Transcript MODELING OF PENETRATING ELECTROMAGNETIC FIELDS OF …

Dejan Krstić, Darko Zigar, Dejan Petković,
Nenad Cvetković, Vera Marković,
Nataša Đinđić, Boris Đinđić
* University of Niš, Faculty of Occupational Safety in Niš, Čarnojevića 10a, Niš, Serbia, e-mail: [email protected]
** University of Niš, Faculty of Electronic Engeenering Nis, Aleksandra Medvedeva 14, Niš
*** University of Niš, Medical Faculty in Niš, Bulevar Zorana Đinđića 81, Niš
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electromagnetic radiation,
electromagnetic pollution or
electromagnetic smog
undesirable phenomena (not
confirmed by the good)
biological effects, performed
on experimental animals.
Fig. 1 - Experimental animals
with a mobile test phone [3]
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Penetrating electromagnetic
field is almost impossible to
measure
Penetrating field in the tissue
must be calculated
Numerical methods in
electromagnetics (integral
method, differential and
variation method)
Commercial software packages
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Model of the source
(mobile phone) with the
antenna pattern
characteristic,
Experimental animal model
with the actual
characteristics of tissues
Model of wave propagation
in half-conductive
environment, i.e. the
choice of numerical
simulation methods (FDM,
MoM, FDTD, FIT, etc.).
Three types of mobile
 Mono-block phone with a
with monopole antenna
which is placed on the top
of the mobile phone (a),
 Mono-block phone with a
planar inverted-F
antennas - PIFA (b and c)
 Flip-down phone with a
PIFA (d).
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FDTD solves Maxwell’s equations in the time domain.
This means that the calculation of the
electromagnetic field values progresses at discrete
steps in time.
Main reason for using the FDTD approach is the
excellent scaling performance of the method as the
problem size grows.
As the number of unknowns increases, the FDTD
approach quickly outpaces other methods in
efficiency.
FDTD has been identified as the preferred method
for performing electromagnetic simulations for
biological effects from wireless devices [3, 4, 7].
Simulation program was carried out REMCOM
XFDTD [8]
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It is significant to known the real
position of all tissues in animal body and
their electromagnetic characteristics.
These complimentary animal meshes
are provided by The Radio Frequency
Branch of the Human Effectiveness
Division of the Air Force Research Lab at
Brooks Air Force Base [11].
Real 3D model with all tissue and
resolution of model is 1mm.
Model have 47 diferent tissues and parts.
Biol. Material
Skin
ligaments
fat
blood
muscle
grey matter
white matter
eye sclera
nerve spine
stomach
kidneys
testicles
eye lens
heart
pancreas
body fluid
liver
Conductivity
(S/m)
0.693293
0.951258
0.0529249
1.86817
1.1975
1.0092
2.42613
1.68613
0.606129
1.30105
1.349
1.34108
0.908172
1.722
1.66
2.899
1.33
Relative Permittivity
39.5868
46.7184
4.78598
55.4796
60.7263
51.8029
68.2932
67.9
33.3591
71.7763
53.898
62.6033
51.4785
55.744
57.2
67.24
43.4
Density
(kg/m3)
1125
1220
916
1058
1046.9
1038
1038
1026
1038
1050
1150
1044
1530
1029.8
1045
1010
1030
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In the simulation process with REMCOM XFDTD
program is used a source of power 1W.
The results for the component EM fields in free
space have been compared with the values
measured by field meter AARONIA HF6080.
The results matched have been satisfactory.
Simulated is real cage with rats and mobile
phone in two possition.
Case 1 - Antena is near to the head
Case 2 - Antena is near to the stomach
Electrical field
Electric field in model of rat
Electrical
field
Case 1 – Distribution of EM field
Electric field in model of rat
Distribution of SAR in trunk of
model cross section liver
Distribution of SAR in head of model cross section of brain and eye tissue
Case 2 – Distribution of EM field
Electric field in model of rat
Distribution of SAR in trunk of
model cross section liver
Distribution of SAR in head of model cross section of brain and eye tissue
Tab. 2 - Calculation Electrical field in some part of body in model of rat.
Electrical field E(V/m)
Position of the antenna
Organ
Average
Next to the head
(Case 1)
Next to the trunk of
the body (Case 2)
liver
5.61
10.8
8.205
brain
16.9
7.65
12.275
eye
13.8
4.31
9.05
Tab. 3 - Calculation SAR in some part of body in model of rat.
SAR(W/kg)
Position of the antenna
Organ
liver
brain
eye
Next to the trunk
Next to the head
of the body
(Case 1)
(Case 2)
0.0132
0.166
0.148
0.046
0.147
0.026
Average
0.089
0.097
0.086
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The results of electric field distribution in the rats bodies suggest that
there is an unequal distribution of the fields, which depends on the
position of the sources and characteristics of each tissue.
It is important to note that there are tissues which absorb 10 times
higher amounts of energy the tissues adjacent to them.
Precise locate point of maximum SAR indicate the possible biological
effects of radiation on these tissues.
These effects were presented and discussed in various papers which
analyzed biochemical indicators of the effects of electromagnetic
fields.
Such calculation enables us to develop the biological quantifiers of the
effects of electromagnetic fields, which is studied by dosimetry.
Thus obtained quantifiers could be applied on the human tissue.
Acknowledgement:This work was supported by the project III43011 and
III43012 of the Serbian Ministry of Education and Science.