Abstract

This paper presents the design of a novel multi-beam Luneburg lens antenna with specific dielectric structure and proposes a new solution for downsizing planar lens antennas. The quasi-conformal transformation optics (QCTO) principle is applied to achieve an equivalent transformation relation between the spatial coordinate and the electromagnetic properties of material, effectively preserving the behavior of electromagnetic waves while achieving a significant reduction in antenna size. The antenna comprises a deformed Luneburg lens with a radius equivalent to $3.75\lambda $ , metal plates flanking the lens, and a linear array of seven microstrip antennas operating at 10 GHz. By selectively activating antenna elements within the array, the antenna can generate seven distinct beams, enabling a scanning range of ±30° in the azimuth plane. Each beam achieves a gain exceeding 15 dBi. In comparison to traditional planar lens antennas, this antenna boasts a reduction in size of more than 30% and has the flexibility of being fed using a linear array.