ABSTRACT As the traditional resources (such as frequency, time, and space) are efficiently utilized, it becomes more and more challenging to satisfy the ever-lasting, capacity-growing, and users-boosting demand for wireless networks. Recently, the orthogonal Orbital Angular Momentum (OAM) modes of electromagnetic waves were exploited to achieve high spectral efficiency in radio and microwave transmission. This research discusses the challenges in OAM signal generation, OAM beam divergence, and OAM signal reception misalignment through a new proposed method. A transmission array with arbitrary shape is used to synthesize the desired OAM waveform at a receiver. The receiver, usually in the form of a ring, could have arbitrary size and location in space and therefore the perfect alignment condition, as required between the transmitter and receiver planes, is relaxed. It is also shown that a notable save in the size of the transmission array is gained against other conventionally used OAM generation methods. This could be of great utility in massive Multiple-Input-Multiple-Output (MIMO) systems. Such reduction in the transmitter size along with the flexibility in choosing the receiver size are all exploited to handle the OAM beam divergence problem. The results are shown using mathematical formulas and are checked by comparing them to numerical simulations.

中文翻译：

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具有任意OAM的通用配置MIMO系统

摘要 随着传统资源（如频率、时间和空间）的有效利用，满足对无线网络持续增长、容量增长和用户增长的需求变得越来越具有挑战性。最近，电磁波的正交轨道角动量 (OAM) 模式被用来在无线电和微波传输中实现高频谱效率。本研究通过提出的新方法讨论了 OAM 信号生成、OAM 波束发散和 OAM 信号接收未对准方面的挑战。具有任意形状的传输阵列用于在接收器处合成所需的 OAM 波形。接收器通常呈环形，可以在空间中具有任意大小和位置，因此具有完美的对准条件，根据需要，在发射机和接收机平面之间，是放松的。还表明，与其他常规使用的 OAM 生成方法相比，传输阵列的大小显着节省。这在大规模多输入多输出 (MIMO) 系统中可能非常有用。发射器尺寸的这种减小以及选择接收器尺寸的灵活性都被用来处理 OAM 波束发散问题。结果使用数学公式显示，并通过将它们与数值模拟进行比较来检查。发射器尺寸的这种减小以及选择接收器尺寸的灵活性都被用来处理 OAM 波束发散问题。结果使用数学公式显示，并通过将它们与数值模拟进行比较来检查。发射器尺寸的这种减小以及选择接收器尺寸的灵活性都被用来处理 OAM 波束发散问题。结果使用数学公式显示，并通过将它们与数值模拟进行比较来检查。