Near-Field MIMO RIS Channel Capacity

The rapid evolution of wireless communication systems has ushered in an era of unprecedented connectivity and data transmission capabilities. Among the key technologies driving these advancements are Multiple-Input Multiple-Output (MIMO) systems and Reflecting Intelligent Surfaces (RIS). On the one hand, MIMO harnesses the power of multiple antennas at both transmitter and receiver ends to exploit spatial diversity and multiplexing gains, enhancing data rates and signal reliability. On the other hand, RIS promise to enable precise manipulation of electromagnetic waves through intelligent reflecting elements. In this work we evaluate the Shannon point-to-point capacity of MIMO RIS systems, when all terminals have multiple antennas and have no limitation on the type of processing performed; in addition, our model includes near-field propagation effects.