Transmission of electric energy without using wires

Abstract

In this presentation, some properties of the wireless power transfer (WPT) problem are elaborated in terms of physical barriers. There are interesting facts in this approach and its related applications. For example, it is neither necessarily true that the power must be transmitted by electromagnetic fields nor entirely correct that the transmitting rnedium should be vacuum or air. The inadequacy of the direct application of Faraday's induction law to provide efficient power transfer will be illustrated. Furthermore, what is necessary to add in order to produce high transfer efficiency will also be shown. The scheme will be classified according to the length of the physical barrier, namely, short (mm), medium (dm), large (m) and ultra large (> 100 rn or km). Some examples of these technologies will be presented.