SAR and Temperature Evaluations of a 900 Mhz TEM Chamber for Cell Exposure

2012 ◽  
Vol 195-196 ◽  
pp. 90-95
Author(s):  
Z. Ren ◽  
J.X. Zhao ◽  
H.M. Lu ◽  
J.N. Zhang ◽  
W. Wang
Keyword(s):  
Finite Difference ◽  
Temperature Rise ◽  
Finite Difference Time Domain ◽  
Maxwell Equations ◽  
Specific Absorption Rate ◽  
Cultured Cells ◽  
Petri Dish ◽  
Transverse Electromagnetic ◽  
Difference Time

A dosimetry study is made for experiments on cultured cells exposed to 900 MHz microwave in the transverse electromagnetic (TEM) chamber. The exposure is characterized by the intensity and homogeneity of the specific absorption rate (SAR), as well as the exposure-induced temperature rise. The SAR distribution is calculated by using the finite-difference time-domain (FDTD) algorithm of the Maxwell equations. The finite-difference formulation of the bioheat conduction equation is used to calculate the temperature rise of the in vitro environment. Evaluations of the SAR and temperature are performed systematically for scenarios including two formations of cultured cells, two maximum fields, and four polarizations of the Petri dish holding the cell culture. The exposure is optimized by selecting scenarios with the highest SAR intensity, the best SAR homogeneity, and the effective temperature control.

Dosimetry and Temperature Evaluation of TEM Chamber for Cell Exposure at 1800 MHz

2012 ◽  
Vol 195-196 ◽  
pp. 879-884
Author(s):  
W. Wang ◽  
J.X. Zhao ◽  
H.M. Lu ◽  
Z. Ren ◽  
J.N. Zhang
Keyword(s):  
Finite Difference ◽  
Temperature Rise ◽  
Cultured Cells ◽  
Thermal Environment ◽  
Fdtd Method ◽  
Petri Dish ◽  
Maximum Temperature ◽  
Absorbed Power ◽  
Transverse Electromagnetic ◽  
In Cells

Using the finite-difference time-domain (FDTD) method, we make a dosimetry study on the specific absorption rate (SAR) in cells exposed to 1800 MHz standing waves produced by the transverse electromagnetic (TEM) chamber. Two types of cultured cells are used, namely, the cell layer and the cell suspension. Based on the calculated SAR distribution, the exposure is characterized by the SAR intensity and homogeneity. We consider different exposure arrangements as the combination of the maximum fields of the standing wave and the polarizations of the Petri dish. The maximum E field and maximum H field are used in turn in the exposure volume, where the Petri dish is polarized in the E, H, k and k directions, respectively. The best exposure arrangements are determined by measuring the intensity and homogeneity of the SAR distribution in cells. For a tight control of the thermal environment, the temperature rise in the cell culture induced by the exposure is calculated by using the finite-difference formulation of the bio-heat conduction equation. The linear relation between the maximum temperature rise and the absorbed power is determined to quantify the exposure power for the temperature control.

scholarly journals A New Design of Metamaterials for SAR Reduction

2013 ◽  
Vol 13 (2) ◽  
pp. 70-74 ◽  
Author(s):  
M. R. I. Faruque ◽  
M. T. Islam ◽  
M. A. M. Ali
Keyword(s):  
Finite Difference ◽  
Time Domain ◽  
Finite Difference Time Domain ◽  
Absorption Rate ◽  
Specific Absorption Rate ◽  
Fdtd Method ◽  
Cellular Phone ◽  
Drude Model ◽  
Specific Absorption ◽  
Difference Time

The purpose of this paper is to calculate the reduction of specific absorption rate (SAR) with a new design of square metamaterials (SMMs). The finite-difference time-domain (FDTD) method with lossy-Drude model is adopted in this analysis. The method of SAR reduction is discussed and the effects of location, distance, and size of metamaterials are analyzed. SMMs have achieved a 53.06% reduction of the initial SAR value for the case of 10 gm SAR. These results put forward a guideline to select various types of metamaterials with the maximum SAR reducing effect for a cellular phone.

scholarly journals Computational Modeling of SAR and Heat Distribution in Lossy Medium at GSM Frequencies

2018 ◽  
Keyword(s):  
Spinal Cord ◽  
Finite Difference ◽  
Time Domain ◽  
Finite Difference Time Domain ◽  
Absorption Rate ◽  
Specific Absorption Rate ◽  
Spinal Cord Tissue ◽  
Specific Absorption ◽  
Lossy Medium ◽  
Difference Time

In recent years, institution has increased imposition of electromagnetic radiation in many applications. This radiation react with the human tissue and may lead to harmful and injurious effects on human health. However a finite difference thermal model of lossy medium as (spinal cord of human body) has been developed to calculate temperature rises generated in the spinal cord by radiation from cellular telephones with different frequencies. The natural metabolic heat production and the power density absorbed from the electromagnetic field have been evaluated. The specific absorption rate (SAR) was derived from a finite difference time domain model (FDTD) of the spinal cord. This is a numerical analysis is technique used for modeling computational electrodynamics. Aside from the specific absorption rate, through the exposure of radiation is an extremely important parameter while assessing the effects on spinal cord tissue. The heat distribution was calculated using the bioheat equation coupled with Maxwell's equation. A one dimensional finite difference time domain method has been used, some simulations for electromagnetic wave through the spinal cord tissue is made using software program. Also for the simulation, the dielectric properties supposed medium are directly taken by numerical program. Results show that electromagnetic fields penetrate the life tissues and attenuate fast to reach zero at large time steps. Specific absorption rate show maximum at the first boundary of tissue and becomes less value by using high frequency. The absorbent power and specific absorption rate show maximum at the interface of tissue, and the technique developed may be used to estimate temperature rises associated with specific absorption rate (SARs) for different types of radiation. Also, the results note that low-frequency waves have significantly affected the biological tissue.

Investigation of Hand Worn Jewellery Effects on the Specific Absorption Rate in the Human Head and Hand

2011 ◽  
Vol 110-116 ◽  
pp. 4559-4563
Author(s):  
Mohammad Islam Tariqul ◽  
Zainool Abidin Hafizah ◽  
Rashed Iqbal Faruque Mohammad ◽  
Misran Norbahiah
Keyword(s):  
Finite Difference ◽  
Mobile Device ◽  
Time Domain ◽  
Finite Difference Time Domain ◽  
Absorption Rate ◽  
Specific Absorption Rate ◽  
Fdtd Method ◽  
Human Head ◽  
Human Hand ◽  
Difference Time

The presence of hand could alter the energy absorbed in the human head. Hence, a study of the interaction between mobile device antennas and human head in the presence of metallic hand worn jewellery on human hand with different holding ways is investigated. A finite-difference time domain (FDTD) method has been performed by considering an internal PIFA antenna as the radiating source mounted at the top of a commercial clamshell phone positioned nearer the ear. With the introduction of hand-worn jewellery in variation parameters, there were perceptible effects on SAR variation in the human head. SAR distribution in the SAM head was found decreases due to different hand positions. Therefore, the head and in particular the hand may further impairment radiation performance of a mobile device.

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