Document Type : Original Paper
Ph.D. Student in Medical Physics, Tarbiat Modares University, Tehran, Iran
Associate Professor, Medical Physics Dept., Tarbiat Modares University, Tehran, Iran
M.Sc. Student in Biomedical Engineering (Bioelectric), Science and Research Campus, Islamic Azad University, Member of Young Researchers Club, Tehran, Iran
Professor, Physiology and Neuroscience Research Center, Shahid Beheshti Medical Sciences University, Tehran, Iran
Introduction: The use of mobile communication systems has dramatically increased over the past
decade. Although many studies have been performed to determine the effect of radio frequency (RF) but
less attention has been paid to the possible biological impact of exposure to extremely low frequency
The objective of this study is two folds. One is to design the equipments needed for the measurement of
the ELF fields of two types of GSM900 mobile phone. Secondly, use a protocol suitable for an accurate
assessment of the ELF fields.
Materials and Methods: First a home-made search coil was provided and calibrated precisely under
several experiments. Using Fast Fourier Transform, the power spectrum density of the induced voltage in
the search coil was analyzed and the amplitudes of 217 Hz and its harmonics were extracted and then the
distribution of magnetic field in the back side of mobile phones was determined.
Results: The values of B-field on the back side of the two kinds of GSM mobile phone were different.
They were between 50 to 160 µT in Nokia 3310 and 14 to 30 µT in Nokia 8310. Considering the
difference between the amplitudes of frequency components at 217 Hz and its harmonics in the two kinds
of mobile phone, a range of magnetic flux density at different times in a five day period was measured.
Discussion and Conclusion: These findings emphasize the need for considering the distribution of low
frequency magnetic field from mobile phone when biological effects of magnetic fields are studied. To
determine the intensity windowing effect, one must consider the physical characteristics of the
fundamental frequency component wave (217 Hz) and its harmonics produced by the mobile phone
similar to the one generated under a real situation.