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Autonomous Sensor Node Powered over WiFi: A Use Case Study
Florian Grante, Ghalid Abib, Muriel Muller and Nel Samama
D
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epartement Electronique et Physique (EPh), T
´
el
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ecom SudParis, Institut Polytechnique de Paris,
19 Rue Marguerite Perey, 91120, Palaiseau, France
Keywords:
RF Electromagnetic Energy, Energy Harvesting, WiFi, Autonomous Sensor, Schottky Diode,
RF/DC Rectifier, Boost, Energy Budget Analysis, Green IoT.
Abstract:
This paper presents a new approach to the sizing of a radio frequency energy harvesting system. Starting
from a sensor node to define our system constraints such as its energy requirement or its supply voltage, an
energy budget analysis protocol is developed to validate whether it is possible to power such a system with a
Radio Frequency to Direct Current (RF/DC) converter. We study a converter capable of harvesting RF signals
in the Industrial, Scientific and Medical (ISM) band at 2.45 GHz whose ambient power has been previously
characterized. Finally, the duty cycle is determined, i.e., how long would it take the converter to recover the
required energy in order to power the sensor node.
1 INTRODUCTION
The Internet of Things (IoT) is gradually revolution-
izing our daily lives as well as in the industrial, med-
ical, connected city projects and electricity distribu-
tion with smart grids. But the explosion in the num-
ber of connected objects also implies the explosion in
the production of batteries, the main source of electric
energy for these objects. Batteries being a depletable
source of energy and requiring regular maintenance,
there is a need to find alternative energy sources that
we can group together as the concept of Energy Har-
vesting.
Among the different harvestable energy sources,
the most common one is the solar energy with the de-
velopment of small organic solar panels. They have
the advantage of making flexible panel and do not
require rare-earth elements in its design. Also, me-
chanical energy is well suited for products such as
connected switches. We can also find research teams
working on thermoelectric energy sources based on
the Seebeck effect or on the source that we will focus
on in this paper, which is the Radio Frequency (RF)
signal. RF sources like WiFi, GSM, TV transmitters,
... emit electromagnetic waves and surround our envi-
ronment. A lot of them are wasted and could be con-
verted into Direct Current (DC) energy to power spe-
cific low consumption electronic devices like a sensor
node, leading to a green IoT.
During the last 10 years, RF energy harvesting
state of the art has evolved from a converter sys-
tem using TV signals (Parks et al., 2013), which was
commonly used and powerful in the early 2010’s, to
more research in the Industrial, Scientific and Medi-
cal (ISM) 2.45 GHz and GSM 900 / 1800 bands (Ho
et al., 2016) because of the emergence of WiFi, 3G,
4G systems...
To our knowledge, few works take into account
the sizing of the harvester system for a dedicated ap-
plication or a sensor node according to its energy re-
quirements. A well-optimized ”wake-up” principle
allows the sensor to be powered for a short period
to measure and send data, then turned off to allow
the converter to charge a capacitor for energy stor-
age. But we would like to go further and propose a
new approach in the study of RF/DC converters by
concretely characterizing the energy requirement of
an application such as powering an IoT sensor node
and thus discuss the feasibility of such a system.
We base this work on WiFi energy harvesting
system in the 2.45 GHz band and we are focus-
ing only on the necessary circuits after the antenna.
This latter will not be discussed here because we can
rely on other works such as (Kurvey and Kunte, ),
(Krakauskas et al., ) or (Shaker et al., ) if needed. We
will contextualize our needs in Section 2 where we
will present the energy requirement of a sensor node
and the available ambient WiFi electromagnetic en-
ergy. Then, we will study the main issue of a RF/DC
converter which is the low output voltage level in Sec-
tion 3. Finally, a calculation model based on energy
budget analysis will be defined in Section 4. It is ca-
Grante, F., Abib, G., Muller, M. and Samama, N.
Autonomous Sensor Node Powered over WiFi: A Use Case Study.
DOI: 10.5220/0009804101270132
In Proceedings of the 17th International Joint Conference on e-Business and Telecommunications (ICETE 2020) - DCNET, OPTICS, SIGMAP and WINSYS, pages 127-132
ISBN: 978-989-758-445-9
Copyright
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2020 by SCITEPRESS – Science and Technology Publications, Lda. All rights reserved
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