Reflectarray Demonstrated to Transform Spherical Waves into Plane Waves

The development of low-cost, high-efficiency array antennas has been the research focus of NASA Lewis Research Center's Communications Technology Division for the past 15 years. One area of current interest is reflectarray development. Reflectarrays have generally been used to replace reflector antennas. In this capacity, different configurations (such as prime focus and offset) and various applications (such as dual frequency and scanning) have been demonstrated with great success. One potential application that has not been explored previously is the use of reflectarrays to compensate for phase errors in space-power-combining applications, such as a space-fed lens and power-combining amplifiers. Recently, we experimentally investigated the feasibility of using a reflectarray as an alternative to a dielectric lens for such applications. The experiment involved transforming the spherical waves from an orthomode horn to plane waves at the horn aperture. The reflectarray consists of square patches terminated in open stubs to provide the necessary phase compensation.