1. Chairman, International Electrotechnical Commission
SCIENTIFIC BASIS OF THE COMPLIANCE ASSESSMENT of PORTABLE WIRLESS DEVICES _____________________________________________________
Jafar Keshvari
Chairman, International Electrotechnical Commission
IEC MT1 (IEC & IEC )

2. Outline ________________________________________________________
Background & Historical review
Ionizing and non-ionizing radiation
EMF exposure standards
Why to develop RF compliance standards
RF measurement/assessment standards in International Electro-technical Commission (IEC)
Future of IEC wireless devices compliance standards

3. Background & Historical review ________________________________________________________
Along the history, philosophers and scientists have explored and developed several natural phenomena that facilitated the life of the humankind.
The philosopher Thales of Milteus ( B.C) is thought to have been the first person who observed the electrical properties of amber and explored the magnetic properties of lodestone.
The twitch of the leg of a dead frog when dissected with a moisted metal scapel that has been noticed by Galvani in 1786, had led Volta to invent the electric battery .
Armstrong demonstrated FM radio transmission in 1933.
Advanced communications and telecommunications infrastructure have reduced transportation needs, led to reduction of fuel consumption and consequently reduction of air pollution from carbon monoxide, carbon dioxide, nitrogen oxides, hydrocarbons and other pollutants.

4. Background & Historical review… ________________________________________________________
Electromagnetic Radiation: consists of waves of electric and magnetic energy moving together through space.
All electromagnetic radiation can be classified by frequency from the extremely low to extremely high frequencies.
Extremely high frequency radiation such as Ultraviolet (UV) and X-rays is called “Ionizing Radiation” because it is powerful enough to effect changes in the atoms of matter it strikes, by breaking chemical bonds (ionization) , thus altering their chemical and biological nature .
Electromagnetic radiation at those frequencies below the UV band are generally classified as “Non-Ionizing Radiation” because they typically lack the energy to effect changes in atomic structure.

6. The Electromagnetic Spectrum

8. Background & Historical review (Ionizing and non-ionizing radiation ________________________________________________________
Non-ionizing radiation, when incident on matter, is incapable of liberating electrons (i.e. ionizing) from atoms and molecules.
There is a minimum quantum energy below which a radiation would be unable to bring about ionization. The quantum energy, E, of radiation is given by:
E = Ћf
where f and Ћ denote frequency of radiation and Plank’s constant respectively.
For minimum ionization energy of 12 electron volts (eV), since h = e-15 eV.s, the minimum frequency of radiation would be around 2.9e15 Hz (2900 TeraHz). This corresponds to a wavelength of about 1.034e-07m or 103.4nm. This lies near the lower wavelength-edge of the Ultraviolet (UV) spectrum
Energy quanta of RF far below level needed to break chemical bonds in DNA

9. Non-ionizing radiation wavelengths and frequencies
Background & Historical review… ________________________________________________________
Non-ionizing radiation wavelengths and frequencies
λ/ƒ 
ULTRAVIOLET
VISIBLE LIGHT
INFRA
RED MW
& RF
UVC**
UVB**
UVA**
(λ ) Wave-
length,
200* –
280 nm
315
315 – 400
400
780
780nm
1mm -
30km
(ƒ)
Fre-quency
1500 – 1071THz
1071– 952
THz
952 – 750
750
385THz
300GHz
10kHz
** WHO (World Health Organization) classification of the non-ionizing UV spectrum.
* 100nm as per the International Commission on Illumination.

10. Background & Historical review… ________________________________________________________
Wirless communication devices operates at frequencies MHz.
Mobile phones operate at a variety of frequencies between about 800 and 2200 MHz.
Mobile Phones base station antennas emit EMR in the range 1800 – 2000 MHz
Computer monitors emit a broad range of EMR from 30 Hz up to 300 GHz.
Electromagnetic waves may produce biological effects which may sometimes, but not always, lead to adverse health effects. It is important to understand the difference between the two:
A biological effect occurs when exposure to electromagnetic waves causes some noticeable or detectable physiological change in a biological system.
An adverse health effect occurs when the biological effect is outside the normal range for the body to compensate, and thus leads to some detrimental health condition.

11. Background & Historical review… ________________________________________________________
Does fast evolving Communications and Information Technologies has negative Impacts on health and Environment:
The electromagnetic exposure associated with equipment use?
Equipment waste disposal?
Leave the answer to you, rather focus on:
How to evaluate the energy absorption in the human body caused by electromagnetic expsoure

12. Wireless technology RF Sources
_________________________________________________________
Many sources
EMF waves have electric and magnetic componets.
The absrption of the Electromagnetic waves in human is measured by SAR

13. Exposure to common EMF sources
_________________________________________________________

14. RF-human body Interaction analysis
The quantification challenge of RF interaction with human body?
Micro and micro approach?
The dimension of the wave is much larger than the human body.
The dimension of the wave is much smaller than the human body.
The dimension of the wave is about the same size as the human body.

15. Low-frequency electric and magnetic fields
f = kHz
=  – 10 km
Magnetic field
Circulating
currents
Electric field
Surface
charge
Currents

16. Radio frequency electromagnetic fields f = 30 kHz – 300 GHz  = 10 km – 1 mm
Radiowave
Heating

17. Optical radiation f = 300 GHz-1000 THz  = 1 mm – 100 nm
Heating,
photochemical
reactions
Dermis
Epidermis

18. σ and ε’ indicate how much energy will be absorbed by the material
How to quantify RF energy absorption, SAR ________________________________________________________
The power absorbed per unit mass of tissue is referred to as Specific Absorption Rate (SAR).
For sinusoidal EM fields, the time rate of energy deposited in a small volume is defined as Specific Absorption Rate:
Many sources
EMF waves have electric and magnetic componets.
The absrption of the Electromagnetic waves in human is measured by SAR
σ and ε’ indicate how much energy will be absorbed by the material

19. Permittivity ε:
Describes how much induced polarization and partial alignment of permanent electric dipoles occures for a given applied electric field E
Conductivity σ:
How much conduction current density will be produced by a given applied E.

20. EMF EXPOSURE STANDARDS __________________________________________________________
ICNIRP
guidelines developed by a committee of appointed experts, no industry members
ICNIRP’s guidance is equally applicable to both base stations, phones and other radio transmitting equipments
closed meetings
Endorsed by WHO

21. __________________________________________________________
Rationale behind limits for human RF exposure in International Commission for Non-Ionizing Radiation Protection (ICNIRP) guidelines
__________________________________________________________
A biological effect occurs when exposure to electromagnetic fields causes some noticeable or detectable physiological change in a biological system.
An adverse health effect occurs when the biological effect is outside the normal range for the body to compensate.
In the RF region thermal effects are the stablished harmfull effect
Only replicated studies can be a scietific basis of expsoure standards.
Identified behavioural changes i.e. a rise in whole body temperature in excess of 1°C at a Specific Energy Absorption Rate (SAR) of 1- 4w/kg.

22. RF exposure limits and safety margins ______________________________________
Limits are given for whole body SAR and localized SAR to prevent excessive tissue heating due to RF exposure
Limit for whole body SAR is based on a threshold of 4W/kg (corresponds to about 1°C body temperature rise). Safety factors 10 and 50 are used for occupational and general public exposure respectively
The rationale for local SAR limit and averaging mass is implicitly based on exposure effects (thermal) on eye with a safety factor of 50

23. Exposure from mobile phone
SAR non-uniform (local SAR value usually below 1 W/kg in 10 g tissue mass)
Temperature more uniform
Equilibrium local temperature increase is <0.2 °C at maximum

24. T in head (10 g average mass, antenna average emitted power of 0
T in head (10 g average mass, antenna average emitted power of 0.25 W)

25. ICNIRP: threshold-based
high
Established health effects
Threshold of established health effects
Reduction factors
Exposure
“Safe” exposure
low
Exposure limit
Source: ICNIRP

26. ICNIRP basic restrictions on exposure on the frequency range 10MHz to 10GHz

27. Flux of electromagnetic energy ______________________________________
EMF source
Approximate energy flux (watts/square meter)
Sunlight at the earth's surface at noon
1350 W/m2
Infrared heat radiation from a living person
20 W/m2
Mobile base station
70 W/m2 – 3 mW/m2 a)
Microwave emission from a living person
3 mW/m2
30 – 2000 MHz, Göteborg and various sites, Sweden (Uddmar T, Thesis, Chalmers U., 1999)
ICNIRP limit 4.5 W/m2 at 900 MHz

28. Introduction: Measurement and Computational standards _________________________________________________________
All portable wireless devices have to comply with RF exposure limits before putting them in the market.
Compliances standards for the portable RF wireless devices were developed by International Electrotechnical Commission IEC and IEEE mainly relevant to the mobile phones [IEC , IEEE-1528, 2003].
The merge of new technologies and different usage positions of the mobile devices led to development of relevant compliance standard to cover the exposure evaluation of the other parts of the body other than the head [IEC , 2010].
Although the SAR was established at the highest certified level, the actual SAR level for the mobile phone during use is generally much lower than the maximum values. In fact, since mobile phones are designed to operate at many different power levels, they only use the minimum level of power required to provide a connection to the network. In theory, the closer you are to a base station antenna, the lower the power level required by the mobile phone.

29. RF compliance assessment standards ______________________________________
Compliance can be assessed through measurements or calculations.
There is no meaning for existence of exposure Guidelines/standards if it is not possible to measure it.
Practically it is not possible to measure the energy absorption in the body of living humans!
In order to assess the exposure limits there has to be standardized procedures to evaluate those limits.
 There is a need to develop phantoms head/body phantoms
Advanced instrumentation is needed for this purpose
Accurate procedure with well defined and quantified uncertainty is needed.

30. International Electro-technical Commission (IEC) Wireless devices RF Assessment Standards ______________________________________
IEC-MT62209,
Part 1, SAR for handsets. To revise the standard IEC : “Procedure to Measure the Specific Absorption Rate (SAR) for Hand-Held Mobile Telephones in the Frequency Range of 300 MHz to 3 GHz” by the end of 2011.
Part 2, SAR for other handheld and body worn devices. To revise the IEC : “Procedure to determine the specific absorption rate (SAR) for wireless communication devices used in close proximity to the human body (frequency range of 30 MHz to 6 GHz) standard by 2013.
To unify IEC62209 part 1 & 2 standards by 2013.

31. Field measurement unit
SAM
Head phantom

32. SAM head phantom ______________________________________
the Standard Anthropomorphic Model - is a head shell phantom intended primarily for use in the measurement of exposure from mobile phones (or other hand-held transmitters)
SAM is defined as standard phantom allowing a conservative measure of the radio exposure of people of all origins and all ages. The ear region is defined with reference points and planes to facilitate reproducible positioning of telecommunications devices.
The dimensions of a 90th percentile male head were selected for the phantom.
IEC, CENELEC, and IEEE have developed standard procedures for assessing exposures from mobile phones which specify the use of a SAM phantom.

33. Tissue simulating liquid
Device under test
Tissue simulating liquid

34. Mobile phone exposure assessment __________________________________________________________

36. Thank you! Questions?