Investigating the Use of Lunar Sand to Expand the Area Where Wireless Power Can Be Supplied to Mobility Vehicles Operating on the Lunar Surface

In this paper, a method for expanding the power supplying area by using the sand as dielectric that assists in the propagation of electric field waves is studied. Wireless power transfer using electric or magnetic resonance in the near field has a high transmission efficiency, but the transmission distance is shorter than the far field wireless power. However, when wireless power transmission is performed by the electric field coupling of capacitive couplers, a metal or dielectric material placed between the couplers can be a transmission medium to deliver electric power over a longer distance. We propose a method to extend the wireless power area by using sand, which is abundant on the Moon, and showed that the transmission efficiency is improved for about 6 dB on average. Our goal is wirelessly powering unmanned rovers traveling on the lunar surface where it is difficult to bring cables from Earth. In this paper, we present the measurement results of verifying the effectiveness of our prototype that we have developed.