Wireless Power Transmission

                                                        Wireless power or wireless energy transmission is the transmission of electrical energy from a power source to an electrical load without man-made conductors. Wireless transmission is useful in cases where interconnecting wires are inconvenient, hazardous, or impossible. The problem of wireless power transmission differs from that of wireless telecommunications. The conditions vary for

• electromagnetic coupling in general and mainly on long distances
• dominant inductive coupling on short distances

With wireless transmission, the efficiency in terms of electrical power is the significant parameter with electromagnetic coupling besides security for all matter around the transmitter and along the line of sight between transmitter and receiver:

• Direct visibility on the path from the transmitter to the receiver is mandatory for low attenuation loss.
• Any matter along the line of sight is endangered to be thermally destroyed by dielectric loss as in a RADAR beam.
• The geometric radiation characteristics of the transmitter antennae defines the portion received with the receiver antennae compared to omnidirectional characteristics.
• Any focusing at the transmitter may increase the portion received at the receiver.

In radio signal transmission, however, mainly the proportion of energy received becomes critical to enable proper discrimination of sent signal from noise.
The most common form of wireless power transmission is carried out using direct induction followed by resonant magnetic induction. This principle is used with many industrial applications and with modern cooking stoves.