Researchers at the University of Michigan (UM) and the University of Tokyo have developed a system that can safely transmit electricity through the air, potentially turning an entire building into a wireless charging zone.

In a new study published by Nature Electronics, the technology can use a magnetic field to provide 50 watts of power.

Research author Alanson Sample, professor of computer science and engineering at the University of Michigan, said that in addition to removing the shackles of mobile phones and laptops, the technology can also power implanted medical devices and open up new possibilities for mobile robots in homes and manufacturing facilities. sex. The team is also working on implementing the system in spaces smaller than the size of a room, such as a toolbox for charging tools placed in it.

"This really boosts the power of the ubiquitous computing world-you can put the computer anywhere without worrying about charging or plugging in," Sample said. "There are still many clinical applications; for example, today's cardiac implants require a wire from the pump through the body to an external power source. This can eliminate this situation, reduce the risk of infection and improve the quality of life of the patient."

The team, led by researchers from the University of Tokyo, demonstrated the technology in a dedicated aluminum test chamber about 10 feet by 10 feet. They wirelessly power lights, fans, and mobile phones, and can draw electricity from anywhere in the room regardless of the location of people and furniture.

The researchers said that the system is a significant improvement from previous attempts at wireless charging systems that use potentially harmful microwave radiation or require the device to be placed on a dedicated charging board. Instead, it uses conductive surfaces and conductive rods on the walls of the room to generate magnetic fields.

The device uses a coil to use a magnetic field, and the coil can be integrated into electronic products such as mobile phones. The researchers said that the system can be easily extended to larger structures such as factories or warehouses, while still meeting existing electromagnetic field exposure safety guidelines.

"Things like this are the easiest to implement in new buildings, but I think renovations are also possible," said Takuya Sasatani, a researcher at the University of Tokyo and corresponding author of the study. "For example, some commercial buildings already have metal support poles, and it should be possible to spray conductive surfaces on the walls, which may be similar to how textured ceilings are made."

Sample said that one of the keys to making the system work is to create a resonant structure that can provide a room-sized magnetic field while limiting the harmful electric fields that can heat biological tissues.

The team’s solution uses a device called a lumped capacitor. Placed in the wall cavity, they will generate a magnetic field that resonates in the room while trapping the electric field inside the capacitor. This overcomes the limitations of previous wireless power systems, which are limited to providing large amounts of power within a few millimeters or very small amounts of power over long distances.

The second obstacle is how to generate the magnetic field that reaches every corner of the room-the magnetic field tends to propagate in a circular pattern, creating blind corners in a square room. In addition, the receiver needs to be aligned with the field in a specific way to obtain power.

"Drawing energy with a coil in the air is like catching a butterfly with a net," Sample said. "The trick is to make as many butterflies rotate in as many directions as possible in the room. This way, you will catch the butterflies no matter where or in which direction your net is pointed."

To achieve this, the system generates two independent 3D magnetic fields. One revolves around the center pole of the room, while the other rotates in the corner, passing between adjacent walls. This method eliminates dead spots and allows the device to draw power from anywhere in the space.

Tests on the anatomical dummy show that the system can provide at least 50 watts of power to any location in the room without exceeding the FCC's electromagnetic energy exposure guidelines. However, Sample said that as the system is further improved, it is possible to provide higher levels of power.

The researchers pointed out that the implementation of the system in a commercial or residential environment may take several years. They are currently working on testing the system in a building on the UM campus. They will implement renovations and new builds in a series of rooms using standard construction techniques. The completion date is set for this fall.

The team also includes Yoshihiro Kawahara, professor of electrical engineering and information systems at the University of Tokyo. The research was supported by the Japan Science and Technology Agency and the Japan Society for the Advancement of Science.

-This press release was originally published on the University of Michigan website

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