This letter presents a novel dual-polarized two-dimensional (2-D) Luneburg lens operated at millimeter-wave band with a low-profile and planar structure. Based on a dual-mode unit cell that supports TE/TM surface wave modes with orthogonal polarizations, the proposed 2-D Luneburg lens with gradient refractive index distribution compresses the beamwidth in one dimension and achieves fan-shaped beams for both of the two polarization modes. To verify the proposed Luneburg lens, a prototype is fabricated using the printed circuit broad process with low cost, weight, and profile. The measured peak gain of H- and V-pol mode is 17.0 dBi and 17.2 dBi, respectively. Because the surface wave modes are applied to both polarizations of the proposed Luneburg lens, the electromagnetic waves transform from the lens to the air smoothly, without the need for additional radiation structures, which reduces the profile further and increases the antenna aperture.

中文翻译：

---

基于 TE/TM 表面波模式的薄型双偏振 Luneburg 透镜

这封信介绍了一种新型双偏振二维 (2-D) Luneburg 透镜，工作在毫米波段，具有低剖面和平面结构。基于支持具有正交偏振的 TE/TM 表面波模式的双模晶胞，所提出的具有梯度折射率分布的二维 Luneburg 透镜在一维上压缩了光束宽度，并实现了两种偏振的扇形光束模式。为了验证所提出的 Luneburg 透镜，使用低成本、重量和外形的印刷电路广泛工艺制造了一个原型。H- 和 V-pol 模式的测量峰值增益分别为 17.0 dBi 和 17.2 dBi。由于表面波模式应用于所提出的 Luneburg 透镜的两个偏振，电磁波从透镜平滑地转换到空气，