An Innovative Design of RF Energy Harvester for Wireless Sensor Devices

An Innovative Design of RF Energy Harvester for Wireless Sensor Devices

Pankaj Agrawal (Mahatma Gandhi Chitrakoot Gramodaya Vishwavidyalaya, India), Akhilesh Tiwari (Madhav Institute of Technology and Science, India) and Uday Pratap Singh (Madhav Institute of Technology and Science, India)
Copyright: © 2018 |Pages: 32
DOI: 10.4018/978-1-5225-3531-7.ch015


Due to growing demand of energy, green technologies are highly attractive among researchers because of their non-conventional nature. Energy harvesting is one of their best parts. Very low cost of maintenance and non-polluting nature are major reasons behind their growing demand. However, for ultra-low power applications, such as in wireless sensor devices, the energy scavenging from RF signal is another alternative. In the last few years, a great interest has been seen in microwave power scavenging for charging wireless devices. This chapter presents a RF energy harvesting circuit with tuned π-matching network that resonates at desired incident RF frequency to boost these signals. Various computer intelligent techniques have been used to optimize parameters value of matching circuit. The designed circuit has been analyzed for input power range from -30 dBm to 0 dBm. Approximately 80% maximum PCE is achieved at RF input of 0 dBm with 4 KΩ load. It is also demonstrated that better output power is produced for power range -15 dBm to 0 dBm at higher load values.
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Energy harvesting is the most prominent solution to increase efficiency and battery life span of low power wireless devices. In the past few decades the application of wireless devices operated from ultra low power sources have drastically increased in wireless communication system. With technological advancement, power requirement of various electrical and electronic devices has decreased, which encouraged researchers to move towards energy harvester to provide continuous power supply for ultra low power devices like wireless sensors. The process of energy harvesting is to collect amounts of radiations from number of available natural and human made energy sources, converting them in to usable electrical energy and store it for charging up wireless sensor devices. Energy is available everywhere in the ambient around us. Table 1 estimate the amount of power hich can be harvested from various energy sources.

Table 1.
Estimation of harvested energy (Nintanavongsa et. al., 2012)
Energy SourcesHarvested Power Density
1. Light energy
(a) Indoor
(b) Outdoor
10 μw / cm2
10 mw / cm2
2. Temperature difference
(a) Human
(b) Industry
25 μw / cm2
1 - 10 mw / cm2
3. Vibration energy
(a) Human
(b) Industry
4 μw / cm2
100 μw / cm2
4. RF energy
(a) GSM network
(b) WiFi network
0.1 μw / cm2
1 μw / cm2

From these available energy, RF power is present everywhere whether indoor or outdoor locations. This energy is useful for harvesting purpose in ultra low power applications especially in wireless sensor devices. Radio frequency (RF) signals are the electromagnetic waves lie in the frequency band of 30 MHz to 300 GHz. These waves are being used in wireless information communication like FM radio, AM radio, Digital TV, Wi-Fi, GSM mobile and UHF or microwave communication.

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