面向5G多波束应用的紧凑宽带Rotman透镜设计

提出了一种基于等光程差原理设计的紧凑宽带Rotman透镜波束赋形网络，用于5G毫米波通信的天线阵列多波束实现。首先，详细介绍了Rotman透镜的基本原理；然后，利用二等分功分器替代传统的单端口馈电模式，产生高定向波束，降低相邻端口处的能量损失以及透镜内部能量的散射；最后利用切比雪夫多枝节匹配变换器，优化原有的锥形阵列输出端口，在保证宽频带的条件下，缩短原有匹配端口尺寸，使得透镜整体尺寸减少20%，实现了Rotman透镜的紧凑性。改进模型的实测结果表明，该透镜工作频带为16.5～33.8 GHz，其中在17.2～32 GHz，S₁₁优于15 dB，扫描角度为±30°。该透镜结构简单紧凑，能够有效地为相邻阵元提供稳定的相位差信号，很好地实现5G毫米波阵列多波束的目标。

Design of compact wideband Rotman lens for 5G multibeam application

In this paper, a compact broadband Rotman lens beamforming network based on equal optical path difference is proposed. The beamforming network is intended for applications in a multi-beam antenna array of 5G millimeter-wave (mm-wave) communication. Firstly, the theoretical design of the Rotman lens is introduced in detail. A power divider is used to replace the standard single-port feeding mode to generate a high-directional beam, reducing the scattering of the lens’ internal energy and the energy loss at adjacent ports. The Chebyshev multi-stub matching converter is used to optimize the original tapered array output port. To ensure a wide frequency band, the original matching port size is reduced, and the overall size of the lens is reduced by 20%. Measurement results of the improved model, show that the working frequency band of the lens is 16.5−33.8 GHz, of which S11 is better than 15 dB at 17.2−32.0 GHz, and the scanning angle is ±30°. The lens has a simple and compact structure, can effectively provide a stable phase difference signal for adjacent array elements, and achieve the goal of 5G millimeter-wave array multi-beam.