Study on high efficiency WPT underseas

Aiming at the undersea WPT (Wireless Power Transfer) system, improvement of power transfer efficiency through saltwater is studied. We have examined the unloaded Q (Q
_u
) and coupling coefficient (k) of the spiral coil resonators for different diameters and different operating frequencies with the number of turns fixed. In addition, introducing a new structure of 4-layered spiral coil resonators, we found the improved transfer efficiency, especially by adopting dense winding of litz wire.