1. ITU-T Technical Session on EMF
Comparison between measurement and calculations EMF-estimator, K.guide
Fryderyk Lewicki
ITU-T SG5, Rapporteur for Q 3/5
Following a discussion in the MCG, I was asked to coordinate a presentation that would highlight the current situation in terms of communication and promotion and would propose areas for improvement with the purpose of changing the current situation.
As we were asked to be brief (less than 5 minutes each), and in order to put the information given today in context, I have prepared a draft strategy paper which was coordinated with the three Bureaux.
Our presentation will therefore limit itself to a few key issues.
ITU-T Technical Session on EMF
Geneva, 27 May 2009

2. ITU-T Technical Session on EMF
Introduction
Human exposure assessment is in responsibility of the ITU-T SG5, Question 3
ITU-T has prepared in this subject the following Recommendations:
K.52 (2000/2004),
K.61 (2003/2008)
K.70 (2007)
K. guide – under development
Details in paragraphs 2 to 6.
While some may think that the past is the past, wisdom is also what we learn from the past.
These paragraphs make interesting reading and should be kept in mind to avoid repeating the same mistakes
ITU-T Technical Session on EMF
Geneva, 27 May 2009

3. ITU-T Technical Session on EMF
Measurement
SAR measurement
human head phantom and automatic system
very important for the hand sets manufacturers
Electric field strength measurement
broad band – cheap but with overestimation
frequency selective – more expensive and time consuming, require post processing
On site and laboratory
Details in paragraphs 2 to 6.
While some may think that the past is the past, wisdom is also what we learn from the past.
These paragraphs make interesting reading and should be kept in mind to avoid repeating the same mistakes
ITU-T Technical Session on EMF
Geneva, 27 May 2009

4. Measurement
Example of the result of the frequency selective measurement
Details in paragraphs 2 to 6.
While some may think that the past is the past, wisdom is also what we learn from the past.
These paragraphs make interesting reading and should be kept in mind to avoid repeating the same mistakes
ITU-T Technical Session on EMF
Geneva, 27 May 2009

5. Measurement Example of the result
of the frequency selective measurement
Details in paragraphs 2 to 6.
While some may think that the past is the past, wisdom is also what we learn from the past.
These paragraphs make interesting reading and should be kept in mind to avoid repeating the same mistakes
ITU-T Technical Session on EMF
Geneva, 27 May 2009

6. Measurement advantages
It takes into account all radiating sources with real parameters
It takes into account real environment (reflections, antenna supporting hardware, obstacles)
Takes into account simultaneous exposure in the real way (phase differences of the different waves are taken into account)
Details in paragraphs 2 to 6.
While some may think that the past is the past, wisdom is also what we learn from the past.
These paragraphs make interesting reading and should be kept in mind to avoid repeating the same mistakes
ITU-T Technical Session on EMF
Geneva, 27 May 2009

7. Measurement advantages
It can be done with little knowledge about radiating sources (initial measurement of the occupied spectrum is required only)
Good quality measurement equipment is accessible on the market
A life demonstration of the measurement to the interested people is possible
Details in paragraphs 2 to 6.
While some may think that the past is the past, wisdom is also what we learn from the past.
These paragraphs make interesting reading and should be kept in mind to avoid repeating the same mistakes
ITU-T Technical Session on EMF
Geneva, 27 May 2009

8. Measurement disadvantages
Measurement is not possible for the radiating sources that do not exist yet
It is difficult to take into account the time variation of the EMF (for example mobile communication)
The effect of the presence of staff and equipment on the EMF distribution has to be avoided
SAR measurements have to use phantoms that are approximations only of the human body
Details in paragraphs 2 to 6.
While some may think that the past is the past, wisdom is also what we learn from the past.
These paragraphs make interesting reading and should be kept in mind to avoid repeating the same mistakes
ITU-T Technical Session on EMF
Geneva, 27 May 2009

9. Measurement disadvantages
It is difficult to confirm and check that all the sources are operating with maximum ERP
In the multiple sources environment a post processing is required because of different limits for different operating frequencies
There is no probe covering the whole required frequency range,
Out of band emissions may lead to overestimation in the in-band measurement
Details in paragraphs 2 to 6.
While some may think that the past is the past, wisdom is also what we learn from the past.
These paragraphs make interesting reading and should be kept in mind to avoid repeating the same mistakes
ITU-T Technical Session on EMF
Geneva, 27 May 2009

10. ITU-T Technical Session on EMF
Calculations
Very easy but with big overestimation – isotropic source with maximum ERP
Far field model
Synthetic model – On the right: example of the vertical cross-section
Details in paragraphs 2 to 6.
While some may think that the past is the past, wisdom is also what we learn from the past.
These paragraphs make interesting reading and should be kept in mind to avoid repeating the same mistakes
ITU-T Technical Session on EMF
Geneva, 27 May 2009

11. ITU-T Technical Session on EMF
Calculations
Full-wave models (MoM, FDTD etc.)
Accuracy of calculation depends on the model used and on the exactness of description of transmitting antennas
Details in paragraphs 2 to 6.
While some may think that the past is the past, wisdom is also what we learn from the past.
These paragraphs make interesting reading and should be kept in mind to avoid repeating the same mistakes
ITU-T Technical Session on EMF
Geneva, 27 May 2009

12. Simultaneous exposure to multiple sources
Typical situation is presented on this chart. Radiation from the broadcasting Transmitting Stations gives higher levels then mobile Base Stations
Details in paragraphs 2 to 6.
While some may think that the past is the past, wisdom is also what we learn from the past.
These paragraphs make interesting reading and should be kept in mind to avoid repeating the same mistakes
ITU-T Technical Session on EMF
Geneva, 27 May 2009

13. Calculations advantages
Non existing radiating sources can be considered
The possibility to take into account the maximum possible radiation levels (ERP’s) that lead to the maximum possible exposure levels
There are many calculation methods with different level of accuracy
The calculation with high level of overestimation is very easy to use
Details in paragraphs 2 to 6.
While some may think that the past is the past, wisdom is also what we learn from the past.
These paragraphs make interesting reading and should be kept in mind to avoid repeating the same mistakes
ITU-T Technical Session on EMF
Geneva, 27 May 2009

14. Calculations advantages
Calculation costs are lower then the cost of measurements
It gives an opportunity to use mitigation technique if required
It is possible to make calculation in areas with no access
Details in paragraphs 2 to 6.
While some may think that the past is the past, wisdom is also what we learn from the past.
These paragraphs make interesting reading and should be kept in mind to avoid repeating the same mistakes
ITU-T Technical Session on EMF
Geneva, 27 May 2009

15. Calculations advantages
VHF TV (ERP=125kW, h=90m), FM (total ERP=423kW, h=55m), GSM900 (ERP=1080W, h=30m), GSM1800 (ERP=1120W h=30m)
Cumulative exposure [V/m]
Vertical
cross-section,
azimuth 333°
Details in paragraphs 2 to 6.
While some may think that the past is the past, wisdom is also what we learn from the past.
These paragraphs make interesting reading and should be kept in mind to avoid repeating the same mistakes
Horizontal
cross-sections:
h=90 m
h=55 m
h=30 m
ITU-T Technical Session on EMF
Geneva, 27 May 2009

16. Calculations disadvantages
Very accurate results require detailed description of the radiating antennas
In most cases do not take into account the influence of reflections
Require good knowledge of the software used
Require at least basic knowledge concerning transmitting antennas
Details in paragraphs 2 to 6.
While some may think that the past is the past, wisdom is also what we learn from the past.
These paragraphs make interesting reading and should be kept in mind to avoid repeating the same mistakes
FEKO software
ITU-T Technical Session on EMF
Geneva, 27 May 2009

17. Comparison measurement vs. calculation
Good agreement if properly done
Details in paragraphs 2 to 6.
While some may think that the past is the past, wisdom is also what we learn from the past.
These paragraphs make interesting reading and should be kept in mind to avoid repeating the same mistakes
ITU-T Technical Session on EMF
Geneva, 27 May 2009

18. Measurement vs. Calculations
Human exposure assessment may be done by measurement or calculations
Both methods have advantages and disadvantages
Both methods have similar level of uncertainty and accuracy depending on the method and equipment or software used
Details in paragraphs 2 to 6.
While some may think that the past is the past, wisdom is also what we learn from the past.
These paragraphs make interesting reading and should be kept in mind to avoid repeating the same mistakes
ITU-T Technical Session on EMF
Geneva, 27 May 2009

19. Resolution 72 Measurement concerns
related to human exposure to electromagnetic fields
Recognizing that some publications about EMF effects on health create doubt among the population, in particular in developing countries
Resolves to invite ITU-T, in particular Study Group 5, to expand and accelerate its work and support
Invites to contribute actively to the work of Study Group 5, in providing relevant and timely information, in order to assist the developing countries by providing information and addressing measurement concerns related to RF exposure
Details in paragraphs 2 to 6.
While some may think that the past is the past, wisdom is also what we learn from the past.
These paragraphs make interesting reading and should be kept in mind to avoid repeating the same mistakes
ITU-T Technical Session on EMF
Geneva, 27 May 2009

20. ITU-T Technical Session on EMF
Resolution 72
Measurement concerns related to human exposure to electromagnetic fields
Recommendation ITU-T K.guide „Guidance on how to manage humane exposure to EMF’s” will be written with Resolution 72 taken into account
Current Technical Session on EMF is an example of action in accordance with Resolution 72
Details in paragraphs 2 to 6.
While some may think that the past is the past, wisdom is also what we learn from the past.
These paragraphs make interesting reading and should be kept in mind to avoid repeating the same mistakes
ITU-T Technical Session on EMF
Geneva, 27 May 2009

21. ITU-T Recommendation K.guide
Guidance on how to handle the problem of the human exposure assessment in order to help the user to apply existing standards
procedures how to evaluate exposure
by measurement
by calculations
procedures how to show the compliance with exposure limits
this Recommendation will be written in the possibly simple way and in order to be easy to understand
Details in paragraphs 2 to 6.
While some may think that the past is the past, wisdom is also what we learn from the past.
These paragraphs make interesting reading and should be kept in mind to avoid repeating the same mistakes
ITU-T Technical Session on EMF
Geneva, 27 May 2009

22. ITU-T Recommendation K.guide
It will include examples of the results of measurements
broad band
frequency selective
examples of evaluation of the exposure levels around typical radiation sources:
mobile base stations
broadcasting transmission stations
wireless access systems
examples of compliance evaluation for the typical cases of simultaneous exposure to multiple sources of radiation
Details in paragraphs 2 to 6.
While some may think that the past is the past, wisdom is also what we learn from the past.
These paragraphs make interesting reading and should be kept in mind to avoid repeating the same mistakes
ITU-T Technical Session on EMF
Geneva, 27 May 2009

23. Recommendation ITU-T K.70
Mitigation techniques to limit human exposure to EMFs
in the vicinity of radiocommunication stations
Modeling of the transmitting antennas
Importance of the Vertical Radiation Pattern (VRP)
Identification of the main source of radiation
Mitigation techniques in order to reduce radiation level – if required
EMF-estimator – software with the library of the examples of transmitting antennas
Details in paragraphs 2 to 6.
While some may think that the past is the past, wisdom is also what we learn from the past.
These paragraphs make interesting reading and should be kept in mind to avoid repeating the same mistakes
ITU-T Technical Session on EMF
Geneva, 27 May 2009

24. ITU-T Technical Session on EMF
Conclusions
ITU-T SG5 takes part in standardization by preparing Recommendations which give appropriate guidance for administrations and telecommunication operators and supports developing countries (Resolution 72)
ITU activity is complementary to the works carried out in other international standardization entities involved in this subject
Details in paragraphs 2 to 6.
While some may think that the past is the past, wisdom is also what we learn from the past.
These paragraphs make interesting reading and should be kept in mind to avoid repeating the same mistakes
ITU-T Technical Session on EMF
Geneva, 27 May 2009

25. Thank you Questions, Comments?
Details in paragraphs 2 to 6.
While some may think that the past is the past, wisdom is also what we learn from the past.
These paragraphs make interesting reading and should be kept in mind to avoid repeating the same mistakes
ITU-T Technical Session on EMF
Geneva, 27 May 2009