Gradient-Index Lens Augmented Reflectarray Feeds

The operation and application of high-power microwave devices is limited by system cost and dielectric breakdown events. Reflectarrays, though, provide a promising lower-cost alternative to phased array solutions, while maintaining a low profile, reduced complexity, and lower weight requirements when steering compared with large reflector antennas so long as their resonant field enhancement is suppressed. However, reflectarrays are limited by their spatial feeding arrangement where the amplitude distribution can only be controlled by the feed choice and position. In this work, we briefly introduce that an additively manufactured gradient index (GRIN) lens can be optimized to engineer the near field reflectarray illumination from a conventional horn antenna to increase the power handling capacity of the array. In particular, the lens is shown to reduce the peak field strength by 17% across the aperture and correspondingly increases the aperture efficiency of the system from 70% to 75.9%, improving the effective radiated power by nearly 50%.