Beamforming in Intelligent Reflecting Surfaces: Simulation, Prototype Design and Field Measurements

Intelligent reflecting surface (IRS) is a promising energy efficient solution to address the high signal attenuation in wireless propagation. The ability to fabricate an IRS array on a metal sheet using microstrip line techniques makes this more appealing. In this paper, we explore the beamforming ability of an IRS fabricated to operate at 5.8 GHz. First, we present the basic working and design of an 1-bit quantized unit element of an IRS. Next, we have extended the design to an array and carried out simulations of arrays of sizes 4×4 and 8×8 to compare the gain variations of arrays of different sizes. To assess the proposed design, we fabricated two arrays of sizes 4×4 and 8×8 and conducted field experiments. The received signal power at selected locations, for various configurations of the two fabricated IRS arrays were measured. According to the obtained measurements, a gain in the received signal power could be observed at certain directions. This validates the design procedure of the array. Furthermore, the developed prototype is capable of beamforming in certain directions.