Transcript EN50360/1

EN50360/1
Measurement of SAR related to human
exposure to EM fields from mobile phones
(300 MHz - 3 GHz)
Group 4A member: Eric(92850219)
Sam(50255035)
Wilbur (97070763)
Celluar phone
Health concern
 Brain cancer?
 Affect memory?
 Affect human analysis ability?
Motorola SAM Scan Profiler in
Hong Kong
What is SAR??
 SAR - Specific Absorption Rate
 It is an indication of the amount of radiation that is
absorbed into a head whilst using a cellular phone
 A SAR value is a measure of the maximum
energy absorbed by a unit of mass of exposed
tissue.
 Units = watts per kilogram (W/kg)
Definition of SAR
 Definition of SAR:
σE
T
SAR 
c
ρ
t
2
 Ei : rms value of the electric field strength in the tissue in
V/m
 σ : Conductivity of body tissue in Kg/m3
 Ci : heat capacity of body tissue in J/Kg K

T
t
: derivative of temperature in body tissue in K/s
Preparation - Laboratory
 15˚c - 30˚c ±2˚c
 No interact with local network
 Be aware of ambient EM sources
 Be aware of reflection from environment
 Validation
 At least once a year
Preparation - Mobile
 battery must be Fully charged
 So that, the worst case (maximum power)
obtained
 At least 50cm between emulator antenna
and the mobile
 1‰ or less power from the antenna with
respect to the mobile
Hardware System Overview
GPIB to grab the data
from the DVM
Change 2x9V batteries
every 16 hours
Position
Controller
Serial Ports:
COM1, COM2,
COM3
x
y
3
channels
DVM
with
DAQ
card
z
Amplifier
Indication
Board
Right head
Flat phantom
Left head
Tests to be performed
 Cheek and tilted
 Left and right sides of the head
 Center frequency of each band
 Retractable antenna
 Extended
 Retracted
 Multi-mode/multi-band
 Performed in each mode with max power
Test Setup
 Mobile phone
operating at the
maximum power level
 Phone holder
described positions at
a shell phantom of a
human being
Test Setup
 Probes with high
sensitivity and low
field disturbance are
used
 Move along X-axis, Yaxis, Z-axis
Test setup
 Electric field strength E is measured in the
tissue simulating liquid
 Tissue simulation liquid:
 Dielectric properties
 900MHz: 64.81% 1,2-propanediol; 34.4% deionized water; 0.79 NaCl salt
Phantom Requirements
 The phantom is a simplified representation
of the human anatomy and comprised of
material with electrical properties similar to
the corresponding tissues. The physical
characteristics of the phantom model shall
resemble the head and the neck of a user
since the shape is a dominant parameter
for exposure.
Phantom Requirements
 Shape is a dominant parameter for
exposure.
 90% large adult male study by
anthropomorphic study in 1989
 Fill with tissue simulating liquid through
head to neck
Test Setup
Handset vertical and horizontal reference lines.
Phantom reference points.
Cheek Position
Tilted position
Validation
 Simplified performance checking




Phantom setup
Dipole source
Dipole input power measurement
System check procedure
 System validation
 known SAR values of selected mobile
Test Setup
Validation Test installation (Use
flat phantom)
Flat Phantom
For SAM Profiler, 250mW output will
give 2.5mW/g.
11mm
250mW
=24dBm
Directional
Coupler
Checked the
reflected power
Amplifier
Signal
Generator
SAM Profiler is used to control the Scan Profiler.
The interface is shown below:
Result
Definition of SAR
 Definition of SAR:
σE
T
SAR 
c
ρ
t
2
 Ei : rms value of the electric field strength in the tissue in
V/m
 σ : Conductivity of body tissue in Kg/m3
 Ci : heat capacity of body tissue in J/Kg K

T
t
: derivative of temperature in body tissue in K/s
Quantization
Having in mind a worst case consideration, the SAR limit is
valid for uncontrolled environment mobile respectively
portable transmitters.
Standard
ICNIRP
Max allowable limit
2 watt/kg
ANSI / IEEE
1.6 watt/kg
The SAR values of your mobile
phone may be found from the
following website
www.SARvalues.com
SAR values of some models
Manufacturer
Model
SAR values
Motorola
V80
0.54
Motorola
V600
0.82
Motorola
E398
1.01
Sony Ericsson K500i
0.53
Sony Ericsson K700
0.48
Sony Ericsson P900
0.91
Sony Ericsson T630
0.88
Nokia
N-Gauge
0.57
Nokia
7200
0.36
Nokia
7600
0.71
Samsung
SGH-E800 0.32
.
.
.
Future Development
 Whole body measurement