使用石墨烯的超宽带轨道角动量螺旋天线设计

轨道角动量涡旋波束各个模态之间相互正交，可以很好地解决频谱资源紧张的问题。针对目前轨道角动量天线普遍存在带宽较窄的问题，设计了一种太赫兹频段的超宽带轨道角动量四臂螺旋天线。研究了馈电端口之间连续相位差与生成模态之间的关系，使用了一种石墨烯双环结构并通过调整优化天线的的结构尺寸来提高天线的性能。实验结果表明，通过简单调整馈电相位差，就能够产生模态数为0、1、2和3的涡旋波，并且不同模态下天线的增益均在7.5 dBi以上。同时所设计的天线绝对带宽达到了8.85 THz,在中心频率6 THz处其相对带宽可以达到147%,S₁₁为-50 dB,与传统天线相比改善较大，为太赫兹频段的模态复用提供了一定的现实意义。

Design of ultra-wideband OAM spiral antenna using graphene

Every mode of orbital angular momentum vortex beam is orthogonal to each other, which can solve the problem of spectrum shortage well. In order to solve the problem of narrow bandwidth of orbital angular momentum antenna, an ultra-wideband orbital angular momentum four-arm spiral antenna in terahertz band is designed. The relationship between the continuous phase difference of the feed ports and the generated modes is studied. A graphene double ring structure is used and the antenna performance is improved by adjusting and optimizing the antenna structure size. The experimental results show that the vortex beams with mode number 0, 1, 2 and 3 can be generated by simply adjusting the phase difference, and the gain under different mode number is above 7.5 dBi. At the same time, the absolute bandwidth of the designed antenna reaches to 8.85 THz, and the relative bandwidth at the center frequency of 6 THz can reach to 147% with the S11 is -50 dB. The designed antenna is greatly improved compared with the traditional antenna, and provides a certain significance for the terahertz band mode multiplexing in practical application.