Specific absorption rate in human fetus with fetal growth for RF far-field exposure

The article presents the investigation results of the electromagnetic field biological effects on adrenal glands functional activity in the rats. The electromagnetic field exposure levels were typical electromagnetic fields of portable radios (walkie-talkies). Experiments were carried out on laboratory male rats. Experimental groups were exposured in a transverse electromagnetic wave cell - TEM cell. Sham animal groups were in similar conditions, but without electromagnetic field exposure. The exposure of experimental animals was carried out in three series (12 rats for each group) for three levels of the electric field strength such as 15; 25 and 35 V/m. Gluco-corticoid and mineral-corticoids adrenal functions were assessed by determining the corticosterone and of Na+ and K+ levels in daily urinary excretion. The animal specific absorption rate evaluations were calculated by using the program SEMCAD X v.14 and experimentally in the TEM cell. The dependences of the excretion of corticosterone and electrolytes on the specific absorption rate and exposure time, which indicate that for small values of electromagnetic energy absorption is stimulation of the adrenal glands functional activity, alternating with depression by specific absorption rate increasing.

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Improved Handset Antenna Performance via an Electrically Extended Ground Plane

ISRN Communications and Networking ◽

10.5402/2012/621526 ◽

2012 ◽

Vol 2012 ◽

pp. 1-7 ◽

Cited By ~ 1

Author(s):

Shirook M. Ali ◽

Huanhuan Gu ◽

Kelce Wilson ◽

James Warden

Keyword(s):

Absorption Rate ◽

Specific Absorption Rate ◽

Near Field ◽

Ground Plane ◽

Practical Approach ◽

Far Field ◽

Specific Absorption ◽

Antenna Performance ◽

Field Patterns ◽

Surface Metal

A novel and practical approach is presented providing improved antenna performance without enlarging the antenna or the ground plane. The approach electrically extends the ground plane using wire(s) that behave as surface metal extensions of the ground plane. The wire extensions can be accommodated within typical handset housing or as part of the stylish metal used on the handset’s exterior perimeter; hence don’t require enlargement of the device. Consequently, this approach avoids the costs and limitations traditionally associated with physically lengthening of a ground plane. Eight variations are presented and compared with baseline antenna performance. Both far-field patterns and near-field electromagnetic scans demonstrate that the proposed approach controls the electrical length of the ground plane and hence its chassis wavemodes, without negatively impacting the characteristics of the antenna. Improvements in performance of up to 56% in bandwidth at 900 MHz and up to 12% in efficiency with a reduction of up to 12% in the specific absorption rate (SAR) are achieved. An 8% increase in efficiency with a 1.3% improvement in bandwidth and a 20% reduction in SAR is achieved at 1880 MHz. Thus, improvements in bandwidth are achieved without compromising efficiency. Further, improvements at lower frequencies do not compromise performance at higher frequencies.

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Effects of frequency, permittivity, and voxel size on predicted specific absorption rate values in biological tissue during electromagnetic-field exposure

IEEE Transactions on Microwave Theory and Techniques ◽

10.1109/22.884194 ◽

2000 ◽

Vol 48 (11) ◽

pp. 2050-2058 ◽

Cited By ~ 42

Author(s):

J.M. Ziriax ◽

K.I. Smith ◽

D.A. Nelson ◽

K.L. Ryan ◽

P. Gajsek ◽

...

Keyword(s):

Electromagnetic Field ◽

Biological Tissue ◽

Absorption Rate ◽

Specific Absorption Rate ◽

Field Exposure ◽

Voxel Size ◽

Specific Absorption

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EVALUATION OF SPECIFIC ABSORPTION RATE IN THE FAR-FIELD, NEAR-TO-FAR FIELD AND NEAR-FIELD REGIONS FOR INTEGRATIVE RADIOFREQUENCY EXPOSURE ASSESSMENT

Radiation Protection Dosimetry ◽

10.1093/rpd/ncaa127 ◽

2020 ◽

Vol 190 (4) ◽

pp. 459-472 ◽

Cited By ~ 3

Author(s):

Ilaria Liorni ◽

Myles Capstick ◽

Luuk van Wel ◽

Joe Wiart ◽

Wout Joseph ◽

...

Keyword(s):

Large Scale ◽

Absorption Rate ◽

Specific Absorption Rate ◽

Numerical Study ◽

Whole Body ◽

Single Frequency ◽

Far Field ◽

Specific Absorption ◽

Rf Systems ◽

Body Tissues

Abstract The specific absorption rate (SAR) induced by wireless radiofrequency (RF) systems depends on different parameters. Previously, SAR was mainly assessed under conditions of a single frequency and technology and for a limited number of localized RF sources. The current and emerging mobile systems involve a wider range of usage scenarios and are frequently used simultaneously, leading to combined exposures for which almost no exposure evaluation exists. The aim and novelty of this study is to close this gap of knowledge by developing new methods to rapidly evaluate the SAR induced by RF systems in such scenarios at frequencies from 50 MHz to 5.5 GHz. To this aim, analytical methods for SAR estimation in several usage scenarios were derived through a large-scale numerical study. These include subject-specific characteristics, properties of the RF systems and provide an estimation of the SAR in the whole body, tissues and organs, and different brain regions.

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