Electrical energy absorption in the human head from a cellular telephone

Journal ArticleThe antenna of a cellular telephone in close proximity to the human head for a variety of time periods raises questions. This research uses finite-difference time-domain (FDTD) method to calculate the power deposition from a cellular telephone on a high-resolution model of a human head as measured by the specific absorption rates (SAR) in W/kg. Visualization has been used to verify the modeling for simulation, assisted in analyzing the data and understanding the physical aspects controlling the power absorption

Calculation of SAR and Measurement of Temperature Change of Human Head Due To The Mobile Phone Waves At Frequencies 900 MHz and 1800 MHz

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 Effec

Electromagnetic absorption in the human head and neck for mobile telephones at 835 and 1900 MHz

Journal ArticleWe have used the finite-difference time-domain method and a new millimeter-resolution anatomically based model of the human to study electromagnetic energy coupled to the head due to mobile telephones at 835 and 1900 MHz. Assuming reduced dimensions characteristic of today's mobile telephones, we have obtained SAR distributions for two different lengths of monopole antennas of lengths λ / 4 and 3λ/8 for a model of the adult male and reduced-scale models of 10- and 5-year-old children and find that peak one-voxel and 1-g SAR's are larger for the smaller models of children, particularly at 835 MHz. Also, a larger in-depth penetration of absorbed energy for these smaller models is obtained. We have also studied the effect of using the widely disparate tissue properties reported in the literature and of using homogeneous instead of the anatomically realistic heterogeneous models on the SAR distributions. Homogeneous models are shown to grossly overestimate both the peak 1-voxel and 1-g SAR's. Last, we show that it is possible to use truncated one-half or one-third models of the human head with negligible errors in the calculated SAR distributions. This simplification will allow considerable savings in computer memory and computation times

Measurement Analysis of Specific Absorption Rate in Human Body Exposed to a Base Station Antenna by Using Finite Difference Time Domain Techniques

The system analysis of specific absorption rate (SAR) in human body exposed to a base station antenna by using finite difference time domain techniques was presented in this research works. The objectives of this work are to evaluate the knowledge and awareness about SAR among human body and mobile base station. The paper investigates the electromagnetic wave absorption inside a human body. The human body has been identified using dataset based on 2D object considering different electrical parameters.The SAR convinced inside the human body model exposed to a radiating base station antenna (BSA) has been considered for multiple numbers of carrier frequencies and input power of 20 W/carrier at GSM 900 band.The distance (R) of human body from BSA is varied in the range of 0.1 m to 5.0 m. For the number of carrier frequency equal to one and R = 0.1 m,the concentrated value of whole-body average SAR obtained by FDTD technique is found to be 0.68 W/kg which decreases either with increase of R or decrease of number of carrier frequencies. Safety distance for general public is found to be 1.5 m for number of carrier frequencies equal to one.The performance accuracy of this analysis meets the high level condition by comparing with the relevant system development in recent time

Uncommon ossicle in Holothuria (Mertensiothuria) leucospilota from Teluk Nipah, Pangkor Island

The high popularity of a commercial sea cucumber species on Pangkor Island (i.e. Stichopus horrens) has resulted in a lack of studies on Holothuria (Mertensiothuria) leucospilota from Pangkor Island, Perak, Malaysia. S. horrens is the main ingredient of gamat-based traditional medicine on the resort island, while H. leucospilota is the most dominant species. For that reason, this study aimed to isolate ossicles from a specimen of morphospecies H. leucospilota collected from Teluk Nipah Beach, Pangkor Island; and to determine the shapes of the ossicles for species verification. A number of six ossicle shapes were observed. Beside buttons and tables as the common ossicle shapes; I-shaped rod, long I-shaped rod, branched rod, and spider-shaped rod were also documented. Nonetheless, the spider-shaped rod is an unusual ossicle shape in H. leucospilota as there was no previous record on it, thus it could be considered as a new finding. In summary, the results of this research indicate the uniqueness of the specimen of morphospecies H. leucospilota as a result of the presence of the spider-shaped rod. More studies with more samples, more morphological approaches as well as more molecular techniques need to be incorporated in future for a better insight

State of the science regarding RF dosimetry, measurement and certification

Journal ArticleCellular telephones and wireless personal communication systems (PCS) are being introduced into society at a very rapid rate. Whereas the present-day cellular telephones in the United States operate at midband transmission frequencies of about 835 MHz (about 900 MHz in Europe), higher frequencies on the order of 1900 MHz (1800 MHz in Europe) are to be used for the PCS systems, including mobile telephones, wireless local area networks, pagers, personal health monitoring systems, global positioning systems, etc. This has resulted in public concern about the health hazards of radiofrequency (RF) electromagnetic fields that are emitted by these devices. To allay public concerns, the Federal Communications Commission (FCC) in the United States has decided to require compliance with the ANSI/IEEE RF safety guidelines (American National Standards Institute/Institute of Electrical and Electronics Engineers [ANSI/IEEE], 1992) for uncontrolled environments for all personal wireless devices that use more than 100 mW of time-averaged input power to the antenna

Effect of Magnetic Field From Mobile Phone on Brain

Human exposure to electromagnetic field (EMF) comes from many different sources and occurs in various situations in everyday life. Man-made static fields are mainly found in occupational settings, such as close to magnetic resonance imaging (MRI) scanners, although DC high-voltage overhead transmission lines are being constructed, which are expected to expose larger parts of the population to static electric and magnetic fields.Today, for power regulation most modern electrical equipment uses electronics instead of transformers. Examples include the switched power supplies to laptops, drilling tools, chargers of mobile phones and similar devices. As a consequence, the frequency content of the daily magnetic field exposure has changed mainly by adding odd harmonics (150 Hz, 250 Hz, 750 Hz, etc.). In particular, the third harmonic (150 Hz) has become another dominating frequency in our environment.In particular for brain tissues, the mobile phone used at the ear remains the main source of exposure. However, since the first generation of mobile telephony, the technology aimed at reducing the emitted power of mobile handsets. In particular, for Global System for Mobile communication (GSM) already the introduction of dynamic power control reduced the average output power to about 50% of its rated value during calls, whereas the use of discontinuous transmission during voice calls gave a further 30% reduction in average emitted power. Adaptive power control became faster and more effective in the third-generation (3G) of mobile telephony systems leading to a further reduction (by about two orders of magnitude) in the specific absorption Specific energy Absorption Rate (SAR) compared to GSM phones. In addition, hands-free kits reduce the energy absorbed by the head drastically. Digital Enhanced Cordless Telecommunications (DECT) phones are another source of everyday exposure

Workgroup Report: Base Stations and Wireless Networks—Radiofrequency (RF) Exposures and Health Consequences

Radiofrequency (RF) waves have long been used for different types of information exchange via the airwaves—wireless Morse code, radio, television, and wireless telephony (i.e., construction and operation of telephones or telephonic systems). Increasingly larger numbers of people rely on mobile telephone technology, and health concerns about the associated RF exposure have been raised, particularly because the mobile phone handset operates in close proximity to the human body, and also because large numbers of base station antennas are required to provide widespread availability of service to large populations. The World Health Organization convened an expert workshop to discuss the current state of cellular-telephone health issues, and this article brings together several of the key points that were addressed. The possibility of RF health effects has been investigated in epidemiology studies of cellular telephone users and workers in RF occupations, in experiments with animals exposed to cell-phone RF, and via biophysical consideration of cell-phone RF electric-field intensity and the effect of RF modulation schemes. As summarized here, these separate avenues of scientific investigation provide little support for adverse health effects arising from RF exposure at levels below current international standards. Moreover, radio and television broadcast waves have exposed populations to RF for > 50 years with little evidence of deleterious health consequences. Despite unavoidable uncertainty, current scientific data are consistent with the conclusion that public exposures to permissible RF levels from mobile telephony and base stations are not likely to adversely affect human health

MEASUREMENT AND ANALYSIS OF RADIO FREQUENCY ENERGY AND SPECIFIC ABSORPTION RATE FROM GLOBAL SYSTEM FOR MOBILE COMMUNICATIONS IN FUNAAB, OGUN STATE, NIGERIA

This work measured and analyzed the Radio Frequency (RF) power densities to determine the absorption rate on human body from the four available 900 MHz Global System for Mobile communication (GSM) base stations, at some selected points in the Federal University of Agriculture, Abeokuta (FUNAAB), Nigeria.ª¤? Measurements were conducted using Frequency-selective spectrum analyzer (Nokia 6800 Network Drive Tester) to determine the RF Power Densities (S), Electric Field Intensities (E) and the Specific Absorption Rates (SAR), using Airtel Base station as reference sample point. Standard Units values of the measured variables were obtained using standard mathematics equations. Out of ten (10) selected sampling points the maximum RF exposure was obtained at COLENG upstairs with its the power density equal 15.2 ª¤?W/m2 which is 3.7 x 10-4% of the maximum allowable value of the maximum exposure at 900 MHz. The recorded highest electric field intensities was 75.7 x 10-3 V/m, which is 0.18% of that specified by the International Commission on Non-Ionizing Radiation Protection (ICNIRP) maximum public exposure levels for 900 MHz. The highest obtained SAR value was 4.2635 x 10-3 W/kg which is 5.329% of the maximum recommended exposure level for the head region and brain tissue at 900 MHz. The results from this study are useful sources of environmental information and database to the FUNAAB communityª¤

Threshold Power of Canonical Antennas for Inducing SAR at Compliance Limits in the 300-3000 MHz Frequency Range

A study of the specific absorption rate (SAR) in an exposed body induced by canonical antennas is presented, with the aim of determining an upper bound for the antenna transmit power that demonstrates that a product is inherently compliant with internationally accepted radio frequency (RF) exposure limits. Starting from the fundamental limits in antenna quality factor (Q) and the corresponding bandwidth, several antenna sizes are selected, and their SAR distributions are computed using the method of moments (MoM) and finite-difference time domain (FDTD) method in the frequency range 300-3000 MHz. The threshold powers are then determined, below which the peak 1-g and 10-g averaged SAR would not exceed the limits specified in international exposure standards. From the data, simple expressions are derived to estimate the threshold power over a wide range of antenna sizes, frequencies, and distances from the body. It is demonstrated that the results presented in this paper are conservative in comparison with the measured SAR data of real products as well as other published data