World’s First Technology for Wireless Communications and Power Supplies on a Single Sheet

– Safe and efficient power and communications without cords –

The University of Tokyo, NEC Corporation (NEC), NEC Engineering, Ltd., CellCross Co., Ltd. and the research group from Teijin Limited have developed new technologies, with support from the National Institute of Information and Communications Technology, that provide electronic devices with wireless LAN communications and a power supply through a single sheet of material.
These technologies enable electronic devices with specialized couplers to access wireless communications and power supplies by capturing electromagnetic waves in the vicinity of a transmission sheet. These electronic devices access high speed communications using electromagnetic waves from microwave bands, as well as power supplies with a transmission efficiency of more than 25{e1f18614b95d3cd6e4b3128e1cd15d99b042a60a5a19c19b7a8e07e7495efa10}.
Communications and power supplies from existing transmission sheets and couplers suffer from high leakage of electromagnetic waves as well as poor efficiency in power transmission.
Recent changes in the structure of both sheets and couplers, however, resulted in new electromagnetic wave control technologies that further suppress the leakage of electromagnetic waves. Moreover, new highly efficient transmission technologies also improve the efficiency of transmissions.
Tests of these new technologies with a prototype transmission sheet that is 60cm on all sides demonstrated high speed communications through a 5GHz wireless LAN and provided a power supply with transmission efficiency of more than 25{e1f18614b95d3cd6e4b3128e1cd15d99b042a60a5a19c19b7a8e07e7495efa10} at more than 4W on a 2.4GHz band. Furthermore, the safety and possible commercialization of these technologies were also demonstrated by their low levels of electromagnetic wave emissions, well within protection guidelines (*1), when near or directly handling the equipment.
The simple placement of this newly developed transmission sheet on an office desk enables individuals to both access a cordless power supply for electronic devices, such as personal computers, and to realize safe power transmission without the interference of other wireless LAN. Furthermore, the comfort of a working environment can be improved by using these technologies for power with cordless lighting and fans, in addition to its wireless communications for multiple displays and personal computers.
Key features of these technologies include the following:
1) Electromagnetic wave leakage suppression for transmission sheets and couplers
In order to suppress the electromagnetic waves leaked from transmission sheets, the edge of sheets are covered with a conductor and each sheet’s internal mesh wiring features an optimized pattern. Furthermore, in order to block electromagnetic waves of specific frequencies for couplers, an EBG (*2) structured coupler was also developed. As a result, external emissions of electromagnetic waves from communications and power supply transmission have been reduced to less than 10{e1f18614b95d3cd6e4b3128e1cd15d99b042a60a5a19c19b7a8e07e7495efa10} of existing technologies.
2) Highly efficient, safe transmissions through resonant circuit design technologies
Structures were developed to realize a low loss in wireless power transmission between the transmission sheet and the coupler. Transmission sheets with a protective layer to reduce electromagnetic fields were also adopted. As a result, these new technologies provide highly efficient, wireless power transfer and communications that safely control electromagnetic fields.
3) Highly reliable transmission sheet
These technologies feature a newly developed transmission sheet featuring heat-resistance, moisture-resistance, high load capacity and durability. Moreover, power supply units and sheets were integrated into transmission sheets for producing electromagnetic waves.
Going forward, this research group will continue developing technologies that promote the commercialization of these products.