UTD-type decomposition employed to interpret the scattering mechanisms of reflectarray antenna

The radar cross section (RCS) of a reflectarray antenna is investigated. The reflectarray antenna is assumed to radiate fields focused in the far zone. The RCS is determined when this reflectarray antenna is illuminated by an incident plane wave. The study focuses on the RCS of the reflectarray with that of feed antenna excluded for simplification. In particular, the UTD-type decomposition is employed to interpret the scattering mechanisms, which allows one to justify the significance of each scattering mechanism. Theoretical development will be presented to illustrate the scattering mechanisms.