ANALYSIS OF BIOLOGICAL EFFECTS OF CELL PHONE RADIATION ON HUMAN BODY USING SPECIFIC ABSORPTION RATE (SAR) AND THERMOREGULATORY RESPONSE

ANALYSIS OF BIOLOGICAL EFFECTS OF CELL PHONE
RADIATION ON HUMAN BODY USING SPECIFIC ABSORPTION
RATE (SAR) AND THERMOREGULATORY RESPONSE
Tanghid Ben Rashid
MS Thesis presentation
Electrical & Computer Engineering Dept.
University of Colorado Colorado springs

Published
Paper link
1/11/2020 12:17:12 PM
If you would like to read my paper
online, please click the below link
• https://mountainscholar.org/handle/10
976/166694
• https://onlinelibrary.wiley.com/doi/abs
/10.1002/mop.31777
How to cite this article: Rashid TB, Song
HH. Analysis of biological effects of cell
phone radiation on human body using
specific absorption rate and
thermoregulatory response. Microw Opt
Technol Lett.2019;61:1482–1490.
• https://doi.org/10.1002/mop.31777
2

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Contents
• Introduction
• Novelty of the Proposed Work
• Theory Review
• Theoretical SAR calculation
• Antenna Design
• SAR simulation in HFSS
• Bioheat equation
• Exposure effects
• Conclusion

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Introduction
• Study and investigate the effect of Radiofrequency (RF) wave radiated from cellular
phone antennas to the human body.
• Perform Specific absorption rate (SAR) simulation for head and chest tissues at five
different frequencies which is 850 MHz, 900 MHz, 2.1 GHz, 2.6 GHz and 5.6 GHz ,
respectively.
• Analyze long term exposure effects of radiation by solving Pennes Bioheat equation
and create a rise of temperature database for human body tissues.

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Novelty of the Proposed Work
• A new analytical method has been shown to solve Pennes Bioheat transfer equation
and temperature rise of tissues has been calculated at 42 different scenarios.
• A complex, multilayered, 3D ANSYS HFSS full human body model is used to calculate
SAR.
• Simulation studies carried out for 13 different human tissues at 6 different
frequencies
• During SAR simulation distance between human body parts to the antenna and also
antenna port power were varied.

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Theory Review
• Cellular band falls in microwave region.
• Radiation : it is the energy propagation as electromagnetic waves or subatomic
particles through a vacuum, space or some material.
Ionizing
Non-ionizing
• Radiation effects: Thermal and Non-thermal
Ref: Ionizing & Non-Ionizing Radiation, Electromagnetic Fields in Biological Systems by James C. Lin

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Theory Review
How to calculate the radiation effects in human tissues?
• Specific absorption rate (SAR) : SAR is the measure of how much energy (in this case Radio Frequency energy) is
absorbed by the human body in a certain volume, over a certain period of time.
• SAR measures exposure to fields between 100 kHz and 10 GHz.
• SAR =
• where: σ = conductivity of the tissue (S/m)
• 𝜌 = mass density of the tissue (kg/𝑚 )
• E = rms electric field strength (V/m)
Spatial peak
SAR
Averaging
mass
Averaging
Time
USA 1.6 W/kg 1 gm 30 min
Europe 2 W/kg 10 gm 6 min
1. Point of avg. SAR
calculation for 1 g
2.Search for 10 g cube
3. Integrate losses in cube
For each
point, a
cube with
defined
mass is
found
The power
loss
density is
integrated
over this
cube
The
integral
power loss
is divided
by cube’s
mass

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Theory Review
Rise of temperature
Long term exposure
Short term
exposure
∆T = SAR .
∆ Pennes Bioheat
equation

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Dielectric Properties of Tissues
• Tissue is a heterogeneous material containing water , macromolecules, ions etc.
• Relative permittivity
• Conductivity
• Penetration depth
Ref: Dielectric properties of body tissues”, http://niremf.ifac.cnr.it/tissprop/
Tissue
Name
Conductivity (S/m) Relative Permittivity
Penetration Depth (m)
850 MHz 900 MHz 2.1 GHz 2.6 GHz 5.6 GHz 850 MHz 900 MHz 2.1 GHz 2.6 GHz 5.6 GHz 850 MHz 900 MHz 2.1 GHz 2.6 GHz 5.6 GHz
Skin 0.85 0.866 1.3075 1.5357 3.5467 41.676 41.405 38.431 37.845 35.28 0.0411 0.04023 0.025431 0.02147 0.009003
Bone 0.328 0.34 0.68515 0.85862 2.0634 20.898 20.788 18.963 18.379 15.554 0.074888 0.07211 0.034133 0.026841 0.010364
Dura 0.945 0.961 1.4721 1.7588 4.1235 44.551 44.426 42.489 41.844 38.121 0.038355 0.037628 0.023758 0.019726 0.008065
CSF 2.392 2.412 3.154 3.5989 7.5201 68.75 68.638 66.764 66.015 60.844 0.019477 0.019215 0.014021 0.012189 0.00561
Brain 0.921 0.942 1.0466 1.2919 3.3307 52.976 52.725 36.6 35.991 32.826 0.042625 0.041536 0.030914 0.024838 0.009249
Fat 0.049 0.051 0.08986 0.11119 0.28016 5.4699 5.462 5.3169 5.2646 4.9733 0.2501 0.24412 0.13658 0.10984 0.042428

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Dielectric Properties of Tissues
Tissue
Name
Conductivity (S/m) Relative Permittivity Penetration Depth (m)
850 MHz 900 MHz 2.1 GHz 2.6 GHz 5.6 GHz 850 MHz 900 MHz 2.1 GHz 2.6 GHz 5.6 GHz 850 MHz 900 MHz 2.1 GHz 2.6 GHz 5.6 GHz
Heart 1.203 1.229 1.984 2.3795 5.606 60.233 59.893 55.57 54.508 49.279 0.034963 0.034074 0.020166 0.016654 0.006754
Lung 0.448 0.456 1.455 1.7869 4.5951 22.099 22 48.903 48.166 44.028 0.056892 0.055636 0.025713 0.020785 0.00777
Liver 0.834 0.854 1.463 1.7879 4.4336 47.077 46.833 43.638 42.79 38.412 0.044391 0.043171 0.024199 0.019621 0.007543
Kidney 1.363 1.392 2.162 2.5503 5.652 59.093 58.675 53.586 52.411 47.077 0.030762 0.02998 0.018231 0.015276 0.006559
Stomach 1.165 1.186 1.92 2.3446 6.0167 65.206 65.062 67.727 61.916 56.831 0.037416 0.036659 0.022079 0.017966 0.006744
Muscle 0.926 0.942 1.513 1.8429 4.7254 55.154 55.032 53.163 52.546 48.751 0.043216 0.042355 0.025761 0.021032 0.007932
Blood 1.516 1.537 2.261 2.6755 6.2208 61.523 61.36 58.851 58.015 52.894 0.028322 0.027828 0.025761 0.015299 0.007936
Dielectric propertiesofCSF tissuesas a functionoffrequency

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SAR Measurement Technique
SAR Measurement
Techniques
DASY52
Dosimetry
Assessment
Simulation
software
Phone Model Head SAR (1 g) Body SAR (1 g)
iPhone 6 1.18 1.18
iPhone 6s 1.14 1.14
iPhone 7 1.19 1.19
iPhone 7s 1.19 1.17

1/11/2020 12:10:59 PM
Theoretical SAR Calculation
Theoretical SAR Calculation for Skin tissue in GSM-850 Systems:
The maximum penetration depth of the skin tissue at 850 MHz is : 𝛿 = 0.041198 m = 41.198 mm
According to Federal Communications Commission (FCC), cellular devices authorized under 47 CFR section 15.247 operate with less power
which is in between 0.125 W to 1 W.
The power density produced by the mobile phone at the maximum penetration depth can be calculated by using the following equation:
𝑊 = where, 𝑃 = Radiated power = 0.125 w
=
. ∗
( . )
𝐺 = Antenna Gain = 1
= 5.88 W/𝑚 d = separation between head and antenna = 0 m
The impedance of the human head tissues (η) can be determined by the formula:
ɳ = ɳ √∈
where, 𝜇 = relative permeability = 1
= 377* (1/41.676) ∈ = relative permittivity of skin = 41.676
= 58.39 (ohm)
Maximum power density, 𝑊 =
ɳ
SAR =
Electric field, E= (𝑊 2ɳ) =
. ∗ .
∗
= (5.88 ∗ 2 ∗ 58.39) = 0.527 W/kg
= 26.22 V/m
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Theoretical SAR Calculation Results
0
0.5
1
1.5
2
2.5
3
SAR(W/Kg)
Tissues
Calculated SAR (W/kg) FCC SAR (W/kg)
0
0.5
1
1.5
2
2.5
3
3.5
SAR(W/Kg)
Tissues
Calculated SAR (W/Kg) FCC SAR (W/kg)
Comparison between calculatedand FCC regulatedSAR valueat 850 MHz Comparison between calculatedand FCC regulatedSAR valueat 900 MHz
1.6
1.6
* CSF = Cerebrumspinalfluid

1/11/2020 12:10:59 PM 14/48
Theoretical SAR Calculation Results
Comparison between calculated and FCC regulated SAR value at Comparison between calculated and FCC regulated SAR value at
2100 MHz 5600 MHz
0
1
2
3
4
5
6
7
8
SAR(W/Kg)
Tissues
Calculated SAR (W/Kg) FCC SAR (W/Kg)
0
20
40
60
80
100
120
Skin Bone Dura CSF Brain Fat Heart Lung Liver Kidney Stomach Muscle Blood
SAR(W/Kg)
Tissues
Calculated SAR (w/kg) FCC SAR (W/Kg)
1.6
1.6

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Reproduced PIFA Antenna Design
Top view of the reproduced antenna Geometry of the reproduced antenna
Bottom view of reproduced antenna Coordinate of the reproduced antenna
Ref: Minho Kim, Woosung Lee, Woojoong Kim and Young Joong Yoon “A multi band internal antenna for all commercial mobile communication bands and 802.11 a/b/g/n WLAN
100 mm
40 mm

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Reproduced PIFA Antenna results
Simulated return loss of the antenna

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ANSYS 3-D Human Body Model
Human body model
Level of details in human head

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SAR Simulation on Human Head
Placement of reproduced antenna on human head
Human head cross section
Ref:Dr. Prsasad, “ Acoustic Neuroma” , http://www.earsite.com/acoustic-neuroma-treatment

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SAR Simulation Setup
‘In a Project
Manager click on a
Mesh operations
Initial mesh
settings.’
‘Copy the
designed
antenna file into
HFSS head model
interface’
‘Draw a plastic
casing around
the antenna. Add
a “plastic”
material to the
library. ’
‘Draw a box around
all objects. Assign
Vacuum material to
it. Apply Radiation
boundary properties
to it’
‘In project
manager go to
Field overlays
Plot fields
Other Average
SAR’
Simulation steps:

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SAR Simulation Steps on Human Head
Head Tissues
Skin Brain CSF Dura Bone Fat
850 MHz 900 MHz 2.1 GHz 2.6 GHz 5.1 GHz
125
mW
1 W 1.5 W 2 W
0 mm 10 mm 20 mm
5.6 GHz

SAR Simulation Results on Human Head
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SAR (W/kg) at 850 MHz frequency for Head tissue
Tissue
Name
Head to antenna Distance (mm)
0 mm 10 mm 20 mm
125
mW
1 W
1.5
W
2 W
125
mW
1 W
1.5
W
2 W
125
mW
1 W
1.5
W
2
W
Skin 0.32 2.6 3.9 5.27 0.19 1.9 2.9 3.17 0.24 1.5 2.3 3.9
Brain 0.34 2.7 4.0 5.45 0.2 2.3 3.4 3.26 0.28 1.6 2.4 4.6
Bone 0.28 2.3 3.4 4.6 0.13 0.7 1.0 2.13 0.08 1.0 1.5 1.4
CSF 0.61 4.9 7.4 9.89 0.32 3.7 5.6 5.18 0.47 2.5 3.8 7.5
Fat 0.32 2.6 3.9 5.22 0.09 0.3 0.5 1.5 0.04 0.7 1.1 0.7
Dura 0.33 2.6 4 5.33 0.21 2.2 3.3 3.48 0.27 1.7 2.6 4.4
𝑆𝐴𝑅 fieldforthe human head at sourcepower1 W at frequencyof850MHz
SAR at850MHzresonantfrequencyforheadtissuesatdifferentantenna
distanceatdifferentinputpower

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0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
Skin Brain Bone CSF Fat Dura
SAR(W/kg)
Head Tissues
0 mm 10 mm 20 mm FCC SAR
SARatdifferentheadtoantennadistanceat125mWpowerat850MHz
frequency
SARatdifferentheadtoantennadistanceat1Wpowerat850MHz
frequency
0
1
2
3
4
5
6
SAR(W/kg)
Head tissues
1.6
1.6

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0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
SAR(W/kg)
Head Tissues
SARatdifferentheadtoantennadistanceat125mWpowerat900MHz
frequency
0
1
2
3
4
5
6
SAR(W/kg)
Head tissues
SARatdifferentheadtoantennadistanceat1Wpowerat900MHz
frequency
1.6
1.6

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0
1
2
3
4
5
6
7
8
SAR(W/kg)
Head Tissues
0
10
20
30
40
50
60
SAR(W/kg)
Head Tissues)
1.6
SARatdifferentheadtoantennadistanceat125mWpowerat2.1GHz
frequency
SARatdifferentheadtoantennadistanceat1Wpowerat2.6GHz
frequency
1.6

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0
1
2
3
4
5
6
7
SAR(W/kg)
Head Tissues
0
5
10
15
20
25
30
35
40
45
50
SAR(W/kg)
Head Tissues
1.6
frequency
SARatdifferentheadtoantennadistanceat1Wpowerat2.6GHz
frequency
1.6

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1.6
1.6
0
2
4
6
8
10
12
SAR(W/kg)
Head Tissues
frequency
0
5
10
15
20
25
SAR(W/kg)
Head tissues
frequency
0
20
40
60
80
100
120
140
160
180
SAR(W/kg)
Head tissues
SAR at different head to antenna distance at 1 W power at 5.6 GHz frequency
1.6

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SAR Simulation on Human Chest
Placement of reproduced antenna on human chest
Anatomy of human chest
Ref:Dr. Prsasad, “ Acoustic Neuroma” , http://www.earsite.com/acoustic-neuroma-treatment

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SAR Simulation Steps on Human Chest
Chest Tissues
Blood Muscle Heart Lung Kidney Liver
850 MHz 900 MHz 2.1 GHz 2.6 GHz 5.1 GHz
125
mW
1 W 2 W
0 mm 40 mm 60 mm
Stomach
5.6 GHz

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SAR Simulation Results on Human Chest
SAR field on lung tissue
SAR field on heart tissue

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Simulated SAR for chest tissue at 850 MHz
SAR at different chest to antenna distance on 125 mW
peak power at 850 MHz resonant frequency
SAR (W/kg) at 850 MHz for Chest tissue
Tissue
Name
Chest to antenna Distance (mm)
0 mm 40 mm 60 mm
125 mW 1 W 2 W 125 mW 1 W 2 W
125
mW
1 W 2 W
Blood 0.11 0.11 0.11 0.04 0.04 0.04 0.02 0.02 0.02
Muscle 0.02 0.02 0.02 0.02 0.02 0.02 0.01 0.01 0.01
Heart 0.25 0.55 0.58 0.07 0.07 0.07 0.04 0.04 0.04
Kidney 0.01 0.26 0.28 0.01 0.01 0.01 0.01 0.01 0.01
Lung 0.43 2.30 2.31 0.44 0.44 0.44 0.23 0.23 0.23
Liver 0.06 0.06 0.06 0.01 0.01 0.01 0.04 0.04 0.02
Stomach 0.02 0.26 0.29 0.01 0.01 0.01 0.01 0.01 0.01
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
Blood Muscle Heart Kidney Lung Liver Stomach
SAR(W/kg)
Chest tissues
1.6

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𝑆𝐴𝑅 at different chest to antenna distance on 125 mW peak
power at 900 MHz resonant frequency
𝑆𝐴𝑅 at different chest to antenna distance on 1 W peak power at
850 MHz resonant frequency
0
0.5
1
1.5
2
2.5
SAR(W/kg)
Chest tissues
0
0.5
1
1.5
2
2.5
SAR(W/kg)
Chest tissues
0
0.5
1
1.5
2
2.5
SAR(W/kg)
Chest tissues
𝑆𝐴𝑅 at different chest to antenna distance on 1 W peak power at
900 MHz resonant frequency
1.6 1.6
1.6

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power at 5.1 GHz resonant frequency
𝑆𝐴𝑅 at different chest to antenna distance on 1 W peak
0
0.5
1
1.5
2
2.5
3
SAR(W/kg)
Head tissues
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
SAR(W/kg)
Chest tissues
0
0.5
1
1.5
2
2.5
3
SAR(W/kg)
Chest tissues
1.6
1.6
1.6

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Temperature Elevation in the Tissues
• Heat transfer is a very fundamental and important process in living things, especially in human bodies to
maintain an almost constant temperature.
• As for the function of heat transfer for systematic thermoregulation, blood is known to have a dual influence on
the thermal energy balance.
 Short term exposure
 Long term exposure
0
0.002
0.004
0.006
0.008
0.01
0.012
0.014
0 2 4 6 8 10 12
Temperaturerise(degreecelsius)
Exposure time (seconds)
Short term exposure effects for head tissue at 850 MHz frequency 1 W peak power
Skin Temperature Rise ,ΔT (degree celsius) Brain Temperature Rise , ΔT (degree celsius)
Bone Temperature Rise ,ΔT (degree celsius) Fat Temperature Rise ,ΔT (degree celsius)
Dura Temperature Rise,ΔT (degree celsius) CSF Temperature Rise,ΔT (degree celsius)

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Analytical Solution of Pennes Bio Heat Transfer Equation
• In 1948 Pennes [31] states a model in which blood perfusion rate was a distribution of tangible heat transfer on a volume part
based on volumetric blood perfusion rate and temperature difference between arterial blood and passing blood in veins.
where,
ρ= mass density of the tissue (kg/m )
c= heat capacity of tissue (J/ (kg /˚C))
k= thermal conductivity of tissue (W/m/˚C)
Q= power generated per unit mass by metabolic processes
S= SAR due to EM fields radiation (W/kg)
ω= blood perfusion rate (ml/g/min)
𝜌 = blood mass density (kg/m )
𝑐 = blood heat capacity (J/ (kg /˚C))
(‘b’ for parameters of blood)
Tb = ambient temperature of the body= 36.6 ˚C
T = final temperature of the body (˚C)

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In the absence of metabolic process : )
The problem is to find the dependence of temperature T (t) as the function of time t > 0. We need to solve the heat equation:
μ = + 𝑞 − 𝜆 (𝑇 − 𝑇 ) (1)
where, μ = , q = and 𝜆 =
We are solving this equation for the fixed position, so T(x) = constant, i.e. = 0
Therefore we can rewrite the equation (1) in the following form:
= - A (𝑇 − 𝑇 ) (2)
where, A =
Thus we have the inhomogeneous first order differential equation:
+ AT = + A 𝑇 (3)

35/50
Solution of equation (3)
Say, + A 𝑇 = D (4)
Therefore, + AT = D
⇒ = D-AT
⇒ 𝜕𝑇 = (D-AT) 𝜕𝑡
⇒ D−AT
= 𝜕𝑡 (5)
Integrate both side of equation (5)
⇒ - log (D-AT) = t + log 𝐶 [ log 𝐶 = integrate constant]
⇒ Log (D-AT) – log 𝐶 = -At
⇒ Log = -At
⇒ = 𝑒
⇒ D-AT = 𝐶 𝑒
⇒ AT = D- 𝐶 𝑒
⇒ T = D - 𝐶 𝑒
⇒ T = ( + A 𝑇 ) - 𝐶 𝑒 [replacing equation (4) ]
⇒ T = + 𝑇 - 𝐶 𝑒
The solution is: T (t) = 𝑇 + + 𝐶 𝑒
We use initial condition T (0) = 𝑇 to express the
unknown constant 𝐶 = -S/cA.
Finally we obtain:
T (t) = 𝑇 + - 𝑒
T (t) = 𝑇 + (1- 𝑒 )
Substituting A we come to final explicit expression of the T (t):
T (t) = 𝑻 𝒃 +
𝑺
𝝆 𝒃 𝒄 𝒃 𝝎
(1 - 𝒆
𝝆 𝒃 𝒄 𝒃 𝝎
𝒄
𝒕
)

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MATLAB Code of Pennes Bio Heat Transfer Equation

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Long Term Radio-frequency Exposure Effects Results
Temperature vs. Exposure time at 850 MHz frequency at 125 mW input
power at 0 mm head to antenna distance.

38/50
Temperature vs. Exposure time at 850 MHz frequency at 1 W input power at
0 mm head to antenna distance.

39/50
0 mm chest to antenna distance.

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Temperature vs. Exposure time at 2100 MHz frequency at 1 W input power
at 0 mm head to antenna distance.

43/50
at 0 mm chest to antenna distance.
at 40 mm chest to antenna distance.

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Temperature vs. Exposure time at 5.1 GHz frequency at 125 mW input
Temperature vs. Exposure time at 5.1 GHz frequency at 1 W input power at

45/50

46/50
power at 0 mm chest to antenna distance.

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Rise of temperature for different head and chest tissues and for different frequencies at 125 mW antenna peak power
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
Skin Bone Dura CSF Brain Fat Heart Lung Liver Kidney Stomach Muscle
Riseoftemperature(degreecelsius)
Tissues
Rise of temperature at 850 MHz (degree celsius)
Rise of temperature at 2.1 GHz (degree celsius)

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Rise of temperature for different head and chest tissues at different frequencies at 1 W antenna peak power
0
1
2
3
4
5
6
Skin Bone Dura CSF Brain Fat Heart Lung Liver Kidney Stomach Muscle
Riseoftemperature(degreecelsius)
Tissues

1/11/2020 12:11:00 PM 49/50
Conclusion
• In head tissues, in lower frequency (850 MHz, 900 MHz) and lower peak power (125 mW) and when there is no distance
between head and antenna, SAR values are lower than the FCC safety limit in all cases.
• In head tissues, in higher frequency (2.1 GHz, 2.6 GHz, 5.1 GHz, and 5.6 GHz) and 125 mW peak power and when there is no
distance between head and antenna, SAR values are higher in all tissues except fat tissues.
• There is an inversely proportional relationship between SAR and the distance between the body model and the excitation source.
• Maximum SAR values are found in CSF, dura,brain, skin and bone in 5600 frequency which is 19.84 W/kg, 15.76 W/kg, 13.72
W/kg, 12.84 W/kg, and 11.91 W/kg, respectively.
• Chest tissues have very low SAR value except the lung tissue. Maximum SAR value at lung tissue which was 2.72 W/kg.
• The peak temperature rise in the head tissues occurs at the 5.6 GHz frequency and 1 W power in CSF, dura, brain, skin, bone
which is 4.9 ˚C, 3.5 ˚C, 3.4 ˚C, 3.2 ˚C and 2.9 ˚C, respectively.
• Research shows that at temperatures above ~42.5 ˚C, central nervous system function can deteriorate and convulsions may
occur.

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Future Work
• Thermal analysis can perform by using Ansoft WB Thermal software to get the
simulated temperature rise within the tissues and compare that simulated
results with analytical results.
• Pennes Bioheat equation can be solve without considering the fixed position.

ANALYSIS OF BIOLOGICAL EFFECTS OF CELL PHONE RADIATION ON HUMAN BODY USING SPECIFIC ABSORPTION RATE (SAR) AND THERMOREGULATORY RESPONSE

ANALYSIS OF BIOLOGICAL EFFECTS OF CELL PHONE RADIATION ON HUMAN BODY USING SPECIFIC ABSORPTION RATE (SAR) AND THERMOREGULATORY RESPONSE

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ANALYSIS OF BIOLOGICAL EFFECTS OF CELL PHONE RADIATION ON HUMAN BODY USING SPECIFIC ABSORPTION RATE (SAR) AND THERMOREGULATORY RESPONSE