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Journal Article•DOI•

EM interaction of handset antennas and a human in personal communications

Michael A. Jensen1, Yahya Rahmat-Samii1•
University of California, Los Angeles1
01 Jan 1995-Vol. 83, Iss: 1, pp 7-17
TL;DR: In this article, the authors investigated the effect of the tissue location and physical model on the antenna performance and found that the head and hand absorb between 48 and 68% of the power delivered to the antenna.
Abstract: In personal communications, the electromagnetic interaction between handset-mounted antennas and the nearby biological tissue is a key consideration. This paper presents a thorough investigation of this antenna-tissue interaction using the finite-difference time-domain (FDTD) electromagnetic simulation approach with detailed models of real-life antennas on a transceiver handset. The monopole, side-mounted planar inverted F, top-mounted bent inverted F, and back-mounted planar inverted F antennas are selected as representative examples of external and internal configurations. Detailed models of the human head and hand are implemented to investigate the effects of the tissue location and physical model on the antenna performance. Experimental results are provided which support the computationally obtained conclusions. The specific absorption rate (SAR) in the tissue is examined for several different antenna/handset configurations. It is found that for a head-handset separation of 2 cm, the SAR in the head has a peak value between 0.9 and 3.8 mW/g and an average value between 0.06 and 0.10 mW/g for 1 W of power delivered to the antenna. Additionally, the head and hand absorb between 48 and 68% of the power delivered to the antenna. >

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Brigham Young University Brigham Young University
BYU ScholarsArchive BYU ScholarsArchive
Faculty Publications
1995-01-01
EM interaction of handset antennas and a human in personal EM interaction of handset antennas and a human in personal
communications communications
Michael A. Jensen
jensen@byu.edu
Yahya Rahmat-Samii
Follow this and additional works at: https://scholarsarchive.byu.edu/facpub
Part of the Electrical and Computer Engineering Commons
Original Publication Citation Original Publication Citation
Jensen, M. A., and Y. Rahmat-Samii. "EM Interaction of Handset Antennas and a Human in
Personal Communications." Proceedings of the IEEE 83.1 (1995): 7-17
BYU ScholarsArchive Citation BYU ScholarsArchive Citation
Jensen, Michael A. and Rahmat-Samii, Yahya, "EM interaction of handset antennas and a human in
personal communications" (1995).
Faculty Publications
. 692.
https://scholarsarchive.byu.edu/facpub/692
This Peer-Reviewed Article is brought to you for free and open access by BYU ScholarsArchive. It has been
accepted for inclusion in Faculty Publications by an authorized administrator of BYU ScholarsArchive. For more
information, please contact ellen_amatangelo@byu.edu.
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Citations
More filters
Journal Article•DOI•
High-impedance electromagnetic surfaces with a forbidden frequency band

[...]

Daniel F. Sievenpiper1, Lijun Zhang2, R.F.J. Broas2, N.G. Alexopolous, Eli Yablonovitch3 •
HRL Laboratories1, University of California, Los Angeles2, University of California, Irvine3
01 Nov 1999-IEEE Transactions on Microwave Theory and Techniques
TL;DR: In this paper, a new type of metallic structure has been developed that is characterized by having high surface impedance, which is analogous to a corrugated metal surface in which the corrugations have been folded up into lumped-circuit elements and distributed in a two-dimensional lattice.
Abstract: A new type of metallic electromagnetic structure has been developed that is characterized by having high surface impedance. Although it is made of continuous metal, and conducts dc currents, it does not conduct ac currents within a forbidden frequency band. Unlike normal conductors, this new surface does not support propagating surface waves, and its image currents are not phase reversed. The geometry is analogous to a corrugated metal surface in which the corrugations have been folded up into lumped-circuit elements, and distributed in a two-dimensional lattice. The surface can be described using solid-state band theory concepts, even though the periodicity is much less than the free-space wavelength. This unique material is applicable to a variety of electromagnetic problems, including new kinds of low-profile antennas.

4,264 citations

Cites background from "EM interaction of handset antennas ..."

  • ...It has been shown that with this configuration, roughly 50% of the radiated power is absorbed by the user [ 43 ]....

    [...]

Book•
Modern Antenna Handbook

[...]

Constantine A. Balanis
01 Jan 2012
TL;DR: The Modern Antenna Handbook as mentioned in this paper provides a comprehensive treatment of classical and modern antennas and their related technologies, including metamaterials, microelectromechanical systems (MEMS), frequency selective surfaces (FSS), radar cross sections (RCS), and advanced numerical and computational methods targeted primarily for the analysis and design of antennas.
Abstract: Find the most up-to-date and comprehensive treatment of classical and modern antennas and their related technologies in Modern Antenna Handbook. Have access to current theories and practices in the field of antennas, with topics like metamaterials, microelectromechanical systems (MEMS), frequency selective surfaces (FSS), radar cross sections (RCS), and advanced numerical and computational methods targeted primarily for the analysis and design of antennas. Written by leading international experts, this book will help you understand recent developments in antenna-related technology and the future direction of this fast-paced field.

911 citations

Journal Article•DOI•
Electromagnetic absorption in the human head and neck for mobile telephones at 835 and 1900 MHz

[...]

Om P. Gandhi1, Gianluca Lazzi1, Cynthia Furse1•
University of Utah1
01 Jan 1996-IEEE Transactions on Microwave Theory and Techniques
TL;DR: In this paper, the authors used the finite-difference time-domain method and a new millimeter-resolution anatomically based model of the human to study electromagnetic energy coupled to the head due to mobile telephones at 835 and 1900 MHz.
Abstract: The authors have used the finite-difference time-domain method and a new millimeter-resolution anatomically based model of the human to study electromagnetic energy coupled to the head due to mobile telephones at 835 and 1900 MHz. Assuming reduced dimensions characteristic of today's mobile telephones, the authors have obtained SAR distributions for two different lengths of monopole antennas of lengths /spl lambda//4 and 3/spl lambda//8 for a model of the adult male and reduced-scale models of 10- and 5-year-old children and find that peak one-voxel and 1-g SARs are larger for the smaller models of children, particularly at 835 MHz. Also, a larger in-depth penetration of absorbed energy for these smaller models is obtained. The authors have also studied the effect of using the widely disparate tissue properties reported in the literature and of using homogeneous instead of the anatomically realistic heterogeneous models on the SAR distributions. Homogeneous models are shown to grossly overestimate both the peak 1-voxel and 1-g SARs. Last, the authors show that it is possible to use truncated one-half or one-third models of the human head with negligible errors in the calculated SAR distributions. This simplification will allow considerable savings in computer memory and computation times.

529 citations

Journal Article•DOI•
Resonator-based analysis of the combination of mobile handset antenna and chassis

[...]

Pertti Vainikainen1, Jani Ollikainen1, Outi Kivekäs1, K. Kelander1•
Helsinki University of Technology1
01 Oct 2002-IEEE Transactions on Antennas and Propagation
TL;DR: In this paper, the performance of the mobile phone handset antenna-chassis combination is analyzed based on an approximate decomposition of the waves on the structure into two resonant wavemodes: the antenna-element wavemode and the chassis wavemode.
Abstract: The performance of the mobile phone handset antenna-chassis combination is analyzed based on an approximate decomposition of the waves on the structure into two resonant wavemodes: the antenna-element wavemode and the chassis wavemode. A double resonator equivalent circuit model is presented and used to estimate the impedance bandwidth and the respective distributions of radiation losses with typical parameter values at 900 and 1800 MHz. It is noticed that at 900 MHz, the radiation losses of the antenna element wavemode represent typically less than 10% of the total power. Thus, the antenna element works mainly as a matching element, which couples to the low-Q resonant wavemode of the chassis. At 1800 MHz, the contribution of the antenna element wavemode is larger. By enhancing the coupling and by tuning the chassis resonance, it is possible to obtain an impedance bandwidth of over 50% (6 dB return loss) at both at 900 and 1800 MHz. The results given by the equivalent circuit study are fully supported by those of three-dimensional phone-model simulations, including calculation of the SAR and efficiency values. In prototyping, the 6 dB bandwidth of 5.5% was obtained at 980 MHz with a nonradiating coupling element with a volume of 1.6 cm/sup 3/ on a 120 mm long chassis.

500 citations

Cites background from "EM interaction of handset antennas ..."

  • ...effect of the chassis is usually not analyzed, though in many published small-antenna designs the antenna is mounted on a phone chassis and from the large bandwidths obtained it can be assumed that the effect of the chassis is significant [4], [8]–[12]....

    [...]

  • ...the benefit of the patch antenna mounted on the backside of the phone [4], [7], does not seem significant at 900 MHz, if the antenna element is small and the bandwidth is about 10%, because the relative amplitude of the patch wavemode is low....

    [...]

Journal Article•DOI•
Small microstrip patch antenna

[...]

Rod Waterhouse1•
RMIT University1
13 Apr 1995-Electronics Letters
TL;DR: In this paper, the advantages of microstrip patch technology over its competitors is its low profile and hence small volume, and the relative ease in which it can be connected to the feed network, as was highlighted in Chapter 2.
Abstract: As stated in Chapter 1, one of the many advantages of microstrip patch technology over its competitors is its low profile and hence small volume. Another key advantage of this printed antenna is the relative ease in which it can be connected to the feed network, as was highlighted in Chapter 2. For these reasons antenna design engineers deduced that microstrip patch antennas could be utilized for applications requiring where there was very limited space to mount the antenna. One such global application is for wireless communication handset terminals.

399 citations

References
More filters
Journal Article•DOI•
Numerical solution of initial boundary value problems involving maxwell's equations in isotropic media

[...]

Kane Yee1•
Lawrence Livermore National Laboratory1
01 May 1966-IEEE Transactions on Antennas and Propagation
Abstract: Maxwell's equations are replaced by a set of finite difference equations. It is shown that if one chooses the field points appropriately, the set of finite difference equations is applicable for a boundary condition involving perfectly conducting surfaces. An example is given of the scattering of an electromagnetic pulse by a perfectly conducting cylinder.

14,070 citations

"EM interaction of handset antennas ..." refers methods in this paper

  • ...The finite-difference timedomain (FDTD) method [ 2 ]-(61 is one such approach which allows accurate prediction of the electromagnetic behavior of general topologies....

    [...]

  • ...The FDTD methodology [ 2 ]-[lo] is derived from...

    [...]

Journal Article•DOI•
Absorbing Boundary Conditions for the Finite-Difference Approximation of the Time-Domain Electromagnetic-Field Equations

[...]

G. Mur1•
Delft University of Technology1
01 Nov 1981-IEEE Transactions on Electromagnetic Compatibility
TL;DR: In this paper, highly absorbing boundary conditions for two-dimensional time-domain electromagnetic field equations are presented for both two-and three-dimensional configurations and numerical results are given that clearly exhibit the accuracy and limits of applicability of these boundary conditions.
Abstract: When time-domain electromagnetic-field equations are solved using finite-difference techniques in unbounded space, there must be a method limiting the domain in which the field is computed. This is achieved by truncating the mesh and using absorbing boundary conditions at its artificial boundaries to simulate the unbounded surroundings. This paper presents highly absorbing boundary conditions for electromagnetic-field equations that can be used for both two-and three-dimensional configurations. Numerical results are given that clearly exhibit the accuracy and limits of applicability of highly absorbing boundary conditions. A simplified, but equally accurate, absorbing condition is derived for two- dimensional time-domain electromagnetic-field problems.

2,553 citations

Journal Article•DOI•
Numerical Solution of Steady-State Electromagnetic Scattering Problems Using the Time-Dependent Maxwell's Equations

[...]

Allen Taflove1, M.E. Brodwin1•
Northwestern University1
01 Aug 1975-IEEE Transactions on Microwave Theory and Techniques
TL;DR: In this paper, a numerical method for the solution of the electromagnetic fields within an arbitrary dielectric scatterer of the order of one wavelength in diameter is described, and an error of less than /spl plusmn/10 percent in locating and evaluating the standing wave peaks within the cylinder is achieved for a program execution time of 1 min.
Abstract: A numerical method is described for the solution of the electromagnetic fields within an arbitrary dielectric scatterer of the order of one wavelength in diameter. The method treats the irradiation of the scatterer as an initial value problem. At t = 0, a plane-wave source of frequency f is assumed to be turned on. The diffraction of waves from this source is modeled by repeatedly solving a finite-difference analog of the time-dependent Maxwell's equations. Time stepping is continued until sinusoidual steady-state field values are observed at all points within the scatterer. The envelope of the standing wave is taken as the steady-state scattered field. As an example of this method, the computed results for a dielectric cylinder scatterer are presented. An error of less than /spl plusmn/10 percent in locating and evaluating the standing-wave peaks within the cylinder is achieved for a program execution time of 1 min. The extension of this method to the solution of the fields within three-dimensional dielectric scatterers is outlined.

1,300 citations

Journal Article•DOI•
Performance analysis of antennas for hand-held transceivers using FDTD

[...]

Michael A. Jensen1, Yahya Rahmat-Samii1•
University of California, Los Angeles1
01 Aug 1994-IEEE Transactions on Antennas and Propagation
TL;DR: The paper presents the analysis of small antennas mounted on hand-held transceivers using the finite-difference time-domain (FDTD) method, which is used to predict the gain patterns and broadband input impedance behavior of monopole, planar inverted F, and loop antenna elements mounted on the handset.
Abstract: The design of antennas for hand-held communications devices depends on the implementation of simulation tools that can accurately model general topologies. The paper presents the analysis of small antennas mounted on hand-held transceivers using the finite-difference time-domain (FDTD) method. The key features of the FDTD implementation are discussed, with particular emphasis placed upon modeling of the source region. The technique is used to predict the gain patterns and broadband input impedance behavior of monopole, planar inverted F, and loop antenna elements mounted on the handset. Effects of the conducting handset chassis, the plastic casing around the device, and lumped elements integrated into the antenna design are illustrated. Experimental results are provided to verify the accuracy of the computational methodology. The concept of antenna diversity is discussed, and key assumptions and expressions are provided that characterize the multipath fading fields. Several computational examples demonstrate the diversity performance of two receiving antennas on a single handset. >

313 citations

"EM interaction of handset antennas ..." refers background or methods in this paper

  • ...to provide dual-branch antenna diversity is illustrated in Fig. l(b) [ 5 ]....

    [...]

  • ...Special considerations are made for modeling wires and lumped elements within the domain [ 5 ], and absorbing boundary conditions [ll] are used to truncate the mesh a reasonable distance from the antenna....

    [...]

  • ...The antenna excitation is introduced into the computational domain using a previously reported simulated coaxial feed model [ 5 ]....

    [...]

Effects on Portable Antennas by the Presence of a Person

[...]

J. Toftgard, Sten Naae Hornsleth, J. Bach Andersen
01 Jan 1992
TL;DR: In this article, the influence of the presence of a person on the performance of antennas for hand-held portable telephones has been investigated by applying the finite-difference time-domain (FDTD) technique to a model of the telephone with a lambda /4 monopole antenna and a simple hand-head model of operator.
Abstract: This work deals with the influence the presence of a person has on the performance of antennas for hand-held portable telephones. It is shown how input impedance, far-field radiation pattern, radiation efficiency, and the magnitude of the near field are affected by the presence of the human body. The investigations have been carried out by applying the finite-difference time-domain (FDTD) technique to a model of the telephone with a lambda /4 monopole antenna and a simple hand-head model of the operator. Results from this configuration are compared with results for the telephone box and antenna alone. Measurements have been performed to verify the results obtained by simulations. The results show that a shadow effect in the far-field pattern occurs in the direction of the person and that the radiation pattern, including polarization, changes considerably from the telephone with the antenna alone. The impedance results show a change in resonance frequency when the telephone is placed next to a person. Results for radiation efficiency show that close to half of the energy is absorbed by hand and head. On average a system loss of 3-4 dB should be included in a link budget, and there is considerable fading, even in a radio-anechoic chamber, when persons move around in a natural manner. >

276 citations

Related Papers (5)
A study of the handset antenna and human body interaction

[...]

01 Oct 1996-IEEE Transactions on Microwave Theory and Techniques
M. Okoniewski, M.A. Stuchly
Electromagnetic absorption in the human head and neck for mobile telephones at 835 and 1900 MHz

[...]

01 Jan 1996-IEEE Transactions on Microwave Theory and Techniques
Om P. Gandhi, Gianluca Lazzi, Cynthia Furse
Numerical solution of initial boundary value problems involving maxwell's equations in isotropic media

[...]

01 May 1966-IEEE Transactions on Antennas and Propagation
Kane Yee
Computational Electrodynamics: The Finite-Difference Time-Domain Method

[...]

31 May 1995
Allen Taflove
Energy absorption mechanism by biological bodies in the near field of dipole antennas above 300 MHz

[...]

01 Feb 1992-IEEE Transactions on Vehicular Technology
Niels Kuster, Q. Balzano