H-shaped slot microstrip reflectarray antenna

Reflectarray antennas combine some of the best features of printed antenna arrays and reflector antennas. The reflectarray concept is based on the scattering properties of individual cells. By varying the parameters of each unit cell, the required phase shift can be obtained, and the incident beam is scattered in a given direction. At the present time, many reflectarrays configurations are based on microstrip technology. Nevertheless, the phase range achieved is less than 360°, which could contribute to the phase error on the overall radiation pattern. In this paper, firstly we have analyzed and compared several configurations of H-shaped slot that is based on microstrip unit-cell. A new structure with the variation of two slots (a and b) has been proposed at 30 GHz. It gives low loss and high phase range (more than 360°). Then, the specifications and design for broadside radiation of the reflectarray are explained. Finally, the radiation pattern of the whole reflectarray is predicted using simplified calculation.