Polymeric ferrite sheets for SAR reduction of wearable antennas

Augustine, Robin; Alvès, Thierry; Sarrebourse, Thierry; Poussot, Benoît; Mathew, K. T.; Laheurte, Jean‐Marc

doi:10.1049/el.2010.3246

Cited by 21 publications

(15 citation statements)

References 2 publications

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“…Foreseeing this limitation, researchers have extensively evaluated various facets of the on-body degradation [7][8][9][10]. Examinations of bending effects [7], worn efficiency [8], and material changes due to environmental conditions [9], in addition to the various suggested methods to limit the influence of body coupling-absorption, have been presented [10,11].…”

Section: Introductionmentioning

confidence: 99%

“…Previous SAR literature mostly reported antennas and communication devices made from conventional printed circuit boards operating near the human head or hands [12][13][14][15][16]. Other researchers have suggested several SAR reduction techniques, e.g., by implementing ferrites [11], electromagnetic bandgap structures [17,18], and resistive sheets [19]. Meanwhile, several recent reports have evaluated antenna SARs radiating inward/toward parts of the human body.…”

Section: Introductionmentioning

confidence: 99%

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Specific Absorption Rate (SAR) Evaluation of Textile Antennas

Soh

Vandenbosch

Wee

et al. 2015

IEEE Antennas Propag. Mag.

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This paper presents a detailed and systematic investigation of the reproducibility of specific absorption rate (SAR) measurements using textile antennas and their simulation accuracy. The ability to accurately predict the SAR is very important for practical textile antenna designers since certified SAR measurements are costly. To that goal, the SAR values of a range of textile antennas operating in various bands of the IEEE 802.15.6 and 802.11 standards are evaluated. The selected textile antenna topologies for the evaluation differ in terms of the bandwidth behavior (broadband, dual band, and ultrawideband). They are chosen to be distinct, have been fabricated using an array of conductive textiles, and are benchmarked against similar structures made from a flexible conductor. SAR values are evaluated at three different frequencies, i.e., 2.45, 5.2, and 5.8 GHz, respectively, using a commercial electromagnetic solver and a certified experimental setup. Factors affecting the SAR behavior are presented and discussed. Results indicate that antennas without a rear ground plane are producing almost three times the SAR of textile antennas that feature a full ground plane. The results of this paper point out that the repeatability of the measurements is about 10Q and that the agreement between simulations and measurements is on the order of about 17Q.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Specific Absorption Rate (SAR) Evaluation of Textile Antennas

Soh

Vandenbosch

Wee

et al. 2015

IEEE Antennas Propag. Mag.

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show abstract

“…In [6], a ferrite sheet was adopted as a protection attachment between the antenna and the human head. In [7], a study on the belongings of attaching conductive materials to the cellular phone for SAR reduction has been offered.…”

Section: Introductionmentioning

confidence: 99%

On the design of low SAR CPW antenna with magneto dielectric AMC based ground plane

Karimian

Pourahmadazar

Nedil

et al. 2016

2016 10th European Conference on Antennas and Propagation (EuCAP)

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A very compact AMC structure based on a magneto-dielectric substrate is proposed in this paper. A lowprofile spiral loop is inserted under a conventional AMC structure to act as a high permittivity/permeability substrate, which leads to a compact AMC plane. A 75-percent reduction was achieved by this technique compared to the conventional AMC. The modified AMC ground plane is inserted between a human's body and a simple CPW antenna. The specific absorption rate calculation from full wave analyzer shows that a 45-percent reduction is attained compared to the antenna without AMC ground plane. To validate the magneto-dielectric AMC structure, two full wave analyzers were used. The comparison between the two simulators shows a good agreement between them.

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“…From a lot of practical and empirical experience we had, the body SAR in 5‐GHz WLAN band is usually higher than that in the 2.4 GHz band from the antenna given by the same input power. A few research studies on the SAR reduction have been reported in the literature , in which two main types of methods were mainly used. First, it has been shown that the SAR can be reduced by placing the ferrite sheet between the antenna and the torso or the metamaterials between the antenna and the head .…”

Section: Introductionmentioning

confidence: 99%

Studies on SAR reduction using impedance mismatch loss for simple printed 5 GHz monopoles

Lee

2015

Micro & Optical Tech Letters

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A new approach to decreasing the specific absorption rate (SAR) for simple, printed monopoles in the 5‐GHz (5150–5825 MHz) WLAN band is presented. The antennas here are the conventional T‐shaped monopoles with a shorting strip located in between the top radiating arm and the antenna ground. The antenna was devised to be less matched (6 dB return loss) with 0.59 dB more insertion loss, yet the far‐field characteristics were slightly degraded and still met the industrial antenna specifications. It was found that the decreased near‐field radiation can be obtained, and the measured body SAR was substantially lowered by about 35–36% with an air gap of 2 mm directly from the antenna, which was provided by various input power. Details of the design approach and the results are discussed in the article. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:2376–2384, 2015

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Polymeric ferrite sheets for SAR reduction of wearable antennas

Cited by 21 publications

References 2 publications

Specific Absorption Rate (SAR) Evaluation of Textile Antennas

Specific Absorption Rate (SAR) Evaluation of Textile Antennas

On the design of low SAR CPW antenna with magneto dielectric AMC based ground plane

Studies on SAR reduction using impedance mismatch loss for simple printed 5 GHz monopoles

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