How Can Radio-Frequency Harvesting Transfer Power Wirelessly?

[olek1991]

Radio-frequency Harvesting

THE INDUCTION SYSTEMS are only the beginning. Some of the most visually arresting examples of wireless electricity are based on what's known as radio frequency, or RF. While less efficient, they work across distances of up to 85 feet. In these systems, electricity is transformed into radio waves, which are transmitted across a room, then received by so-called power harvesters and translated back into low-voltage direct current


I found this on the web and i really want to know how this works, could anyone explain to me how i could build this?

 

[marcusl]

Short distance power transfer is a commercial reality (it's how electric toothbrushes recharge and wireless teakettles work). Long-distance transfer has been a dream starting with extensive experiments in the mid-1800's and, most famously, by Tesla around 1900. Efficiency is extremely low, however. Highly directional microwave antennas have been proposed since the 1970's to beam power collected by space-based solar panels down to earth, but safety concerns have prevented any experimentation. If interested in the history, you can find a wealth of information on the web.