According to a U.S. Patent and Trademarking application that was made public today, Apple appears to be looking for a way to charge devices like the iPhone and iPad using wifi-router signaling. The technique is somewhat similar to the induction charging that it uses for the Apple Watch but increases the distance that the device can be from the charging antenna.
Apple titled the technique “Wireless Charging and Communications Systems With Dual-Frequency Patch Antennas” and appears to have several ideas on how they can get it to work. According to Apple Insider, they theorize that power transfer can occur in communication signals ranging from 700 MHz and 2700 MHz and on the 2.4 GHz and 5 GHz wifi bands.
The proposed device would use something similar to the “beam steering” technology that Apple uses in its current routers to improve signal quality, except that in this case power would "piggyback" on the data signal and trickle-charge the device.
The filing touches on ways that Apple could extend the range of its induction charging technology. While it does not go into great detail, some of the concepts mentioned include dual mode circuitry, dual-polarization, dual-frequency patch antennas, substitute antenna arrays, and wireless circuitry configurations.
Apple Insider also reports that a “purportedly leaked 'iPhone 8' schematics appeared to reveal space for a large wireless charging pad to be positioned in the handset's rear casing. Interestingly, the area resembles a patch antenna similar to applications described in today's patent filing.”
It has been speculated that the iPhone 8 will indeed have some form of wireless charging, but AI doubts that the tech described in the patent are a part of that. However, the patent was first filed in 2015, so who knows how far Apple has come in its research since then. We might be seeing wifi charging or something similar in the not so distant future.