Non-fixed flexible antenna architectures, such as fluid antenna system (FAS), movable antenna (MA), and pinching antenna, have garnered significant interest in recent years. Among them, rotatable antenna (RA) has emerged as a promising technology for enhancing wireless communication and sensing performance through flexible antenna orientation/boresight rotation. By enabling mechanical or electronic boresight adjustment without altering physical antenna positions, RA introduces additional spatial degrees of freedom (DoFs) beyond conventional beamforming. In this paper, we provide a comprehensive tutorial on the fundamentals, architectures, and applications of RA-empowered wireless networks. Specifically, we begin by reviewing the historical evolution of RA-related technologies and clarifying the distinctive role of RA among flexible antenna architectures. Then, we establish a unified mathematical framework for RA-enabled systems, including general antenna/array rotation models, as well as channel models that cover near- and far-field propagation characteristics, wideband frequency selectivity, and polarization effects. Building upon this foundation, we investigate antenna/array rotation optimization in representative communication and sensing scenarios. Furthermore, we examine RA channel estimation/acquisition strategies encompassing orientation scheduling mechanisms and signal processing methods that exploit multi-view channel observations. Beyond theoretical modeling and algorithmic design, we discuss practical RA configurations and deployment strategies. We also present recent RA prototypes and experimental results that validate the practical performance gains enabled by antenna rotation. Finally, we highlight promising extensions of RA to emerging wireless paradigms and outline open challenges to inspire future research.

翻译：非固定柔性天线架构，如流体天线系统（FAS）、可移动天线（MA）和夹捏天线，近年来引起了广泛关注。其中，旋转天线（RA）作为一种通过灵活调整天线方向/视轴旋转来增强无线通信与感知性能的 promising 技术脱颖而出。通过在不改变物理天线位置的情况下实现机械或电子视轴调整，RA 引入了超越传统波束赋形的额外空间自由度（DoFs）。本文对RA赋能无线网络的基础原理、架构及应用进行了全面教程。具体而言，我们首先回顾了RA相关技术的历史演进，并阐明了RA在柔性天线架构中的独特作用。接着，我们建立了RA系统的统一数学框架，包括通用天线/阵列旋转模型，以及涵盖近场和远场传播特性、宽带频率选择性和极化效应的信道模型。在此基础上，我们研究了典型通信与感知场景中的天线/阵列旋转优化。此外，我们探讨了RA信道估计/获取策略，包括利用多视角信道观测的定向调度机制和信号处理方法。除理论建模和算法设计外，我们还讨论了RA的实际配置与部署策略。同时，介绍了近期RA原型及实验结果，验证了天线旋转带来的实际性能增益。最后，我们展望了RA在新兴无线范式中的拓展方向，并指出了开放性问题以启发未来研究。