CECIL, S

Joseph, Wout

KUHN, S

KUSTER, N

Martens, Luc

NEUBAUER, G

PREINER, P

Vermeeren, Günter

English

Ghent University Academic Bibliography

Poster Session 333P-44 AVERAGING METHODS FOR RELIABLE MEASUREMENTSGeorg Neubauer1, Patrick Preiner1, Stefan Cecil1, Gunter Vermeeren2, Wout Joseph2, LucMartens2, Sven Ku¨hn3, Niels Kuster31ARC GmbH, Seibersdorf, Austria 2Ghent University, Gehnt, Belgium 3ITIS, Switzerland,SwitzerlandObjectives. Assessment and evaluation of exposure in radio frequency (RF) fields requiresaveraging procedures of electric field strengths, e.g. the ICNIRP guidelines of 1998 includethe requirement that the electric field strengths have to be averaged over a volume corre-sponding to the body of a human being. It is stated in such documents that the measuredelectric field strengths have to be averaged over a volume corresponding to the human body.Some of these documents give rather general recommendations, others define very precisean averaging procedure. Anyway, there is almost no scientific rationale available to justifyspecific averaging procedures. Therefore there is high need to earn knowledge on specificfield distributions in the environment of fixed installed RF transmitters, e.g. base stationsand to identify reliable averaging procedures for limited numbers of assessed field levels.Based on the field distributions assessed in [1], the reliability of different averaging proce-dures was examined. In the frame of the EUREKA project BASEXPO specific averagingprocedures were developed for mobile communication frequency bands. First results of thiswork are presented within this abstract.Methods. Based on the results and evaluated data presented in [1] different averagingschemes were applied to volumes corresponding to the dimensions of the human body ex-posed to RF fields. A large amount of simulations performed in this project with a simu-lation tool solving the Maxwell’s equations delivered a considerable data base taking intoaccount multipaths propagation. To make the data comparable with data obtained in theframe of measurement campaigns [2], the chosen templates were built by averaging the 3mmvoxels over the volume of a measurement antenna (i.e. a biconical antenna [3] with an inte-grating volume of a sphere with approximately 13.6cm diameter). To simplify evaluationsthe sphere was replaced by a cube with the same volume (edge length of 11cm). Deviationsof -0.22 to 0.42dB were found by comparing the mean value of the field strength averagedover a sphere with the volume averaged over a cube. Averaging over such a cube deliveredthe mean field level for a single position of a template. In order to get different templatesa certain amount of such positions (3 and 4) were extracted and arranged consecutive toeach other with a distance of 15cm or 30cm as well as four positions arranged in a squarewith a distance of 15cm to each other from center to center (see Figure 1). These templateswere than moved through the whole examined volume and the mean value of the 3 or 4positions was calculated to obtain averaged field values. The grid step for moving the builttemplates through a volume was for all cases 15cm in each orthogonal direction. Analysesof the evaluated data will be performed to find suitable averaging schemes for assessing themean field strength value averaged over the whole body.Results. Preliminary results are available for 946 MHz. For the Line 3 Template the meanvalues of the electromagnetic field strength are shown in Table 1. The variation of themean value of the 4 templates moved through each volume gives preliminary results of the334 BEMS2007—Monday & Tuesdayvariability of the local averaged field levels compared to the global electromagnetic fieldstrength.Conclusions. Only very limited and preliminary conclusions can be drawn at the presentstate of the evaluated data due to the lack of results. It can be said that the simpler shape ofa cube instead of a sphere can be applied with only sparse uncertainties. At the moment itlooks as if the derived mean values delivered by the templates are showing no big differencebetween the four tested templates, so more positions building a template or a more complexconfiguration (square instead of a line) might not lead to more precise results.Figure 1. Averaged Voxels over a cube building the position of a template.Cube with an edge length of 11cm. Four different templates are shown con-sisting of a different number of positions (3, 4) and with a different distanceof each consecutive position (15cm, 30cm). The right graphic should displaya template consisting of 3 positions moved through the investigated volume.On each location the mean value of the e.g. 3 positions was build.P-45 AN ON SITE SAR EVALUATION USING PLANE WAVE SPECTRUMREDUCTIONFadila Saidi1, Man-Fai Wong1, David Lautru2, Azeddine Gati1, Emmanuel Nicolas3,Fronc¸ois Jacquin3, Joe J. Wiart1, Victor Fouad Hanna21France Telecom R&D, issy les Moulineaux, France 2Universite´ Pierre et Marie Curie, Paris,France 3Te´le´diffusion de France, Paris, FranceObjectives. In this paper we present a study which aims at developing an evaluationmethod of the human exposure to electromagnetic fields in terms of specific absorption rate(SAR) in order to compare to the ICNIRP or IEEE limits. The objective of this study isthe direct evaluation of the SAR through on site measurements of electric filed. Straight on   The Bioelectromagnetics Society 29th Annual Meeting  Abstract Collection  Kanazawa-shi Bunka Hall Kanazawa, Japan June 10 - 15, 2007        

Averaging methods for reliable measurements

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Averaging methods for reliable measurements

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