Reconfigurable Intelligent Surface Constructing 6G Near-field Networks

Near-field propagation, especially when facilitated by reconfigurable intelligent surface (RIS), has become a significant field of inquiry in recent times. Despite this, there remains a noticeable absence of an exhaustive literature review concerning RIS-empowered near-field technologies. This paper seeks to bridge this knowledge gap by presenting a concise overview of near-field principles, coupled with a systematic examination of the latest advancements in RIS-driven near-field technologies. It specifically concentrates on three pivotal areas: the establishment of pervasive near-field wireless propagation environments through RIS, the introduction of novel near-field frameworks for 6G networks via RIS, and the array of challenges inherent in RIS-based near-field technologies. The objective of this technical review is to bolster the progression and innovative exploration in the realm of RIS-oriented near-field technologies.