OrbWeaver: A Geometric Optics-Based RIS for Omnidirectional 3D Beam Steering

Abstract

Reconfigurable Intelligent Surfaces (RIS) are a key 6G technology for controlling the wireless environment and eliminating signal blockages. However, dominant planar meta-surfaces suffer from high cost, complex control, limited 3D coverage, and high beam alignment overhead. This paper presents OrbWeaver, an RIS that replaces complex metasurfaces with a 3D-printed Luneburg lens and a simple reconfigurable RF switching fabric. It leverages geometric optics for cost-effective, programmable signal redirection across an omnidirectional 3D field of view. A key advantage is its ability to perform in-situ power measurements, enabling a decoupled beam alignment protocol that drastically simplifies multi-node coordination. We validate OrbWeaver with mmWave and sub-6 GHz prototypes, demonstrating its frequency-agnostic design. In real-world 5G and Wi-Fi deployments, OrbWeaver eliminates dead zones, achieving throughput gains up to 430 Mbps and 241 Mbps, respectively. Our results establish OrbWeaver as a practical RIS solution to overcome the deployment barriers of conventional metasurfaces.