Jul 6, 2021

8 min read

Battery-free IoT - using 5G as wireless power grids

Photo by Matthew Henry on Unsplash

Today, we live in a world that is chock full of IoT sensors. IoT sensors are becoming an indispensable component in the way we do things today -  Today, wireless sensors feature heavily in our lives. They play an integral role in nearly every aspect of our lives - from the way we grow our foods to the way we keep ourselves entertained.

But as we’ve mentioned several times in the past, most IoT devices in the world today are powered by batteries - This is just no good. Batteries come with an entire laundry list of disadvantages, not least of which is the fact that they are terrible for our environment.

So, can’t we just find a way to power IoT devices without batteries?

Well, that’s the million dollar question. Or rather, the multi-billion dollar question to which  many answers are being furnished as we speak. This is the whole premise behind self-powered sensors. 

These sensors are basically IoT devices that do not need a battery to work. They run on one of several technologies that enable them to draw the power they need from an alternative source - Most popularly, these types of sensors run on energy harvesting technologies - which are technologies that enable IoT devices to collect and use some of the massive amounts of energy that are constantly around us - i.e ambient energy. 

Mobile data as a power source?

Researchers from the Georgia Institute of Technology have come up with a way to put the over-capacity of 5G mobile data networks to good use, they have pioneered a novel technique to turn 5G mobile networks into power grids for IoT devices. 

This essentially means that IoT devices that currently need a battery to function could theoretically be powered by these 5G based grids in the near future. 


Researchers have come up with a way to use a flexible Rotman lens-based rectenna system which is capable of harvesting waves in a certain frequency band. This type of lens is often used  in radar-based surveillance systems and enables targets to be visualised in multiple directions without disturbing the system. 

The team published these findings in the January 12th issue of the well known scientific journal Scientific Reports.

Wait, hold up! That got very technical! I need a bit of background!

OK, we got excited! Here’s how it works

Let’s start with a brief look at the history of mobile data technologies. The history of mobile internet as we know it, goes back to 1996, when access to the internet through mobile web was offered for the very first time, in Finland. Over the next few years, mobile internet technology developed rapidly, with 3G, the third generation of mobile internet technology being widely available across the developed world by the late 2000s. 

Today, if you are reading this, chances are you are no stranger to LTE, the fourth generation of mobile internet technology. 5G is basically the next generation in this line of technologies. Basically, here’s what 5G promises - 5G promises to be, you guessed it, faster. But not just that - 5G internet technology is claimed to have lower latency and in addition, the possibility to include a greater number of connected devices. This means that 5G networks can provide more adjusted connectivity. 

So, how does 5G achieve these blazing fast speeds and everything else that follows?

In a nutshell, 5G technology uses radio waves of a higher frequency in addition to using low and medium band frequencies that were used in previous generations of cellular networks. In fact, with 5G, the FCC has allowed unprecedented levels of radiated power densities. 

What this means is that the creators of 5G have unknowingly designed a power grid that is 100% wireless, that is capable of transmitting energy to devices that are located at a distance. If that’s not mind-blowing enough, researchers involved in the area claim that the potential of this technology far exceeds that of any existing technology in terms of being able to power devices without batteries. 

This is incredibly relevant in the world we are headed towards. As such, battery-free technologies like RF energy harvesting and piezoelectric energy harvesting are making huge ripples in the IoT world, with seemingly everyone wanting to jump in on the action. This is by no means just a fad. There is a real need here - like we’ve mentioned before, batteries just don’t make sense as a power solution for IoT devices.  

An important problem to solve

Now, back to the technology that the georgia tech researchers have come up with. This technology is based on a Rotman lens, which is an essential component in beamforming networks. 

Without getting too much into the dreary technicalities, let’s take a look at why this is significant. 

Basically, systems like these need large aperture antennas in order to power devices located at a distance. The big challenge that these large aperture antennas pose is that they don’t offer a very wide field of view. This restricts their operation if the antenna is too wide for the 5G station. The researchers involved in this project have solved that problem by employing a single-directional antenna that  has a wide coverage area. The team reports that these high-frequency networks that we have today hold enormous potential for energy harvesting applications. 

This unused energy, that would otherwise go to waste, can be utilised to power low-power  IoT node devices, enabling the dream that is perpetual IoT.

One of the researchers involved in this project claims that this innovation will allow antennas of large sizes to operate at higher frequencies and get power from multiple directions. This “direction-agnosticism” makes it a lot more suited for practical purposes. All the energy that is collected is fed into a rectifier. This makes the process a lot more efficient. 

How much more efficient, you ask?

The technology accounts for a purported 21-fold increase over other similar modalities. This is simply a landmark in the world of energy harvesting. An energy harvesting rubicon that has been crossed. 

“We’ve solved the problem of only being able to look from one direction with a system that has a wide angle of coverage, People have attempted to do energy harvesting at high frequencies like 24 or 35 Gigahertz before, but such antennas only worked if they had line of sight to the 5G base station; there was no way to increase their angle of coverage until now.” says Aline Eid a senior researcher involved in the project. 

5G revolution well on its way

In spite of all the conspiracy theories and the resulting apprehension surrounding 5G, there is a tremendous amount of anticipation around the latest standard of mobile data. This is largely due to the tremendous promise that 5G holds in terms of unreal speeds and low-latency communication. 

Although 5G is just in its infancy as a technological standard, it is not going to be long before it catches up and gains traction. If popular estimates are to be believed, this process is not going to take all that long - by the end of this year, we could see 5G having thrice the penetration it does now - wrap your heads around that - three times the present usage. 

That’s fast. Like, ridiculously fast.

“The fact is 5G is going to be everywhere, especially in urban areas. You can replace millions, or tens of millions, of batteries of wireless sensors, especially for smart city and smart agricultural applications”, quips Emmanouil Tentzeris, who is a professor of flexible electronics in GIT’s School of Electrical and Computer Engineering.

Tentzeris goes on to suggest that he expects power to be the next biggest service that is provided by the telecom industry. 

Again, take a second to process that. 

This is a major paradigm shift that’s being spoken about here. Tentzeris claims that just like mobile data overtook conventional telephonic services as the most sought after telecom product and ergo, the most significant revenue generator, pretty soon, we’re going to see wireless power become the biggest money maker for telecom companies. 

This is the vision that the research team sees becoming a reality very soon - a future where telecom service providers embrace these kinds of technologies to offer “over the air” electricity that completely eliminates the need for batteries. 

We live in truly exciting times indeed! Just imagine the possibilities that this could open up - Wherever there’s data, there’s also power for an IoT device to use. Now, that sounds absolutely magical! This might be where we’re headed.

“I've been working on energy harvesting conventionally for at least six years, and for most of this time it didn't seem like there was a key to make energy harvesting work in the real world, because of FCC limits on power emission and focalization,” says Jimmy Hester, who is a senior lab advisor and a senior executive at Atheraxon, a concern that is developing 5G based RFID technology.. “With the advent of 5G networks, this could actually work and we’ve shown it. That’s extremely exciting — we could get rid of batteries entirely.”

About the author

Runar Finanger


Runar, the co-founder and CMO of ONiO, adeptly connects product innovation to customer desires. Championing brand-building, he heightens consumer awareness and consistently propels brand preference through diverse channels.

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