High-efficient beam-converging for UCA based radio vortex wireless communications
High-efficient beam-converging for UCA based radio vortex wireless communications
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DOI：
10.1109/iccchina.2017.8330517
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发表时间：
2017-10
期刊：
影响因子：
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通讯作者：
Shanghua Gao;Wenchi Cheng;Hailin Zhang;Zan Li
中科院分区：
文献类型：
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作者：
Shanghua Gao;Wenchi Cheng;Hailin Zhang;Zan Li
基于轨道角动量（OAM）的涡旋无线通信由于提供了新的角正交OAM模式/态，从而显著提高了频谱效率，近年来受到了广泛的关注。为了实现最大频谱效率，高度要求需要利用所有OAM模式。均匀圆阵（UCA）作为一种简单的多OAM模式传输天线结构，便于实现高频谱效率的涡流无线通信。然而，已经表明，基于OAM的电磁波是涡旋中空的和发散的。随着OAM模阶数的增加，相应电磁波的发散度也随之增加。因此，如果OAM模式的阶数相对较大，则不可能使用高阶OAM模式，因为接收到的相应信噪比（SNR）非常小。为了有效利用高阶OAM模式提高频谱效率，本文提出了一种基于透镜天线的电磁波会聚方案，该方案保持了多个OAM模式的角分辨特性，用于无线电涡流无线通信。我们发展出一种新颖的双焦点透镜天线，不仅可以将电磁波会聚，而且可以降低传统电磁波所对应的衰减。仿真结果表明，双焦点透镜可以将OAM波会聚成圆柱形光束，这将有利于无线通信的频谱效率。
Orbital angular momentum (OAM) based radio vortex wireless communications, which provide the new angular orthogonal OAM-modes/states to significantly boost the spectrum efficiency, have received much attention recently. To achieve maximum spectrum efficiency, it is highly demanded that all OAM-modes need to be utilized. The uniform circular array (UCA), as a simple antenna structure for multiple OAM-modes transmissions, is convenient to be implemented for high spectrum efficiency radio vortex wireless communications. However, it has been shown that the OAM based electromagnetic waves are vortically hollow and divergent. Also, the divergence of corresponding electromagnetic wave increases as the order of OAM-mode increases. Therefore, if the order of OAM-mode is relatively large, it is impossible to use high order OAM-mode since the received corresponding signal-to-noise ratio (SNR) is very small. To efficiently utilize high order OAM-modes for spectrum efficiency enhancement, in this paper we propose the lens antenna based electromagnetic waves converging scheme, which keeps remain the angular-distinguishing property of multiple OAM-modes, for radio vortex wireless communications. We develop the novel bifocal lens antenna to not only converge the electromagnetic wave, but also decrease the attenuation corresponding to traditional electromagnetic waves. Simulation results are presented to show that the bifocal lens can converge the OAM waves into cylinder-like beams, which are expected to benefit the spectrum efficiency of wireless communications.