Numerical analysis of absorption mechanisms for mobile phones with integrated multiband antennas

Manteuffel, Dirk; Bahr, A.; Waldow, P.; Wolff, I.

doi:10.1109/aps.2001.960036

Cited by 16 publications

(17 citation statements)

References 2 publications

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“…Similar results were published in [Manteuffel et al, 2001] for mobile phones with integrated antennas for 900 MHz and in the 1800-2000 MHz frequency range. In Kivekäs et al [2004] it was shown that for 900 MHz the SAR distribution is mainly caused by the dipole-type resonant mode of the PCB, that is, it depends on the surface currents on the PCB [Kuster and Balzano, 1992].…”

Section: Resultssupporting

confidence: 90%

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Dosimetric assessment of an exposure system for simulating GSM and WCDMA mobile phone usage

Bahr

Dorn

Bolz

2006

Bioelectromagnetics

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An exposure system for investigation of volunteers during simulated GSM and WCDMA mobile phone usage has been designed. The apparatus consists of a dual band antenna with enhanced carrying properties that enables exposure for at least 8 h a day. For GSM a 900 MHz pulse modulated carrier was used. The QPSK modulated WCDMA signal at 1966 MHz comprises a power control scheme, which was designed for investigations of biological effects. The dosimetry of the exposure system by measurements and calculations is described in detail within this paper. It is shown that the SAR distribution of the antenna shows similar characteristics to mobile phones with an integrated antenna. The 10 g averaged localized SAR, normalized to an antenna input power of 1 W and measured in the flat phantom area of the SAM phantom, amounts to 7.82 mW/g (900 MHz) and 10.98 mW/g (1966 MHz). The simulated SAR(10 g) in the Visible Human head model agrees with measured values to within 20%. A variation of the antenna rotation angle results in an SAR(10 g) change below 17%. The increase of the antenna distance by 2 mm with respect to the human head leads to an SAR(10 g) change of 9%.

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Section: Resultssupporting

confidence: 90%

“…The WCDMA signal is generated according to Mbonjo et al [2004]. The 1966 MHz WCDMA signal with a bandwidth of 5 MHz is QPSK modulated with a root raised cosine filter (0.22).…”

Section: Exposure System Exposure Apparatusmentioning

confidence: 99%

Dosimetric assessment of an exposure system for simulating GSM and WCDMA mobile phone usage

Bahr

Dorn

Bolz

2006

Bioelectromagnetics

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“…Note that, for the sake of simplicity, the index n is now (and in the following) chosen symmetrical around 0. H (2) n−l (kr s ) is the Hankel function of the second kind and order n−l, taken at kr s ; H (1) n (kR) the Hankel function of the first kind and order n, taken at kR. By means of (C9), one can show that:…”

Section: Available Power For Electromagnetic Fieldsmentioning

confidence: 99%

“…H (2) l (kr ) and H (2) l (kr ) are respectively the Hankel function of second kind and order l, and its first derivative. K is a normalization factor such as K = 2kp/π, which allows to obtain 1 2 ||(s )|| 2 = P rad (p is the length of the considered cylinder portion).…”

Section: Appendix C Application Of the Equivalent Junction Model To mentioning

confidence: 99%

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Analytical Lower and Upper Bounds of Power Absorption in Near-Field Regions Deduced From a Modal-Based Equivalent Junction Model

Derat¹,

Bolomey²

2006

PIER

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Abstract-Due to the proximity of mobile phones to users' heads and resulting interrogations on potential health effects, as well as to the development of promising medical applications of electromagnetic waves such as non-invasive RF Hyperthermia treatments, near-field interactions between antennas and lossy scatterers, such as human beings, have been a topic of growing interest over the last decade. More generally, for various kinds of radiating sources and targets, much scientific effort has been done to answer the following question in particular configurations: what is the minimal/maximal power that can be absorbed in a lossy object located in the reactive field region of an antenna? The aim of this paper is to propose a general and analytical solution to this problem, applicable to any sourcescatterer system. To this purpose, a method, allowing to describe power deposition mechanisms in near-field regions, is introduced. This approach is based on an equivalent junction/circuit model which is shown here to result from an appropriate modal expansion of the radiated field. The dual interpretation of this model in terms of localized circuit and lumped junction is used to demonstrate how trends and bounds in power absorption phenomena can be derived. Firstly, the analogy with the microwave circuit theory provides the concepts of available power and load factor for electromagnetic fields, which allow to highlight the parameters influencing power dissipation and to analyze consequent trends. Secondly, the junction matrix 22 Derat and Bolomey formalism is used to obtain analytical lower and upper bounds of the power absorbed in a lossy object, located in the near field region of any radiating source. Those bounds give a clearer insight of the relationship between the total radiated power due to the antenna and the minimal or maximal power potentially dissipated in any scatterer exposed to such a radiated field. An example of bounds in a simple source-load configuration is finally provided, showing the link, to be further investigated, between the near-zone electric-field pattern of the antenna and the total dissipated power. This example also suggests that the power dissipated in a given object can be rapidly increased or reduced as the modal complexity of the source increases.

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Effects of exposure to electromagnetic fields emitted by GSM 900 and WCDMA mobile phones on cognitive function in young male subjects

Sauter¹,

Dorn²,

Bahr³

et al. 2010

Bioelectromagnetics

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Results of studies on the possible effects of electromagnetic fields emitted by mobile phones on cognitive functions are contradictory, therefore, possible effects of long-term (7 h 15 min) electromagnetic field (EMF) exposure to handset-like signals of Global System for Mobile Communications (GSM) 900 and Wideband Code-Division Multiple Access (WCDMA) on attention and working memory were studied. The sample comprised 30 healthy male subjects (mean ± SD: 25.3 ± 2.6 years), who were tested on nine study days in which they were exposed to three exposure conditions (sham, GSM 900 and WCDMA) in a randomly assigned and balanced order. All tests were presented twice (morning and afternoon) on each study day within a fixed timeframe. Univariate comparisons revealed significant changes when subjects were exposed to GSM 900 compared to sham, only in the vigilance test. In the WCDMA exposure condition, one parameter in the vigilance and one in the test on divided attention were altered compared to sham. Performance in the selective attention test and the n-back task was not affected by GSM 900 or WCDMA exposure. Time-of-day effects were evident for the tests on divided and selective attention, as well as for working memory. After correction for multiple testing, only time-of-day effects remained significant in two tests, resulting in faster reactions in the afternoon trials. The results of the present study do not provide any evidence of an EMF effect on human cognition, but they underline the necessity to control for time of day.

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Numerical analysis of absorption mechanisms for mobile phones with integrated multiband antennas

Cited by 16 publications

References 2 publications

Dosimetric assessment of an exposure system for simulating GSM and WCDMA mobile phone usage

Dosimetric assessment of an exposure system for simulating GSM and WCDMA mobile phone usage

Analytical Lower and Upper Bounds of Power Absorption in Near-Field Regions Deduced From a Modal-Based Equivalent Junction Model

Effects of exposure to electromagnetic fields emitted by GSM 900 and WCDMA mobile phones on cognitive function in young male subjects

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