A systematic approach for reconfigurable reflecting metasurface synthesis: From periodic analysis to far-field scattering

Abstract

We present a consistent approach for a systematic design of an intelligent reflecting surface (IRS), based on a new unit cell with efficient reconfigurability functionalities and a three-step electromagnetic methodology for a rigorous IRS synthesis. First, we design and simulate a reconfigurable unit cell, in which the reconfigurability is accomplished by varactor diodes. Next, we model the IRS as a periodic structure of infinite size, according to Floquet theory. By utilizing the theory of anomalous reflection, we arrive at approximate analytical solutions to calculate the set of necessary varactor diodes’ capacitances, which is subsequently fine-tuned by a fast optimization process to achieve enhanced operation. Finally, to arrive at a more realistic design, we properly analyze the IRS as a finite-sized structure. To this end, we employ an efficient finite element method (FEM) analysis, with a properly developed simulation tool, in which the IRS is modeled as an equivalent impedance sheet of zero-thickness. Overall, we extract the far-field scattered pattern of the IRS and evaluate the angular and frequency response of the design for normal and oblique incidence. Our results show that the proposed design exhibits very promising characteristics, both in terms of reconfigurability and frequency response that can be exploited in contemporary and future wireless communication systems.