Analysis and Implementation of Underwater Single Capacitive Coupled Simultaneous Wireless Power and Bidirectional Data Transfer System

This article investigates an underwater single capacitive coupled simultaneous wireless power and data transfer (USCC-SWPDT) system, aiming to extend the operational range and communication capability in submerged environments. Traditional inductive methods face limitations due to seawater's eddy current loss, which the USCC-SWPDT system addresses, thereby enabling power and bidirectional data transmission over 1 m. The system represents a marked improvement in range and capability compared to its inductive counterparts. First, the working principle of wireless power transfer by a single capacitive coupled mechanism is explained. Second, the transfer properties of the power and data channels are analyzed in detail by employing the two-port network theory. Next, the crosstalk and misalignment characteristics of the power and data channels are investigated. Finally, an experimental prototype with a separation distance of 1 m, transmission power of 300 W, and bidirectional data rate of 500 kb/s verifies the feasibility of the USCC-SWPDT system. By comparing the bit error rate of communication system in differential phase shift keying modulation mode at different transfer power and different data rates, the USCC-SWPDT system proposed in this article can achieve simultaneous wireless power and data transfer in seawater at 1mlevel.