Advantages of RF Energy Harvesting | Disadvantages of RF Energy Harvester

This page covers advantages and disadvantages of RF Energy Harvesting Technique. It mentions benefits or advantages of RF energy harvesting and drawbacks or limitations or disadvantages of RF energy harvesting.

Introduction: There are various types of energy harvesting techniques which are mainly categorized into environmental and Human generated. The sources of environmental energy harvesting include ambient sunlight, acoustic infrared waves, Radio frequency (RF) waves, fluid flow, air flow, temperature variation etc. Human energy harvesting techniques include vibration due to magnetic induction or piezoelectric, push buttons, shoe inserts, hand generators, Heel Strike etc. All these energy harvesting techniques are used to generate power which can be used for various applications or stored for future usage. RF energy harvesting technique is wireless form of energy harvesting which captures electromagnetic (EM) waves from surroundings.

There are wide variety of applications of RF energy harvesting such as recharging of devices (e.g. super capacitors, coin cells or thin film cells), battery-less power sources or wireless sensors, RF tags, smart switches and other IoT (Internet of Things) applications etc.

What is RF Energy Harvesting and how it works

RF harvesting device uses antenna to receive EM waves and converts it to electric energy. The frequency range and operating power range of RF harvester depends on the transmitting source available. The common wireless sources include 2G/3G/4G/5G cellular towers or BSs (Base Stations), radio signal transmitting stations, TV signal broadcasting stations, Satellites, Wi-Fi kiosks/routers, satellites, NFC transmitter, RFID readers, BLE (Bluetooth Low Energy) transmitter, UHF transmitter etc.

RF Energy Harvesting

The RF energy harvesting system consists of three parts viz. antenna, RF to DC converter and charge management module. Moreover it requires RF generators in the vicinity. RF antenna captures EM waves as per its operating frequency and its mechanical structure. Charge management module can either be rechargeable battery (lithium ion based) or can directly be used to power batteryless electronic devices. Refer articles on types of energy harvesting systems >> and RF energy harvesting system basics >> for more information.

Advantages of RF Energy Harvesting

Following are the benefits or advantages of RF Energy Harvesting:
➨It traps the electro-magnetic waves for power generation/storage which is freely available around us due to cellular towers, WiFi kiosks and other wireless technologies.
➨It is alternative method to recharge batteries where power demands are very high.
➨It is best efficient source of energy generation with good amount of RF to DC conversion efficiency (~75%).
➨There is no wastage produced by this technique and hence it is one of the viable alternative for green energy generation.
➨It offers savings in electric bills due to less usage of mains power for recharging of battery and other consumer electronic devices.
➨RF to DC power converters can be used as alternate backup power source during travel.
➨Unlike solar power source, RF energy harvesters can work in dark atmospheric conditions also.

Disadvantages of RF Energy Harvesting

Following are the limitations or drawbacks or disadvantages of RF Energy Harvesting:
➨The RF based harvesting technique relies on wireless sources which are affected due to atmospheric changes and other factors such as obstacles, weather etc.
➨The received power at RF to DC converter input of RF harvesting chip is very low and also varies in time.
➨RF harvester uses electronic components such as diodes, capacitors, battery etc. Hence its efficiency largely depends on performance of these components.
➨Design of RF energy harvesting receiver is complex for wide frequency range specification.
➨The RF harvester system does not work in the absence of RF sources.

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