This study presents a novel radial uniform circular array (UCA) antenna for quad-mode orbital angular momentum (OAM) multiplexing in the 5.2   GHz band. The antenna can simultaneously generate four OAM modes (±1, ±2) using two radial UCAs printed concentrically on a single substrate. Each UCA is connected to an individual dual-mode feeding network, and generates a pair of complementary OAM modes. The feeding network for each UCA consists of one quadrature hybrid coupler and two circular feedlines, and they can be integrated onto a single substrate. The measured radiation patterns and helical phase wavefronts show the successful generation of four OAM modes by the proposed antenna. The quad-mode OAM transmission test was performed using two prototypes of the proposed antenna, and good isolations >13.7   dB were obtained between four OAM mode channels, which demonstrates that the antenna can be successfully used for OAM multiplexing.

中文翻译：

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用于OAM复用的四模径向均匀圆形阵列天线

这项研究提出了一种新颖的径向均匀圆形阵列（UCA）天线，用于5.2中的四模式轨道角动量（OAM）复用   GHz频段。使用同心印刷在单个基板上的两个径向UCA，天线可以同时生成四个OAM模式（±1，±2）。每个UCA连接到单独的双模式馈电网络，并生成一对互补的OAM模式。每个UCA的馈电网络均由一个正交混合耦合器和两条圆形馈线组成，它们可以集成到单个基板上。测得的辐射方向图和螺旋相位波前表明所提出的天线成功生成了四种OAM模式。使用拟议天线的两个原型进行了四模式OAM传输测试，隔离度> 13.7   在四个OAM模式信道之间获得了dB，这表明该天线可以成功用于OAM多路复用。