Fundamentals of Design and Operation of Reconfigurable Intelligent Surfaces

Abstract—Reconfigurable intelligent surfaces (RISs) are a promising technology for increasing the information capacity and coverage of future wireless networks. Various available types of these devices consist of different elements that can be used for signal absorption, increasing the information capacity, and phase shift keying. This causes a lack of a single concept and misunderstanding of functionality of specific RISs. The aim of this study is to eliminate this gap by describing one of the most widely used RIS structures and its operating principles, which make it possible to formulate the main functionalities of the RIS.