International Journal of Emerging Technology and Advanced Engineering
Website: www.ijetae.com (ISSN 2250-2459, ISO 9001:2008 Certified Journal, Volume 5, Issue 5, May 2015)
Identification and Measurement of Possible Electromagnetic
Radiation in Wireless Communication
Célestin Twizere1, Said Rutabayiro Ngoga2, Felicien Kanamugire3
Electrical and Electronics Engineering Department, University of Rwanda, Avenue de l’Université, P.O Box 117 Butare
Rwanda
I. INTRODUCTION
Every day household electrical devices such as
hairdryers, electric and microwave ovens, fluorescent
lights, stereos, mobile phones, computers and the base
station transmitters, often air out electromagnetic radiations
of varying intensities. The electromagnetic spectrum is
divided into ionizing and non –ionizing bands based on
how the wave interacts with tissues. Radio frequencies
emitted by mobile phone, base transmitter stations (BTS)
are classified as non ionizing radiation, although these
frequencies can enter the body and cause harm according to
the level and the total time we are exposed. Though some
research has indicated the theory that radio frequency
emissions might have adverse effects on the human body,
so, proper evaluation with tangible evidences are required
to confirm that long-term exposure to electromagnetic
radiation from identified distance is harmful as this world
of ours is increasing highly in technologies for its better
development[1].
It is now identified that technology is increasingly
developing at a very high rate across over the world, by
considering the time when technology came into existence.
It is now 30 years from when mobile telephone system and
wireless communication came into existence, 70 years
since radio transmission existed and 100 years since
electricity generation started. Even though all these kind of
technologies compensated for the world to be where it is by
today, they were also accompanied by concerned possible
health risks due to their electromagnetic radiations. Due to
the electromagnetic radiation exposure at the highest
frequencies (x-rays, gamma rays) is a source of serious
biological damage. Health effects from exposure to this
form of radiation vary from no effect at all to death, and
can cause diseases such as leukaemia or bone, breast, and
lung cancer. The seriousness of the effects depends on the
how long your exposed to it and length of the distance from
the source. Man- made sources account for most of the
electromagnetic radiation in our environment. With the
proliferation of new technological devices in our home and
work place we are all exposed to electromagnetic radiation
daily.
Electromagnetic radiation can be described as a stream
of photons, each travelling in a wave like pattern, carrying
energy and moving at the speed of light. EMR carries
energy sometimes called radiant energy and both
momentum and angular momentum. These may be
imparted to matter with which it interacts. EMR is
produced from other types of energy when created, and it is
converted to other types of energy when it is destroyed.
The photon is the quantum of the electromagnetic
interaction, and is the basic "unit" or constituent of all
forms of EMR. The quantum nature of light becomes more
apparent at high frequencies (or high photon energy). Such
photons behave more like particles than lower-frequency
photons do. Propagation of electromagnetic waves may
occur by ground wave, troposphere wave, or sky wave.
Most contemporary communication systems use either
direct line of site (LOS) or indirect propagation where the
signals are strong enough to enable communication by
reflection, diffraction, or scattering. Maxwell’s equations
form the basis of electromagnetic wave propagation.
Abstract— From the point that technology is developing
very fast, this goes hand in hand with the increase in number
of Base Transceiver Stations(BTS) for good mobile
communication and later increase in both positive and
negative effects on all living features.
The aim of this paper is to identify and measure the
possible electromagnetic radiations in wireless communication
and by specifying the secured zone around Base Transceiver
stations according to the International Commission on NonIonizing Radiation Protection (ICNIRP) guidelines. After
describing Electromagnetic Radiations (EMR) from wireless
antennas and different international guidelines and standard
limits for human exposure to EMR, we concluded determining
secured zone around BTS according to the measurements
taken from the ground using a Trifield meter.
Keywords—Electromagnetic Radiation, ICNIRP, Trifield
meter.
II. THEORETICAL ANALYSIS
228
International Journal of Emerging Technology and Advanced Engineering
Website: www.ijetae.com (ISSN 2250-2459, ISO 9001:2008 Certified Journal, Volume 5, Issue 5, May 2015)
The relationship between the time varying electric and
magnetic fields is expressed mathematically for uniform
plane wave. The electromagnetic spectrum is the range of
all possible frequencies of electromagnetic radiation. The
"electromagnetic spectrum" of an object is the
characteristic distribution of electromagnetic radiation
emitted or absorbed by that particular object. The
electromagnetic spectrum extends from low frequencies
used for modern radio communication to gamma radiation
at the short-wavelength (high-frequency) end, thereby
covering wavelengths from thousands of kilometres down
to a fraction of the size of an atom. It is for this reason that
the electromagnetic spectrum is highly studied for
spectroscopic purposes to characterize matter. The limit for
long wavelength is the size of the universe itself, while it is
thought that the short wavelength limit is in the vicinity of
the Planck length, although in principle the spectrum is
infinite and continuous.
Figure 1: Electromagnetic spectrum [1].
The IEEE Standard Definitions of Terms for Antennas
defines the antenna or aerial as ―a means for radiating or
receiving radio waves[3].‖ In other words the antenna is the
transitional structure between free space and a guiding
device, and it is used to transport electromagnetic energy
from the transmitting source to the antenna or from the
antenna to the receiver.
In addition to receiving or transmitting energy, an
antenna in an advanced wireless system is usually required
to optimize or accentuate the radiation energy in some
directions and suppress it in others. Thus the antenna must
also serve as a directional device in addition to a probing
device.
It must then take various forms to meet the particular
need at hand, and it may be a piece of conducting wire, an
aperture, a patch, an assembly of elements (array), a
reflector, a lens, and so forth. For wireless communication
systems, the antenna is one of the most critical components.
A good design of the antenna can relax system
requirements and improve overall system performance. A
typical example is TV for which the overall broadcast
reception can be improved by utilizing a high-performance
antenna[3]. The power radiated by antenna is expressed by
solving Maxwell’s equations.
229
International Journal of Emerging Technology and Advanced Engineering
Website: www.ijetae.com (ISSN 2250-2459, ISO 9001:2008 Certified Journal, Volume 5, Issue 5, May 2015)
These equations relate the electric field E (V/m) and the
magnetic field H (A/m) to the current density J (A/m2) and
the charge density  (C/m3) [4].
According to the World health organization, the ICNIRP
guidelines are highly protective and are based on all the
available scientific evidence. They take into accounts all
known impacts and offer protection against all confirmed
risks from exposure to electromagnetic fields. Moreover,
the ICNIRP guideline incorporate large safety factors, 50
times below the limit value at which no effects on the
human body have been reported. In their publication called
―guidelines for limiting exposure to time varying electric,
magnetic, and electromagnetic fields (up to 300GHZ)‖,
they are based on short term, immediate health effects such
as stimulation of peripheral nerves and muscles, shocks and
burns caused by touching conducting objects, and elevated
tissue temperature resulting from absorption of energy
during exposure to EMF. In the case potential long- term
effects of exposure, such as an increased risks of cancer,
ICNIRP concluded that available data are insufficient to
provide a basis for setting exposure restrictions, although
epidemiological research has provided suggestive, but un
convincing evidence of an association between possible
carcinogenic effects and exposure at levels of 50/60HZ
magnetic flux densities substantially lower than those
recommended in these guidelines [6].
Figure 2: Trifield meter[7]
Most of the communication antennas are located on
top of the mountains where it can be easy to have a wide
antenna coverage area, but there are some which are
located on top of elevated hills. Several times these
mountains and hills are used as residential area where you
find people stay in few meters from transceiver antennas.
Here we are describing three locations found in Huye
District namely; Tumba site, Ngoma (Huye) and cyarabu.
TABLE I
DATA COLLECTED FROM NGOMA BTS OF 45M HIGH
N0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
III. METHODS AND DATA PRESENTATION
In wireless communication[5] we use different antennas
for transmitting signals from one point to the other,
different levels of power are radiated during transmitting
and receiving processes. The radiated power may be
harmful to the human being according to how strong it is.
Now, our task was to show that the electromagnetic
radiations from mobile transceiver stations are either harm
or not. This was done by collecting data using different
methods here include; using Trifield meter to measure the
power radiated from different antennas.
A trifield meter is an electronic device used to measure
the power radiated, magnetic fields and electric fields from
any electromagnetic radiating object. With this instrument
we can determine the level of radiated power from wireless
communication antennas which we are exposed to.
230
D(m)
2
4
6
10
12
20
25
30
40
50
60
70
100
120
H(mG)
0 – 0.08
0.04-0.6
0.8-1.4
1.0-1.8
0.2-0.8
2.4-2.8
3.2-3.4
3.0-3.5
2.4-2.9
2.4-2.9
1.6-2.0
1.2-1.6
0-0.02
0
Average
0.04
0.5
1.1
1.4
0.5
2.6
3.3
3.25
2.65
2.65
1.8
1.4
0.01
0
E(V/m)
0.188
2.35
5.18
6.59
2.35
12.25
15.55
15.31
12.48
12.48
8.48
6.59
0.047
0
W(w/m2)
0.017
2.77
13.43
21.76
2.77
75.06
120.9
117.28
77.97
77.97
35.97
21.76
0.0011
0
International Journal of Emerging Technology and Advanced Engineering
Website: www.ijetae.com (ISSN 2250-2459, ISO 9001:2008 Certified Journal, Volume 5, Issue 5, May 2015)
TABLE II
DATA COLLECTED FROM CYARABU BTS OF 30M HIGH
N0
D(m)
H(mG)
Average
E(V/m)
W(w/m2)
1
2
3
4
5
6
7
8
9
10
11
12
2
4
6
10
12
20
25
40
50
55
60
62
0 – 0.08
0.4-0.6
0.8-1.4
1.0-1.8
0.4-0.8
2.4-2.8
3.2-3.4
1.2-1.6
1.0-1.5
0.8-1.4
0.4-0.6
0
0.04
0.5
1.1
1.4
0.6
2.6
3.3
1.4
1.3
1.1
0.5
0
0.188
2.35
5.18
6.59
2.35
12.25
15.55
6.59
6
5.18
2.35
0
0.017
2.77
13.43
21.76
2.77
75.06
120.9
21.76
17.1
13.43
2.77
0
It is of great importance to know clearly that, long term
exposure to Non- ionizing radiations according to their
level, surely harm by comparing calculated results and
theory.
In Data collection, there some factors that may hinder us
from having very accurate information. Here we may say;
- Instrument used which was operating in analogue mode,
that is to say, readings were not fixed.
- Shielding effects, that is to say, there was some points
where the indications was as not as
expected due to
houses, trees and others which may attenuate the power of
the signal.
The comparison between collected data, theories and
international guidelines show us that close to some BTS
antennas, the power density can exceed guideline levels.
Operators calculate compliance distances in various
directions from their antennas in order to define a boundary
outside which the guidelines can never be exceeded.
Preventative measures such as administrative procedures or
physical barriers are implemented to ensure that people do
not accidentally enter regions defined as exclusion zones.
The design of sites would normally be such that the general
public would not be able to stay into regions designed as
exclusion zones. For large macrocellular base stations
radiating around 100 W or more, exclusion zones in the
range 10-15 m may be required in front of the antennas to
ensure exposures remain within the ICNIRP guidelines for
public exposure. In other directions such as below and
behind the antennas, the exclusion zones would extend for
lesser distances. Low power microcellular base stations
radiating around 1-2 W would require much smaller
exclusion zones than microcells and it may be possible to
encompass fully all regions where exposure could exceed
guidelines within the plastic cover of the antenna[6].
Here, the results were taken in the direction of antenna.
Compared to ICNIRP, where an antenna that radiates
100W its exclusion zone is in 10-15m, due to our results
from Tumba site where maximum radiation is 608.04W
and 91.4m high, its exclusion zone is in the range of 6091.2m from antenna. Also due to data from Ngoma and
Cyarabu with radiated power of 120W, at 45m and 30m
high respectively, exclusion zone is in the range of 12-18
meters from antenna.
There so many factors that should be considered in
determining the secured zone from base transceiver; and
from data collected we notice the following factors: the
height of the antenna, the antenna transmission capacity,
the antenna transmission band, the antenna gain and the
antenna radiating surface.
TABLE III
DATA COLLECTED FROM TUMBA BTS OF 91,4M HIGH
N0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
D(m)
2
4
6
10
12
16
20
25
30
40
50
60
70
100
150
200
220
250
H(mG)
0 – 0.02
0.04-0.08
1.6-2.0
1.8-2.4
0.8-1.2
2.4-2.8
3.8-4.2
7.2-7.6
5.2-6.0
2.2-2.4
3.4-3.8
2.9-3.6
2.0-2.6
1.6-1.8
1.2-1.4
1.4-1.8
0.6-0.9
0.04-0.08
Average
0.01
0.06
1.8
2.1
1
2.6
4
7.4
5.6
2.3
3.6
3.25
2.3
1.7
1.3
1.6
0.75
0.06
E(V/m)
0.04
0.28
8.48
9.89
4.71
12.25
18.85
34.87
26.39
10.83
16.96
15.31
10.83
8.01
6.12
7.54
3.53
0.28
W(w/m2)
0.001
0.039
35.97
48.96
11.1
75.06
177.66
608.04
348.21
58.73
143.9
117.28
58.73
32.09
18.76
28.42
6.24
0.039
Where;
D= Distance from antenna to the point where the data were
taken.
H= Instantaneous magnetic-field intensity in milligausse.
E= Instantaneous electric-field intensity.
W= Instantaneous Poynting vector.
IV. RESULTS ANALYSIS AND INTERPRETATION
From different International guidelines and standard
limits for human exposure to Non-ionizing EMR except
ICNIRP guideline, it is commonly known that Nonionizing radiations are not harmful to the human being.
231
International Journal of Emerging Technology and Advanced Engineering
Website: www.ijetae.com (ISSN 2250-2459, ISO 9001:2008 Certified Journal, Volume 5, Issue 5, May 2015)
Future studies will focus on measurements using others
instruments like Spectrum Analyser combined with a
digital Trifield meter with good accuracy in order to
evaluate and identify the limit zones for better advising
telecommunication companies on how to protect citizens to
Electromagneitcs Radiation.
V. CONCLUSION.
The main concern of this paper was to analyze the level
of electromagnetic radiation emitted by transceiver
antennas at Tumba, Ngoma and Cyarabu. As
Telecommunication companies increases continuously,
many antennas are established everywhere in the country
which can have negative impacts on Human being when
the time of exposition to EMRs increase. It is better to
locate residential area at 100 meters from microwave
transceiver base stations in order to avoid health risks and
even people are not advised to continuously be in the
mentioned above area since radiation power reduces as
distance increases.
The verification is true and sincere because the collected
data was compared with standards limit for Human
exposure to Non-ionizing EMR established by ICNIRP
association. Here we have indicated the dangerous zone
from antenna. In this paper we only concentrated on the
level of power radiated from the transceiver base stations in
three sites.
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