Tunable 2-bit Unit Cell Based in a Square Loop for Reconfigurable Intelligent Surface Application

This document describes a study of a tunable frequency selective surface (FSS) for applications in reconfigurable intelligent surface (RIS) with millimeter wave beamforming, for applications in the Fifth generation of mobile networks (5G). The work developed a square loop that changes its reflection coefficient and reflection phase shift controlled by PIN diodes. The study was based on the simulation of two tunable unit cells, the 1-bit FSS and the 2-bit FSS, designed by the ANSYS HFSS. Simulated results obtained a phase shift difference of 123.10° for the 1-bit FSS and 177.48° for the 2-bit FSS at 26.25 GHz.