This study centers on Line-of-Sight (LoS) MIMO communication enabled by a Transmissive Reconfigurable Intelligent Surface (RIS) operating in the Terahertz (THz) frequency bands. The study demonstrates that the introduction of RIS can render the curvature of the wavefront apparent over the transmit and receive arrays, even when they are positioned in the far field from each other. This phenomenon contributes to an enhancement in spatial multiplexing. Notably, simulation results underline that the optimal placement of the RIS in the near-field is not solely contingent on proximity to the transmitter (Tx) or receiver (Rx) but relies on the inter-antenna spacing of the Tx and Rx.

翻译：本研究聚焦于太赫兹频段下由透射式可重构智能表面（RIS）支持的视距（LoS）MIMO通信。研究表明，即使发射和接收阵列彼此位于远场区域，RIS的引入仍可使波前曲率在这些阵列上变得显著。这一现象有助于增强空间复用能力。值得注意的是，仿真结果强调，RIS在近场中的最优布局并非仅取决于其与发射端（Tx）或接收端（Rx）的邻近性，而是依赖于Tx和Rx的天线间距。