Magnetic fields offer new method for wireless communication

Electrical engineers at the University of California, San Diego, have been trialling a new technique that uses magnetic fields to send signals through the body wirelessly.


Prototype of the magnetic field human body communication, developed in Mercier's Energy-Efficient Microsystems Lab at UC San Diego, consists of magnetic-field-generating coils wrapped around three parts of the body, including the head, arm and leg.
Prototype of the magnetic field human body communication, developed in Mercier’s Energy-Efficient Microsystems Lab at UC San Diego, consists of magnetic-field-generating coils wrapped around three parts of the body, including the head, arm and leg.

The research, presented at the recent International Conference of the IEEE Engineering in Medicine and Biology Society in Italy, details a technique called magnetic field human body communication. Whereas the electromagnetic radiation of Bluetooth struggles to penetrate the human body, this new technology uses the body as a vehicle to communicate information between electronic devices.

The researchers claim it could lead to a new generation of wearable electronics that use much less power than current devices, as well as providing better security.

“In the future, people are going to be wearing more electronics, such as smart watches, fitness trackers and health monitors,” said leader of the study Patrick Mercier, a professor in the Department of Electrical and Computer Engineering at UC San Diego and the co-director of the university’s Centre for Wearable Sensors.

“All of these devices will need to communicate information with each other. Currently, these devices transmit information using Bluetooth radios, which use a lot of power to communicate. We’re trying to find new ways to communicate information around the human body that use much less power.”

According to the research, the path losses associated with magnetic field human body communication are more than10 million times lower than those associated with Bluetooth.

“This technique, to our knowledge, achieves the lowest path losses out of any wireless human body communication system that’s been demonstrated so far,” said Mercier. “This technique will allow us to build much lower power wearable devices.”

Because the body is acting as the medium of communication, the researchers claim the technology should be more secure than methods such as Bluetooth, which transmit data through the air. One drawback, however, is that magnetic fields need circular geometries to communicate through the body. This would make the technology suitable for smartwatches, headbands or belts, but not for a patch on the body, such as a heart monitor.