Orbital angular momentum (OAM) is a promising feature of electromagnetic (EM) wave to increase the communication link capacity. It is possible to use the OAM over the whole spectrum from radio frequency to optic. EM waves would experience a vortex phase boundary while transmitting the data. According to the infinite number of vortex modes, there would be infinite data transmission in theory. Here, a plasma medium with a complex structure is exploited to construct the vortex phase plane at microwave frequencies. Plasma as the ionized gas transmits, reflects, and absorbs EM wave under some conditions. The ratio of plasma physical parameters with the impinging wave frequency presents the condition of wave interaction with the plasma medium. A reflector plane is realized with the help of multilayered low-pressure plasma. By radiation of a plane wave toward the reflector surface, vortex beams of several modes are realized. The controllability of plasma electron frequency makes it a reconfigurable reflect-array antenna for vortex beam generation. The design is based on the scattering theory of the dielectric plasma model for a vast frequency of 8-16 GHz. The proposed advanced EM structure to generate the vortex beams is simulated with a full-wave analysis that verifies the studied design.

中文翻译：

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微波频率下基于等离子体反射阵列表面的涡旋光束生成


轨道角动量（OAM）是电磁波（EM）的一个很有前途的特性，可以增加通信链路容量。可以在从射频到光学的整个频谱上使用 OAM。电磁波在传输数据时会经历涡旋相界。根据涡旋模式的无限个数，理论上可以实现无限的数据传输。这里，利用具有复杂结构的等离子体介质来构造微波频率下的涡旋相平面。等离子体作为电离气体在某些条件下传输、反射和吸收电磁波。等离子体物理参数与冲击波频率的比值代表了波与等离子体介质相互作用的情况。反射面是在多层低压等离子体的帮助下实现的。通过向反射器表面辐射平面波，可以实现多种模式的涡旋光束。等离子体电子频率的可控性使其成为用于产生涡旋束的可重构反射阵列天线。该设计基于介电等离子体模型的散射理论，适用于 8-16 GHz 的广阔频率。所提出的用于生成涡旋光束的先进电磁结构通过全波分析进行模拟，验证了所研究的设计。