Power Without Wires

Recent advancements in wireless power transmission (WPT) technologies are enabling various engineering applications with potential product implementation. In the 1960s, William C. Brown restarted WPT experiments with high-efficiency microwave technologies based on the wireless communications and radar remote sensing technology developments during World War II. He carried out many kinds of MPT experiments with 2.45 GHz microwave tubes. MPT technologies were also developed with a solar power satellite (SPS). In the 2000s, advances in microwave technologies pushed WPT back into consideration for commercial applications. With the development of mobile communications technologies, the required power decreases for WPT [Figure 1(8)]. This means that we can receive enough power via microwaves, just as with a wireless communication. Wireless power can be received through broadcast service radio waves also. The other recent trend in WPT started from the use of resonant coupling by MIT in 2006. In Japan, a technical forum known as Broadband Wireless Forum has been established to discuss the future of WPT. SPS researchers have also submitted a proposal for WPT to the International Telecommunication Union (ITU). In the IEEE MTT Society, the Technical Committee MTT-26 Wireless Energy Transfer and Conversion was established in June, 2011 to discuss the future of WPT.