Theory for the wireless charging and procedure to convert or creat charger that can charge our existing mobile wirelessly with help of electricity.
As you might know that bluetooth is also one kind of Radio Frequency genrator. that do genrate radio wave on specific frequency (Analog Signal) that could be turn into to digital signal (a specific kind Voltage to Electricle Circuit) that will flow the specific empier current into circuit. which could be turn into electrical power supply. a following Image might help you for understanding.
Here Tx Controller is Transmitter and RX Controller is Receiver you could see at the end Inductor has been place that will fluctuate the power at the end.
to read more about wireless chaging techniques please follow the link.