Reconfigurable and dual-polarization folded reflectarray antenna

This paper proposes a novel version of folded reflectarray antenna that allows a full electronic reconfigurability of the radiation pattern. The reconfigurability is obtained adopting an elementary cell on the main reflector able to provide at the same time the required phase-shift to the incident field and the necessary twist of the incident polarization. Since in many applications an antenna with dual-polarization operation is required, the proposed design allows the reflectarray to manage at the same time two orthogonal linear polarizations in two adjacent frequency bands. This achievement is obtained by replacing the polarizing grid, as typically adopted, with a dualband and dual-polarized FSS. As a proof of concept, two test antennas have been designed, manufactured and tested.

I. Introduction

Planar reflectarrays represent a promising solution for the design of low-weight, low-cost and versatile antennas [1], [2]. Folded reflectarray antennas further improve the main features of the reflectarrays through a reduction of the overall weight and profile without affecting the antenna performance. The folded reflectarray principle, originally introduced in [3], is shown in Fig. 1. The field radiated by a central feed is reflected by a polarizing grid, on the top of the antenna. A second reflection is performed by the main reflector in which the printed elements add the required phase shift, compensating for the free space delay occurred along the paths between them and the feed. A polarization twist of 90° is to be performed on the lower reflector together with the phase adjustment so that the wave can pass the grid.