A method in determination of the specific absorption rate of multi-antenna devices

Le, Dinh Thanh; Hamada, Lira; Watanabe, Soichi; Onishi, Teruo

doi:10.1109/aps.2014.6904925

Cited by 8 publications

(7 citation statements)

References 1 publication

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“…Fig. 2 (f) of [13] Two dipole antennas (1:1 ratio), handheld device. a 1 + a 2 cos(θ k,1 ) + a 3 sin(θ k,1 )…”

Section: System Modelmentioning

confidence: 99%

“…[11], [10], which accurately model the exposure dose of single antenna WPD users in multi-user multi-carrier systems or link level exposure models, e.g. [12], [13] [14], [15], [7], that model the specific absorption rate (SAR) of multi-antenna WPD users (a.k.a MIMO-SAR), but none combining both. The model of [12], which considers a two antenna WPD and has subsequently been extended in [6], [14], and [15] for more transmit antennas, is based on an experimental result of [16].…”

Section: Introductionmentioning

confidence: 99%

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On the Exposure Dose Minimization of Multi-Antenna Multi-Carrier System Users

Héliot

Brown

2022

IEEE Trans. Veh. Technol.

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From the fourth generation (4G) of cellular systems onward, wireless personal devices (WPDs) support multi-input multi-output (MIMO) communication. However, the impact of MIMO communication on the electromagnetic field (EMF) of WPD users has yet to be fully understood and analyzed at the system level. In this paper, we first provide a generic model for assessing the individual exposure dose of multi-antenna WPD users in a multi-user multi-carrier communication system. An optimization framework for minimizing this exposure dose is then developed based on our exposure model. This framework helps us to identify a new criterion, i.e., the ratio between the normalized exposure dose and the channel to noise ratio (CNR), as the main system level criterion for minimizing the individual exposure dose of multi-antenna WPD users. This criterion is further integrated in the design of two novel centralized resource allocation schemes that take advantage of the multiple antennas at the WPD to minimize the per-user exposure dose, when full or limited knowledge of each user channel is available. Our new schemes can significantly reduce the individual exposure dose of WPD users (by approximately 80%) in comparison with the most relevant existing resource allocation schemes. Our results also provide insights into the logarithmic relationship between the per-user exposure dose and the number of receive antennas (or the number of time slots), and how such a parameter can be exploited to further reduce the exposure and/or provide a higher SE while maintaining a low exposure dose.

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“…Fig. 2 (f) of [13] Two dipole antennas (1:1 ratio), handheld device. a 1 + a 2 cos(θ k,1 ) + a 3 sin(θ k,1 )…”

Section: System Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

On the Exposure Dose Minimization of Multi-Antenna Multi-Carrier System Users

Héliot

Brown

2022

IEEE Trans. Veh. Technol.

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“…This is partly attributed to the 0 phase difference not being easy to obtain in the measurement. A more sophisticated way to obtain an accurate relative phase is provided in [16]. In addition, a slight asymmetry in the measured SAR distribution is observed for Prototype A (see Table II).…”

Section: Prototypes and Experimentsmentioning

confidence: 99%

Analysis and Estimation of MIMO-SAR for Multi-antenna Mobile Handsets

Tsiaras

Lau

2017

IEEE Trans. Antennas Propagat.

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Measuring MIMO-SAR is an important part of mobile handset evaluation, following the introduction of uplink MIMO transmission schemes in LTE-Advanced. However, the measurement of MIMO-SAR is complex and time-consuming. In this paper, 6 unique dual-antenna mobile handsets, including both typical and novel designs, are analyzed to determine the dependence of MIMO-SAR on antenna configuration and correlation. It is found that, for certain antenna configurations, the location of the maximum MIMO-SAR and the corresponding relative phase between the ports can be predicted. This can be applied to drastically reduce measurement time. In addition, dual-antennas with low envelope correlation coefficients in the radiation patterns also offer near-orthogonal electric near-fields. This leads to smaller MIMO-SAR than stand-alone SAR (S-SAR) over all relative phases, making MIMO-SAR measurement unnecessary. The results also provide guidelines for designing multi-antenna handsets with low SARs. For verification, the S-SAR and MIMO-SAR at relative phase of 0° were measured for several prototypes. The measured SAR distributions showed good agreement with the simulated ones.

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“…The second terminal has two antennas exciting two orthogonal modes of the chassis [1], so that the current is more distributed along the chassis. The terminals were placed on a flat phantom with dimensions of 225 × 150 × 150 mm 3 and the same properties as those of a human body. To evaluate SAR, the accepted power at the antennas was set to 24 dBm (0.25W) at 0.859 GHz, the center frequency of LTE Band 5.…”

Section: Tasps For Dual-antenna Mobile Handsetsmentioning

confidence: 99%

“…However, the schemes were shown to be conservative for multi-antenna devices. A simplified method to obtain simultaneous SAR was proposed in [3], but the method becomes complicated as the number of transmitting antennas increases.…”

Section: Introductionmentioning

confidence: 99%

Simple assessment of Specific Absorption Rate (SAR) for MIMO terminals

Lau

2015

2015 IEEE International Symposium on Antennas and Propagation &Amp; USNC/URSI National Radio Science Meeting

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Abstract-Evaluating SAR for multi-antennas is difficult and impractical due to the arbitrary power allocation and phase of the electric fields from different antennas causing the total field to change randomly. In this context, a simple approach was recently proposed for assessing SAR when more than one antenna is transmitting simultaneously. The metric of time averaged simultaneous peak SAR (TASPS) was derived for the purpose of showing that only the stand-alone SAR for each antenna needs to be evaluated in order to verify if the SAR for multi-antenna transmissions also stays within the exposure limit. In this paper, we briefly review the derivation and illustrate the physical mechanism underlying this result for a two-antenna prototype using stand-alone and simultaneous SAR distributions.

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A method in determination of the specific absorption rate of multi-antenna devices

Cited by 8 publications

References 1 publication

On the Exposure Dose Minimization of Multi-Antenna Multi-Carrier System Users

On the Exposure Dose Minimization of Multi-Antenna Multi-Carrier System Users

Analysis and Estimation of MIMO-SAR for Multi-antenna Mobile Handsets

Simple assessment of Specific Absorption Rate (SAR) for MIMO terminals

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