From an efficiency point of view, wireless inductive
power transfer is feasible for general power applications
only if transmitter and receiver coils are in close proximity
to each other. Inductive power transfer in a larger space is
not feasible due to the very low efficiency. An inductive
power pad to charge mobile devices is presented, which
allows arbitrary positioning and local detection. To trigger
the market introduction of this technology to charge mobile
devices, the international Wireless Power Consortium with
meanwhile more than 90 industry members released the first
standard named “Qi” (pronounce “chee”) for devices up to
5 W.