Doubly Curved Reflectarray for Dual-Band Multiple Spot Beam Communication Satellites

The design, manufacturing, and testing of a 0.65 m doubly curved polarization selective reflectarray for dual-band multiple spot beam communication satellites in $Ka$ -band is presented. The configuration is based on a single-offset reflectarray consisting of rotated split hexagonal-loop dipole elements printed on a single-layer substrate. For right-hand circular polarization (RHCP), the reflectarray scans the reflected beam half a beamwidth in one direction, and for left-hand circular polarization (LHCP), the reflectarray scans the reflected beam half a beamwidth in the opposite direction. This is achieved in both transmit (Tx) (17.7-20.2 GHz) and receive (Rx) (27.5-29.3 GHz) frequency bands. Using a feeding array with 22 feeds, 41 beams over the Earth can be generated, permitting to cover the entire Earth coverage from a geostationary satellite employing the 4-color frequency/polarization reuse scheme using only two reflectarrays while maintaining single-feed-per-beam operation. The reflectarray has been manufactured and measured, and an excellent agreement between simulated and measured patterns is obtained, thus validating the proposed concept.