| 1. |
- He, Wang, et al.
(author)
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RF Compliance Study of Temperature Elevation in Human Head Model Around 28 GHz for 5G User Equipment Application : Simulation Analysis
- 2018
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In: IEEE Access. - : IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC. - 2169-3536. ; 6
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Journal article (peer-reviewed)abstract
- The crowdedness of current cellular bands and the demand for higher transmission speed prompt the use of the millimeter-wave spectrum for the next-generation mobile communication. In the millimeter-wave frequencies, the dosimetric quantity for human exposure to electromagnetic fields changes from the specific absorption rate to incident power density. In this paper, we used 28-GHz beam-steering patch arrays, a dipole antenna, and plane waves to investigate the temperature elevation in a multi-layer model of human head and its correlation with power density metrics. The power density averaged over one square-centimeter in free space and the peak temperature elevation in tissue at 28 GHz have good correlation. The peak temperature elevation indicated by the power density averaged one square-centimeter also agrees well with the peak temperature elevation induced by the plane waves. The results show that the averaging area of a few square-centimeters may be a good candidate for the spatial-average power density. The findings provide valuable input to the ongoing revision and updating of relevant safety standards and guidelines.
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| 2. |
- Helander, Jakob, et al.
(author)
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Characterization of Millimeter Wave Phased Array Antennas in Mobile Terminal for 5G Mobile System
- 2015
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In: [Host publication title missing]. ; , s. 7-8
-
Conference paper (peer-reviewed)abstract
- This paper presents a characterization method for millimeter wave (mmWave) phased array antennas in the mobile terminal for 5G communication. Arrays of different antenna designs, operating at 28 GHz, are evaluated according to novel characterization methods in this context - the total scan pattern of the phased array and its respective coverage efficiency. The results show the relevance of evaluating antenna array designs according to these characteristics, and illustrate, by introducing pattern diversity through sub-array schemes, that the coverage efficiency can be enhanced.
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| 3. |
- Xu, Bo, et al.
(author)
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Investigation of Planar Near-Field Measurement of Millimeter-Wave Antenna for 5G Application
- 2016
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In: 2016 INTERNATIONAL SYMPOSIUM ON ANTENNAS AND PROPAGATION (ISAP). - : IEEE. - 9784885523137 ; , s. 600-601
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Conference paper (peer-reviewed)abstract
- The requirement of higher data rates and the emergence of new wireless device demands in future 5G communication put millimeter-wave frequencies in focus. To investigate electromagnetic-filed exposure at such frequencies for 5G cellular phone application, a planar near-field antenna measurement system is established. A tapered open-ended rectangular waveguide was used as the probe antenna, and a patch array antenna operating at 28 GHz was used as antenna under test. The distribution of power density above the antenna surface was calculated based on the measured data and the plane wave expansion method.
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| 4. |
- Xu, Bo, et al.
(author)
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Radiation Performance Analysis of 28 GHz Antennas Integrated in 5G Mobile Terminal Housing
- 2018
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In: IEEE Access. - : Institute of Electrical and Electronics Engineers (IEEE). - 2169-3536. ; , s. 48088-48101
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Journal article (peer-reviewed)abstract
- Radiation from printed millimeter-wave antennas integrated in mobile terminals is affected by surface currents on chassis, guided waves trapped in dielectric layers, superstrates, and the user’s hand, making mobile antenna design for 5G communication challenging. In this paper, four canonical types of printed 28 GHz antenna elements are integrated in a 5G mobile terminal mock-up. Different kinds of terminal housing effects are examined separately, and the terminal housing effects are also diagnosed through equivalent currents by using the inverse source technique. To account for the terminal housing effects on a beam-scanning antenna subarray, we propose the effective beam-scanning efficiency to evaluate its coverage performance. This paper presents the detailed analysis, results, and new concepts regarding the terminal housing effects, and thereby provides valuable insight into the practical 5G mobile antenna design and radiation performance characterization.
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| 5. |
- Xu, Bo, et al.
(author)
-
Radio Frequency Exposure Compliance of Multiple Antennas for Cellular Equipment Based on Semidefinite Relaxation
- 2019
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In: IEEE Transactions on Electromagnetic Compatibility. - : IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC. - 0018-9375 .- 1558-187X. ; 61:2, s. 327-336
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Journal article (peer-reviewed)abstract
- Human exposure to radio frequency (RF) electromagnetic fields should not exceed the exposure limits set by the relevant regulatory guidelines. In this paper, we provide approaches to determine upper bounds of maximum exposure from multiple antennas. When the total transmitted power is fixed, the maximum exposure can be determined by an eigenvalue decomposition. If an individual antenna has additional power constraint, the exposure maximization problem can be relaxed to a semidefinite program. Two case studies are given to demonstrate the approaches to the maximum exposure of cellular equipment using multiple antennas. The methods and the obtained results provide valuable insights into RF compliance procedures of cellular equipment.
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| 6. |
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