Two-Layer Stacked Intelligent Metasurfaces: Balancing Performance and Complexity

2026-03-11

AI Summary

Conventional multilayer intelligent metasurfaces struggle to meet practical wireless communication demands due to structural complexity, high computational overhead, and severe interlayer power attenuation. This work proposes two dual-layer stacked architectures—MF-SIM and FILM—that jointly optimize signal processing flexibility and power efficiency directly in the electromagnetic wave domain. By integrating meta-fiber interconnects with a flexible layered design and performing co-optimization within MIMO and multi-user systems, the approach explicitly characterizes the trade-offs among functionality, configuration, and performance. Case studies demonstrate that the proposed architectures substantially reduce both power loss and optimization complexity while preserving excellent signal processing capabilities, thereby offering an efficient and viable pathway for intelligent metasurface deployment in 6G networks.

Technology Category

• Search and Optimization: Metareasoning and Metaheuristics
• Intelligent Robots: Multi-Robot Systems
• Machine Learning: Hardware-aware ML

Application Category

• Systems and Infrastructure for Web, Mobile and WoT: Applied ML and AI for Web-based mobile applications
• Search and Retrieval-Augmented AI: Efficiency and scalability of Web search engines
• Social Networks and Social Media: Generative AI / large language models and their impact on social systems

Abstract

Stacked intelligent metasurfaces (SIMs) have emerged as a powerful paradigm for wave-domain signal processing, enabling fine-grained control over electromagnetic (EM) propagation in next-generation wireless systems. However, conventional multi-layer SIMs often suffer from excessive structural complexity, high computational overhead, and significant power attenuation across layers, limiting their performance. In this paper, we first characterize SIMs from the perspectives of functionality, application, and layer configuration, revealing the inherent trade-offs between signal processing flexibility and power efficiency. Then, two representative 2-layer architectures, the meta-fiber-connected SIM (MF-SIM) and the flexible intelligent layered metasurface (FILM), are introduced, each advocating a distinct 2-layer SIM design philosophy. Moreover, we identify several open challenges in topology optimization for MF-SIM, shape control for FILM, and hybrid 2-layer architectures. Finally, case studies considering 2-layer MF-SIM and FILM assisted point-to-point multiple-input multiple-output (MIMO) and multi-user communication systems validate that properly designed 2-layer SIMs can significantly reduce power loss and optimization burden while maintaining good signal processing performance, offering a promising pathway toward practical SIM-enabled 6G systems.

Problem

• stacked intelligent metasurfaces
• structural complexity
• computational overhead
• power attenuation
• signal processing performance

Innovation

• stacked intelligent metasurfaces
• two-layer architecture
• power efficiency
• wave-domain signal processing
• 6G wireless systems