Realistic Evaluation of Impedance-Based RIS Modeling: Practical Insights and Applications

TL;DR

This paper evaluates the realism of impedance-based RIS models by analyzing structural scattering effects through simulations, revealing limitations of current models and emphasizing the need for improved optimization strategies for practical wireless applications.

Contribution

It provides a comprehensive comparison between traditional and EM-consistent RIS models, highlighting the impact of structural scattering and offering practical insights for future RIS design improvements.

Findings

Traditional models overlook structural scattering effects.

EM-consistent models reveal significant structural scattering impacts.

Current RIS designs require new optimization strategies to mitigate scattering.

Abstract

Reconfigurable Intelligent Surfaces (RISs) have emerged as a promising technology for next-generation wireless communications, offering energy-efficient control of electromagnetic (EM) waves. While conventional RIS models based on phase shifts and amplitude adjustments have been widely studied, they overlook complex EM phenomena such as mutual coupling, which are crucial for advanced wave manipulations. Recent efforts in EM-consistent modelling have provided more accurate representations of RIS behavior, highlighting challenges like structural scattering-an unwanted signal reflection that can lead to interference. In this paper, we analyze the impact of structural scattering in RIS architectures and compare traditional and EM-consistent models through full-wave simulations, thus providing practical insights on the realistic performance of current RIS designs. Our findings reveal the limitations of current modelling approaches in mitigating this issue, underscoring the need for new optimization strategies.