapter introduces the areas of arrays and reflectors come together in the reflectarray antenna. In design and operation, reflectarrays are inherently a combination of arrays and reflectors. Since the 1980s, reflectarrays have increasingly been made with microstrip patch elements on a substrate with a metal ground plane. These microstrip reflectarrays are illuminated by a feed and consist of a number of discrete resonant elements that are conventionally passive and arranged on a plane or conformal to another surface such as a cylinder. The chapter also includes details of some other aperture antennas not treated elsewhere, in particular, lenses, and the Fabry‐Perot cavity antennas. The Fabry‐Perot cavity is highly efficient and flexible as a radiator, but in its basic form, it is a narrowband device.