Information Technology Reference
In-Depth Information
An Ecient RF Energy Harvester
with Tuned Matching Circuit
Sachin Agrawal, Sunil Pandey, Jawar Singh, and P.N. Kondekar
PDPM-Indian Institute of Information Technology,
Design and Manufacturing Dumna, Khamaria P.O., Jabalpur, India-482005
{
sachin.agrawal,sunilpandey,jawar,pnkondekar
}
@iiitdmj.ac.in
Abstract.
Microstrip line with
ˀ
matching circuits are very attrac-
tive because of high output power and good impedance matching which
makes it an alternative over earlier matching circuit. This paper presents
an RF energy harvester with microstrip line in series with tuned
ˀ
-
matching circuit that enables ecient power conversion at different RF
input power under different load conditions. Matching circuit parameters
were optimized for better eciency. We have focused for specific input
power range -15 to 10dBm for 3-stage, 5-stage and 7-stage of energy har-
vesting circuit. Optimum eciency of approximately 80% is achieved at
input power 0 to 10dBm for higher stages. Effect of load variation also
shows that better eciency is achieved for input power -10 to 10dBm for
3-stage, 5-stage and 7-stage of the harvesting circuit.
1 Introduction
In recent years use of wireless battery operated devices are increasing in broad-
cast and communication system. These devices continuously provide availability
of free RF energy. The device like mobile phone, FM transmitter, AM and Wi-Fi
operates at different frequency. The frequency spectra of these devices have dif-
ferent characteristics that depends on environmental conditions and surrounding
locations for instance, humidity of the location. Energy harvesting circuits may
be an atteractive solution to provide sucient voltage for driving low power
electronic circuits, which requires power in microwatts or milliwatts[1]. Energy
harvesting is a process of extracting ambient energy available from the environ-
ment converting them into usable electrical energy.
Some related work has been done on solar energy harvesting since it has
the highest energy density among other choices. However, it has a drawback of
being able to operate only when sunlight is present. Wireless battery charging
system as discussed in[2], shows the concept of charging a cellular phone battery,
using monopole antenna that gives 50% eciency for commercial product. Main
motivation behind this work is the demand for self powered devices is increasing
day by day and it become an attractive choice for remotely deployed low voltage
battery wireless sensors.
This paper focuses on improving the eciency of RF energy harvester that
uses Wi-Fi and mobile signal because the maximum power intensity lies within
