Relatórios técnicos da Exposição à Radiação Proveniente de Antenas de Terminais Móveis
Electromagnetic Energy Exposure of Simulated Users of Portable Cellular Telephones
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.
Human Exposure to Radio Frequency and Microwave Radiation from Portable and Mobile Telephones and Other Wireless Communication Devices
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.
Institute of Electrical and Electronics Engineers (IEEE) Committee on Man and Radiation (COMAR)
Influência Mútua entre o Telefone Celular e a Cabeça Humana
Esta comunicação aborda o problema da influência mútua entre a antena de um telefone móvel e a cabeça humana. Depois de uma breve referência aos métodos usados para a obtenção de valores para as várias grandezas que caracterizam o problema, discute-se as duas perspetivas dessa influência, apresentando-se alguns resultados. Referem-se ainda os limites máximos permitidos para as potências emitidas pelos telefones, de acordo com os organismos internacionais.
Actas das III Jornadas Portuguesas de Protecção contra Radiações
Luis M. Correia
Sociedade Portuguesa de Protecção contra Radiações, Lisboa, Portugal
SAR Generated by Commercial Cellular Phones — Phone Modeling, Head Modeling, and Measurements
This paper presents the computation of the specific absorption rate (SAR) generated by cellular phones inside an anatomical model of a head. Four models of commercially available phones have been considered working at 900- and 1800-MHz bands (global system for mobile communication system). The phones have been modeled by using a computer-aided design representation obtained through the reverse engineering technique. Both SAR distributions and SAR averaged values have been computed inside the anatomical model of a head, by using the finite-difference time-domain method. Computations have been experimentally validated through measurements performed inside anthropomorphic phantoms irradiated by a dipole and cellular phones.
IEEE Transactions on Microwave Theory and Techniques
Andrea Schiavoni, Paola Bertotto, Gabriella Richiardi, Paolo Bielli
The Dependence of Electromagnetic Energy Absorption Upon Human Head Tissue Composition in the Frequency Range of 300-3000 MHz
The requirements for testing compliance of cellular phones with electromagnetic safety limits demand evaluation of the maximum exposure that may occur in the user group under normal operational conditions. Under these conditions, the tissues of the ear region are most exposed, the tissue composition of which is complex and varies considerably from user to user. The objective of this paper is to derive head tissue equivalent dielectric parameters that enable the utilization of one generic homogeneous head for testing compliance for the entire user group, i.e., granting no underestimation, but also not greatly overestimating the actual maximum user exposure. As a primary study, a simple analytical model of an infinite half-space layered tissue model exposed to a plane wave was utilized to investigate the impact of impedancematching standing waves, etc. on the spatial-peak specific absorption rate. The tissue layers were varied in composition and thickness, representing the anatomical variation of the exposed head region covering the user group including adults and children ( 10% to 90% percentile). Based on the worst-case tissue layer compositions with respect to absorption at each frequency, head tissue equivalent dielectric parameters for homogeneous modeling were derived, which result in the same spatial-peak absorption. The validity of this approach for near-field exposures was demonstrated by replacing the plane wave by different near-field sources (dipoles and generic phones) and the layered structure with magnetic-resonance-image-based nonhomogeneous human head models.
IEEE Transactions on Microwave Theory and Techniques