By Narbeh Derhacobian
When I tell people I work in wireless power transfer technology, the first question I hear is, “What exactly is wireless power?” This is usually followed by, “Why hasn’t this technology taken off yet?” In this blog, we’ll explore the basics of wireless energy and offer insights into why it hasn’t gone mainstream—yet.
Understanding Wireless Power
To understand wireless power transfer, it’s useful to compare it with data transfer. Today, we transfer data effortlessly using various methods including Ethernet, fiber, Wi-Fi, Bluetooth, and cellular networks. When you’re reading this blog, for instance, numerous protocols and wired and wireless connectivity schemes are working behind the scenes to move data from our servers to your device.
But transferring energy is different. Currently, energy is transferred physically. Electricity moves through cables and batteries, while fuel is transported in trucks or pipelines. These methods all require a direct physical connection from the source to the destination. Wireless energy transfer, on the other hand, envisions transferring power without any physical connection—an untethered flow of electricity. Nikola Tesla, in the late 1800s, dreamed of a world where power could be transmitted wirelessly across long distances, but more than a century later, we’ve yet to see this vision fully realized.
Today’s Wireless Power Technology
There is one form of wireless power transfer that we use today, known as proximity charging. This technology powers the inductive charging pads we use for smartphones and wireless earbuds. The key limitation of proximity charging is that it only works over very short distances—just a few centimeters between the charging pad and the device.
Tesla’s dream was much more ambitious: delivering power wirelessly over several meters or even kilometers. So why haven’t we achieved this? The reasons come down to technology complexity, cost, and market readiness.
The Technology Challenges
The ability of a wireless power transfer system to deliver meaningful power at a distance depends on its frequency. Over the past 25 years, different technologies have been developed to transmit power wirelessly over distances, using frequencies such as 915 MHz, 2.4 GHz, and 5.8 GHz—the same frequencies used for Wi-Fi, Bluetooth, and other wireless communication technologies.
These frequencies are great for transmitting data but fall short in delivering meaningful power. For example, a 1m2 wireless power system that is designed to operate at 915 MHz RF will deliver less than 0.5mW of useable power to a receiver measuring 25cm2 over a 10-meter distance. With this level of power recovered at 10 meters, a AAA battery will take about 60 days to charge. Clearly, this is an impractical use case.
Operating at higher frequencies, however, allows for more compact antennas, which improve performance. Additionally, technologies like targeted beamforming can also direct the energy toward a specific receiver, enhancing power delivery. For instance, using a 5.8 GHz system with beamforming and the same dimensions as in the above example, the time to charge a AAA battery drops from 60 days to around eight hours. This is a significant improvement but still not too practical.
At GuRu Wireless, we’ve pushed this further by developing a 24 GHz wireless power beaming system. Additionally, our system uses ‘Smart Lensing’ technology to not only direct but also focus the RF energy, similar to how a flashlight lens focuses light. In the same example above, our system would be able to deliver up to five watts of power to a device 10 meters away (given the same transmitter and receiver dimensions)—enough to charge a AAA battery in just 20 minutes. That’s a significant leap in performance as compared to lower frequencies.
Since building our first 24 GHz system in 2016, we’ve tackled various challenges, from hardware to thermal management, EMI, and manufacturability. We’ve iterated through multiple system generations, and today have the best-in-class technology for wireless power beaming at distance. Our system offers superior Size, Weight, Power, and Cost (SWaP-C) performance, solving many of the technical hurdles that have previously held back wireless power transfer.
The Cost Barrier
Cost is another major hurdle to mainstream adoption. Wireless power is undeniably convenient—imagine not needing to plug in your smartphone or replace batteries in your Bluetooth devices. However, in the consumer market, convenience often comes with a price tag. The costs associated with implementing wireless power transfer at a distance, along with regulatory challenges, have so far outweighed the benefits for most of the broader consumer market.
What’s Next for Wireless Power at a Distance?
As other new technology adoption life cycles have shown, while cost and regulatory barriers remain, they aren’t insurmountable. In fact, the future of wireless power likely lies in applications where traditional power delivery methods—such as cables and batteries—are impractical or prohibitively expensive. We believe these opportunities will be the early adopters of wireless power, with opportunities in critical sectors like defense, national security, utilities, and energy resiliency.
In our next blog, we’ll explore the potential of wireless power in these sectors, where traditional power methods simply don’t cut it. We’ll discuss the applications that could be revolutionized by wireless energy transfer—moving beyond convenience and focusing on real-world enablement.
