Enhanced Channel Capacity Underwater Multi-Diver Communication with Dual-Resonant Magnetoquasistatic Coupling

In underwater group missions, where effective communication among divers is crucial, delays in information exchange present significant challenges. Such delays can compromise mission success and pose serious risks to diver safety. Existing communication technologies, including RF, optical, magnetic-induction, and acoustic-based systems, suffer from low data rates due to limitations imposed by underwater medium properties (conductivity, permeability, visibility). Among these, magnetically coupled systems exhibit reduced signal attenuation in highly conductive media but are constrained by their limited data transmission rates. This work introduces a novel wideband communication system utilizing dual-resonant MQS coupling, employing human-sized coils for multi-diver communication. The proposed system demonstrates a data rate of $\sim 30 \text{Mbps}$ over a 70 cm range using single-turn 10 cm coils in seawater. Additionally, a larger 40 cm single-turn coil achieves a data rate of 10 Mbps over a 1 -meter distance, showcasing the system's potential to overcome the limitations of existing near-field magnetically coupled systems.