Frequency response optimization of a double layer reflectarray antenna

In this work, preliminary results of the design of a double layer planar reflectarray are presented with emphasis on its frequency response. Since the number of free parameters is big, the design has been carried out using evolutionary optimization, in order to adjust the elements size and position on the reflector, i.e. the reflection phase distribution on the reflecting surface; in order to achieve high gain radiation pattern in the broadside direction and to reduce the side lobe level.