Chipless And Wireless Electronic Skin

On August 18th, MIT engineers detailed their final design of a new wearable sensor in the journal “Science”. The sensor does not require any chip or battery to communicate wirelessly. This opens up a new path for chipless and wireless sensors.

Wearable sensors are commonly used. With the wireless technology, it is able to transmit a person’s physiological indicators to a smartphone for further analysis, such as, glucose concentration, blood pressure, heart rate, and other health-related index. Those traditional wearable sensors are too “bulky” compared to the next-generation sensors because they require chips and batteries.

The sensor developed by the team, called “e-skin”, is a flexible semiconductor film that fits on the skin like an electronic transparent tape. The core component of the sensor is an ultra-thin, high-quality gallium nitride film. The researchers used the bidirectional piezoelectric properties of gallium nitride for sensing and wireless communication. The results show that when the device is sensitive enough, it can generate vibrations based on a person’s heartbeat as well as the salt in their sweat. The vibrations then generate an electrical signal that can be read by a nearby receiver. Therefore, the device can transmit sensing information wirelessly without the need for chips and batteries.

The researchers believe that the design is the first step toward a chipless and wireless sensor. They also plan to pair the device with other selective sensing membranes in the future to monitor other important physiological indicators.