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Enhancing Battery Life for IoT Devices: MIT’s Terahertz Wake-Up Receiver Chip

An ultra-compact terahertz wake-up receiver chip has been created by MIT engineers that uses only a few microwatts of power and comes with a low-power authentication system to defend against denial-of-sleep assaults. Wake-up receivers have grown more important as smaller Internet of Things (IoT) devices have gained popularity. 

Eunseok Lee, a graduate student in MIT’s Electrical Engineering and Computer Science Department, said, “If it is turned on constantly, it will consume a whole lot of power, right? So what a wake-up receiver does is keep an electronic device at a very low power mode [until] we send a signal to the receiver so that it can activate the entire system.”

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“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,” he added further. 

Reduced antenna size and increased security of terahertz waves

Most common wake-up receivers currently in use employ Wi-Fi or Bluetooth, with frequencies around 2.4 GHz and wavelengths of about 12.5 centimeters, necessitating the use of centimeter-scale receivers. The MIT researchers’ receiver is substantially smaller since it was designed to transmit at terahertz frequencies, equivalent to wavelengths between 1 and 0.03 millimeters. In addition to being more secure than radio waves, terahertz waves are also much less mobile due to their high frequencies.

The researchers blended two terahertz frequencies using two small transistors as antennas for its detector at a low power cost, leveraging terahertz self-mixing to prevent the large power consumption brought on by mixing with another signal. To guard against denial-of-sleep assaults, in which an attacker tries to activate the gadget repeatedly in an effort to drain its battery, they also installed a wake-up authentication circuit within their terahertz receiver.

Potential applications

There are many potential uses for the tiny terahertz wake-up receiver, including putting it inside microbots that watch over spaces too small or unsafe for humans, using the sensors in unobtrusive indoor security applications, and using robot swarms to gather localized data. The team is constructing a platform for terahertz wave harvesting. Lee also mentioned that they are enhancing the wake-up receiver’s angular sensitivity and wish to optimize terahertz technologies for practical applications.