Tiny Wake-Up Receiver for IoT Devices: Low Power & High Security

Tuesday - May 2 2023, 12:12 UTC - 1 year ago

MIT researchers have developed a tiny wake-up receiver for Internet-of-Things (IoT) devices which is a one-tenth the size and power of traditional receivers. It also incorporates an authentication system that protects the device from certain kinds of battery-draining attacks. The receiver is based on terahertz waves, which are fast and secure, but difficult to utilize in devices. It could be used in miniaturized sensors and other emerging applications, such as field-deployable radio networks.

MIT researchers have created a terahertz-based wake-up receiver for IoT devices, significantly reducing size and power consumption while improving security features.

Researchers at MIT have developed a new wake-up receiver that is less than one-tenth the size of previous devices and consumes only a few microwatts of power. Their receiver also incorporates a low-power, built-in authentication system, which protects the device from a certain type of attack that could quickly drain its battery.

Many common types of wake-up receivers are built on the centimeter scale since their antennas must be proportional to the size of the radio waves they use to communicate. Instead, the MIT team built a receiver that utilizes terahertz waves, which are about one-tenth the length of radio waves. Their chip is barely more than 1 square millimeter in size.

They used their wake-up receiver to demonstrate effective, wireless communication with a signal source that was several meters away, showcasing a range that would enable their chip to be used in miniaturized sensors. For instance, the wake-up receiver could be incorporated into microrobots that monitor environmental changes in areas that are either too small or hazardous for other robots to reach. Also, since the device uses terahertz waves, it could be utilized in emerging applications, such as field-deployable radio networks that work as swarms to collect localized data.

"By using terahertz frequencies, we can make an antenna that is only a few hundred micrometers on each side, which is a very small size. This means we can integrate these antennas to the chip, creating a fully integrated solution. Ultimately, this enabled us to build a very small wake-up receiver that could be attached to tiny sensors or radios," says Eunseok Lee, an electrical engineering and computer science (EECS) graduate student and lead author of a paper on the wake-up receiver.

Lee wrote the paper with his co-advisors and senior authors Anantha Chandrakasan, dean of the MIT School of Engineering and the Vannevar Bush Professor of Electrical Engineering and Computer Science, who leads the Energy-Efficient Circuits and Systems Group, and Ruonan Han, an associate professor in EECS, who leads the Terahertz Integrated Electronics Group in the Research Laboratory of Electronics; as well as others at MIT, the Indian Institute of Science, and Boston University. The research is being presented at the IEEE Custom Integrated Circuits Conference.

Terahertz waves, found on the electromagnetic spectrum between microwaves and infrared light, have very high frequencies and travel much faster than radio waves. Sometimes called "pencil beams," terahertz waves travel in a more direct path than other signals, which makes them more secure, Lee explains.

However, the waves have such high frequencies that they have been difficult to utilize in devices, as their wavelengths are very close in size to transistors, limiting the amount of circuitry that can be available on the chip. The MIT team was able to isolate the terahertz waves they used by using a small patch antenna, connected to the rest of the device with what the team calls an "asymmetric coplanar waveguide." .