Far-field wireless power transfer takes big step forward - Embedded.com

Far-field wireless power transfer takes big step forward


Following approval in Europe, the US certification will enable the expansion of Energous wireless power transfer solutions at any distance, especially for IoT devices.

Energous Corporation was recently granted the U.S. Federal Communication Commission (FCC) Part 15 approval for unlimited distance over-the-air (OTA) wireless charging. Following the previous approval received in Europe and announced in May 2021, the U.S. certification will enable the expansion of the wireless power transfer solutions at any distance, especially for IoT devices.

Energous’ WattUp technology enables both near field and distance charging in a single ecosystem. WattUp is positioned to offer improvements in power, efficiency, foreign device detection, freedom of movement, and overall cost over legacy first generation coil-based charging technologies for consumer electronics, medical devices, retail, military, industrial/com mercial IoT, automotive, military, retail, and industrial RF-based charging technologies. With over 200 patents, Energous creates silicon-based wireless power transfer (WPT) technology and customized reference designs for global customers, while providing regulatory assistance, a dependable supply chain, quality assurance, and sales and technical support.

“The recent FCC certificate approval for unlimited distance follows a similar approval granted in Europe a few months back, the first one in the world for this type of technology,” said Cesar Johnston, acting CEO, EVP of engineering and COO at Energous Corporation. “We went to Europe and we opened up the future of wireless power networks.”

With this new approval, Energous hopes to create a new industry, by enabling wireless power transfer not only over short distances, but also over longer distances. What the company created in Europe was the beginning of wireless power network deployment. Now, with this new certification, their WPT technology can be extended to the U.S. market.

“Now, we have opened up our two largest potential markets, and over time we will continue to add in other countries,” said Johnston. “Going into other countries means there are a lot of government regulatory issues we will have to deal with. However, I believe that other countries will now be able to recognize the benefits of our technology, opening up their regulatory and, hopefully, helping us to extend our solutions all throughout the world.”


Energous has developed a technology capable of sending power at a distance, and the amount of power that can be sent is actually not restricted by the technology itself, but it is again restricted by regulatory constraints.

Energous’ 900 MHz 1W Active Energy Harvesting transmitter, which has received US FCC authorization for wireless power transfer at any distance, can charge several devices simultaneously. This allows the ever-increasing ecosystem of IoT devices (e.g. retail sensors, electronic shelf labels, industrial devices) to be charged over-the-air at any distance. Figure 1 shows the block diagram of the DA4100, a highly integrated system-on-chip WattUp RF-transmitter IC designed to provide optimal charging of WattUp receiver devices. Specifically designed by Energous to charge a range of WattUp-enabled receivers, it features a complete transmitter system solution, including an RF transmitter, power management, and integrated DC-DC supply. Among the relevant applications is the wireless charging of low-power and battery-powered devices, such as IoT sensors, Electronic Shelf Labels (ESLs), asset trackers, access sensors, air quality monitors, motion detectors, and more.

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Figure 1: WattUp DA4100 Wireless Power Transmitter (Image source: Energous)

Based on an ARM Cortex M0+ processor, the SoC integrates an embedded secure element for 2-way authentication with 128-bit encryption, requiring only an external crystal and power amplifier, and operating directly from a 3.3V power supply.

The recently granted FCC approval for unlimited distance OTA wireless charging opens new far-field scenarios which go far beyond the above described near-field system.

“What we have opened now is the possibility of deploying multiple transmitters across a room, a warehouse, a supermarket, or wherever you want, and being able to actually have no distance limitation,” said Johnston. “Also, by constraining the number of transmitters, we can actually control the density of the power.”

As the number of deployed IoT devices keeps on growing, especially in the retail market, a far-field wireless power transfer solution can reduce the need for a long-lasting battery or for any battery at all. Most important is the fact that more power and greater distances are now available, giving a chance to add more intelligence into the receiver. System engineers can now start thinking of applications such as artificial intelligence, being able to get and process huge amounts of data from the devices.

If electronic shelf labels not only had the ability to display information, which they have so far, but could also exchange data through a Bluetooth interface (a feature already supported by Energous’ WattUp system) new features could be added to these IoT devices, and more intelligence could be embedded into single receivers that would no longer be limited by battery size. One of the largest obstacles to BLE IoT technology adoption is the management and maintenance of battery-powered BLE devices. BLE-based devices with no battery and with energy harvesting provide a whole new tool to the IoT wireless toolbox.

Now, imagine that a customer is approaching with his/her smartphone an electronic shelf label provided with a two-way communication feature. The BLE could automatically connect the phone to an application, knowing who the customer is and where he/she is. A number of different things could happen there, such as offering the customer special prices or discounts on his/her preferred products. Energous’ WattUp technology provides a bridge between IoT smart devices and Wi-Fi gateways, unlocking the power of the cloud and artificial intelligence (AI) algorithms.

“We can think of a similar scenario in medical, warehousing, and industrial applications, where more smarts could be effectively added into the receiver devices, without increasing the battery size or capacity,” concluded Johnston.

>> This article was originally published on our sister site, EE Times Europe.

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