Wireless Power Transmission

The phenomenon known as electricity is said to have been discovered or at least first recorded around 2700BC when the Egyptians noticed the painful shocks given to them by the fish of the River Nile[10]. It wasn`t until almost two millennia later however that the famous kite experiment carried out by Benjamin franklin that a more theoretical understanding was developed. Since then extensive research was carried out in fields such as bioelectricity concerning the electric pulses within the nervous system of the human body, the discovery of the photo-electric effect and also the characterisation of charge, now known as current mediated by the movement of negatively charged particles, known as electrons.

Electricity has been a huge field for research since its discovery, and in society today is greatly depended upon to power the majority of household possessions, public transport, public amenities etc. Electricity generation most commonly occurs in power stations through the burning of fossil fuels or nuclear fission where the energy is used to heat water which in turn powers a generator creating an alternating current. Other renewable methods such as hydroelectricity or wind power use renewable sources to convert kinetic energy of the water or the wind in to the rotational kinetic energy to power the generator. This electrical power is then managed in a station known as the grid and is then distributed via cables to sub-stations and is then further distributed by more cables to houses or places of need for use.

Due to the tedious nature of connecting devices with cables the demand for wireless connectivity over the last few decades has slowly increased. Inventions such as Wi-Fi or Bluetooth are two examples of technologies which have removed the need for cables and have made it possible for data transfer wirelessly between devices. Not only does this remove the physical tethering of cables it also allows for a more diverse range of connectivity and it has a positive effect on the environment with a reduced demand on cable production. Experiments involving wireless power transfer (WPT) were first carried out by Nikola Tesla between 1891 and 1904 using tesla coils and inductive coupling. He managed to transmit electricity across a stage in front of an audience to wirelessy power a light bulb. This report will discuss the theory for different methods of wireless power transfer before discussing the real world applications currently in use. The two categories of near field and far field transfer will be explained in detail expanding on the different methods within each category. References available on request.