随着通信技术的迅猛发展，电磁波束调控作为其关键的研究方向，在提高通信系统性能和适应复杂通信环境方面具有重要意义。本文基于电磁超表面对波束调控及应用展开了深入研究，旨在提升波束调控的精确性和灵活性，为通信技术的进步提供有力支持。

      (1)设计了一个工作在矿用频率3.5 GHz的无源编码波束调控超表面，其编码单元的幅度达到0.99以上，相位均匀覆盖0°-360°。通过精确调控2 bit极化不敏感的方形超表面单元，实现了对入射波相位的精确调节。所设计的编码超表面不仅能对垂直入射的线极化波进行双波束和单波束调控(波束调控范围为-60°至60°)，还具备对斜入射电磁波精确调控的功能，能够应对复杂的电磁环境。在电磁仿真软件FEKO中进行煤矿巷道建模，将设计的波束调控超表面等效为定向天线进行电磁强度仿真。结果显示所设计的电磁超表面在信号补盲方面表现优异。微波暗室测试实验验证了仿真结果，证实了超表面能够实现定向波束辐射。在矿井巷道等复杂环境进行的现场工业测试进一步验证了超表面在信号补盲方面的良好性能。

      (2)设计了一个工作在3.5 GHz的2 bit有源编码波束调控超表面，其中编码单元的反射幅度高于0.85，相位均匀覆盖0°-360°。引入PIN二极管结合人工排列和算法排列进行相位调制，成功实现了对y极化波在半空间内的任意调控。通过人工排列验证了超表面在(-40°, 40°)范围内的良好波束调控性能。进一步引入遗传算法对阵列进行优化，相较于人工布阵，算法排列阵列的RCS达到17.6 dBsm，旁瓣能量减小为原来的1/2，半功率波束宽度缩减为4.4°，表现出更为出色的波束指向性。仿真结果显示所设计的超表面在半空间内具备任意调控电磁波的能力。同时，研究了阵列大小对波束的影响。相对于无源编码超表面，有源编码超表面在灵活性上表现出更大的优势。通过自由空间法对样品进行实验测试，实验结果与仿真结果吻合。分别在炮掘工作面、综掘工作面和综采工作面三个巷道进行信号补盲测试，结果显示，所设计的编码超表面在三个巷道中，分别可以将信号强度提高7.42 dBm、10 dBm、和7.42 dBm，在不同的巷道中均具有良好的信号补盲能力。

      研究结果显示，所设计的编码超表面成功实现了对线性极化波的波束定向控制，在煤矿巷道等特殊有限空间中，具备提升信号质量和覆盖盲区的潜力。

With the rapid development in communication technology and electromagnetic wave control, beamforming technology has emerged as a crucial research area, holding significant implications for enhancing communication system performance and adapting to complex communication environments. This thesis delves into an in-depth study based on metasurfaces, aiming to enhance the precision and flexibility of beamforming, providing robust support for the advancement of communication technology.

(1) A passive coded beamformer operating at 3.5 GHz was designed, where the amplitude of each coding element exceeded 0.99, ensuring a uniform phase coverage from 0° to 360°. Through precise control of 2-bit polarization-insensitive square metasurface elements, accurate adjustments of both phase and amplitude for incident waves were achieved. The designed coded metasurface not only enables dual-beam and single-beam control for vertically incident linearly polarized waves (with a beamforming range from -60° to 60°) but also exhibits control capability for obliquely incident electromagnetic waves, addressing complex electromagnetic environments. By utilizing the electromagnetic simulation software FEKO for tunnel modeling, the designed beamformer was equivalent to a directional antenna for electromagnetic intensity simulation. Results demonstrated its outstanding performance in signal nulling. Experimental validation confirmed the simulation results, affirming the metasurface's ability to achieve directional beam radiation. Field industrial tests conducted in complex environments such as mine tunnels further validated the metasurface's outstanding performance in signal nulling.

(2) A 2-bit active coded beamformer operating at 3.5 GHz was designed, featuring reflection amplitudes higher than 0.85 and a phase coverage from 0° to 360°. The introduction of PIN diodes combined with manual and algorithmic arrangements facilitated phase modulation, successfully achieving arbitrary control of y-polarized waves in half-space. Manual arrangements verified the metasurface's excellent beamforming within the range of -40° to 40°. Further introduction of a genetic algorithm for array optimization resulted in an array with an RCS value reaching 17.6 dBsm, a 50% reduction in sidelobe energy, and a 4.4° reduction in half-power beamwidth, showcasing superior beam directionality. Simulation results illustrated that the designed metasurface possessed the capability for arbitrary electromagnetic wave control in half-space. Additionally, the study investigated the influence of array size on beamforming. In comparison to passive-coded metasurfaces, active-coded metasurfaces demonstrated greater flexibility. Experimental tests using free-space methods aligned with simulation results, confirming the precise and flexible beam control of the designed active coded metasurface. Signal blind spot tests are conducted in three different tunnels: drilling, tunneling, and mining faces. The results show that the designed active-coded metasurfaces enhances signal strength by 7.28 dBm, 7.42 dBm, and 7.62 dBm, respectively, in the three tunnels, demonstrating effective signal enhancement capabilities across diverse tunnel environments.

The research findings demonstrate that the designed encoded metasurface has successfully achieved beamforming control of linearly polarized waves. It possesses the potential to improve signal quality and cover blind spots in specific confined spaces such as coal mine tunnels.

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