Using a single patch antenna to generate a vortex electromagnetic wave greatly simplifies the application systems of orbital angular momentum (OAM) modes. OAM modes can be synthesized from degenerate modes, and thus, characteristic mode theory is a helpful tool to guide the construction of OAM antennas. Based on this idea, a single-fed circular patch with an arc segment as a symmetrical perturbation element is proposed to radiate a second-order OAM wave. Since the arc segment is independent of the radiation element, it is easy to reconstruct the OAM mode order or vortex direction by adjusting it. In this regard, two symmetrical arc segments switched on and off using p-i-n diodes are applied to implement the reconfiguration of the second-order OAM mode. The structure effect on the vortex wave is discussed by using modal weighting coefficients.

中文翻译：

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一种结构简单的可重构二阶OAM贴片天线

使用单个贴片天线产生涡旋电磁波，大大简化了轨道角动量（OAM）模式的应用系统。OAM模式可以由退化模式合成，因此特征模式理论是指导OAM天线构建的有用工具。基于这一思想，提出了一种以弧段作为对称扰动元的单馈圆形贴片来辐射二阶OAM波。由于弧段与辐射单元无关，因此很容易通过调整重建OAM模式阶次或涡旋方向。在这方面，应用使用 pin 二极管打开和关闭的两个对称弧段来实现二阶 OAM 模式的重新配置。利用模态加权系数讨论结构对涡旋波的影响。