Bai Xudong, Zhang Fuli, Sun Li, Cao Anjie, He Chong, Zhang Jin, Zhu Weiren
School of Microelectronics, Northwestern Polytechnical University, Xi'an, 710129, China.
Shanghai Aerospace Electronics Co., Ltd., Shanghai, 201821, China.
Nanophotonics. 2022 Feb 17;11(7):1389-1399. doi: 10.1515/nanoph-2021-0790. eCollection 2022 Mar.
Millimeter-wave (mmWave) and orbital angular momentum (OAM) multiplexing are two key technologies for modern wireless communications, where significant efforts have been devoted to combining these two technologies for extremely high channel capacities. Recently, programmable metasurfaces have been extensively studied for stimulating dynamic multi-mode OAM beams, owing to their ability of subtle dynamic modulation over electromagnetic waves in a digital manner. However, programmable metasurfaces for mmWave OAM stimulation are rarely mentioned, due to the requirement of extremely high processing precision for mmWave applications. In this paper, a programmable metasurface is presented to stimulate dynamic multi-mode mmWave vortex beams. The proposed metasurface is composed of electronically reconfigurable units, which is obtained through configuration integration of a PIN diode within each radiation patch for modulating the unit resonant property. Both low reflection losses and stabilized inverse phase states are obtained for the binary unit coding states within the operation band. Through modulating the real-time coding distribution on the metasurface by programmable bias circuit, the generation of mmWave OAM beams with mode numbers = 0, = +1, = +2, and = +3 are numerically designed and experimentally verified. Our study paves a new perspective for the cross amalgamation of both mmWave and multi-mode OAM technologies.
毫米波（mmWave）和轨道角动量（OAM）复用是现代无线通信的两项关键技术，人们已投入大量精力将这两种技术结合起来以实现极高的信道容量。最近，可编程超表面因其能够以数字方式对电磁波进行精细动态调制而被广泛研究用于激发动态多模OAM光束。然而，由于毫米波应用对处理精度要求极高，很少有人提及用于毫米波OAM激发的可编程超表面。本文提出了一种可编程超表面来激发动态多模毫米波涡旋光束。所提出的超表面由电子可重构单元组成，这些单元通过在每个辐射贴片内集成PIN二极管进行配置来调制单元谐振特性而获得。在工作频段内，对于二元单元编码状态，均获得了低反射损耗和稳定的反相状态。通过可编程偏置电路调制超表面上的实时编码分布，对模式数 = 0、 = +1、 = +2和 = +3的毫米波OAM光束的产生进行了数值设计和实验验证。我们的研究为毫米波和多模OAM技术的交叉融合开辟了新的视角。
