Effects of electromagnetic absorption toward a human head due to variation of its dielectric properties at 900 and 1900 MHz with different antenna substrates

2012 ◽  
Vol 19 (3) ◽  
pp. 271-277 ◽  
Author(s):  
Nur Aisyah Husni ◽  
Mohammad Rashed Iqbal Faruque ◽  
Mohammad Tariqul Islam ◽  
Norbahiah Misran ◽  
Nik Abdullah Nik Mohamed
Keyword(s):  
Dielectric Properties ◽  
Time Domain ◽  
Finite Difference Time Domain ◽  
Specific Absorption Rate ◽  
Fdtd Method ◽  
Human Head ◽  
Helical Antenna ◽  
Electromagnetic Absorption ◽  
Increase With Increase ◽  
Difference Time

AbstractThe aim of this paper is to analyze the effects of electromagnetic (EM) energy absorption at 900 and 1900 MHz when the human head’s dielectric properties are varied. This radiation is measured in terms of specific absorption rate (SAR). The characteristics of the helical antenna and its substrates with variation of the human head dielectric properties were simulated via the finite-difference time domain (FDTD) method using the CST Microwave studio. The human head dielectric properties are manipulated by increasing and decreasing 10% and 20% of each dielectric property. In this study, SAR values increase with increase of the human head’s conductivity, while increase of permittivity and densities decreases it. A helical antenna with a substrate of FR4 resulted in higher SAR values in all frequencies. The head SAR values are higher in the upper frequency exposures. The helical antenna with a substrate of Rogers RO3006 (loss free) was found to be the best-tested substrate, which contributed toward much lower SAR values in all GSM frequency bands.

Biological effect of SAR on the human head due to variation of dielectric properties at 1800 and 2450 MHz with different antenna substrate materials

2015 ◽  
Vol 22 (4) ◽  
Author(s):  
Mohammad Rashed Iqbal Faruque ◽  
Mohammad Tariqul Islam ◽  
Mohammad Habib Ullah
Keyword(s):  
Dielectric Properties ◽  
Time Domain ◽  
Finite Difference Time Domain ◽  
Biological Effect ◽  
Absorption Rate ◽  
Specific Absorption Rate ◽  
Fdtd Method ◽  
Human Head ◽  
Substrate Material ◽  
Difference Time

AbstractThe aim of this study was to consider a possible discrepancy in electromagnetic (EM) absorption in the human head. The finite-difference time-domain (FDTD) method with the lossy Drude model was adopted in this study. Here, the permittivity and conductivity of all head tissues were increased from 10% to 20% except when not using the same exposure conditions. Recognizable mobile phone frequencies of 1800 and 2450 MHz were studied in this simulation. The increase of up to 20% in conductivity and permittivity and varied substrate material always caused an EM absorption variation of 32.59% for specific absorption rate (SAR) 1 g and 35.25% for SAR 10 g at 1800 MHz, and variation of 20.37% for SAR 1 g and 17.99% for SAR 10 g at 2450 MHz, respectively.

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.

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 From Time-Collocated to Leapfrog Fundamental Schemes for ADI and CDI FDTD Methods

Axioms ◽  
2022 ◽  
Vol 11 (1) ◽  
pp. 23
Author(s):  
Eng Leong Tan
Keyword(s):  
Finite Difference ◽  
Time Domain ◽  
Finite Difference Time Domain ◽  
Fdtd Method ◽  
Unconditionally Stable ◽  
Alternating Direction Implicit ◽  
One Dimensional ◽  
Alternating Direction ◽  
Fdtd Methods ◽  
Difference Time

The leapfrog schemes have been developed for unconditionally stable alternating-direction implicit (ADI) finite-difference time-domain (FDTD) method, and recently the complying-divergence implicit (CDI) FDTD method. In this paper, the formulations from time-collocated to leapfrog fundamental schemes are presented for ADI and CDI FDTD methods. For the ADI FDTD method, the time-collocated fundamental schemes are implemented using implicit E-E and E-H update procedures, which comprise simple and concise right-hand sides (RHS) in their update equations. From the fundamental implicit E-H scheme, the leapfrog ADI FDTD method is formulated in conventional form, whose RHS are simplified into the leapfrog fundamental scheme with reduced operations and improved efficiency. For the CDI FDTD method, the time-collocated fundamental scheme is presented based on locally one-dimensional (LOD) FDTD method with complying divergence. The formulations from time-collocated to leapfrog schemes are provided, which result in the leapfrog fundamental scheme for CDI FDTD method. Based on their fundamental forms, further insights are given into the relations of leapfrog fundamental schemes for ADI and CDI FDTD methods. The time-collocated fundamental schemes require considerably fewer operations than all conventional ADI, LOD and leapfrog ADI FDTD methods, while the leapfrog fundamental schemes for ADI and CDI FDTD methods constitute the most efficient implicit FDTD schemes to date.

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