The great flexibility offered by transformation optics for controlling electromagnetic radiation by virtually re-shaping the electromagnetic space has inspired a myriad of dream-tailored electromagnetic devices. Here we show a 3D-transformed microwave Luneburg lens antenna which demonstrates high directivity, low side-lobe level, broadband response and steerable capabilities. A conventional Luneburg lens is redesigned accounting for dielectric materials that implement a coordinate transformation, modifying the lens geometry to accommodate its size and shape for potential high power applications. An all dielectric flat lens is manufactured following a thorough holistic analysis of ceramic materials with different volume fractions of bi-modal distributed titanate fillers. Fabrication and measurements of a 3-D flat Luneburg lens antenna validate the design and confirm a high-directivity performance. A maximum directivity of 18.03dBi, low side-lobe levels for both main planes ~ -15dB, bandwidth limited only by the source employed and beam-steering up to 35° were achieved.
Mateo-Segura, C., Dyke, A., Dyke, H., Haq, S., & Hao, Y. (2014). Flat Luneburg Lens via Transformation Optics for Directive Antenna Applications. IEEE Transactions on Antennas and Propagation, 62(4), 1945-1953. https://doi.org/10.1109/TAP.2014.2302004