Final Summary Report
Three years after its start, the SEAWIND project was successfully finalized. The summary of the final report can be downloaded here:
Complementary Information & Tools
Public Event on Monte Verità 2012 - EMF Health Risk Research: Lessons Learned and Recommendations for the Future – Seven Years Later
Video recording of the public event: "Health Risk From Exposure To Wireless Network Devices?" organized on Wednesday 24 October on Monte Verità. This public event served to summarize the work performed and the resulted collected in the context of the EU-funded SEAWIND project.
Web Tool WHIPP for Exposure Calculation & Optimization of Device Location (available soon)
WHIPP stands for Wireless & Cable Heuristic Indoor Propagation Prediction Tool, University of Ghent. The tool predicts the exposure and guides the user to optimize the placement of rooters, etc.is designed to estimate EMF exposure from wireless networks operating at 2.4 GHz in an indoor environment. EMF exposure in entire rooms is estimated after drawing the ground plan of the rooms, assigning materials to walls, doors, etc., and indicating the placement of the wireless access point(s). The web-based exposure tool will be released on the internet in June 2013 by the WiCa research group of iMinds and a link will be available as soon as it is relased.
Syntheses of WP10
The recommendations for risk governance, integrating assessment, perception and communication are summarized in this short report
EU Newsletter No. 07
Breif summary about the SEAWIND project.
Peer-Reviewed SEAWIND Publications
Bamba, A.; Joseph, W.; Andersen, J.B.; Tanghe, E.; Vermeeren, G.; Plets, D.; Nielsen, J.O.;
Martens, L. : Experimental Assessment of Specific Absorption Rate Using Room Electromagnetics. IEEE Transactions on Electromagnetic Compatibility 54(4): 747- 757
A closed room environment is viewed as a lossy cavity, characterized by possibly a line-of-sight component and diffuse scattering parts from walls and internal obstacles. A theory used in acoustics and reverberation chambers is applied for the electromagnetic case, and main issues related to measurement systems, antennas characteristics, diffuse energy properties, and human exposure are investigated. The goal of this paper aims first toward validation of the assessment of the reverberation time in an environment using a virtual multiple-input-multiple-output channel system. Second, the reverberation time in an adjacent room is investigated, and hence, a measurement-based method is readily developed to assess the absorption cross section and the whole-body specific absorption rate of humans at 2.3 GHz in a realistic closed environment.
Andersen, Jørgen Bach; Chee, Kin Lien; Jacob, Martin; Pedersen, Gert Frølund; Kürner, Thomas K.: Reverberation and Absorption in an Aircraft Cabin With the Impact of Passengers. IEEE Transactions on Antennas and Propagation 60(5):2472 – 2480
Using a similar approach to that applied in acoustics and in microwave reverberation chambers, a theory of wideband propagation in a closed environment is discussed. Here, a room environment is viewed as a lossy cavity, characterized by diffuse scattering from walls and internal obstacles. For experimental results, measurements from 3 to 8 GHz were performed in a 24 passenger section of an aircraft cabin. This UWB system has the transmitter at ceiling height and the receivers at armrest and headrest positions. The measurements were performed for the cabin being unoccupied and fully occupied. In the theoretical model, the closed room environment is characterized by the reverberation time and volume, and these parameters allow derivation of the the remaining parameters such as path loss and average passenger absorption. The RMS delay spread and mean excess delay are also studied. For the mean power the agreement between the theory and measurements is good to within 1-2 dB, indicating the excellent accuracy of the method, which extends to estimating body absorption in real world environments. The total absorption from the seated passengers is dominated by the few who are near the transmitter. In general, this absorbed power is relatively small, so the effect of passengers is marginal for this configuration of a cabin communication system.
Nielsen, Jesper Ødum; Andersen, Jørgen Bach; Pedersen, Gert Frølund; Pelosi, Mauro: On
Polarization and Frequency Dependence of Diffuse Indoor Propagation. Vehicular Technology Conference (VTC Fall), 2011 IEEE
The room electromagnetics (RE) theory describes the radio propagation in a single room assuming diffuse scattering. A main characteristic is the exponential power-delay profile (PDP) decaying with the so-called reverberation time (RT) parameter, depending only on the wall area, the volume of the room and an absorption coefficient. The PDP is independent on the location in the room, except for the arrival time. Based on measurements in a room with a spherical array of 16 dual- polarized wideband horn antennas, the current work studies how the RE parameters depend on the receiver (Rx) antenna polarization and orientation. Also the frequency dependence is investigated, with measurements done at both 2.3 GHz and 5.8 GHz center frequencies. The RE theory was found to fit well to the measurements with a RT in the range 22- 25 ns. Only small differences were found due to the polarization and the channel gain was depending approximately as expected with frequency.
Nadakuduti, Jagadish; Kühn, Sven; Fehr, Marcel; Douglas, Mark G.; Pokovic, Katja; Kuster, Niels: The Effect of Diode Response of Electromagnetic Field Probes for the Measurements of Complex Signals. IEEE Transactions on Electromagnetic Compatibility 54(6): 1195 - 1204.
Diode detectors present inside electromagnetic field probes are typically calibrated for linearity using continuous sinusoidal waveforms (CW). In this paper, we have shown that CW linearization is not adequate for the measurement of complex wireless communication signals with high peak-to-average power ratios. While previous analog and digital communication signals (1G and 2G) can be more easily corrected for linearity, newer 3G and 4G communication protocols employ complex modulations with stochastic signal envelopes. As a result, proper linearization depends on the diode response and signal characteristics, and large errors results if CW linearization is used. The errors introduced when measuring such signals with probes employing CW linearization are quantified in this paper. A numerical model of the diode response is provided and validated against measurements. Errors due to CW linearization can exceed 2 dB, whereas linearity errors within 0.4 dB are attainable using the proposed calibration procedures for even increased dynamic ranges.
The scientific and technical impact of the study can be summarized as:
- An accurate numerical model has been developed for the response of diode detector probes to complex signals.
- The numerical model was experimentally validated for different diode detectors, probe constructions and communication signals.
- A new probe calibration methodology is developed to reduce the large SAR measurement errors for LTE, UMTS, Wi-Fi and other communication signals.
- This paper aims to significantly advance electromagnetic measurement standards under development by international committees.
I. Markakis, T. Samaras, “Radiofrequency Exposure in Greek Indoor Environments,” Health Physics, vol. 104, pp. 293 – 301, March 2013.
This is the first measurement campaign that takes place in Greece in order to assess the exposure levels in different microenvironments (offices, bedrooms, living rooms, schools). Due to the exponential growth in the use of wireless network devices, the aim of this work was to perform indoor measurements with the use of personal dosimeters. The measurement period was 3 d in each of the 40 different locations that were selected, both in the urban and suburban area of Thessaloniki, the second largest city of Greece. The measurements took place from 23 July 2010 to 19 January 2012. After processing the obtained data with the robust regression on order statistics (ROS) method, various statistical exposure quantities were calculated. Compared to similar measurement campaigns across Europe, a larger proportion of measurement data above the detection limit for specific frequency bands (at most 56% for the DCS Rx frequency band) was found. Furthermore, mean exposure levels in the mobile downlink frequency bands were higher than those in other studies (GSM Rx: 0.259 V/m, DCS Rx: 0.131 V/m, UMTS Rx: 0.12 V/m), yet many times below the ICNIRP guidelines. On the other hand, maximum exposures were found to be of the same magnitude (GSM Rx: 0.38 V/m, DCS Rx: 0.3 V/m, UMTS Rx: 0.28 V/m). These measurement results indicate that signals from mobile base stations are dominant in workplaces and schools, whereas wireless phones and computer networks play the leading role in home environments. While the former reach their maximum values during daytime, the latter have an observable increase in the evening after work hours.
M-C. Gosselin et al., “SAR Exposures by Wireless Network Device,” publication in preparation.
C. Ziemann, et al., “In Vivo Studies,” publication in preparation.
D. Schürmann, et al., “Other approaches: SCE, life-cell imaging,” publication in preparation.
D. Schürmann, et al., “Combined about PARP & co-genotoxicity,” publication in preparation.
C. Ziemann, et al., “In vitro, Comet data,” publication in preparation.
J.O. Nielsen et al., “On Polarization and Frequency Dependence of Diffuse Indoor Propagation.” publication in preparation.
M. Capstick et al., “In-vitro Exposure System for Live Cell Imaging at 2.45 GHz,” publication in preparation.
M. Capstick et al., “2.45GHz In-vitro Exposure System for Use During Live Cell Imaging,” publication in preparation.
O. Renn et al., "The Delphi process and its outcomes," publication in preparation.