Wireless Power Transfer

Remote powering of devices is fast becoming one of the most important technological pursuits in engineering. An efficient means of transferring power from a source to a receiver wirelessly is through electromagnetic near-fields. The near-field of a source consists of electromagnetic fields that do not radiate, but rather build up around a source and fall off quickly with distance from the source. Being mostly magnetic, near-fields are considered safe for human exposure and can be used in highly efficient wireless power transfer schemes; however, the distance between the source and the item receiving power must be very small—usually on the order of a few feet at most. Metamaterials have a potentially interesting role to play in wireless power transfer, as they can manipulate and focus near-fields, much as a lens can focus or modify visible light. In recent work, CMIP researchers have shown that the distance between a source/receiver pair of coils can be increased with the insertion of a metamaterial near-field ‘lens’ between them. More about this work can be found in the article by G. Lipworth et al., “Magnetic metamaterial superlens for increased range wireless power transfer,” Nature Scientific Reports 4, 3642 (2014).