The new directive EC 2004/40/EC "Physical Agents Directive" will make the provisions of the International Commission on Non-Ionizing Radiation Protection (ICNIRP) a legal requirement across Europe with respect to the exposure of workers to electromagnetic fields (EMF). The basic restrictions of ICNIRP limit the specific absorption rate (SAR) of radio frequency (RF) power between 100 kHz and 10 GHz, and the incident power flux density (PFD) from 10 GHz to 300 GHz. Existing standards within Europe do not give comprehensive coverage of SAR and PFD over this range. The project, which started on April 1, 2008 aims to provide traceable metrology for SAR and EM field strength measurements at all frequencies that are in widespread public use. It is developing the expertise including contribution to international documentary standards, devices and measurement techniques to make these standards widely accessible for traceable measurements regarding exposure assessment in the environment, product compliance testing, and studies into biological effects of EMF which underpin the international exposure limits.

Within the project artefact standards for SAR covering the frequency ranges 100 kHz to 380 MHz and 2.6 GHz to 10 GHz, and PFD from 40 GHz to 300 GHz will be developed. To support the new SAR standards and facilitate their accurate and widespread dissemination, liquids will be formulated having similar properties to human tissue for 100 kHz to 300 MHz and 6 GHz to 10 GHz. Improvements will be made to the accuracy and traceability of dielectric measurements of these liquids, including providing better reference data for the liquids used as calibration standards in dielectric measurement systems. New smaller measurement probes will be developed for accurate measurements above 3 GHz and the errors due to isotropy and spatial resolution measured. Techniques will be developed for micro-dosimetry in very small biological samples to facilitate research into biological effects of EMF. Methods for applying low-frequency SAR standards to exposure assessment in industrial and medical environments will be developed, in particular exposure assessment during Magnetic Resonance Imaging (MRI). The effect of signal modulation, multiple frequency sources and broadband signals on the accuracy of field probes will be assessed. A range of commercially available probes and personal RF dosimeters will be tested. Numerical modelling activities are included in all relevant work-packages. They are essential for uncertainty analyses, for optimising measurement techniques and for deciding the best techniques to adopt. Also, computational simulations will serve to develop in vivo models for MRI, where SAR metrology is essential for assessing the exposure of patients, in particular of children.

The project has been started with a kick-off meeting on May 21 - 22, 2008 in Braunschweig where all participating partners introduced their laboratories and backgrounds. A board of management for important decisions regarding the progress of the project was established. A detailed planning of the activities within the work-packages has been agreed on and work-package leaders responsible for the organisation of the collaboration within the work-package and reporting have been assigned. Project partners from VSL received extensive training at NPL in dielectric measurement techniques.
Activities have then been started including the design, preparation and characterization of measurement setups for the metrological assessment of communication signals and of reference liquid dielectric material properties. By now, measurements have been obtained on the response of field sensors to pulsed, multi-frequency and digitally modulated signals, on the assessment of digital signal properties (error vector magnitude) and on reference liquid and phantom material properties. Existing measurement setups and theoretical models, e.g. relating surface currents to internal fields during MRI scanning, have been optimized further and intercomparisons on SAR calibrations, on specific heat measurements and on theoretical calculations have been performed. Both, a broadband spiral antenna with diode sensor covering the frequency range of 40 GHz to 120 GHz and a thermal sensor based on a fibre-coupled semiconductor thermometer for field strength measurements in free-space have been realized, tested and characterized. For the calibration of SAR sensors between 6 and 10 GHz, a setup has been designed and is built currently.
First numerical calculations for the SAR distribution in artefact standards, phantoms and biological material monolayers as required for micro-dosimetry have been performed. Results include field distributions in field generators and field maps, SAR distributions and temperature profiles in sample containers and in biological layers. Dyes for the measurement of temperature distributions in biological layers have been purchased and tested and a coplanar waveguide with optimized stray fields to generate a SAR pattern in a thin film has been designed and fabricated. Dielectric parameters of the dye solution have been determined. A confocal microscope measurement setup for the characterization of the thermal sensitivity of the dye solution and a second setup for spatially resolved measurements in a thin film on top of the coplanar waveguide have been prepared.
Project results and further procedures have been discussed at the first periodical project meeting which has been performed at UME in Istanbul from October 26 - 28, 2008, at a Topical Forum during the 20th International Zurich Symposium on Electromagnetic Compatibility (EMC Zurich 2009) on January 14, 2009 and during a project meeting in Helsinki from April 27 - 28, 2009. In the meantime further progress was achieved in identifying multifrequency environments and in examining the behaviour of field probes while exposed to multifrequency, pulsed and digitally modulated signals. For low-frequency SAR measurements, MRI scanner measurements on SAR liquids and phantoms have been performed and compared to simulations. For high-frequency SAR measurements, the design of waveguide calibrators has been completed and the assembly of experimental setups is almost finished. For micro-dosimetry on RF exposure, a field generator for a sample container containing the dyes has been fabricated. The latest results have been presented and discussed during a project meeting in Turin, held from October 12 - 13.
In the future, we expect to generate further competences and capabilities within this project that are necessary for traceable measurements of SAR and EM field strength at all frequencies that are in widespread public use. This will allow to improve the protection of the public in Europe from electromagnetic field exposure as envisioned by the Physical Agents Directive. Furthermore, it will foster research in the field of non-thermal effects of EM waves and in the area of field sensor technology.

2009:
EMC Zürich 2009 - Topical Forum 2

Congrès de Métrologie 2009 - Metrology Congress 2009.

2010:
Asia-Pacific Symposium & Exhibition on Electromagnetic Compatibility - Metrology Congress April 2010 in Beijing, China.

Asia-Pacific Microwave Conference (APMC2010), 7-10 Dec. 2010, Yokohama – Japan.

2011:
The outcome of this project will be presented on a full-day workshop at the EBEA Conference 2011 taking place in Rome, Italy,
For further details see http://www.ebea2011.org

• M. Salhi et al., “Broadband Electromagnetic Field Strength Sensors for 40-300 GHz Based on Planar Log Per Antennas and High-Speed Schottky Diodes”, accepted by the APMC2010, Yokohama, Japan.
• B. Loader et al., “Phantom Target Properties For The Frequency Range 3 GHz to 10 GHz. BEMS 32^nd annual meeting” – Korea 2010.
• O. Bottauscio et al., “A model to relate SAR to surface field measurements in human phantoms”. (Compumag 2009) Florianopolis, Brasil, 22-28 Nov. 2009.
• T. Schrader et al.,  “Traceable measurements of field strength and SAR for the Physical Agents Directive - an update”, Electromagnetic Compatibility (APEMC), Asia-Pacific Symposium on, Bejing, China, 2010.
• T. Schrader et al., “EMF and SAR: An Overview about the European Research Project”, in: Proceedings of the 20^th Int. Zurich Symposium on EMC, Zurich, Switzerland, pp. 143-158, 2009.
• Alireza Kazemipour, "Feasibility of a broadband SAR-probe calibration cell", EMC Zurich 2009.
• D. Allal et al., "Métrologie du débit d'absorption spécifique (DAS) : un soutien à l'application de la directive européenne 2004/40/CE" in the "Journée des Métrologues", Paris
•  W. Liang et al., “Traceable calibration of specific absorption rate (SAR) for mobile phone dosimetry”, Digest of Conference on Precision Electromagnetic Measurements, pp.  496 - 497, Sydney 2000.
• B. G. Loader et al., “Coaxial Artefact Standard for Specific Absorption Rate 100 kHz to 400 MHz”, Progress In Electromagnetics Research Symposium, Beijing, China, March 23–27, 2009.
• D.Trinchero, et al., “Measurement of spread-spectrum radio signals by means of wideband field probes”. Proceedings of the 20th Intern. Zurich Symposium on EMC, January 2009.
• D.Trinchero et al.: “Experimental setup for the characterization of field probes performance in presence of digitally modulated radio signals”. IEEE Antennas and Wireless Propagation Letters, Vol.8, pp. 224-227, 2009.
• D.Trinchero et al.: “Field probes performance for the measurement of spread-spectrum radio signals”. IEEE Antennas and Wireless Propagation Letters, Vol.8, pp. 494-497, 2009.
• T. Toivo et al., Calibration System for SAR Probes at Frequencies from 20 to 450 MHz, Bioelectromagnetics Society and the European Bioelectromagnetics Association in the Congress Centre, Davos, Switzerland on 15-19 June 2009.
• M. Cetintas et al., “Investigation of Radio-Optic Resonances on Far Field and Free Space Condition”, 17th International Conference on Advanced Laser Technologies (ALT'09), 26.9 – 01.10 Antalya, Turkey 2009.
• “A three-step approach for accurate permittivity measurement using transmission line methods”, Oral presentation at Agilent fourth annual complimentary workshop on Metrology in connection with the Euramet TC EM sub-committee RF & MW meeting ,  11 - 15 May 2009, Boras, Sweden
• T. Schrader et al., “EMF and SAR: An Overview about the European Research Project”, in: Proceedings of the 20^th Int. Zurich Symposium on EMC 2009, Zurich, Switzerland, pp. 143-158.
• M. Çetintaş, “Traceable Field Strength Measurements based on Laser Spectroscopy”, in: Proceedings of the 20^th Int. Zurich Symposium on EMC 2009, Zurich, Switzerland, pp. 159-172.
• B. Loader, “Calibration and Characterisation of Probes for Measuring the Specific Absorption Rate”, in: Proceedings of the 20^th Int. Zurich Symposium on EMC 2009, Zurich, Switzerland, pp. 173-188.
• A. Kazemipour et al., “Feasibility of a Wideband SAR-Probe Calibration Cell”, in: Proceedings of the 20^th Int. Zurich Symposium on EMC 2009, Zurich, Switzerland, pp. 189-196.
• A. Gregory, “An Overview of Traceable Methods for the Measurement of the Dielectric Properties of Liquids used in SAR Measurements”, in: Proceedings of the 20^th Int. Zurich Symposium on EMC 2009, Zurich, Switzerland, pp. 197-210.
• O. Bottauscio et al., “A Boundary Element Approach for Low Frequency SAR Computation in Homogeneous Objects”, in: Proceedings of the 20^th Int. Zurich Symposium on EMC 2009, Zurich, Switzerland, pp. 211-214.
• F. Seifert, “Electromagnetic Field Measurements based on Magnetic Resonance Imaging”, in: Proceedings of the 20^th Int. Zurich Symposium on EMC 2009, Zurich, Switzerland, pp. 215-228.

GUIDELINES FOR LIMITING EXPOSURE TO TIME-VARYING ELECTRIC, MAGNETIC, AND ELECTROMAGNETIC FIELDS (UP TO 300 GHz)
Exposure to electromagnetic fields