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Título An Automated SAR Measurement System for Compliance Testing of Personal Wireless Devices
Resumo An automated specific absorption rate (SAR) measurement system has been developed for compliance testing of personal wireless devices. Unlike other systems, this system uses a model with a lossy ear-shaped protrusion and the accuracy of this experimental setup has been checked by comparing the peak 1-g SAR’s for ten cellular telephones, five each at 835 and 1900 MHz, with the results obtained using a 15-tissue anatomically based model with the finite-difference time-domain (FDTD) numerical electromagnetic technique. The SAR measurement system uses a three-dimensional (3-D) stepper motor to move a Narda Model 8021 E-field probe to measure the SAR distribution inside a headshaped tissue-simulant phantom near the radiating device. The head and neck part of the model with an ear-shaped protrusion of 3 mm thickness is made of a lossy outer shell of 5–7 mm thickness of epoxy laced with KCl solution. The phantom is filled with appropriate frequency-specific fluids with measured electrical properties (dielectric constant and conductivity) that are close to the average for gray and white matters of the brain at the center frequencies of interest (835 and 1900 MHz). The implantable E-field probe is calibrated using the FDTD calculated SAR variations for a slab model at two commonly used frequencies, 835 and 1900 MHz and is checked to have good isotropic characteristics (+/- 0.23 dB) and a wide dynamic range (0.01–10 W/kg). The system is validated using a 223 mm diameter sphere model. Peak 1-g SAR’s for ten telephones using different antennas are within +/-1 dB of those obtained using the FDTD numerical method for the anatomical model of the head and neck region.
Fonte IEEE Transaction on Electromagnetic Compatibility
Origem Internacional
Autor/Editor Qishan Yu, Om P. Gandhi, Magnus Aronsson, and Ding Wu
Disponibilidade Disponível por encomenda
Link ieeexplore.ieee.org
Referência vol. 41, no. 3, pp. 234-245
Data Agosto 1999
Título Automated E-field Scanning System for Dosimetric Assessments
Resumo The interest in accurate dosimetric measurements inside phantoms that simulate biological bodies has burgeoned since several regulatory commissions began calling for or recommending the testing for compliance with safety standards of low power devices. This paper presents a newly developed, robot-based system that allows automated E-field scanning in tissue simulating solutions. The distinguishing characteristics of the system are its high sensitivity and its broad dynamic range (1 uW/g to 100 mW/g) over the entire frequency range (10 MHz to over 3 GHz) used for mobile communications. The reproducibility of the dosimetric evaluations has been shown to be considerably better than +/- 5%. This has been accomplished by the use of an improved isotropic E-field probe connected to amplifiers with extremely low noise and drift characteristics in conjunction with digital processing of data. Special emphazis has been placed on system reliability, user-friendliness and graphic visualization of data.
Fonte IEEE Transactions on Microwave Theory and Techniques
Origem Internacional
Autor/Editor Thomas Schmid, Oliver Egger, Niels Kuster
Disponibilidade Disponível por encomenda
Link ieeexplore.ieee.org
Referência vol. 44, no. 1, pp. 105-113
Data Janeiro 1996
Título Electromagnetic Energy Exposure of Simulated Users of Portable Cellular Telephones
Resumo This paper describes a method to quantify the RF exposure of the users of portable cellular phones in terms of Specific Absorption Rate (SAR). The method involves a robotic system to accurately position an isotropic E-field probe within equivalent biological tissue. The user of cellular phones is simulated by a simple human model (a phantom) consisting of a thin shell of fiberglass filled with a liquid having the complex dielectric constant of human brain tissue. The paper presents the results of the dosimetric assays conducted using current and previous models of cellular telephones. The peak SAR values detected using the measurement method described herein are below the limits recommended by the National Council for Radiation Protection and Measurements (NCRP) Report 86 for the protection of humans exposed to RF electromagnetic energy.
Fonte IEEE Transactions on Vehicular Technology
Origem Internacional
Autor/Editor Quirino Balzano, Oscar Garay, Thomas J. Manning
Disponibilidade Disponível por encomenda
Link ieeexplore.ieee.org
Referência vol. 44, no. 3, pp. 309-403
Data Agosto 1995
Título Guide to the Expression of Uncertainty in Measurements
Resumo When reporting the result of a measurement of a physical quantity, some quantitative indication of the result has to be given to assess its reliability and to allow comparisons to be made. The Guide to the expression of uncertainty in measurement establishes general rules for evaluating and expressing uncertainty in measurement that can be followed at many levels of accuracy and in many fields.
Fonte International Electrotechnical Commission (IEC) / International Organization for Standardization (isso)
Origem Internacional
Autor/Editor ISO/IEC
Disponibilidade Disponível por encomenda
Link iso.org
Referência ISO/IEC Guide 98-3:2008
Data Outubro 2008
Título Human Exposure to Radio Frequency and Microwave Radiation from Portable and Mobile Telephones and Other Wireless Communication Devices
Resumo The Institute of Electrical and Electronics Engineers (IEEE) Committee on Man and Radiation (COMAR) recognises that there is public concern about the safety of exposure to the radio frequency (RF) and microwave (MW) fields from hand-held, portable, and mobile cellular telephones. This report addresses the concerns that have been expressed by some members of the public about the safety of exposure to RF radiation from handheld communications devices, with particular reference to cellular telephone handsets. It gives information about RF Safety Standards and Guidelines, Exposures Produced by Cellular Telephones, Interference to Medical Devices. Some conclusions are drawn.
Fonte Institute of Electrical and Electronics Engineers (IEEE) Committee on Man and Radiation (COMAR)
Origem Estados Unidos da América
Autor/Editor IEEE COMAR
Disponibilidade Disponível online
Link Documento online
Referência
Data Setembro 2000
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