Energy is one the most important factor for any active system to work. At any given moment, RF energy is transmitted from millions of transmitters and device across the globe. There is lot of advantages if we could harvest this energy from surrounding sources. Let’s find what is Radio Frequency based wireless energy harvesting its applications.
We have been depending on many energy sources for centuries. Since the modern science and electronics industry growing rapidly, there is a huge demand for various efficient energy sources.
What is wireless (RF) energy harvesting?
The concept of energy harvesting is to receive energy from surroundings sources and convert it into a useful form to power any applications or store the energy for future usage. In wireless (RF) energy harvesting, electromagnetic energy from multiple sources received by an antenna, converts it into an electric energy and use as a power source for other devices.
How RF based wireless energy harvesting works
There are mainly three components in a typical RF energy harvesting device. An antenna designed and perfectly tuned to a specific frequency which receives signals from its surroundings. Antenna converts electromagnetic waves into low power electrical signals which will be feed to an AC to DC converter. DC voltage will be controlled by a controlling unit which regulates the output to the load or storage.
Sources of radio waves
Any radio transmitting devices can be considered as a source for wireless energy harvesting. The frequency range and operating power depends on the specific application of the transmitter.
Most common radio wave sources are mobile base stations, radio broadcasting stations, TV broadcasting, satellites, wireless LAN transmitters (Wi-Fi) and mobile devices.
Applications of wireless energy harvesting
- Battery-less power source
- RF tags for shopping
- Smart lighting applications
- Smart switches for home automation used with ZigBee technology
- Internet of Things applications
- Recharging of devices
- Power source for smart sensors
- Simple design and cost effective
- Easier implementation
Advantages of wireless energy harvesting
- Conventional power sources can be replaced
- Unlimited spectrum of sources
- Efficient source of energy
- No wastage, green energy
- No need for periodic replacement of battery
- Extended life for devices due to recharging of storage battery during sleep mode
Future of wireless energy harvesting
There are lot of potential for wireless energy harvesting for application like Internet of Things and home automation projects. Smart sensor technology is capable of producing low power devices with advanced embedded technology which typically operates at micro watt input power.
Wireless sensors for temperature, humidity and proximity sensors are used in industrial, home automation and automobile industry. Wire-free charging of any electronics device would be possible with advancement in wireless energy harvesting technology.
Our future mobile devices will be capable of using wireless charging technology as an alternate power source. Wearable devices and medical sensors will be using wireless energy as power source.
Enhanced security devices with smart sensor technology can make use of power from wireless energy harvesting. It has advantages due to wire-free wireless transmission, compact size and the modules can be easily implemented anywhere.
Limitation of wireless energy harvesting
Wireless energy harvesting has lot of limitations due to its dependency on external sources which are prone to atmospheric changes, physical obstacles and radio wave source uptime. Received power from the sources is too low and level is often varies in time.
System efficiency is reduced over time due the performance of the components used in the devices like capacitors, diodes, back up storage battery etc… Design of receivers in wide frequency range is often challenging, device designed to operate at one frequency band is limited only on that spectrum.
In conclusion, emerging technologies like Internet of Things will require efficient energy source to connect billions of smart devices and sensors for wide spectrum of applications. Long term sustainable and reliable energy sources are inevitable for any efficient system. Wireless energy harvesting is an area for future developments to deliver effective solutions for IoT, medical, industrial and other smart home applications.