Inexpensive, low-power devices operate on mmWave and use a single transistor to transfer large amounts of data anywhere

The promise of 5G Internet of Things (IoT) networks requires more scalable and robust communication systems – those that deliver dramatically higher data rates and lower power consumption per device.

Backscatter radios? passive sensors that reflect rather than radiate energy? are known for their low cost, low complexity and battery-free operation, which makes them a potential key factor of this future, although they typically have low data rates and their performance is highly dependent on the environment.

Researchers at Georgia Institute of Technology, Nokia Bell Labs, and Heriot-Watt University have found a cost-effective way for backscatter radios to communicate with high throughput and 5G speeds Gb / sec requiring expensive and multi-stacked transistors.

With a unique modulation approach in the bandwidth of 5G 24/28 gigahertz (GHz), the researchers have shown that these passive devices can transmit data from practically any environment safely and robustly. The results were published in the journal earlier this month Natural electronics.

Traditionally, mmWave communication, known as the extremely high frequency band, is considered “the last mile” for broadband with directive point-to-point and point-to-multipoint radio links. This spectrum offers many advantages, including a wide available GHz bandwidth that enables very high communication rates and the ability to implement electrically large antenna arrays that enable beamforming capabilities as needed. However, such mmWave systems are dependent on costly components and systems.

The battle for simplicity versus cost

“Usually it was simplicity versus cost. You can either do very simple things with one transistor, or you need multiple transistors for more complex functions, which made these systems very expensive, ”said Emmanouil (Manos) Tentzeris, Ken Byers professor of flexible electronics at Georgia Tech School of Electrical and Computer Engineering (ECE). “Now we’ve increased the complexity and made it very powerful, but very inexpensive, so that we can get the best of both worlds.”

“Our breakthrough is that we can communicate over 5G / millimeter wave (mmWave) frequencies without actually having a full mmWave radio transmitter – only a single mmWave transistor is needed with much lower frequency electronics like those found in cell phones or WiFi is devices. A lower operating frequency keeps electronics power consumption and silicon costs down, ”added first author Ioannis (John) Kimionis, a Georgia Tech Ph.D. The graduate is now a technical assistant at Nokia Bell Labs. “Our work is scalable for any type of digital modulation and can be applied to any fixed or mobile device.”

The researchers are the first to use a backscatter radio for mmWave communication at gigabit data rates while minimizing front-end complexity to a single high-frequency transistor. Their breakthrough included modulation as well as adding more intelligence to the signal that drives the device.

“We kept the same RF front end for scaling the data rate without adding any more transistors to our modulator, making it a scalable communicator,” Kimionis said, adding that her demonstration showed like a single one
The mmWave transistor can support a variety of modulation formats.

Power supply for a large number of “intelligent” IoT sensors

The technology opens up a wide variety of IoT 5G applications, including energy harvesting, which Georgia Tech researchers recently demonstrated using a special Rotman lens that gathers 5G electromagnetic energy from all directions.

Tentzeris said additional applications for backscatter technology could include “rugged” high-speed personal area networks with non-current wearable / implantable sensors to monitor blood oxygen or glucose levels or cardiac / EEG functions; Smart home sensors that monitor temperature, chemicals, gases, and humidity; and smart agricultural applications for detecting frost on plants, analyzing soil nutrients, or even tracking farm animals.

Researchers developed an early proof of concept of this backscatter modulation, which won third prize in the 2016 Nokia Bell Labs Prize. At the time, Kimionis was a Georgia Tech ECE PhD student working with Tentzeris in the ATHENA laboratory, which is advancing novel technologies for electromagnetic, wireless, RF, millimeter wave and sub-terahertz applications.

Key factor for low costs: additive manufacturing

For Kimionis, the breakthrough in backscatter technology reflects his goal of “democratizing communication”.

“During my career, I have looked for ways to make all types of communication more cost-effective and energy-efficient. Because the entire front end of our solution was created with such little complexity, it is compatible with printed electronics. We can literally print an mmWave antenna array that supports a low power, low complexity and low cost transmitter. “

Tentzeris believes affordable printing is critical to future-proof its backscatter technology market. Georgia Tech is a pioneer in inkjet printing on practically every material (paper, plastic, glass, flexible / organic substrates) and was one of the first research institutes to use 3D printing down to millimeter frequency ranges as early as 2002.

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Other researchers who contributed to this work were Apostolos Georgiadis and Spyridon Nektarios Daskalakis, both former visiting professors at Georgia Tech, now on the faculty of the School of Engineering and Physical Sciences at Herriot-Watt University in Edinburgh.

This work was supported by the National Science Foundation-EFRI, the Defense Threat Reduction Agency (DTRA), and the European Union’s Horizon 2020 research and innovation program under the Marie Skodowska-Curie fellowship agreement.

CITATION: J. Kimionis, et al., “A millimeter-wave printed modulator and antenna array for backscatter communication at gigabit data rates.”Natural electronics, 2021) https: //doi.Organization/10.1038 /s41928-021-00588-8.

The Georgia Institute of Technology, or Georgia Tech, is one of the top 10 public research universities developing leaders who advance technology and improve the human situation.

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Media contacts: Anne Wainscott-Sargent (404-435-5784) ([email protected] ) and Tracey Reeves ([email protected] ).

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