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Wireless power harvesting pulls energy from radio waves, Wi-Fi signals, and other electromagnetic sources floating through the air around you. Instead of plugging a device into a wall outlet or swapping batteries, the device itself captures ambient RF energy and converts it into usable electricity. The amount of power you can harvest this way is tiny – microwatts to low milliwatts – but that’s enough to run small electronics like remote controls, Bluetooth sensors, asset tracking tags, and IoT devices indefinitely without a battery change.
Samsung demonstrated this at CES 2022 with a solar/RF-powered TV remote that has since shipped across its entire TV lineup. But Samsung’s remote was just the most visible example. Behind the scenes, companies like Wiliot, Atmosic, Powercast, Ossia, and Energous have been building the chips, antennas, and protocols that could eventually make batteries optional for entire categories of devices.
How Does Wireless Power Harvesting Work?
Every Wi-Fi router, cell tower, TV broadcast antenna, and Bluetooth device around you is constantly radiating radio frequency (RF) energy. That energy doesn’t disappear after it delivers your Netflix stream or phone call. It keeps traveling outward, getting weaker with distance, until it dissipates. RF energy harvesting captures a fraction of that ambient energy using a rectifying antenna (called a rectenna) and converts it from AC radio waves into DC electricity that can charge a capacitor or power a circuit directly.
Think of it like a tiny solar panel, except instead of harvesting light waves from the sun, it harvests radio waves from your router. The physics are the same principle Nikola Tesla demonstrated in the 1890s when he wirelessly lit lamps across his lab. The difference is scale. Tesla wanted to power cities. Modern RF harvesting powers a temperature sensor.
| Energy source | Frequency range | Typical harvestable power | Practical range |
|---|---|---|---|
| Wi-Fi router (2.4 GHz) | 2.4 – 2.5 GHz | 1 – 100 microwatts | Up to 30 feet |
| Wi-Fi router (5 GHz) | 5.1 – 5.8 GHz | 0.5 – 50 microwatts | Up to 15 feet |
| Cell tower (4G/5G) | 700 MHz – 3.5 GHz | 0.1 – 10 microwatts | Up to several hundred feet |
| Dedicated RF transmitter | 915 MHz (US) / 868 MHz (EU) | Up to 3-4 milliwatts | Up to 80 feet |
| Bluetooth Low Energy | 2.4 GHz | 0.5 – 20 microwatts | Up to 15 feet |
| Digital TV broadcast | 470 – 890 MHz | 0.1 – 5 microwatts | Varies by proximity to tower |
The numbers look small because they are. A single AA battery holds about 9,000 joules of energy. At 10 microwatts of harvested power, you’d need roughly 28 years to accumulate that same energy from ambient RF. That’s why wireless power harvesting doesn’t replace batteries for power-hungry devices like smartphones or laptops. It targets devices that use so little power that even microwatts are enough – things like temperature sensors that wake up once every 30 seconds, take a reading, transmit it over Bluetooth, and go back to sleep.
What Devices Use Wireless Power Harvesting Today?
Samsung Eco Remote. Samsung’s SolarCell Remote, included with every Samsung smart TV since 2022, combines a small solar panel with an RF energy harvesting circuit. The remote draws power from indoor lighting and ambient Wi-Fi/RF signals. Samsung says it eliminates roughly 99 million AAA batteries over its lifespan across all units sold. The remote has no battery compartment. It works, and millions of people use one daily without thinking about it.
Wiliot IoT Pixels. Wiliot makes postage-stamp-sized Bluetooth tags that have no battery at all. They harvest energy from ambient Bluetooth, Wi-Fi, and cellular signals and use that power to transmit a Bluetooth Low Energy signal containing sensor data (temperature, humidity, fill level, tamper detection). Major companies use them for supply chain tracking – monitoring whether a vaccine shipment stayed cold or a pallet of food reached the right warehouse. Each tag costs under $0.50 at scale, which makes them disposable.
Atmosic Bluetooth Chips. Atmosic Technologies builds Bluetooth 5 system-on-chip (SoC) modules with integrated RF energy harvesting. Their chips power wireless keyboards, mice, remote controls, and beacons. The ATM33 series can operate on harvested RF energy alone or use it to extend a small battery’s lifespan by 5-10x. Atmosic has partnered with keyboard and remote manufacturers to build products that never need battery replacements.
Powercast Wireless Charging at a Distance. Powercast takes a different approach. Instead of harvesting ambient RF that’s already in the environment, they deploy dedicated RF transmitters that beam focused 915 MHz energy to receivers embedded in devices. Their system delivers milliwatts at distances up to 80 feet – enough to charge AA-battery-equivalent devices wirelessly. They’ve deployed systems in retail stores (powering electronic shelf labels) and warehouses (powering sensors and trackers).
| Company | Technology | Power source | Target devices | Status |
|---|---|---|---|---|
| Samsung | SolarCell + RF harvesting | Ambient light + RF | TV remote controls | Shipping since 2022, included with all Samsung smart TVs |
| Wiliot | Battery-free Bluetooth tags | Ambient Bluetooth/Wi-Fi/cellular | Supply chain tracking, smart packaging | Commercial production, used by major CPG and pharma companies |
| Atmosic | Bluetooth SoC with RF harvesting | Ambient RF | Keyboards, mice, remotes, beacons | Chips shipping to OEMs, consumer products in market |
| Powercast | Dedicated RF transmitter + receiver | Dedicated 915 MHz transmitter | Electronic shelf labels, sensors, trackers | Commercial deployments in retail and industrial |
| Ossia (Cota) | Focused RF beamforming | Dedicated 5.8 GHz transmitter | IoT sensors, medical devices, wearables | FCC-approved, commercial pilots underway |
| Energous (WattUp) | Near-field and mid-field RF | Dedicated transmitter | Hearing aids, wearables, IoT | FCC Part 18 certified, shipping in hearing aid market |
Wireless Power Harvesting vs Wireless Charging
Wireless power harvesting and wireless charging (like Qi pads for smartphones) are not the same thing. People confuse them because both involve “wireless” and “power,” but the underlying technology and use cases are completely different.
Qi wireless charging uses tightly coupled magnetic induction. You place your phone directly on a charging pad – typically within 4-10mm – and the pad transfers 5-15 watts of power through magnetic fields. It’s fast and efficient but requires direct contact. You’re replacing a cable with a pad, not eliminating the need for a power source.
RF energy harvesting works at distances measured in feet or meters, not millimeters. It captures ambient or directed radio waves from the air. The power levels are microwatts to milliwatts, not watts. You could never charge a smartphone this way. But you can power a sensor that draws 10 microwatts indefinitely without any battery or charging pad at all.
| Feature | Qi wireless charging | RF energy harvesting |
|---|---|---|
| Range | 4-10mm (contact) | 1-80+ feet |
| Power delivered | 5-15 watts | 1 microwatt – 4 milliwatts |
| Requires dedicated transmitter | Yes (charging pad) | Sometimes (ambient harvesting needs none) |
| Target devices | Smartphones, earbuds, watches | Sensors, tags, remotes, low-power IoT |
| Can replace device battery entirely | No (still needs internal battery) | Yes, for ultra-low-power devices |
| Standard | Qi (WPC) | No single standard yet |
Can Wireless Power Harvesting Run Smart Home Devices?
Not the power-hungry ones. A smart security camera draws 2-5 watts continuously. A smart speaker draws 2-3 watts while idle and 10+ watts while playing audio. Even the most advanced RF harvesting systems max out around 3-4 milliwatts at short range. You’d need roughly 1,000x more power than harvesting can deliver to run a camera.
But smart home devices aren’t all cameras and speakers. Many of the newer ones are low-power sensors: door/window sensors, motion detectors, temperature and humidity sensors, water leak detectors, air quality monitors. These devices sleep most of the time and only wake up briefly to transmit a reading. A typical Zigbee door sensor draws under 20 microwatts on average, and that’s within reach of ambient RF harvesting.
The realistic path for wireless power harvesting in the smart home is bottom-up. It won’t start by powering your Ring camera. It’ll start by eliminating the coin cell batteries in your door sensors, the AAA batteries in your TV remote (Samsung already did this), and the watch batteries in your leak detectors. Over the next several years, expect to see more smart home sensors that simply have no battery compartment at all.
What’s Holding Wireless Power Harvesting Back?
Physics. RF energy density drops off with the square of the distance. Double the distance from a Wi-Fi router and you get one-quarter the harvestable energy. Walls, furniture, and bodies absorb RF energy further. In a typical home, the ambient RF energy density is around 0.1 to 1 microwatt per square centimeter – barely enough to power the most efficient circuits.
Efficiency. Current rectennas convert about 20-40% of received RF energy into usable DC power. The rest is lost as heat. Improving this conversion efficiency is an active area of research. Recent work with metamaterial-based antennas and multi-band harvesters has pushed lab results above 50%, but commercial products still lag behind.
Regulation. RF transmitters are regulated by the FCC (in the US) and equivalent agencies worldwide. Dedicated power transmitters must stay within power limits to avoid interfering with communications. The FCC has approved specific devices from companies like Ossia and Energous, but the regulatory framework for widespread RF power transmission is still being developed.
No universal standard. Unlike Qi for wireless charging, there’s no single standard for RF energy harvesting. Each company uses different frequencies, protocols, and hardware. The AirFuel Alliance is working on an RF wireless power standard, but adoption is early. Without a standard, device makers can’t guarantee interoperability between different vendors’ transmitters and receivers.
Wireless Power Harvesting FAQs
Is wireless power harvesting safe?
Yes. The RF energy levels involved are far below what your phone, router, or microwave oven already produce. Ambient harvesting captures energy that’s already present in the environment – it doesn’t generate any new radiation. Dedicated RF transmitters like Powercast’s operate at power levels well within FCC safety limits (typically under 3 watts EIRP at 915 MHz), which is lower than a typical Wi-Fi router’s output.
Can I build a DIY RF energy harvester?
You can, but the output will be tiny. Hobbyist rectennas using Schottky diodes and printed circuit board antennas tuned to 2.4 GHz can harvest a few microwatts near a Wi-Fi router – enough to barely light an LED. Instructables and Hackaday have documented builds. For anything practical, you need purpose-built ICs like those from Atmosic, e-peas, or Powercast that integrate power management circuits optimized for ultra-low input power.
Will wireless power harvesting replace batteries completely?
Not for most devices. Phones, laptops, cameras, speakers, and anything with a screen will continue using batteries for the foreseeable future – the power gap is too large by orders of magnitude. But for the billions of small IoT sensors, trackers, and tags expected to be deployed over the next decade, wireless power harvesting makes batteries unnecessary. The World Economic Forum estimates over 1 trillion IoT sensors will be deployed by the 2030s. Most of those can’t have batteries that need replacing. Harvesting is the realistic answer for powering them.
How far away can wireless power harvesting work?
Ambient harvesting (from existing Wi-Fi, Bluetooth, cell signals) works effectively within about 15-30 feet of the signal source. Dedicated RF transmitters extend the range to 80+ feet for systems like Powercast, and Ossia’s Cota system claims effective power delivery at room-scale distances (up to about 30 feet) using beamforming to focus energy toward specific receivers. Beyond those distances, the harvestable power drops below what even the most efficient circuits can use.
What happened to the Samsung battery-free remote?
It shipped. Samsung’s SolarCell Remote has been included with all Samsung smart TVs since 2022. The remote uses a combination of a small solar cell (works under indoor lighting) and an RF energy harvesting circuit. It charges from both light and ambient RF signals. Samsung has confirmed that the remote has eliminated the need for millions of AAA batteries. It’s the most widely deployed consumer RF energy harvesting product in the world right now.
Does 5G help wireless power harvesting?
Potentially, but not yet in a meaningful way. 5G mmWave (millimeter wave) signals carry more energy per unit area than 4G, and their higher frequencies are theoretically easier to harvest efficiently. However, 5G mmWave coverage is still limited to dense urban areas and has very short range. Sub-6 GHz 5G, which is more widely deployed, operates at similar power levels to 4G and doesn’t meaningfully change the harvesting equation. Researchers are exploring 5G mmWave energy harvesting, but commercial applications are still years out.
See Also
Reference links:
https://www.cnet.com/news/