J. Phys. Soc. Jpn. 75 (2006) 084801 (5 pages) |Previous Article| |Next Article| |Table of Contents|
|Full Text PDF (454K)| |Buy This Article|
Passive Exposure to Mobile Phones: Enhancement of Intensity by Reflection
Department of Physics, Tohoku University, Sendai 980-8578
1Japan Offspring Fund, 2-5-2 Kojimachi, Chiyoda-ku, Tokyo 102-0083
2Department of Physics, Ritsumeikan University, Kusatsu, Shiga 525-8577
3Department of Information and Communication Engineering, Sendai National College of Technology, Sendai 989-3128
(Received March 14, 2006; Revised May 18, 2006; Accepted May 23, 2006; Published July 25, 2006)
In a recent Letter [J. Phys. Soc. Jpn. 71 (2002) 432], we reported a preliminary calculation and concluded that public exposure to mobile phones can be enhanced by microwave reflection in public spaces. In this paper, we confirm the significance of microwave reflection reported in our previous Letter by experimental and numerical studies. Furthermore, we show that “hot spots” often emerge in reflective areas, where the local exposure level is much higher than average. Such places include elevators, and we discuss other possible environments including trains, buses, cars, and airplanes. Our results indicate the risk of “passive exposure” to microwaves.
©2006 The Physical Society of Japan
KEYWORDS:passive exposure, boundary condition problem, biological effect, microwave, Maxwell's equations, mobile phone
- G. Hyland: Lancet 356 (2002) 1833.
- G. Hyland: The physiological and environmental effects of non-ionising electromagnetic radiation. STOA Project number 2000/07/03 (European Parliament, Luxembourg, 2001).
- L. Salford, B. Persson, L. Malmgren and A. Brun: Mobile Communication and the Blood-Brain Barrier (Lecture organized by ECOLO, le CEFE, European Parliament, 29 June, 2000).
- H. Pearson: Mobile-phone radiation damages lab DNA, doi:10.1038/news041220-6 (firstname.lastname@example.org, London, 2004).
- REFLEX project (funded by the EU under the programme “Quality of Life and Management of Living Resources”, Project coordinator, Prof. F. Adlkofer): Risk Evaluation of Potential Environmental Hazards from Low Energy Electromagnetic Field Exposure Using Sensitive in vitro Methods (VERUM foundation, Munchen, 2004).
- D. Pomerai, C. Daniells, H. David, J. Allan, I. Duce, M. Mutwakil, M. Thomas, P. Sewell, J. Tattersall, D. Jones and P. Candido: Nature 405 (2000) 417.
- H. Kimata: Allergy 60 (2005) 838.
- The Netherlands Organisation for Applied Scientific Research TNO: Effects of Global Communication system radio-frequency fields on Well Being Cognitive Functions of human subjects with and without subjective complaints, TNO-report No. FEL-03-C148 (2003).
- L. Hardell, M. Carlberg and K. H. Mild: Neuroepidemiology 25 (2005) 120.
- J. Schüz, E. Böhler, G. Berg, B. Schlehofer, I. Hettinger, K. Schlaefer, J. Wahrendorf, K. Kunna-Grass and M. Blettner: Am. J. Epidemiol. 163 (2006) 512.
- Electromagnetic Compatibility Conference Japan: Guidelines on the Use of Radiocommunication Equipment such as Cellular Telephones–Safeguards for Electronic Medical Equipment (Association of Radio Industries and Businesses, Tokyo, 1997) [in Japanese].
- FDA (U.S. Food and Drug Administration): FDA report on “Electromagnetic Interference (EMI) Testing of Medical Devices” (1996), available at http://www.fda.gov/cdrh/ost/index.html.
- AAMI/American National Standard: Active implantable medical devices EMC test protocols for implantable cardiac pacemakers and implantable cardioverter defibrillators, AMMI PC69 (1999).
- T. Hondou:
J. Phys. Soc. Jpn. 71 (2002) 432[JPSJ].
- I. Sample (reporter): New Scientist 174 (2002) No. 2341, 23.
- C. K. Chou: New Scientist 174 (2002) No. 2348, 52.
- Y. Sakata: Bussei Kenkyu (Kyoto) 83 (2004) 189 [in Japanese].
- The equivalent Poynting vector, P, is defined by P=|E2|/cµ0, where E, c and µ0 are the electric field, velocity of light and magnetic permeability in a vacuum, respectively.
- The movie file corresponding to Fig. 4 is available at our website (http://www.cmpt.phys.tohoku.ac.jp/~hondou/ref/movie1A.mov). This movie shows the results of the simulation of the intensity distribution in an elevator model produced using HFSS software, where the intensity is indicated by a color scale. The door of the elevator is kept fully open in the simulation. The enhancement of intensity by reflection is evident. Note that the temporal period of oscillation of the intensity in the movies corresponds to one-half the period of radiation, or 1/(2×0.9×109) s (QuickTime; 1.1 MB).
- The movie file corresponding to Fig. 5 is available at our website (http://www.cmpt.phys.tohoku.ac.jp/~hondou/ref/movie2.mov). This movie shows the control study (simulation) for the case without reflection (free boundary condition), in which all the parameters are the same as those in refs. 19 and 21 with the exception of the boundary condition. The intensity monotonically decreases from the antenna, which clearly contrasts with the case under reflection (QuickTime; 660 KB).
- Emergence of hot spots is clearly observed by a 3D visualization of the intensity distribution in an elevator model. The movie file is available at our web site (http://www.cmpt.phys.tohoku.ac.jp/~hondou/ref/movie1B.mov). The 3D movie shows the localized and unpredictable distribution of hot spots more clearly than Fig. 4 (QuickTime; 3.3 MB).
- The movie file corresponding to Fig. 6 is available at our website (http://www.cmpt.phys.tohoku.ac.jp/~hondou/ref/movie3.mov). This movie shows the results of the simulation of the container model produced using a 2D-FDTD method. The red and white circles represent the radiation source and human model, respectively. The period of intensity oscillation at a fixed position corresponds to one-half the period of radiation, or 1/(2×1.2×109) s. The enhancement of intensity as well as hot spots can be observed as with the elevator model (QuickTime; 3 MB).
- A. Toropainen: Bioelectromagnetics 24 (2003) 63.
- A. Kramer, J. Frohlich and N. Kuster:
J. Phys. Soc. Jpn. 71 (2002) 3100[JPSJ].
- ELF Electromagnetic Fields Committee: Electromagnetic Fields: Annual Update 2003 (Health Council of the Netherlands, The Hague, 2004).
- T. Hondou:
J. Phys. Soc. Jpn. 71 (2002) 3101[JPSJ].
- http://www.cmpt.phys.tohoku.ac.jp/~hondou/ref/1.hfss. We have provided the project file for the HFSS simulation shown in Figs. 3 and 4. Any user of HFSS (version 9 and later) can verify the present result using the project file (MSWord; 184 KB).
- http://www.cmpt.phys.tohoku.ac.jp/~hondou/ref/2.hfss. We have provided the project file for the HFSS simulation shown in Fig. 5. Any user of HFSS (version 9 and later) can verify the present result using the project file (MSWord; 140 kB).
- Tissue dielectric properties are obtained by the resources at Federal Communications Commission, http://www.fcc.gov/fcc-bin/dielec.sh, where we use the values of “Skin (Dry)” at a frequency of 1.2 GHz.