Sar and Thermal Effect Prediction in Human Head Exposed to Cell Phone Radiations (original) (raw)
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International Journal of Heat and Mass Transfer, 2012
This study presents a numerical analysis of specific absorption rate (SAR) and temperature distributions in the realistic human head model exposed to mobile phone radiation at 900 MHz and 1800 MHz. In the realistic human head model, the effects of operating frequency and gap distance between the mobile phone and the human head on distributions of specific absorption rate and temperature profile within the human head are systematically investigated. This study focuses attention on each tissue in the human head in order to investigate the effects of mobile phone radiation on the human head. The SAR and the temperature distribution in various tissues in human head during exposed to mobile phone radiation, obtained by numerical solution of electromagnetic wave propagation and unsteady bioheat transfer equations, are presented. For both frequencies, the highest SAR values are obtained in the region of the skin near the antenna. It is found that the highest SAR values are 0.823 W/kg and 1.187 W/kg for the frequencies of 900 MHz and 1800 MHz, respectively. The SAR values obtained from this study are well below ICNIRP limit for all cases. In addition, it is found that the temperature distributions are not directly proportional to the local SAR values. Moreover, the experimental validation has been carried out by using the infrared camera in order to complement the simulation results.
Study of Thermal Interaction of Cell-Phone Radiations Within Human Head Tissues
Asian Journal of Pharmaceutical and Clinical Research
In the present investigation, a theoretical model based on Maxwell equations, microscopic form of ohm’s law and Joules law of heating effect is proposed for the study of penetration depth, attenuation coefficient and specific absorption rate (SAR) with varying distance between the source of radiation and exposed human head tissues (skin, fat, brain and bone). In addition, corresponding temperature increase inside these various human head tissues is also calculated. Results of present study indicate that the temperature rise in human tissue depends upon specific absorption rate and the duration for which human body is actually exposed to GSM radiations. By assuming the distance of 1cm and exposure time of 5 minutes, the highest SAR was estimated to be 1681.7 W/Kg for the brain tissue at 900 MHz and 4038.5 W/Kg for 1800 MHz. Maximum skin depth and attenuation coefficient was found to be in the case of fat and brain tissue, respectively amongst rest head tissues. The corresponding hig...
PIERS Online, 2006
Since the 1990's, use of mobile phones has augmented worldwide generating a public concern as to whether frequent utilization of such devices is unsafe. This provoked EMF researchers to find suitable techniques of assessing radiation blueprint and exposure hazards if any. Most research groups focused on two techniques: experimental measurements and finite-difference time-domain (FDTD) computations. Computation of the specific absorption rate (SAR) generated by cellular phones inside two models of the human head is presented in this paper. Two models of mobile phones were considered working at 900 and 1800 MHz bands according to the Global System for Mobile Communication. Radiated energy distributions and averaged SAR values in 1 g and 10 g of tissue were computed inside the models of head using FDTD. Computations were compared with a realistic head model constructed with the MRI scans. The distribution of the local SAR in the head was similar to that of the simplified head models. The maximum local SAR calculated was 53.43 W/kg and the maximum SAR(10 g) was 2.96 W/kg, both for 1 W output power from the antenna. The results indicated the area of the maximum local SAR was situated in outer layer of skull, where muscle and skin were. The important parameters in absorbed energy in the head were the type of antenna, current distribution and the distance between head and antenna. The head models used for simulation proved as insignificant parameter in the calculations.
Scientific Research …, 2011
The bioheat equation is solved for an anatomically based model of the human head with a resolution of 2.5 × 2.5 × 2.5 mm to study the thermal implications of exposure to electromagnetic (EM) fields typical of cellular telephones at 900 MHz. Attention has first been posed on a particular phone model, and a comparison between the absorbed power distribution and steady-state temperature increases has been carried out. The antenna output power was set to be consistent with the portable telephones of 600 mW, maximum SAR values, averaged over 1 gm, from 2.1 to 3.6 W/kg depending on the considered phone. The maximum temperature increases are obtained in the ear and vary from 0.22°C to 0.39°C, while the maximum temperature increases in the brain lie from 0.07°C to 0.17°C. These steady-state temperature increases are obtained after about 48 min of exposure, with a time constant of approximately 6 min. Application of the ANSI/IEEE safety guidelines restricting the 1 gm averaged spatial peak SAR to 1.6 W/kg results in the maximum temperature rise in the brain from 0.07°C to 0.15°C at 900 MHz. Finally, considerations about the exposure limits in the considered studied frequency are made.
SAR assessment in a human head model exposed to radiation from mobile phone using FEM
IEEE International Symposium on Electromagnetic Compatibility
It is important to be able to quantib both the absorption of electromagnetic energp in the human body and the resulting thermal effect. In this study, the specific absorption rate (SAR) of electromagnetic radiation /+om mobile phones on the human head was investigated As if is not possible to perform the experiments on human in vivo, the human head and the antenna radiated in 900 MHz were simulated. In this study, the spherical model as single layer and three layers was simulated by using Agilent High Frequency Sfructure Simulator, which employs the finite element method (FEW, and the EMpower absorption rate of tissue was calculated by a C++ program. The results were compared with the results of the sfudies in the literalure and a good agreement was obtained. To evaluate the efticiency of the method, a rat head was simulated and the results were compared with the experimental results obtained @om the in vivo experiments conducted on the rats.
University of Colorado Colorado Springs, 2017
Health and science have reached a point of intersection which has never existed before. With the recent rapid increase in the use of cellular phones and long periods of usage of these devices near the human body, public concern regarding potential health hazards due to the absorption of electromagnetic energy has been growing. To address these issues, this research evaluates the average Specific Absorption Rate in different human tissues by varying source to antenna distance and radiated power using the ANSYS 3D human body model. The Pennes bioheat transfer equation was solved analytically to calculate the longtime exposure effect and temperature rise. The results show that regardless of the frequency if the antenna radiated power is low (less than 125 mW), temperature increase within the human tissues is low; how-ever if the antenna operates at high radiated power (1 W), temperature tends to increase eight and a half times.
Specific absorption rate and temperature increases in the head of a cellular-phone user
IEEE Transactions on Microwave Theory and Techniques, 2000
In this paper, a complete electromagnetic and thermal analysis has been performed considering the head of a subject exposed to various kinds of cellular phones available on the market, and focusing the attention on important organs like the eye lens and brain. Attention has first been posed on a particular phone model, and a comparison between the absorbed power distribution and steady-state temperature increases has been carried out. The influence of different antennas (dipole, monopole, whip, and planar inverted F antenna) on the power absorption and on the consequent tissue heating has then been analyzed. The obtained results show, for a radiated power of 600 mW, maximum SAR values, averaged over 1 g, from 2.2 to 3.7 W/kg depending on the considered phone. The maximum temperature increases are obtained in the ear and vary from 0.22 C to 0.43 C, while the maximum temperature increases in the brain lie from 0.08 C to 0.19 C. These steady-state temperature increases are obtained after about 50 min of exposure, with a time constant of approximately 6 min. Finally, the results evidence a maximum temperature increase in the external part of the brain from 0.10 C to 0.16 C for every 1 W/kg of SAR, averaged over 1 g of brain tissue.
Today, cell phone technology is an integral part of everyday life and its use is not only restricted to voice conversations but also conveying news, high resolution pictures and internet. As the number of mobile phone usage increased exponentially nowadays, issues related to the electromagnetic radiation produce by mobile phone is becoming a big concern in the society. Mobile phone produced electromagnetic waves and when placed near the ear skull, will produce electromagnetic radiation so called thermal effect. The transfer of electromagnetic field to the body producing thermal effect leads to heating of body tissue at specific rate. This effect is differ depending on the period of time the mobile phone being used and type of mobile phone. This paper discussed on the result of thermal distribution generated by handheld mobile phone towards human head via collection of image from thermal imaging camera. The analysis is conducted in an anechoic chamber with average of 45 minutes talking hour with two different types of mobile phone, internal and external antenna serving different radio frequency range, 900 MHz and 1800 MHz. The results showed an increased of heat especially at the place near the ear skull after 45 minutes of operation. When comparing both different types of mobile phone, mobile phone with external antenna produce more heat compared to mobile phone with internal antenna. Key words: Electromagnetic Radiation of 900 MHz and 1800 MHz Frequencies , Handheld Device, Thermal Effect, Non Thermal Effect
The Environmentalist, 2005
The aim of this work is to examine the differences in power absorption in the brain of adults and children exposed to the radiation of mobile phone terminals at 1710 MHz. To this end, simulations using the Finite-Difference Time-Domain (FDTD) method have been carried out to study the interaction between heterogeneous anatomically correct models of the human head and a linear or helical monopole mounted on the top of a metal box representing a realistic mobile communication terminal. The study includes computations of specific absorption rates (SARs) inside the human head and the total power absorbed by the head. Emphasis is placed on the comparative assessment of power absorption characteristics in heads of adults and children as well as on the effect of various parameters such as the age-related changes in dielectric properties and the usage distance between the user's head and the mobile terminal.