We derive a novel closed-form lower bound on the ergodic capacity of holographic multiple-input multiple-output (HMIMO) systems enhanced by stacked intelligent metasurfaces (SIMs) under Rayleigh fading conditions. The proposed expression is valid for systems with a finite number of antennas and SIM elements and exhibits tightness throughout the whole signal-to-noise ratio (SNR) range. Furthermore, we conduct a comprehensive low-SNR analysis, offering meaningful observations on how key system parameters influence the capacity performance.

翻译：本文在瑞利衰落信道条件下，推导了堆叠智能超表面（SIM）增强型全息多输入多输出（HMIMO）系统遍历容量的新型闭式下界。所提出的表达式适用于天线与SIM单元数量有限的系统，并在整个信噪比（SNR）范围内保持紧致性。此外，我们进行了全面的低信噪比分析，针对关键系统参数如何影响容量性能提供了具有实际意义的观测结论。