Compact beam-scanning Luneburg lens antenna using transformation optics and low-cost additive manufacturing

This paper presents the design and fabrication of a three-dimensional Luneburg lens (LL) using transformation optics (TO). A cost-effective additive manufacturing approach employing polylactic acid (PLA) material enables wideband operation. Our methodology implements an effective medium strategy through a cube-based space-filling structure, achieving precise control of the permittivity distribution derived from TO principles. The proposed lens design incorporates 2,928 unit cells, resulting in compact dimensions of $80\text{mm}\times 80\text{mm}\times 75\text{mm}$. To evaluate the beam-scanning capability, an X-band WR90 waveguide serves as the feed source. The TO-based LL demonstrates a peak gain of $15.84\text{dBi}$ with beam-steering ranges of $\pm 42^{\circ }$ and $\pm 31^{\circ }$ in orthogonal planes. Near-field measurements validate the simulations, showing excellent agreement between theoretical and experimental results.