The world is becoming increasingly populated with wireless devices, not only the billions that are already in the hands of human users, but also the billions more coming online in the form of consumer and industrial Internet of Things devices, many of which will operate unattended by humans.
The quickly raises a fundamental question: How do we keep the power on all those IoT devices, especially those deployed in remote or tightly-confined spaces, fully charged?
There are different approaches, and Fierce Electronics recently spoke to one company, San Jose, California-based Energous, that is using the radio frequency technology of wireless networks as a bridge to keeping these devices powered up.
Energous CEO Cesar Johnston told Fierce Electronics, “You have the world of communications, which is based on that RF that you use to send data and receive data, …and where we actually focus on developing those technologies specifically for sending wireless power over the air, being able to receive over RF and then charge devices, such as IoT devices.”
The company’s PowerBridge products, available in 1 watt and 5.5 wat versions, combine sensor technology, RF transmitters, Bluetooth Low Energy (BLE) and power amplifiers to wirelessly charge a variety of IoT devices. They use the licensed and regulated 900 Mhz RF band, which allows the transmitters to avoid the challenges of trying to achieve reliability in busier unlicensed bands like 2.4 GHz and 5 GHz.
The lower band also enables longer transmission distances, as well as power charging benefits. “The lower the frequency, the better your specific absorption rate, which is a measure of how much power you actually can take as a human and how much power level our tissue can stand. lower frequency does always
Energous also offers a PowerHub that combines multiple devices, as well as chips, software and evaluation kits to help users get started.
Energous last last month took the latest step in commercializing this approach with the announcement that it was teaming with Atmosic Technologies, a developer of energy harvesting wireless System-on-Chips (SoCs) and modules for IoT applications, launch availability of the Wirelessly Powered Sensor Evaluation Kit, which features Atmosic’s ATM3 energy harvesting BLE SoC solution and Energous’ FCC-certified 1W WattUp PowerBridge transmitter.
The company also has worked closely with Wiliot to charge the small, intelligent asset tracking tags that Wiliot is using as the basis for “sensing as a service” for inventory management and other applications.
Ultimately, using RF for reliable over-the-air power charging will allow companies to save money on device batteries and other methods of charging those batteries. There could further pay off in terms of sustainability if not as many energy-sucking, wasteful and difficult-to-recycle traditional batteries are used. Companies may eventually be able to redesign IoT devices to be smaller and cheaper because they will be able to reduce battery size, Johnston said.
He added that as IoT brings about more edge devices with AI and edge computing capabilities, RF-based charging will be able to provide plenty of power to those devices to keep the processing running even as it requires more energy. “This has tremendous advantages for battery sustainability, keep the devices charged, removing the wires that were needed before and being able to add in even more functionality with AI and edge processing,” Johnston said.