AI 中文总结
针对准分布式模块化阵列的近场栅瓣干扰问题，本文提出模块化最小冗余阵列（M-MRA），可同时抑制角度与距离域栅瓣，提升多用户近场通信频谱效率。
AI 中文摘要
极大规模天线阵列（ELAA）已成为6G多项关键候选技术的共性特征，其近场特性占据主导地位。准分布式阵列可进一步扩展近场范围，利用近场优势提升系统性能，但其典型的模块化阵列实现会产生严重栅瓣，引发不可忽略的用户间干扰。为解决该问题，本文提出模块化最小冗余阵列（M-MRA），通过重新设计子阵配置抑制近场栅瓣。具体而言，首先表征了传统模块化均匀线性阵列（M-ULA）的方向图；与栅瓣仅存在于角度域的普遍认知相反，本文揭示近场栅瓣也可能出现在距离域。进一步分析了M-ULA近场栅瓣的抑制方法，结果表明增加每个模块的天线数量可抑制栅瓣，且所需天线数量与模块间间距呈线性增长，因此天线数量有限时栅瓣干扰仍较严重。该局限性促使本文通过重新设计子阵结构提出M-MRA，其每个子阵内的非均匀天线间距可提供更窄的空间包络，使其能同时抑制角度域和距离域的近场栅瓣。仿真结果验证，在天线数量相同的情况下，所提M-MRA可显著提升多用户近场通信的频谱效率。
英文摘要
Extremely large-scale antenna array (ELAA) has emerged as a common feature of many key candidate technologies for 6G, where the near-field characteristics become dominant. The quasi-distributed array can further extend the near-field range and utilize the near-field benefits to improve the system performance. However, its typical implementation with modular arrays suffers from severe grating lobes that cause non-negligible inter-user interferences. To solve this problem, we propose the modular minimum-redundancy array (M-MRA) to suppress near-field grating lobes by redesigning the subarray configuration. Specifically, we first characterize the beam pattern of the conventional modular uniform linear array (M-ULA). Contrary to the common belief that grating lobes only exist in the angle domain, we reveal that near-field grating lobes may also occur in the distance domain. We further analyze how to suppress near-field grating lobes for the M-ULA. The results demonstrate that increasing the number of antennas per module can suppress grating lobes. In particular, the number of antennas required grows linearly with the inter-module spacing, thus the grating lobe interferences are severe under a limited number of antennas. This limitation inspires us to propose the M-MRA by redesigning the subarray structure. For M-MRA, the nonuniform antenna spacing within each subarray provides a narrower spatial envelope, allowing it to suppress near-field grating lobes in the angle and distance domains simultaneously. Simulation results verify that the proposed M-MRA can significantly improve the spectrum efficiency of multi-user near-field communications under the same number of antennas.
