MetaScatter: Enabling High-Order Underwater Backscatter via Piezoelectric Metasurface

Abstract

Underwater communication has long been constrained by the fundamental requirement for low power consumption, driven by applications such as environmental monitoring that demand long-term operation. While backscatter technology is promising in terms of power consumption, existing systems rely on simplistic reflection states (e.g., binary modulation), resulting in low data rates and the communication range is also limited. In this paper, we present MetaScatter, the first piezoelectric metasurface that overcomes these limitations by simultaneously enabling high-order backscatter modulation and beamforming. Unlike conventional mechanical metasurface designs, MetaScatter leverages programmable piezoelectric meta-atoms to control the phase of reflected acoustic signals in real time at milliwatt-level power. By decoupling beamforming and modulation via novel meta-surface codebook designs, we achieve long-range communication and high-order modulation with significantly reduced complexity. Experimental results in real-world underwater environments show that MetaScatter supports reliable high-order modulation, including 16-QAM, achieving over 500% higher throughput than the state-of-the-art underwater backscatter system [24].