在隧道场景中使用双泄漏同轴电缆(leaky coaxial cable，LCX)和单个 LCX，研究孔径效应对多输入多输出 (multiple-input multiple-output，MIMO)性能的影响。先从理论上研究 LCX 槽口中的孔径效应，然后在矩形隧道和 拱形隧道中使用 1.8 GHz 的 LCX 进行 2×2 MIMO 测量。测量结果表明：在隧道场景中，由双 LCX 和单 LCX 部 署的孔径效应的概率非常有限。 最后提供双 LCX 和单 LCX 情况下的信道容量结果，可为在隧道中采用 MIMO 技术提供前瞻性指导。

This study investigates the influence of the keyhole effect on multiple-input multiple-output (MIMO) performance by using double leaky coaxial cables (LCXs) and a single LCX in a tunnel scenario. The keyhole effect in the slots of the LCX was theoretically studied. Then, a 2×2 MIMO measurement campaign using LCXs at 1.8 GHz in a rectangular tunnel and an arched tunnel was conducted. The results reveal that the keyhole effect does not exist in the double LCXs case, and the keyhole probability in the single LCX case is also limited. The results of channel capacity in the double LCXs case and single LCX case can provide prospective guidance for employing MIMO technology in tunnels.

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