Wireless energy transmission

             Wireless energy transfer also known as wireless power is a method of electrical energy transmission from a source to load without the use of wires to connect it. This is an emerging transmission method expected to be realized sooner. It may provide a solution for many of the problems caused in the field of electricity transmission. This type of transmission is most effective when the use of connecting wires is hazardous or in convenient. As in any other transmission systems, the wireless energy transfer has also limitations. But the problem of this field is quite different from that of normal telecommunications such as radio. In the case of radio, if the proportion of energy received is too low to be distinguished from the background noise, then it becomes critical. And for wireless power, the efficiency parameter is the more significant one. If the system is to be efficient and economical, then the main or large portion of the generated power should reach the receivers.

               The most common method to implement wireless energy transfer is by using direct induction succeded by resonant magnetic induction. The new innovative methods available are electromagnetic radiation as microwaves or lasers.

              The flow of electrical energy involves the phenomena inside the conductor and those outside the conductor, that is, in the electric field. In the conventional electric power transmission and distribution, it is the phenomena inside the conductor that is of prime importance. Here the electric field outside the conductor is just checked occasionally. But if we use electric power for radio transmission or wireless energy transmission, it is the electric and magnetic fields outside the conductor which is called the electromagnetic radiation that is important in the message transmission.  And we do not use the phenomenon in the conductor. A magnetic field and electric lines of force resulting from it are produced by the electric charge displacement in the conductor. In the concentricdirection to the conductor, the magnetic field will be maximum which describes the property of a ferromagnetic body to align itself in right angles to the conductor.

                      But the electric field is maximum in a direction radial to the conductor and will cause the dielectric bodies to be attracted or repelled radially to the conductor.

                       The wireless transmission through electro dynamic induction is near field up to one- sixth of the used wave length used. Even though it is non radiative, some radiative losses occur. An electrical transformer is the simplest example of wireless transmission.