Conformal Reconfigurable Intelligent Surfaces: A Cylindrical Geometry Perspective

TL;DR

This paper systematically investigates cylindrical reconfigurable intelligent surfaces (RISs), developing models and practical strategies to enable directive scattering with minimal hardware complexity for next-generation wireless communication.

Contribution

It introduces a comprehensive modeling framework and practical design strategies for cylindrical RISs, advancing from idealized synthesis to real-world implementation with simple meta-atoms.

Findings

One-bit RISs can achieve directive scattering with low sidelobes.

The developed models enable efficient beam synthesis and optimization.

Validation confirms the practicality of cylindrical RISs for wireless applications.

Abstract

Curved reconfigurable intelligent surfaces (RISs) represent a promising frontier for next-generation wireless communication, enabling adaptive wavefront control on nonplanar platforms such as unmanned aerial vehicles and urban infrastructure. This work presents a systematic investigation of cylindrical RISs, progressing from idealized surface-impedance synthesis to practical implementations based on simple one-bit meta-atoms. Exact analytical and geometrical-optics-based models are first developed to explore fundamental design limits, followed by a semi-analytical formulation tailored to discrete, reconfigurable architectures. This model enables efficient beam synthesis using both evolutionary optimization and low-complexity strategies, including the minimum power distortionless response method, and is validated through full-wave simulations. Results confirm that one-bit RISs can achieve directive scattering with manageable sidelobe levels and minimal hardware complexity. These findings establish the viability of cylindrical RISs and open the door to their integration into dual-use wireless platforms for real-world communication scenarios.