Dr Nikola Tesla work into wireless transmission of power
The idea of wireless electrical power transmission was first put forward at the beginning of the last century by the Croatian-born US electrical engineer Dr Nikola Tesla (1856-1943).

In 1899, Tesla succeeded in developing a means of transmitting electricity without the use of a conductor. Between 1901-03, Tesla constructed a 57-metre high tower at Long Island in the USA known as the Wardenclyffe tower to test his idea of wireless transmission of power across the Atlantic. Yet surprisingly, owing to a lack of funds and limited interest by business people at the time (probably because they did not know how to charge customers for using the power that would have been transmitted by the tower), the project was abandoned and the idea has remained largely forgotten.
All we are left with is a patent from Tesla relating to the Wardenclyffe project titled "Apparatus for Transmitting Electrical Energy" (1,119,732, filed in 1902, but was not issued until 1914). (1)
Sir Raymond Phillips and his radio wave to electrical current converter circuit
The feasibility of wireless transmission of power, however, was proved by the electrical engineer Sir Raymond Phillips of Texas, USA, who in 1988 patented a simple electronic circuit for converting the energy in electromagnetic waves in the radio spectrum directly into electrical current. (2)
Phillips' patented circuit behaves just like a solar cell as far as collecting the energy in electromagnetic waves is concerned. The only difference is that the circuit taps the abundant electromagnetic energy of radio waves for generating direct current using a few simple electronic components rather than the visible region of the electromagnetic spectrum, as solar cells do.
The circuit consists of diodes (i.e., a piece of special silicon crystal for directing current in one direction only) to rectify the radio frequency signals into direct current and a plurality of 'electronic cells' consisting of a handful of capacitors, diodes and coils to help store and amplify the voltage and current for powering electrical circuits such as radios and battery chargers.
A larger-size antenna will also help to collect more energy from radio waves, which would have the effect of generating more power to run larger electrical devices.

Where would the radio waves come from?
To power any electrical device using this patented circuit, the radio waves could come from any natural or man-made source.
In the case of Tesla's Wardenclyffe tower, the energy would have been derived from the radio broadcasts that would have been transmitted from the tower at the time it was constructed.
Today, it is possible for any local "free-to-air" radio and television stations to supply all the electrical energy needed to power any electrical device. Or the radio waves could be obtained from natural "free" sources such as the Sun or other radio noises emanating from all directions in the universe.
As Tesla once said in 1891:
[In] many generations pass ours, machinery will be driven by power obtainable at any point in the universe....It is a mere question of time when men [and women] will succeed in attaching their machinery to the very wheelwork of Nature.' (3)
Can we make Tesla's dream come true? Or are we too profit-motivated to allow people to have free energy devices?