When you think about the future of smart homes, a common dream many of us have is never having to charge a device again. Not only are cords always tangling, managing endless plugs for all your devices can be a pain. Batteries also have a limited lifespan and aren't great for the environment.
While many innovations have sought to improve this experience through things like solar panels, they're typically not the most effective or aesthetically pleasing option. Here's why RF harvesting technology can be the key to the cordless smart home experience.
How Does RF Energy Harvesting Work?
Through radio frequency (RF) harvesting, RF energy is pulled into an electronic device.
RF harvesting differs from traditional power sources because it can pull energy out of the air, reducing or eliminating the need for a battery charge to power devices that require energy at all times to run.
Harvesting RF with metal plates can be achieved by placing a dipole antenna (a coiled wire) on each side of the plate. This sources two oppositely charged coils, which in turn generate a current.
If done properly, RF harvesting technology eliminates the need for plugs, cords, and batteries. In addition, smaller devices may never even run out of power with its help.
Where Is Ambient RF Harvesting Used?
For decades, RF harvesting technology has been used to power sensors and other programs in remote locations. Often, it is used where access to a power source is difficult or impossible.
In large quantities, traditional batteries are impractical or wasteful and potentially dangerous. In general, batteries are also difficult to dispose of, which makes ambient RF harvesting an attractive alternative.
For this reason, RF harvesting technology is also slowly becoming a staple in consumer electronics, especially for small devices. For example, Samsung revealed a remote that could remain perpetually charged through a combination of solar panels and ambient RF energy harvesting using Wi-Fi in 2022.
The Limits of RF Harvesting Technology
While it is promising, there are still numerous drawbacks to ambient RF harvesting technology as we know it. In 2020, Joule published a study that cites issues with a lack of optimization of antennas for ambient RF harvesting:
"Although antennas designed for communication purposes have been studied for decades, energy harvesting antennas are still far from being optimized. The design of energy harvesting antennas needs to accommodate unknown polarization of EM waves."
However, the study did emphasize that a tradeoff can exist between efficiency and bandwidth. With time, resolving this issue can help maximize this technology for larger devices that need more power.
Is RF Energy Dangerous?
When it comes to using RF energy harvesting, the amount of current produced can be small or scaled up to have an effect. However, ordinary consumers have nothing to worry about when it comes to possible harm.
In general, devices that utilize RF energy use very little power. For example, a wireless light switch uses only the small amount of energy it needs to activate an LED or small relay.
Afterward, it sends that energy back out as radio waves in a similar frequency to the Wi-Fi router or cordless phone that you have at home. So if you haven't died from talking on your cordless phone at home, it's likely not a cause for concern.
In fact, RF energy harvesting has also been used for wearable biomedical sensors. For example, a 2015 Institute of Engineering and Technology study found that researchers were able to monitor physiological signals in patients continuously.
It would take a great deal of power for RF energy to cause physical damage. However, there are other ways that electromagnetic attacks can occur.
Imagining a Cordless Future
While it may take more time for RF harvesting technology to be a staple in our homes, it is definitely a huge step in terms of creating the picture-perfect, cordless future.
With time, technology like this can reduce our dependence on batteries, wall plugs, and sockets. However, just because we may have the technology never to have to put our phone down, it doesn't mean that we shouldn't take breaks from it.