Wireless electronics can power trillions of IoT sensors. Here's how

The IoT revolution is due, here is what will drive it.
Rupendra Brahambhatt

How great it would have been if your smartphone, laptop, car, and home appliances could interact and share information with one another all the time —- to make your life more comfortable and easy-going. 

This exciting possibility can be turned into reality via the Internet of Things (IoT), a technology that employs sensors, software, and the internet to establish a network between all your physical devices and gadgets. Although IoT is still a budding technology, you’d be surprised to know that it’s already in play. 

For example; smartwatches, fitness trackers, smart home security systems, and various other gadgets that continuously share data with your smartphone to keep you updated about your calls, meetings, heart rate, door locks, etc —- are all IoT applications.

We are yet to witness the full potential of IoT, but before that, we need to overcome a big challenge. The sensors that make IoT networks possible require power to stay functional, and unfortunately, our existing energy solutions are not enough to support this demand. 

A team of researchers at King Abdullah University of Science and Technology (KAUST) in Saudi Arabia has been working on this problem and in their latest study, they propose an interesting solution. The authors reveal details about wireless-powered electronics that promise to meet the energy demands of IoT networks in a sustainable and eco-friendly manner. 

Batteries won’t work 

Sensors are currently powered by technologies like Li-ion batteries. Although batteries can power a large network of devices, they need to be replaced again and again. Therefore a battery-based approach is expensive, unsustainable, and harmful to the environment. 

For instance, conventional batteries are made of metals that are procured through mining activities resulting in air and soil contamination. Plus, when these batteries are not carefully disposed of, they release toxic chemicals into our environment. 

Moreover, in the future, when IoT applications become more common, there could be billions or even trillions of sensors working together. These large networks might disrupt the battery supply and demand dynamics in such a way that either we won’t have enough batteries to power all the sensors in the world, or the batteries might become unaffordable for most consumers.

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But wireless power can

Wireless electronics can power trillions of IoT sensors. Here's how
Trail of light depicting wireless power.

The study authors suggest that supplying energy to IoT sensors via wireless power instead of batteries could be a perfect solution to this problem. Emerging technologies like photovoltaic cells (PVCs, used in solar panels), large-area electronics (LAEs), and radio-frequency (RF) energy harvesters can make this possible.

While RF energy harvesting employs metal oxides and special semiconductors devices called Schottky diodes to generate wireless power through electromagnetic waves. LAEs are new-generation electronics that can be printed or manufactured using soft, flexible, hybrid, and customizable materials. 

According to the researchers, such materials allow the production of biodegradable circuits and substrates (LAEs) even at low temperatures. Unlike conventional silicon-based electronics, these LAEs can supply wireless power to sensors in an eco-friendly manner. 

While explaining the significance of RF energy harvesters and LAEs for wireless-powered sensor nodes, one of the researchers and KAUST alumni, Dr. Kalaivanan Loganathan said, “These devices are crucial components in wireless energy harvesters and ultimately dictate the performance and cost of the sensor nodes.”

He further added, “(The technologies) provide the needed building blocks toward a more sustainable way to power the billions of sensor nodes in the near future.”

We still need to integrate the technologies

The authors propose that wireless-powered sensor nodes can draw energy from PVCs and RF harvesters via LAEs and make IoT networks work on a large scale. For instance, in their research paper, the KAUST team highlights a scalable method that employs RF diodes to harvest energy that falls in the 5G and 6G frequency ranges.

The research is quite exciting because it completely takes out batteries from the IoT picture and introduces an eco-friendly and sustainable approach. However, the KAUST team is yet to see how technologies like PVCs, LAEs, and RF harvesters would work together. 

The idea of wireless-powered sensor diodes seems pretty cool, but its success depends on the successful integration of the above mentioned technologies. Dr. Loganathan revealed that integration is the next step of their research. He said, “The team is investigating the monolithic integration of these low-power devices with antenna and sensors to showcase their true potential.”

The study is published in the journal Nature Electronics.