Indian Journal of Science and Technology, Vol 9(20), DOI: 10.17485/ijst/2016/v9i20/85835, May 2016
ISSN (Print) : 0974-6846
ISSN (Online) : 0974-5645
Electromagnetic Radiation Hazards on Humans Due
to Mobile Phones
A. Christina Josephine Malathi
School of Electronics and Engineering, VIT University, Near Katpadi Road, Vellore - 632014, Tamil Nadu, India;
achristina@vit.ac.in, achristinadominic@gmail.com
Abstract
There is an escalation in the amount of mobile phone users day by day with the availability of low cost, highly featured
mobiles in the market. In the present investigation, the radiation characteristics of cell phone hand set is being analyzed
at the frequency of 900 MHz and the interaction of these radiations with the human body is to be evaluated. The effects of
radio frequency (RF) energy are related to the rate of energy absorption and it is computed using the parameter specific
absorption rate. The specific absorption rate (SAR) of EM radiation from cell phones on human body is being analyzed at
the regions of skin, muscle and heart. A novel method for the modeling of human body is carried out using the MATLAB
software, which uses the finite difference time domain (FDTD) method for the SAR calculations. Further its effects are
being analyzed from our investigation and it is reported that the measured SAR are within the FCC limits.
Keywords: EM (Electromagnetic Radiation), MOM (Method of Moments), RF (Radio Frequency), Radiation Hazards, SAR
(Specific Absorption Rate)
1. Introduction
There is an increasing demand for the use of wireless communication systems along with the concern for human’s
contact to EM radiation. This is mostly evident in the
usage of mobile phones. Many countries have set various
guiding principles and standards for limits for exposure
to RF radiation.
EM Radiation can be defined as waves of electric and
magnetic energy radiating through space. Cell phones
and its base stations produce EM radiations. These radiations are observed by their frequency and power. The
frequency range for the cell phone is around 800 MHz to
1900 MHz with a maximum power of 2 watts. The power
emitted is expressed in units of milli watt per cm2,1.
When human body is unprotected to EM radiation an
internal field is generated in the body. The absorption of
power by the tissues will cause a temperature rise which
is dependent on the cooling mechanism of the tissue. The
field produced due to heating depends on the frequency,
tissue dielectric properties and source configuration2.
When the thermo regulatory capability of the system
*Author for correspondence
exceeds, tissue damage results. The Electromagnetic
energy absorbed per unit mass of tissue is called Specific
Absorption Rate (SAR)
SAR = σE2/2ρ
Where σ = Conductivity (m /m)
ρ = Density of the tissue (Kg/m3)
E = Internal Electric Field (V/m)
The SAR of EM radiation from cell phones on the human
body is being studied. A novel method for the modeling of
human body is being carried out by using MATLAB software
which employs the FDTD method for SAR calculations.
There are several techniques available for measuring the
full body electromagnetic absorption, but there is no specific technique to calculate SAR within the body. MOM is a
frequency domain method which was followed, still MOM
requires storage memory of the order of (3N)2 and time for
computing of (3N)3 where N is the number of cells.
The FDTD has been used extensively in computing
the interaction of EM fields with complex, lossy dielectric
bodies. This method has memory and time ­requirements
communicate.
The The
human
brain
weigh
pounds(1300-1400
(1300-140g
communicate.
human
brain
weighup
uptoto about
about 33 pounds
mattermatter
(40%),
white
matter
(60%)
contained
the skull.
skull.The
Theblood
blood
(40%),
white
matter
(60%)
contained inside
inside the
is ai
Electromagnetic
Radiation
Hazards onis
Humans
Due to
Mobile and
Phones temperature is generally about 37 degr
Its specific
gravity
about
1.06
Its specific
gravity
is about
1.06
and
temperature generally about 37 de
bioelectrically
controlled
blood
pump.There
The
heart
of between
all
contracts
bioelectrically
blood
pump.
The
heart
of
all mammals
mammals
proportional to N.controlled
This Paper describes
the FDTD
is a major
difference
the NRPB and the contra
electric
potential
across
which
reaches
method
and utility
of the FDTDdifference
method is demonstrated
IEEE
specifically
in the 10 toa1000
MHz range asvalue
shown just p
electric
potential
difference
across
it itwhich
reaches
a maximum
maximum
value jus
by a 3D model of the human body model using MATLAB
in Figure 1. ICNIRP figures are reduced half when compumping
contraction.
Electrical
properties
are
needed
to
assess
the
rate of
software. contraction.
The acquired results validate
that the FDTD
pared to theare
two standards
above to
1 GHz.
The Figurethe
2
pumping
Electrical
properties
needed
assess
rate
method
of computing
internal field
a comparison
for the
category. The SAR is c
SARis capable
is used
to measure
thedistribueffectsshows
of EM
fields
onpublic
humans.
with
acceptable
per the
standards on
given humans.
by FCC, ANSI/IEEE
and SAR i
SARtionis
used
to accuracy.
measure
the effects
of AsEM
fields
cases
to quantify
the effects
of the deposition
thermal
energy
inThe
the
NCRP, there is aof
limit
on EM absorption
in humans
and biologi
cases2. toEquantify
the effects
thermal
energy
inFCC,
the biolo
emission from of
RF devices
given in terms
of SAR. By
lectrical Properties
of of the deposition
RF absorption limits are upto 1.6 watts/Kg, over one gram
Biological
SubstancesLimit
of tissue .
3. RF Exposure
4,5
Electrical properties of the biological substances can
Frequency
and Limit
intensity of the incident EM field
3. The
RF
Exposure
be classified as the active properties and passive properties.
4. FDTD Method
decides the exposur
considering
theintensity
average
whole
body
SAR notEM
exceeding
0.4
wkg-1 for
Active
defines theand
capability
to
generate electrical
Frequency
of potenthe
incident
field
decides
theworker
expo
The FDTD method was proposed by YEE -1
and then
tials and fields while the passive describes the responses
public, the
along
withstimuli.
experimentally
threshold
4wkg
. -1 for wor
developed
by Taflove
. It is the of
solution
for
Maxwell’s
to externally applied
electrical
considering
average
whole bodydetermined
SAR
not
exceeding
0.4
wkg
1
equations6,7.
The absorption of EM waves in full body depends on
-1
frequency and the positioning of the electric field ‘E’ to the
dimension ‘L’ of the body, where L is major length of the
body. The highest rate of energy absorption happens for E
ll L (E orientation) for frequencies where major length is
approximately 0.36 to 0.4 times the free space wavelength
(λ) of radiation. Understanding about the electrical properties is needed to investigate the interaction mechanism
of EM fields.
The human brain creates electrical signals and along
with chemical reactions with which the body parts communicate. The human brain weigh up to about 3 pounds
(1300-1400 gm)3. The brain entails gray matter (40%), white
matter (60%) contained inside the skull. The blood is an Figure 1. Comparison of occupational limits.
opaque rather viscid fluid. Its specific gravity is about 1.06
and temperature is generally about 37 degree centigrade.
The heart is a bioelectrically controlled blood pump. The
Figure
Comparison of occupational
limits.
heart of all mammals contracts or beats in response to an
Figure
1.1. Comparison
of occupational
limits.
electric potential difference across it which reaches a maximum value just prior to the start of the blood pumping
contraction. Electrical properties are needed to assess the
rate of the energy absorption. The SAR is used to measure
the effects of EM fields on humans. The SAR is considered
sufficient in most cases to quantify the effects of the deposition of thermal energy in the biological systems.
public, along with experimentally determined threshold of 4wkg .
There is a major difference between the NRPB and the IEEE specifically i
as shown in Figure 1. ICNIRP figures are reduced half when compared to the
The Figure 2 shows a comparison for the public category.
There is a major difference between the NRPB and the IEEE specificall
as shown in Figure 1. ICNIRP figures are reduced half when compared to t
The Figure 2 shows a comparison for the public category.
3. RF Exposure Limit
Frequency and intensity of the incident EM field decides
the exposure limit. The limits are set considering the average whole body SAR not exceeding 0.4 wkg-1 for workers
and 0.08 wkg-1 for general public, along with experimentally determined threshold of 4wkg-1.
2
Vol 9 (20) | May 2016 | www.indjst.org
Figure
2. Comparison
of public
Figure
2. Comparison
of public limits.
limits.
Indian Journal of Science and Technology
A. Christina Josephine Malathi
Approximation of derivatives in discrete form is done
using FD and the time domain simulations indicate TD. In
this method, the region considered is divided into number of cubic cells in which the fields are defined at fixed
locations. Maxwell’s equations are discretized by using the
FD approximation. After discretizing the Maxwell’s equation, it is solved by providing the excitation field to the
cells as a function of time, the initial conditions and the
boundary conditions.
Extensively used method for approximating EM.
No matrices are involved in implementing.
Quick learning time.
Wave interaction and coupling mechanisms can be
studied.
 It is robust, flexible, efficient, versatile, user friendly to
solve Maxwell’s equations in time domain.
 It is widely used for solving open region scattering,
electromagnetic interference (EMI), Electromagnetic
compatibility (EMC).




Advantages
(a) It is simple.
(b) No need of integral equations, inversion of matrices.
(c) Simple to implement
(d) Less memory requirement.
(e) Easy to convert to frequency domain from time domain.
Disadvantages
(a) Modeling of surrounding is needed along with the
object modeling.
(b) Execution time is large.
(c) Accuracy is less when compared to method of
moments.
(d) Computation cannot be done for curved surfaces.
(e) The field quantities are known only at grid points.
Applications
 Antenna/Radiation problems
 Eigenvalue problems
 EM Absorption in human tissues
The EM waves simulation generated by a Pulse is studied.
Maxwell’s equations in free space are given by
Vol 9 (20) | May 2016 | www.indjst.org
(2)
Both E and H denote the electric field and magnetic
field. Equations (1) and (2) can be in expressed using del
operator,
∇=i
∂
∂
∂
+ j +k
∂x
∂y
∂z
Let E = (Ex, Ey, Ez). The cross product of ∇ and E is
given below
i
∂
∇×E =
∂x
Ex
j
∂
∂y
Ey
k
∂
∂z
Ez
Using the above expressions we rewrite (1) and (2) as
 ∂E x 
 ∂t 
i


 ∂E y  1 ∂
 ∂t  = e ∂x
 o

Hx
 ∂E z 
 ∂t 


 ∂H x 
 ∂t 


1
 ∂H y 
 ∂t  = − m
o


 ∂H z 
 ∂t 


i
∂
∂x
Ex
j
∂
∂y
Hy
j
∂
∂y
Ey
 ∂H z ∂H y 
−


k
∂z 
 ∂y
∂H z 
∂
1  ∂H
=  z −

∂z eo  ∂z
∂x 
 ∂ H y ∂H z 
Hz
−


∂y 
 ∂x
k
∂
∂z
Ez
(3)
 ∂E z ∂E y 
−


∂z 
 ∂y
∂E 
1  ∂E
= −  z − z  (4)
∂x 
mo  ∂z
 ∂E y ∂E z 
−


∂y 
 ∂x
E field is in the direction of xz plane and waves ­travels
in the z direction (Ey = 0). Ez = Hz = 0, and hence E = (Ex,
0, 0). The E field and H field travel at right angles to each
another and hence E. H = 0. Since Ex ≠ 0 and by zero factor property Hx = 0. As Hz = 0, we have H = (0, Hy, 0).
Equations (3) and (4) changes to
5. Elecromagnetic Simulation in
Free Space
∂E 1
= ∇×H ∂t e0
∂H
1
= − ∇×E m0
∂t
(1)
 ∂H y 
 ∂E x 


 ∂t 
 1  ∂z 

 0 =  0 
 0  eo  0 








(5)
Indian Journal of Science and Technology
3
denoted by the gray and blue grid line. The initial values considered are set as gre
borders are shown as orange and violet circles.
Electromagnetic Radiation Hazards on Humans Due to Mobile Phones
FDTD Approximation Grid
 ∂H y 


 ∂t 
1
 0 =−
mo
 0 




 0 
 E 
∂ x   ∂z 
 0 


(6)
Equations (5) and (6) indicates the wave propagation
in z direction, as shown in (Figure 3)
6. The Algorithm
Figure 4. The FDTD Approximation Grid.
Figure 4. The FDTD Approximation Grid.
Having got the system, we need to Every
approximate
Ex and
Hy. three arrows pointing towards it (Figure 4)8,9. Of the three a
triangle
has
∆x corresponds to the change along
the z from
axis and
previous
timeremaining
step. The remaining
twofrom
comesa from
emerges
thea time
previous the
time
step. The
two comes
half-step down
change is denoted by ∆t. By central difference approximaa
half-step
down
and
a
half-step
to
the
right
or
left.
is
the right or left. It is clearly evident that the algorithm is inter weaved inItspatial
and tim
tion in both space and time, we modify (5) and (6) as
clearly evident that the algorithm is inter weaved in spatial
to partial differential equations in time and space. This technique is also named as
1
n+
(Ex )k 2
1
n−
− (Ex )k 2
∆t
1
n+
(H y )k 2
=−
1
n−
− (H y )k 2
∆t
where
ν =−
1
eo
(H y )n
k+
n
=−
1
mo
(Ex )
1
2
− (H y )n
k−
∆x
1
k+
2
1
2
− (Ex )n
∆x
1
k−
2
1 ∆t
1 ∆t
and ν = −
µ o ∆x
ε o ∆x
The Figure 4 below represents the FDTD grid created8,9.
The Ex approximations are represented by orange triangles
while the Hx approximations by violet triangles. Each row
relates to a specific instant in time, at half time steps and each
column indicates a one whole time step. The whole and half
steps are denoted by the gray and blue grid line. The initial
values considered are set as green circles and the borders are
shown as orange and violet circles.
FDTD Approximation Grid
Every triangle has three arrows pointing towards it
(Figure 4)8,9. Of the three arrows, one arrow emerges from
and time domain similar to partial differential equations
in time and space. This technique is also named as leap
frog method. Imagine a frog as triangle, for instance
n+
1
(Ex )k + 22 and leaping his legs to jump up to the triangle,
3
2
(Ex )k + 2.
n+
The path it makes first moves outward and then
inward making a triangle and the path drawn by his legs
make a triangle.
The magnitudes of (5) and (6) are not equal because of
the permittivity of free space and the permeability of free
space, εo and µo. Since the values are modified as,
E =
eo
E
mo
E=
mo 
E
eo
and substituting this in equations (7) and (8) we have
1


n−
n
n

= h (H y )5 1 − (H y ) 1  + (Ex )k 2
k+
k− 

2
2
1
1

n−
n+ 
(H y )n+11 = h (E x )k 2 − (E x )k 2  + (H y )n 1
k+
k+


2
2
n+
(E x )k
where h =
1
2
∆t
e0 mo ∆x
1
This method is being implemented in our project by
generating an incident wave and the equations for E and
H are solved. Human body model was created using the
Figure 3. Propagation of Transverse Plane-Polarized EM
dielectric properties and the conductivity.
Figure 3.
Propagation
of
Transverse
Plane-Polarized
EM
Waves.
Waves.
ithm
4
9 (20) | May 2016 | www.indjst.org
e system, weVolneed
to approximate Ex and Hy.
corresponds to the change along the zIndian Journal of Science and Technology
change is denoted by
. By central difference approximation in both space and time, we
A. Christina Josephine Malathi
7. Body Model
The calculated E and H fields (Figure 5.) are categorized
into,
• The Total field
• The Scattered field
Where δt - the time step
δ - the cell size
c - speed of the electromagnetic waves
The equation (8) indicates that the smaller step size leads
to more number of time steps6 (high resolution).
1
3
Results
Body Model
as triangle,
for instance ( E x ) k 22 the
andfield
leaping
his legs to jump up9.
to the
triangle,for
( E x Human
) k 22 .
field, propagates through
and is subtracted out
Thepath
Modeldrawn
for theby
Human
body is being done by MATLAB
kes first moves
outward
and then
a triangle
his legs
the other
end. Hence,
E andinward
H fields making
to reach the
scatteredand the
software
based
on
FDTD
method.
The results obtained are
e.
field volume are those which are scattered off the scataccurate,
efficient
and
versatile.
Here
the SAR distribution
theequal
implementation
udes of (5)terer.
andThis
(6)explains
are not
because ofofthe
the­radiation
permittivity of free space and the
is obtained using incident frequencies at 900 MHz. The
f free space,condition.
εo and µo. Since the values are modified as,
n
The incident wave is created
along one edge of the total
8. Constraints
~
E
and
n
tabulation for conductivity, relative permittivity and mass
density of heart, muscle and skin at 900 MHz ­frequency
are shown in Table 1.
The SAR distribution in human model is shown below
in Figure 6.
E
Limitations
o
o
The constraint in this method is the radiation
condition is
o ~
E
E may reflect back
not implicit ie. outgoing scattered
waves
o
into the scattered object. This problem
can however be
overcome by introducing an absorption condition around
10. Conclusion
and
substituting
thismatrix
in equations
(7) andthe(8)
we have
the
edge
of each E field
which absorbs
outgo1
1
For cell phones operating at 900 MHz, the maximum value
ing scattered
This is based on a two-pole expansion
~ nwaves.
~ n 2
n
n
2
( H y ) and
( H y ) which
(results
E x ) k in
of electric field is calculated to be 400 V/m for 2W power
method( E
according
to Bayliss
Turkel,
x )k
1
1
k
k
2
2
output. But we have found the Electric field strengths
error given by,
1
1
inside the body with the incident field of 1V/m. Inorder
n
~ n
5~
n
2
to compare our results accurately, we do the ­following cal( H y ) n 11
( E x ) k c2 (2.E
)
(
H
)
x k
y
1
k
k (7)
Error = O 
 2
2
culations.
 2p fr 
Assuming the cellphone is cylindrical and considering
t
1
. f - incident
.
the
antenna length l = λ (lambda),
Where
frequency
x
0 o
r - distance from center of the scattering body to
We know, C = f λ,
is being implemented
in our project
by generating
for
the boundary
of the computing
field. an incident wave and the equations
λ = C / f,
lved. Human body model was created using the dielectric properties and the conductivity.
8
When low incident frequency is used, large volume surrounding the body is needed to overcome the error due to
del
truncation conditions.
ed E and H imperfect
fields (Figure
5.) are categorized into,
The stability can be ensured by taking the step size as
l field
ered field
δt = δ/2c
(8)
Total Field
Scattering Object
Scattering Fields
Lattice Truncation
= (3 × 10 )/(900 × 106)
= 0.33 m
The Power density at a distance r = 2.2cm, from the
antenna is roughly equal to p/2πrl, since nearly all the radiated power has to pass through a cylinder of area 2πrl. We
know the power radiated by a cell phone at 900 MHz is 2
watts, and hence p =2 watts. Substituting the above values
Table 1. Tabulation for conductivity, relative
permittivity and mass density
Tissue
Conductivity
Frequency
Name
(s/m)
Skin
900MHz
0.86674
Muscle 900 MHz
0.94294
Figure
A. Division
of FDTD
lattice lattice
into Total
Scattered
Figure5. 5.
A. Division
of FDTD
intoand
Total
and fields.
Heart
900
MHz
waveScattered
is created
along one edge of the total field, propagates through the field1.2298
and is
fields.
ident
the other end. Hence, E and H fields to reach the scattered field volume are those which are
e scatterer. This explains the implementation of the radiation condition.
Vol 9 (20) | May 2016 | www.indjst.org
nts and Limitations
Relative
Permittivity
Mass Density of
the Tissue
(Kg/m3)
41.405
1100
55.032
1041
59.893
1060
Indian Journal of Science and Technology
nt in this method is the radiation condition is not implicit ie. outgoing scattered waves may
5
Figure 6. Field Distribution at 900 MHz - Skin, Muscl
Electromagnetic Radiation Hazards on Humans Due to Mobile Phones
8
At distance of 10 c
At distance of 13 cm
At distance of 16 cm
Figure 6. Field Distribution at 900 MHz - Skin, Muscle, Heart in human body.
At distance of 10 cm - SkinFigure 7. Field Strength at 900 MHz.
Figure 7. Field Strength at 900 MHz.
At distance of 13
cm - Muscle
At distance of 1610.
cm Conclusion
– Heart
For cell phones operating at 900 MHz, the maximum
V/m for 2W power output. But we have found the Elec
Figure 6. Field Distribution at 900 MHz - Skin, Muscle, Heart in human body.
Figure 6. FieldAtDistribution
900cm
MHz
- Skin, Muscle,
incident field of 1V/m. Inorder to compare our results accur
distance ofat10
- Skin
Heart in human body.
Assuming the cellphone is cylindrical and considering the a
At distance of 13 cm - Muscle
At distance of 10 cm - Skin
We know,
C = f λ,
At distance of 16 cm – Heart
At distance of 13 cm - Muscle
λ = C / f,
At distance of 16 cm – Heart
= (3 x 108)/(900 x 106)
= 0.33 m
the power density is found to be 43.86 watts. Now we have
The Power density at a distance r = 2.2cm, from the antenna
to find the Electric field from power density. We know,
radiated power has to pass through a cylinder of area 2πrl. W
900 MHz is
2 watts,
and hence
p =2 watts.
Figure 7. Field
900 MHz.
Figure
8. Specific
Absorption
Rate. Substituting the
E2 / RStrength
= power at
density
Figure 8. Specific Absorption Rate.
0.5
43.86
watts.
Now
we
have
to
find
the
Electric
field from po
E = (43.86 × 377)
2
E / R = power density
= 129.59 V/m
10. Conclusion
Table 2. Specific
Rate0.5
E =Absorption
(43.86 x 377)
For
operating
Thiscell
willphones
be the incident
fieldatto900
the MHz,
human the
bodymaximum value of electric field is calculated to be 400
FrequencyRate. = 129.59 V/m
ure 7. Field
at MHz
900power
MHz.
Figure
8. Specific
Skin
Muscle the body
Heartwith the
at 900
and hence
we can
multiply
with
the
result
V/mStrength
for
2W
output.
But
we have
found
the Absorption
Electric
fieldwill
strengths
inside
(MHz)This
be the incident field to the human body at
which
we of
obtained
for,Inorder
with 1 V/m.
Thus the Electric
field accurately, we do the following calculations.
incident
field
1V/m.
to compare
our results
900 which0.44
W/Kg
W/Kg
result
weW/Kg
obtained0.36
for,
with 10.75
V/m.
Thus the Elec
ion Assuming
strength
obtained
at
different
tissue
layers
Skin,
Muscle,
the cellphone is cylindrical and considering thelayers
antenna
length
l
=
λ
(lambda),
Skin, Muscle, Heart are found to be 33.43 V/m, 28.2
ll phones operating
at found
900 MHz,
the maximum
of V/m
electric
Heart are
to be 33.43
V/m, 28.28value
V/m, 36
and field is calculated to be 400
We
know,
C
=
f
λ,
The
obtained
SARand
of parcel
Skin, of
Muscle,
and HeartThe
are shown in
power output.
weinhave
the bodyis part
with
the
EM radiation
the environment.
areBut
shown
Figurefound
6, 7. the Electric field strengths inside
λ
=
C
/
f,
of 1V/m. InorderThe
to compare
accurately,
we Heart
do theare
following
calculations.
­number
of mobile users has been drastically increased.
obtained our
SARresults
of8 Skin,
Muscle,6 and
)/(900
xantenna
10in)Table
= (3
x 10
cellphone is cylindrical
and
the
length
It was predicted to have 1.2 billion wireless device users
shown in Figure
8considering
and
tabulated
below
2. l = λ (lambda),
= 0.33
C = f λ,
around the world by 200512 and 2.7 billion in 2015. There
These results
are mcompared with the (Federal
λ = CThe
/ f, Power
density atCommission)
a distance FCC
r = 2.2cm,
from
the antenna
is roughly
to p/2πrl,
since nearly
is no way
to controlequal
this change.
EM radiation
is alsoall
a the
Communication
limits for
general
6
10,11
= (3radiated
x 108)/(900
x
10
)
kind
of
pollution
which
should
be
controlled.
power
has
to
pass
through
a
cylinder
of
area
2πrl.
We
know
the
power
radiated
by
a
cell
phone
at
uncontrolled/exposure (100 KHz – 6 GHz) .
= 0.33
m
all the researchers
aredensity
working towards
theto be
900 MHz is 2 watts, and hence p =2 watts. Substituting theCurrently
above values
the power
is found
nsity at43.86
a distance
r =Now
2.2cm,
from
the
antenna
is
roughly
equal
to
p/2πrl,
since
nearly
all
the
•watts.
< 0.08
W/Kgwe
Full
Body
production
of
harmless
wireless
devices.
Smaller
cell
size,
have to find the Electric field from power density. We know,
r has to pass through
a cylinder
area 2πrl. We know the power radiated
by abase
cellstation
phoneantennas
at
• <2 1.6 W/Kg
PartialofBody
improved
and some advanced techE / R = power density
watts, and hence p =2 watts. Substituting
densitywill
is found
to be
make the
cell phones to radiate less power.
0.5the above values the powernologies
Ethe=Electric
(43.86
xAbsorption
377)
Thefind
obtained
Specificfield
rates density.
are within
Now we have to
from power
Wethe
know, It is huge research topic which needs to be investigated
FCC limits.= 129.59 V/m
= power density
further.
0.5 will be the incident field to the human body at 900 MHz and hence we can multiply with the
This
= (43.86 x 377)
result
which we obtained for, with 1 V/m. Thus the Electric field strength obtained at different tissue
= 129.59
V/m
11.
Future Development
12.
References
will be the
incident
to the Heart
humanare
body
at 900
and hence
can V/m,
multiply
layers Skin,field
Muscle,
found
to MHz
be 33.43
V/m, we
28.28
36 with
V/m the
and are shown in Figure 6,7.
we obtained
for,
withSAR
1 V/m.
Thusspread
the
Electric
field
strength
obtained
at different
tissue
EM radiation
is all
amongand
the
environment.
1. inSadiku
MNO.
numerical
Techniques
in Electromagnetics.
The obtained
of over
Skin,
Muscle,
Heart
are shown
Figure
8 and
tabulated
below
in Table 2.
Muscle, Heart Because
are found
33.43 V/m,
36 V/m
and are shown
Figure
2009in
April
9. 6,7.
of to
thebeemergence
of 28.28
variousV/m,
wireless
services
SAR of Skin, Muscle, and Heart are shown in Figure 8 and tabulated below in Table 2.
6
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Indian Journal of Science and Technology
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