Large-Area Deployable Reflectarray Antenna for CubeSats

Abstract

Herein is described a 1.5 m x 1.5 m reflectarray antenna designed to stow in a cylinder of 20 cm diameter and 9 cm height, and then be unfolded to provide an aperture suitable for radio frequency (RF) operations at X-band (8.4 GHz) and produce 39.6 dB of gain. The mass of the reflectarray, as measured for a full-scale prototype, is 1.75 kg. The reflectarray comprises a number of crossed-dipoles held 5 mm above a ground plane. The dipole layer and the ground plane are supported by thin planar composite facesheets; the separation between these facesheets is provided by thin composite collapsible 'S'-shaped-springs. The structure is divided into a number of quartz-epoxy composite strips arranged in concentric squares and connected to each other using slipping folds. The strips can be flattened, star-folded, and wrapped to package within the compact cylindrical volume. A full-scale prototype of this reflectarray was constructed and tested. Stowage in the design volume was successfully demonstrated, and all RF performance requirements were met, as shown by a pre-stowage RF test and a post-stowage RF test.