Beam steering reflectarray using varactor diodes

It is known that varactor diodes can be used as phase shifting devices by varying the reverse voltage applied to it to change its capacitance. This can be utilized to achieve the realization of scanning antennas. This paper presents a design of a tunable reflectarray based on elements tuned using varactor diodes. The reflectarray element consists of a C-shaped patch, printed on a substrate loaded with one varactor diode. The reflectarray is designed to operate at 13 GHz. It is composed of 21×21 elements with area 27.3 × 27.3 cm². The reflectarray is fed by linearly polarized pyramidal horn antenna. Full-wave analysis using the finite integration technique and the finite element method is applied. The mutual coupling between the feeding horn and the elements of the reflectarray is considered. The normalized gain patterns, the frequency bandwidth, and the aperture efficiency for the reflectarray are calculated.