scholarly journals Assessment of Electromagnetic Absorption towards Human Head Using Specific Absorption Rate

2018 ◽  
Vol 7 (4) ◽  
pp. 657-664
Author(s):  
Abdul Rashid O. Mumi ◽  
R. Alias ◽  
Jiwa Abdullah ◽  
Samsul Haimi Dahlan ◽  
Jawad Ali
Keyword(s):  
Specific Absorption Rate ◽  
Wireless Body Area Network ◽  
Human Head ◽  
Head Model ◽  
Area Network ◽  
High Radiation ◽  
Radiation Level ◽  
Antenna Performance ◽  
Electromagnetic Absorption ◽  
Different Types

This paper presents a compact square slot patch antenna characterstics for wireless body area network (WBANs) applications.The assessment of the effects of electromagnetic energy (EM) on the human head is necessary because the sensitivity of human head to high radiation level. Although, structuring of low EM antennas is a major problem in the improvement of portable device and reducing the size of of the antenna is a major concern. However, performance of antenna reduces when antenna operates near human body which is lossy and complex in nature. The proposed antenna operates at 5.8GHz of the ISM Band for WBAN applications. The antenna has been designed and simulated with two different types of multilayer human head phantoms to characterize the antenna near the human head.The multilayer head phantom is constructed by five layers tissues head model using CST Microwave studio. Therefore, antenna with spherical phantom has the highest SAR value 0.206 W/Kg, while antenna with cubical phantom contributed the lowest SAR value of 0.166 for 10 g tissue at 5.8 GHz frequency exposed, whereas, the antenna with cubical phantom and spherical phantom have gain of 6.46 dBi and 6.2 dBi GHz respectively. It was observed that antenna performance significantly increased. The presented prototype has a potential to work for ISM applications.

scholarly journals Levels of detail analysis of microwave scattering from human head models for brain stroke detection

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e4061 ◽  
Author(s):  
Awais Munawar Qureshi ◽  
Zartasha Mustansar
Keyword(s):  
Scattering Problem ◽  
Human Head ◽  
Computational Time ◽  
Head Model ◽  
Microwave Scattering ◽  
Levels Of Detail ◽  
Realistic Head Model ◽  
Different Types ◽  
Brain Stroke ◽  
Brain Tissues

In this paper, we have presented a microwave scattering analysis from multiple human head models. This study incorporates different levels of detail in the human head models and its effect on microwave scattering phenomenon. Two levels of detail are taken into account; (i) Simplified ellipse shaped head model (ii) Anatomically realistic head model, implemented using 2-D geometry. In addition, heterogenic and frequency-dispersive behavior of the brain tissues has also been incorporated in our head models. It is identified during this study that the microwave scattering phenomenon changes significantly once the complexity of head model is increased by incorporating more details using magnetic resonance imaging database. It is also found out that the microwave scattering results match in both types of head model (i.e., geometrically simple and anatomically realistic), once the measurements are made in the structurally simplified regions. However, the results diverge considerably in the complex areas of brain due to the arbitrary shape interface of tissue layers in the anatomically realistic head model.After incorporating various levels of detail, the solution of subject microwave scattering problem and the measurement of transmitted and backscattered signals were obtained using finite element method. Mesh convergence analysis was also performed to achieve error free results with a minimum number of mesh elements and a lesser degree of freedom in the fast computational time. The results were promising and the E-Field values converged for both simple and complex geometrical models. However, the E-Field difference between both types of head model at the same reference point differentiated a lot in terms of magnitude. At complex location, a high difference value of 0.04236 V/m was measured compared to the simple location, where it turned out to be 0.00197 V/m. This study also contributes to provide a comparison analysis between the direct and iterative solvers so as to find out the solution of subject microwave scattering problem in a minimum computational time along with memory resources requirement.It is seen from this study that the microwave imaging may effectively be utilized for the detection, localization and differentiation of different types of brain stroke. The simulation results verified that the microwave imaging can be efficiently exploited to study the significant contrast between electric field values of the normal and abnormal brain tissues for the investigation of brain anomalies. In the end, a specific absorption rate analysis was carried out to compare the ionizing effects of microwave signals to different types of head model using a factor of safety for brain tissues. It is also suggested after careful study of various inversion methods in practice for microwave head imaging, that the contrast source inversion method may be more suitable and computationally efficient for such problems.

scholarly journals Finite-element analysis of microwave scattering from a three-dimensional human head model for brain stroke detection

2018 ◽  
Vol 5 (7) ◽  
pp. 180319
Author(s):  
Awais Munawar Qureshi ◽  
Zartasha Mustansar ◽  
Samah Mustafa
Keyword(s):  
Finite Element ◽  
Dielectric Properties ◽  
Electric Field ◽  
Three Dimensional ◽  
Human Head ◽  
Head Model ◽  
Different Types ◽  
Brain Stroke ◽  
Human Head Model ◽  
Brain Stroke Detection

In this paper, a detailed analysis of microwave (MW) scattering from a three-dimensional (3D) anthropomorphic human head model is presented. It is the first time that the finite-element method (FEM) has been deployed to study the MW scattering phenomenon of a 3D realistic head model for brain stroke detection. A major contribution of this paper is to add anatomically more realistic details to the human head model compared with the literature available to date. Using the MRI database, a 3D numerical head model was developed and segmented into 21 different types through a novel tissue-mapping scheme and a mixed-model approach. The heterogeneous and frequency-dispersive dielectric properties were assigned to brain tissues using the same mapping technique. To mimic the simulation set-up, an eight-elements antenna array around the head model was designed using dipole antennae. Two types of brain stroke (haemorrhagic and ischaemic) at various locations inside the head model were then analysed for possible detection and classification. The transmitted and backscattered signals were calculated by finding out the solution of the Helmholtz wave equation in the frequency domain using the FEM. FE mesh convergence analysis for electric field values and comparison between different types of iterative solver were also performed to obtain error-free results in minimal computational time. At the end, specific absorption rate analysis was conducted to examine the ionization effects of MW signals to a 3D human head model. Through computer simulations, it is foreseen that MW imaging may efficiently be exploited to locate and differentiate two types of brain stroke by detecting abnormal tissues’ dielectric properties. A significant contrast between electric field values of the normal and stroke-affected brain tissues was observed at the stroke location. This is a step towards generating MW scattering information for the development of an efficient image reconstruction algorithm.

scholarly journals Analysis of Specific Absorption Rate on Six Layer Human Head Model

2020 ◽  
Author(s):  
Anand Swaminathan ◽  
Ramprakash A ◽  
Dhejonithan K
Keyword(s):  
Absorption Rate ◽  
Specific Absorption Rate ◽  
Mass Density ◽  
Human Head ◽  
Federal Communications Commission ◽  
Head Model ◽  
Health Issues ◽  
Specific Absorption ◽  
Proposed Model ◽  
The Impact

Despite numerous advantages, mobile phones cause serious health issues to people due to electromagnetic radiation. Various head models already exist to study the impact of radiation on a human head. The accuracy of the measurement of power absorbed by different layers of a head should be high. A new head model with six layers is proposed in this paper. Parameters such as dielectric constant, conductivity and mass density of different tissue layers skin, fat, bone, Dura, cerebrospinal fluid (CSF), and brain are extracted from the Federal Communications Commission (FCC) database. To study the impact of radiation in the proposed model, standard planar inverted F-antennas (PIFA) capable to radiate at 1.7 GHz and 2.4 GHz are used. Simulations are performed using ANSYS Electromagnetics Suite. The analysis shows that the specific absorption rate (SAR) in the brain layer decreased in the proposed model when compared to the existing model.

scholarly journals Anticipated Impact of Hand-Hold Position on the Electromagnetic Interaction of Different Antenna Types/Positions and a Human in Cellular Communications

2008 ◽  
Vol 2008 ◽  
pp. 1-22 ◽  
Author(s):  
Salah I. Al-Mously ◽  
Marai M. Abousetta
Keyword(s):  
Specific Absorption Rate ◽  
Electromagnetic Interaction ◽  
Fdtd Method ◽  
Human Head ◽  
Human Hand ◽  
Model Design ◽  
Antenna Performance ◽  
The Impact ◽  
Internal Antenna ◽  
Difference Time

This paper is intended to investigate intensely the impact of multipossible hand-hold positions on the electromagnetic (EM) interaction of handset antennas and a human by using a finite-difference time-domain (FDTD) method. Candy-bar handsets with different external and internal antenna positions operating in the GSM900, GSM1800/DCS, and UMTS/IMT-2000 bands are hereby simulated with configuration of the most parts in order to achieve the commercially available handset model design. Homogeneous and heterogeneous phantoms both are used to simulate the human head, whereas, a semirealistic model with three different tissues is designed to simulate a human hand holding a set. Both of the antenna performance including the total isotropic sensitivity (TIS) and the specific absorption rate (SAR) in tissues are examined for the different suggested applicable cases, where various positions of antenna, handset and hand are considered in simulations. This simulation study determines that both of the antenna performance and the SAR in tissues significantly alter owing to the positioning of the handset against user's head at different hand levels; where a maximum alteration is observed due to the exposure of handset with internal antenna, as compared with the handset having external antenna.

scholarly journals Dual-Band On-Body Repeater Antenna for In-on-On WBAN Applications

2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
Jinpil Tak ◽  
Kyeol Kwon ◽  
Sunwoo Kim ◽  
Jaehoon Choi
Keyword(s):  
Human Body ◽  
Wireless Body Area Network ◽  
Biological Information ◽  
Dual Band ◽  
Area Network ◽  
Ism Band ◽  
Network Applications ◽  
Antenna Performance ◽  
Human Body Surface ◽  
Implanted Devices

A dual-band on-body repeater antenna for in-on-on wireless body area network applications is proposed. The proposed antenna has a maximum radiation normal to the human-body surface for communication with implanted devices in the 5.8 GHz industrial, scientific, and medical (ISM) band. In addition, to transmit the biological information received from the implanted devices to other on-body devices, the proposed antenna was designed to have a monopole-like radiation pattern along the surface of the human body for communication in the 2.45 GHz ISM band. The antenna was fabricated, and its performance was measured by attaching it to a human-equivalent semisolid phantom. In addition, the human-body effect was studied to ensure antenna performance under an actual situation.

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