Generation of Standard EM Fields Using TEM Transmission Cells

Crawford, M. L.

doi:10.1109/temc.1974.303364

Cited by 437 publications

(164 citation statements)

References 2 publications

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“…The propagation distance from the source to the load is two wavelengths to build a standing wave with 4 loops. The transversal dimensions of the rectangular section are calculated to hold the Petri dish in the area of quasi-uniform exposure and to avoid the excitation of TE 10 and other higher-order modes [15]. The source and load are added to both ends of the TEM cell.…”

Section: Exposure Setupmentioning

confidence: 99%

DOSIMETRY AND TEMPERATURE EVALUATIONS OF A 1800 MHz TEM CELL FOR IN VITRO EXPOSURE WITH STANDING WAVES

Zhao¹,

Lü²,

Deng³

2012

PIER

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Abstract-A 1800 MHz transverse electromagnetic wave (TEM) cell is introduced for experiments investigating effects on biological samples caused by the exposure from mobile communications. To characterize and quantify the exposure environment in the setup for standardized in vitro experiments, we evaluate the dosimetry and the exposureinduced temperature rise in cultured cells. The study is numerically based on the finite-difference time-domain (FDTD) formulation of the Maxwell equations and the finite-difference formulation of the bioheat transfer equation, with all algorithms and models strictly validated for accuracy. Two sample formations of cells are considered including the cell layer and the cell suspension cultured in the 35 mm Petri dish. The TEM cell is designed to establish standing waves with the maximum E field and the maximum H field, respectively, at the position of the Petri dish. The Petri dish is oriented to E, −E, H, k, and −k directions of the incident field, respectively, to receive the exposure. The specific absorption rate (SAR) is calculated in cells for 10 exposure arrangements combined from the maximum fields and Petri dish orientations. A comparison determines the best arrangement with the highest exposure efficiency and the lowest exposure heterogeneity. The dosimetry and the exposure-induced temperature rise in cells are evaluated for the selected arrangement. To avoid thermal reactions caused by overheating, the maximum temperature rises in cells are recorded during the exposure. Based on the records, the temperature control is performed by setting limits to the exposure duration. We introduce a method to further reduce the exposure heterogeneity and evaluate the influence of the Petri dish holder on the dosimetry and temperature rise. The study compares the TEM cell to the waveguide, as well as the standing wave exposure 488Zhao, Lu, and Deng to the propagating wave exposure. The TEM cell and the selected arrangement of the standing wave exposure improve the exposure quality over the traditional methods, with increased efficiency and decreased heterogeneity of the exposure.

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Section: Exposure Setupmentioning

confidence: 99%

DOSIMETRY AND TEMPERATURE EVALUATIONS OF A 1800 MHz TEM CELL FOR IN VITRO EXPOSURE WITH STANDING WAVES

Zhao¹,

Lü²,

Deng³

2012

PIER

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“…These TEM-cells have been designed by dimensional scaling from previously constructed cells at the National Bureau of Standards [6], which are known to generate uniform TEM-fields for standard measurements. The experimental setup has been described in detail in the first part of the present long term study that reported on cognitive effect after repeated exposure [17].…”

Section: Gsm Exposurementioning

confidence: 99%

Histopathological examinations of rat brains after long-term exposure to GSM-900 mobile phone radiation

Grafström

Nittby

Brun

et al. 2008

Brain Research Bulletin

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2 AbstractIn order to mimic the real life situation, with often life-long exposure to the electromagnetic fields emitted by mobile phones, we have investigated in a rat model the effects of repeated exposures under a long period to Global System for Mobile Communication-900 MHz (GSM-900) radiation. Out of a total of 56 rats, 32 were exposed once weekly in a two hours period, for totally 55 weeks, at different specific absorption rates (SAR) (of in average 0.6 and 60 mW/kg at the initiation of the experimental period). The animals were exposed in a transverse electromagnetic transmission line chamber (TEM-cell) to radiation emitted by a GSM-900 test phone. Sixteen animals were sham exposed and eight animals were cage controls, which never left the animal house. After behavioural tests, 5-7 weeks after the last exposure, the brains were evaluated for histopathological alterations such as albumin extravasation, dark neurons, lipofuscin aggregation and signs of cytoskeletal and neuritic neuronal changes of the type seen in human ageing. In this study, no significant alteration of any these histopathological paramteters was found, when comparing the GSM exposed animals to the sham exposed controls.

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“…The TEM cell produces highly accurate, uniform electromagnetic fields and may be used as a standard facility for calibrating radiofrequency field strength meters (6). During irradiation, the rats were housed separately in cylindrical Plexiglas cages (20 cm long and 10 cm in diameter) perforated with 12-mm holes.…”

Section: Aninzalsmentioning

confidence: 99%

Absence of embryotoxic effects from low-level (nonthermal) exposure of rats to 100 MHz radiofrequency radiation.

Lary¹,

Conover²,

Johnson³

1983

Scand J Work Environ Health

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LARY JM, CONOVER DL, JOHNSON PH. Absence of embryotoxic effects from lowlevel (nonthermal) exposure of rats to 100 MHz radiofrequency radiation. Scand j work environ health 9 (1983) 120-127. Pregnant Sprague-Dawley rats were exposed to radiofrequency radiation at a frequency of 100 MHz and a power density of 25 mW/cmz for 6 h 40 min daily on gestation days 6-11.The total exposure time was 40 h. The exposure resulted in a specific absorption rate of 0.4 Wlkg. This value corresponds to the maximum permissible level for specific absorption rate in the 1982 American National Standards Institute (ANSI) standard for radiofrequency/microwave exposure. The exposure produced no increase in maternal colonic temperature. Irradiated rats did not differ from sham-irradiated rats with respect to the number of implantations per litter, percentage of implantations dead or resorbed, percentage of fetuses malformed, fetal weight, fetal crown-rump length, or fetal sex ratio. The irradiated fetuses had fewer minor skeletal variations than the controls. These results suggest that radiofrequency/microwave radiation is not teratogenic or embryotoxic for rats at the maximum permissible exposure level of the 1982 ANSI standard.

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Generation of Standard EM Fields Using TEM Transmission Cells

Cited by 437 publications

References 2 publications

DOSIMETRY AND TEMPERATURE EVALUATIONS OF A 1800 MHz TEM CELL FOR IN VITRO EXPOSURE WITH STANDING WAVES

DOSIMETRY AND TEMPERATURE EVALUATIONS OF A 1800 MHz TEM CELL FOR IN VITRO EXPOSURE WITH STANDING WAVES

Histopathological examinations of rat brains after long-term exposure to GSM-900 mobile phone radiation

Absence of embryotoxic effects from low-level (nonthermal) exposure of rats to 100 MHz radiofrequency radiation.

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