We all know that electromagnetic waves can be used to transmit information, so in theory, as long as the frequency is high enough, it can also transmit energy. This wireless charging method may be the closest approach to people's imaginary wireless charging. An electromagnetic wave generator is installed at the power source, and the energy is transmitted to the receiving antenna through the transmitting antenna, and then the electromagnetic wave signals are returned into electrical energy for the use of the equipment. But this power transmission mode also has obvious weaknesses, such as electromagnetic wave interference, low transmission efficiency and radiation to human body.
There had been a message that Apple has joined the Wireless Power Consortium, but has been responding to Apple's QI standards in wireless charging technology. At present, the QI standard's wireless charging power is maintained around 15W. There is a guess that the iPhone 8 wireless charge will use the power of 5V/1.5A, while 7.5W's charging power is likely to be full of a cell phone for a whole night. Therefore, at present, long-distance transmission in a small scope is not yet mature at the technical level.