Antenna arrays have a long history of more than 100 years and have evolved closely with the development of electronic and information technologies, playing an indispensable role in wireless communications and radar. With the rapid development of electronic and information technologies, the demand for all-time, all-domain, and full-space network services has exploded, and new communication requirements have been put forward on various space/air/ground platforms. To meet the ever increasing requirements of the future sixth generation (6G) wireless communications, such as high capacity, wide coverage, low latency, and strong robustness, it is promising to employ different types of antenna arrays (e.g., phased arrays, digital arrays, and reconfigurable intelligent surfaces, etc.) with various beamforming technologies (e.g., analog beamforming, digital beamforming, hybrid beamforming, and passive beamforming, etc.) in space/air/ground communication networks, bringing in advantages such as considerable antenna gains, multiplexing gains, and diversity gains. However, enabling antenna array for space/air/ground communication networks poses specific, distinctive and tricky challenges, which has aroused extensive research attention. This paper aims to overview the field of antenna array enabled space/air/ground communications and networking. The technical potentials and challenges of antenna array enabled space/air/ground communications and networking are presented first. Subsequently, the antenna array structures and designs are discussed. We then discuss various emerging technologies facilitated by antenna arrays to meet the new communication requirements of space/air/ground communication systems. Enabled by these emerging technologies, the distinct characteristics, challenges, and solutions for space communications, airborne communications, and ground communications are reviewed. Finally, we present promising directions for future research in antenna array enabled space/air/ground communications and networking.

中文翻译：

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天线阵列支持 6G 空间/空中/地面通信和网络

天线阵列已有100多年的悠久历史，并随着电子和信息技术的发展密切演变，在无线通信和雷达中发挥着不可或缺的作用。随着电子信息技术的飞速发展，全时、全域、全空间的网络服务需求爆发式增长，对各种天/空/地平台提出了新的通信需求。为了满足未来第六代（6G）无线通信不断增长的需求，如大容量、广覆盖、低延迟和强健壮性，采用不同类型的天线阵列（例如，相控阵、数字阵列, 和可重构的智能表面等) 与各种波束成形技术 (例如, 模拟波束成形, 天/空/地通信网络中的数字波束成形、混合波束成形和无源波束成形等），带来了可观的天线增益、复用增益和分集增益等优点。然而，为空间/空中/地面通信网络启用天线阵列带来了具体、独特和棘手的挑战，引起了广泛的研究关注。本文旨在概述支持天线阵列的空间/空中/地面通信和网络领域。首先介绍了启用天线阵列的空间/空中/地面通信和网络的技术潜力和挑战。随后，讨论了天线阵列的结构和设计。然后，我们讨论了由天线阵列推动的各种新兴技术，以满足空间/空中/地面通信系统的新通信要求。在这些新兴技术的支持下，我们回顾了空间通信、机载通信和地面通信的独特特征、挑战和解决方案。最后，我们提出了未来研究天线阵列空间/空中/地面通信和网络的有希望的方向。