BlueME: Robust Underwater Robot-to-Robot Communication Using Compact Magnetoelectric Antennas

TL;DR

BlueME addresses the challenge of reliable, low-power underwater robot-to-robot communication by leveraging a compact magnetoelectric antenna array operating near mechanical resonance to enable VLF RF transmission. The authors design, simulate, fabricate, and field-test a $3×5$ ME antenna array embedded in pressure-compensated enclosures, validating performance in freshwater and saltwater environments. Their results show robust links beyond $730~m$ in saltwater at $10~W$ and substantial range in freshwater at $1~W$, with resilience to turbidity, multipath, and obstructions. The work establishes the first practical field deployment of ME antennas for underwater robotics and highlights the technology as a scalable, low-cost alternative for multi-robot networks and remote sensing in challenging aquatic environments.

Abstract

We present the design, development, and experimental validation of BlueME, a compact magnetoelectric (ME) antenna array system for underwater robot-to-robot communication. BlueME employs ME antennas operating at their natural mechanical resonance frequency to efficiently transmit and receive very-low-frequency (VLF) electromagnetic signals underwater. We outline the design, simulation, fabrication, and integration of the proposed system on low-power embedded platforms, focusing on portable and scalable applications. For performance evaluation, we deployed BlueME on an autonomous surface vehicle (ASV) and a remotely operated vehicle (ROV) in open-water field trials. Ocean trials demonstrate that BlueME maintains reliable signal transmission at distances beyond 700 meters while consuming only 10 watts of power. Field trials show that the system operates effectively in challenging underwater conditions such as turbidity, obstacles, and multipath interference -- conditions that generally affect acoustics and optics. Our analysis also examines the impact of complete submersion on system performance and identifies key deployment considerations. This work represents the first practical underwater deployment of ME antennas outside the laboratory and implements the largest VLF ME array system to date. BlueME demonstrates significant potential for marine robotics and automation in multi-robot cooperative systems and remote sensor networks.

Figures (16)

• Figure 1: The proposed BlueME system includes a novel ME antenna design; we use a $3$$\times$$5$ array of these antennas to enable real-time communications between underwater robots.
• Figure 2: The Magnetoelectric (ME) effect illustrating the coupling between magnetostrictive and piezoelectric layers. This mechanical coupling enables direct conversion between the magnetic and electric fields.
• Figure 3: (Top) Illustrations for (a) Cross-sectional schematic showing the three-layer structure: two 25µm Metglas layers with a 150µm PZT layer, dimensions $40\times20$ mm$^2$; (b) COMSOL simulation showing displacement at the predicted fundamental resonance frequency of $40.85$ kHz. (Bottom) Magnetic flux density across a single fabricated ME antenna (dashed outline) under applied bias. Measurements are taken at a uniform height, with the Gaussmeter positioned 1.8 mm above the antenna surface.
• Figure 4: A fabricated ME antenna and its components (top); the packaged enclosure of an array frame with $15$ antennas (bottom).
• Figure 5: Data communication and signal processing flow between a BlueME transmitter (ASV) and receiver (ROV) antenna arrays.