Researchers indicated that human tissue is a good transmission medium for connecting wireless wearable devices.
Zigbee, Bluetooth and various other communication standards use antennas to radiate and receive power. But this technique is not suitable for wearable technologies as it demands a high amount of power. Researchers from the Tokyo University of Science have suggested that human tissue is a good transmission medium for connecting wireless binaural hearing aids.
For wearables to truly transcend portables, we will need to rethink the way in which devices communicate with each other,” according to the university. “The usual approach of using an antenna to radiate signals into the surrounding area while hoping to reach a receiver won’t cut it for wearables – this method of transmission not only demands a lot of energy but can also be unsafe from a cybersecurity standpoint. Moreover, the human body itself also constitutes a large obstacle because it absorbs electromagnetic radiation and blocks signals.”
“Some electric fields can propagate inside the body very efficiently without leaking to the surrounding area,” said the university. “By interfacing skin-worn devices with electrodes, we can enable them to communicate with each other using relatively lower frequencies than those used in conventional wireless protocols like Bluetooth.”
Binaural hearing aids were chosen as a part of this study as they work in pairs, have to be synchronised, and are naturally in contact with the skin. 10, 20 and 30MHz were selected as potential operating frequencies, plus 2.45GHz to compare results with Bluetooth.
“We calculated the input impedance characteristics of the transceiver electrodes, the transmission characteristics between transceivers, and the electric field distributions in and around the head. In this way, we clarified the transmission mechanisms of the proposed HBC system,” said researcher Dairoku Muramatsu.
“With our results, we have made progress towards reliable low-power communication systems that are not limited to hearing aids but also applicable to other head-mounted wearable devices,” said Muramatsu. “Not just this, accessories such as earrings and piercings could also be used to create new communication systems.”
The study has been published in the Electronics journal.