Analysis of SAR on flat phantom for different multi-antenna mobile terminals

Li, Hui; Tsiaras, Apostolos; Derat, Benoît; Lau, Buon Kiong

doi:10.1109/eucap.2014.6902194

Cited by 5 publications

(5 citation statements)

References 8 publications

(12 reference statements)

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“…The rate of absorption energy from the EMF radiation by human body, which causes thermal effect can be computed by a dosimetric measurement known as specific absorption rate (SAR). SAR is the dosimetric measure of the rate at which energy is absorbed in body tissue, in unit of watt per kilogram (W/kg) that can be expressed as the following expression (1) [8]:…”

Section: Introductionmentioning

confidence: 99%

Specific Absorption Rate Assessment of Multiple Microstrip Patch Antenna Array

2018

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Interaction between electromagnetic field (EMF) radiated from multiple antennas and human body is crucial to be explored as multiple antennas are the essential implemented devices to achieve the requirements of the future evolved fifth generation (5G) technology. Thus, this article presents a significant study of the radiated EMF effect from a single, and multiple antennas towards human through the assessment of specific absorption rate (SAR). The single antenna, 1 x 2, 1 x 3 and 1 x 4 arrays of microstrip patch antennas are designed to cover mobile operating frequencies of 0.8, 0.85, 0.9, 1.8, 2.1 and 2.6 GHz. Two types of human head phantoms are implemented in this study, which are specific anthropomorphic mannequin (SAM) and Voxel head model that placed close to single antenna or antenna array to investigate the penetration of EMF towards the human tissue. The single antenna or antenna array is placed with fixed distance of 10 mm from the phantom, which excited by maximum allowable power of 19 dBm in CST Microwave Studio 2016. The effect of the radiated EMF that quantified by SAR parameter, which depicts satisfying results against the established standard limits at averaged 1g and 10g mass of tissues for all designated frequencies that utilized for single and multiple antennas.

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Section: Introductionmentioning

confidence: 99%

Specific Absorption Rate Assessment of Multiple Microstrip Patch Antenna Array

2018

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“…Several recent studies focused on evaluating and estimating SAR for multi-antennas [5]- [11]. In [5], Wang et al provided a tighter upper bound of MIMO-SAR than one based only on electric field magnitudes, improving SAR estimation accuracy.…”

Section: Introductionmentioning

confidence: 99%

“…The influence of the ground plane on the SAR for several dual-antenna mobile prototypes was evaluated in [10], mainly for the stand-alone SAR (S-SAR). Average MIMO-SAR (over all relative phases) was studied for 5 dual-antenna prototypes in [11], focusing on the impact of antenna type on SAR.…”

Section: Introductionmentioning

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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“…Such a comprehensive evaluation is not only technically challenging, but also prohibitively expensive and time-consuming. So far, there have been only a few reports in the literature on SAR evaluation for multi-antennas [2][3][4], especially for simultaneous SAR. In particular, field summation schemes based on the conventional scalar probes and the corresponding testing methodologies were proposed in [4] for simultaneous peak SAR evaluation.…”

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confidence: 99%

“…When m antennas (1 < m ≤ n) are transmitting simultaneously, the total power is divided among m ports. The power allocated to the pth port is given by P p = a p P total (2) where α p is a real constant with 0 ≤ a p ≤ 1, m p=1 a p = 1. Since the square of the electric field magnitude is linearly proportional to the input power, i.e.…”

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confidence: 99%

Efficient evaluation of specific absorption rate for MIMO terminals

Li¹,

Lau²

2014

Electron. lett.

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, "Efficient evaluation of specific absorption rate (SAR) for MIMO terminals," Electron. Lett., vol. 50, no. 22, pp. 1561-1562, Oct. 23, 2014 1 Efficient evaluation of specific absorption rate (SAR) for MIMO terminals H. Li and B. K. Lau Department of Electrical and Information Technology, Lund University, 221 00 Lund, Sweden E-mail: Hui.Li@eit.lth.se Abstract: Multi-antenna enabled terminal devices are required to comply with the standards for limiting human exposure to electric fields. However, when compared to traditional single-antenna terminals, a comprehensive evaluation of specific absorption rate (SAR) for multi-antenna terminals is impractical. This is because both the power allocation and phase of the electric fields from different antennas are arbitrary in practical MIMO operation, hence requiring exhaustive evaluation over all possible cases. In this context, this paper first proposes time averaged simultaneous peak SAR (TASPS) as an efficient metric to evaluate exposure when more than one antenna is transmitting simultaneously. Then, it is analytically derived that TASPS will be below a given exposure limit, as long as the stand-alone peak SAR for each antenna is smaller than that limit. Thus, SAR evaluation is greatly simplified since only stand-alone SAR needs to be measured. Several examples of dual-antenna mobile handsets are shown to illustrate and validate the analytical result.Introduction: The initial focus of multiple-input multiple-output (MIMO) in wireless communications was to improve the downlink (e.g., LTE), meaning that the uplink transmission still only involved one antenna. With the recent launch of LTE-Advanced (LTE-A) [1], multi-antennas can also be used to enhance the uplink. As in the case of single-antenna transmission, devices with multi-antenna transmission are required to comply with the standards for limiting human exposure to electric fields. The exposure of the body to a RF electromagnetic field is usually measured by specific absorption rate (SAR). In a MIMO terminal, stand-alone SAR measures the exposure when only one antenna is transmitting, with the other antennas terminated by their source impedances. In contrast, simultaneous SAR characterises the exposure when more than one antenna is transmitting. In this case, the power level and phase of each transmitting antenna vary rapidly due to MIMO pre-coding and link adaptation. Thus, the superposition of fields from different antennas, i.e., the total electric field, at a given point also varies rapidly. To capture the true simultaneous SAR values, field measurements should be performed quickly over time and at multiple spatial points. Such a comprehensive evaluation is not only technically challenging, but also prohibitively expensive and time-consuming.So far, there are few literatures on SAR evaluation for multi-antennas [2-4], especially for simultaneous SAR. In particular, field summation schemes based on conventional scalar probes and the corresponding testing methodologies were proposed in [4] for simultaneous pea...

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Analysis of SAR on flat phantom for different multi-antenna mobile terminals

Cited by 5 publications

References 8 publications

Specific Absorption Rate Assessment of Multiple Microstrip Patch Antenna Array

Specific Absorption Rate Assessment of Multiple Microstrip Patch Antenna Array

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

Efficient evaluation of specific absorption rate for MIMO terminals

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