Intelligent Reflecting Surfaces for THz Communications: Fundamentals, Key Solutions, and System Prototyping

TL;DR

This paper reviews the use of intelligent reflecting surfaces in terahertz communications, discussing hardware, signal processing, and deployment, supported by experiments at 220 GHz demonstrating improved signal quality.

Contribution

It provides a comprehensive overview of IRS architectures, analyzes fundamental effects in THz systems, and validates IRS benefits through practical experiments.

Findings

IRS improves signal strength and reliability at 220 GHz.

Various reconfigurable metasurface architectures are analyzed.

Fundamental effects like near field and beam squint impact system performance.

Abstract

Intelligent reflecting surfaces (IRSs) have emerged as a cost-effective technology for terahertz (THz) communications by enabling programmable control of the wireless environment. This paper provides a comprehensive overview of IRSs-aided THz communications, covering hardware designs, advanced signal processing techniques, and practical deployment strategies. It first examines key THz reconfigurable metasurface architectures, including electronic, optical, phase-change material, and micro-electromechanical systems (MEMS)-based implementations, highlighting their reconfiguration mechanisms and challenges. Then, fundamental effects including near field and beam squint in wideband THz systems are analyzed, along with their impacts on system performance. The paper further explores conventional and beam-squint-assisted channel estimation methods, innovative beam management strategies, and deployment considerations across large- and small-scale scenarios. Practical experiments at 220 gigahertz (GHz) validate the effectiveness of IRS in improving signal strength and communication reliability for both single-user and multi-user setups.