Performance Comparison of Traditionally Manufactured and Additively Manufactured Luneburg Lenses

Luneburg lenses are popular antenna apertures for applications requiring a wide field of view and beam steering capability as they are a lower cost alternative to phased array apertures with straightforward beam-switching. Traditionally, Luneburg lenses are fabricated by layering shells of different dielectric constants to approximate a theoretically continuous dielectric gradient. Recent developments in additive manufacturing (AM) for radio frequency (RF) applications have led to advances in AM Luneburg lenses. AM enables functional dielectric printing where the dielectric properties can vary spatially within a print. Lenses manufactured using AM can continuously vary the dielectric constant through the material based on the theoretical Luneburg lens dielectric gradient; these AM lenses more accurately match the dielectric gradient of the theoretical Luneburg lens. Additionally, the integration of transformational optics (TO) to AM Luneburg lenses allows for physical reshaping of the lens structure while maintaining the same electrical properties. TO allows reshaping of the focal surface, which enables lateral translations of the feed location to steer the beam instead of radial rotations. This lowers the complexity of the feed arrangement without loosing the beam steering capability. This paper presents the results and analysis of a simulation and measurement study including performance comparisons between three Luneburg lens fabrication methods: traditionally manufactured, AM, and TO-AM.