A Novel Cellular Handset Design for an Enhanced Antenna Performance and a Reduced SAR in the Human Head (original) (raw)
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This paper presents a thorough investigation into the effect of the external antenna and printed circuit board (PCB) positions in cellular hand-sets on the coupling between the handset and human-head at GSM-900 frequency standard. The antenna performance and the specific absorption rate (SAR) induced in a human head were computed using a Finite Difference Time-Domain based platform (SEMCAD). A numerical correct model of a European female head was adopted and a semi-realistic hand model was designed during the simulation. The results showed that the optimum position for the antenna and PCB in hand-set close to head is the far right-corner for the right-hand users and the far left-corner for the left-hand users, where a minimum SAR in head is achieved.
2016
The scope of this paper is to examine the Specific Absorption Rate (SAR) inside the human head model exposed to the radiation of a lowprofile printed monopole antenna with coupling feed for GSM/UMTS/LTE/WLAN operation in the slim mobile phone. The presented antenna operates for most of the mobile phone applications such as the GSM850, GSM900, GSM1900, UMTS2100, LTE2300, LTE2500 and WLAN2400 bands. In this study, two different human head models are used: homogenous spherical head and spherical seven layer model. In addition, the effects of operating frequency and the gap distance between the mobile phone antenna and the human head model on distributions of the SAR within the human head are analyzed. All the simulations are done for three different distances between the antenna and the head model (5 mm, 10 mm, 20 mm). Furthermore, the SAR levels for the head tissues are calculated for and with accordance to the two currently accepted standards: Federal Communications Commission (FCC) ...
Analysis of SAR levels in human head tissues for four types of antennas with portable telephones
2011
In this paper, a comparative study of several antennas commonly used in portable telephones is investigated. These include a monopole, a helix, a patch and a PIFA antenna. Each one of these structures is modeled and numerically tested using finite-difference time-domain (FDTD) method by using CST Microwave Studio. The testing procedure involves antenna simulation in the proximity of the human head and hand. The behavior of each antenna is evaluated for variable distances from the head geometry (0-20 mm). The simulation outputs used as measures for this comparative study include the specific absorption rate (SAR). The computed SAR levels within each of the considered tissues vary for the four antennas under investigation and are within the determined health safety standards. Results suggest that the patch antenna may be the structure of choice when considering safety standards, as its radiation yields the lowest local SAR in the head tissues.
The Interactions Between the Mobile Handset Antenna of Various Types and the Human Head
One lingering concern is the effect of the radiation produced by the mobile handset antenna on the human head. This topic has been studied widely, but still there is no definitive answer. Since mobile telephones are typically used in close to the human head, significant levels of power can be absorbed by the head, the primary effect is to cause local heating of the brain and head tissues. This is of concern to some people who work continually with mobile telephones, and some form of ''preventative'' research should be done. This paper describes some kinds of models of antennas (dipole, monopole and patch antennas) and human, and the calculation of the Specific Absorption Rate (SAR) in the human head at 1800 MHz. Also, this paper studies the effect of the human head model on the return losses of these models of the antennas. The obtained results show that at the same frequency, the patch antenna induces SAR in the human head of smaller values than that induced by dipole and monopole antennas. In addition, the return loss of the patch antenna is affected greatly by the presence of the human model, when it is compared with the return losses of the dipole and monopole antennas.
Analysis of the human body on the radiation of FM handset antenna
Microwave and Optical Technology Letters, 2009
A simple human body phantom model is proposed and used to demonstrate that the radiation efficiency of an internal handset antenna operating at the FM band can be improved for a particular holding position up to 10 dB. To corroborate the numerical results, an experiment using a real human body has been performed showing very good agreement. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2588–2590, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24686
PIERS Online, 2006
Since the 1990's, use of mobile phones has augmented worldwide generating a public concern as to whether frequent utilization of such devices is unsafe. This provoked EMF researchers to find suitable techniques of assessing radiation blueprint and exposure hazards if any. Most research groups focused on two techniques: experimental measurements and finite-difference time-domain (FDTD) computations. Computation of the specific absorption rate (SAR) generated by cellular phones inside two models of the human head is presented in this paper. Two models of mobile phones were considered working at 900 and 1800 MHz bands according to the Global System for Mobile Communication. Radiated energy distributions and averaged SAR values in 1 g and 10 g of tissue were computed inside the models of head using FDTD. Computations were compared with a realistic head model constructed with the MRI scans. The distribution of the local SAR in the head was similar to that of the simplified head models. The maximum local SAR calculated was 53.43 W/kg and the maximum SAR(10 g) was 2.96 W/kg, both for 1 W output power from the antenna. The results indicated the area of the maximum local SAR was situated in outer layer of skull, where muscle and skin were. The important parameters in absorbed energy in the head were the type of antenna, current distribution and the distance between head and antenna. The head models used for simulation proved as insignificant parameter in the calculations.
Analysis of Mobile Phone Antenna Performance within the Head and Hand Phantoms
International Journal on Advanced Science, Engineering and Information Technology, 2011
This paper proposes the effect of the hand-hold position on the electromagnetic (EM) wave interaction of a candy bar type and clamshell type cellular handset and a human head and hand is investigated. The human hand influences the performance of terminal antennas, and it is the main cause for absorption and detuning. In spite of its importance in mobile-phone design and validation processes, it is still complicated to take it into account because a lack of knowledge in the area. In this paper, a rigorous investigation methodology is described for the study of candy bar, and clam shell mobile phone CAD model is used to numerically investigate the effect of hand phantom of mobile phone antenna radiation performance. The simulation results show that mobile phone grip styles of the hand phantom material properties, wrist and length, and hand phantom sizes and different positions is the important parameter to antenna performance. The grip style has direct implications in the definition of phantom head. The preference of the handset with respect to the side of the user's head depends on the mobile phone form factor and size. The results established high reliability and suitability for providing decision rationale for the design of complex high-end multi-band mobile phones. Keywordsantenna closeness factors, finite-difference time-domain (FDTD) method, hand phantom, mobile communication.
International Journal of Antennas and Propagation, 2008
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 o...
A New Design of Cell Phone Body for the SAR Reduction in the Human Head
Applied Computational Electromagnetics Society Journal
In this paper, a new design of cell phone body is presented to reduce the specific absorption rate (SAR) in the human head. The SAR in the human head and total absorbed power by the cell phone user are calculated along with antenna performances in terms of radiation efficiency and directivity to validate the effects of cell phone body. It is found that the SAR in the head is reduced significantly for both the lower and upper global systems for mobile (GSM) frequency band. The new mobile body provides 63.8% reduction in the SAR at 900 MHz and 69.2% reduction at 1800 MHz in comparison of without mobile cover configuration. Moreover, the mobile casing improves the radiation efficiency 6% and 7% in the lower and the upper GSM frequency band respectively.