In this paper, an eight-arm Archimedean spiral antenna (ASA) is proposed to generate multiple orbital angular momentum (OAM) modes over a respectable frequency band (1.9-3GHz). Firstly, the principle of radiation by eight-arm ASA with right-hand spiral line is analyzed and simulated. It is demonstrated that the OAM modes and polarizations of the generated vortex waves are reconfigurable by changing the fed phases of the eight arms and controlling the radius of the antenna arm. Meanwhile, a prototype is fabricated and measured, in which experimental results agree well with simulation ones. At last, compared with other recently reported OAM-generating antennas, the proposed antenna with the smaller structure ( $\Phi 2.45\lambda _{0}$ , where $\lambda _{0}$ is the wavelength of the center frequency) can produce the higher gain (4.5-11.2dBi) vortex waves carrying multiple OAM modes (five modes) in the broad band of 1.9-3GHz.

中文翻译：

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八臂阿基米德螺旋天线 (ASA) 的宽带多 OAM 生成

在本文中，提出了一种八臂阿基米德螺旋天线 (ASA)，可在可观的频段 (1.9-3GHz) 上生成多个轨道角动量 (OAM) 模式。首先，分析和模拟了右旋螺旋线八臂ASA的辐射原理。结果表明，通过改变八臂的馈电相位和控制天线臂的半径，可以重新配置所产生涡旋波的 OAM 模式和极化。同时，制作并测量了样机，实验结果与仿真结果吻合较好。最后，与其他最近报道的 OAM 生成天线相比，所提出的天线结构更小（ $\Phi 2.45\lambda _{0}$ ， 在哪里 $\lambda _{0}$ 是中心频率的波长）可以产生更高增益（4.5-11.2dBi）的涡流波，在1.9-3GHz的宽带中携带多种OAM模式（五种模式）。