Multi-beam antennas are critical components in future terrestrial and non-terrestrial wireless communications networks. The multiple beams produced by these antennas will enable dynamic interconnection of various terrestrial, airborne and space-borne network nodes. As the operating frequency increases to the high millimeter wave (mmWave) and terahertz (THz) bands for beyond 5G (B5G) and sixth-generation (6G) systems, quasi-optical techniques are expected to become dominant in the design of high gain multi-beam antennas. This paper presents a timely overview of the mainstream quasi-optical techniques employed in current and future multi-beam antennas. Their operating principles and design techniques along with those of various quasi-optical beamformers are presented. These include both conventional and advanced lens and reflector based configurations to realize high gain multiple beams at low cost and in small form factors. New research challenges and industry trends in the field, such as planar lenses based on transformation optics and metasurface-based transmitarrays, are discussed to foster further innovations in the microwave and antenna research community.

中文翻译：

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用于 B5G 和 6G 毫米波和太赫兹网络的准光学多波束天线技术：综述

多波束天线是未来地面和非地面无线通信网络中的关键组件。这些天线产生的多波束将实现各种地面、机载和星载网络节点的动态互连。随着工作频率增加到超过 5G (B5G) 和第六代 (6G) 系统的高毫米波 (mmWave) 和太赫兹 (THz) 频带，准光学技术有望成为高增益多路复用器设计的主导。 - 波束天线。本文及时概述了当前和未来多波束天线中采用的主流准光学技术。介绍了它们的工作原理和设计技术以及各种准光学波束形成器的工作原理和设计技术。这些包括传统和先进的基于透镜和反射器的配置，以低成本和小尺寸实现高增益多光束。讨论了该领域的新研究挑战和行业趋势，例如基于变换光学和基于超表面的发射阵列的平面透镜，以促进微波和天线研究界的进一步创新。