Reflectarray Feeds Augmented With Size-Reducing GRIN Lenses for Improved Power Handling and Aperture Efficiency

The feed for reflectarrays and transmitarrays is crucial for determining the overall antenna aperture efficiency, gain, and power handling. In the past, several methods, such as altering the horn shape to achieve higher modes, have been employed to modify the feed radiation pattern to improve these key parameters. However, another approach is to use gradient index (GRIN) lenses, which offer unprecedented control over the radiation pattern and can be used to shrink the overall antenna. In this paper, we demonstrate highly effective approaches for optimizing GRIN lenses to achieve different design objectives including high gain radiation with a compact feed as well as improved aperture efficiency and power handling. Additive manufacturing is employed to fabricate the lenses, and measured results agree well with simulations.