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Experimental investigation of adaptive impedance matching for a MIMO terminal with CMOS SOI tuners

Vasilev, Ivaylo LU ; Lindstrand, Jonas LU ; Plicanic, Vanja LU ; Sjöland, Henrik LU and Lau, Buon Kiong LU (2016) In IEEE Transactions on Microwave Theory and Techniques 64(5). p.1622-1622
Abstract
It is well known that user proximity introduces absorption and impedance mismatch losses that severely degrade multiple-input multiple-output (MIMO) performance of handset antennas. In this work, we experimentally verified the potential of adaptive impedance matching (AIM) to mitigate user interaction effects and identified the main AIM gain mechanism in realistic systems. A practical setup including custom-designed CMOS silicon-on-insulator (SOI) impedance tuners implemented on a MIMO handset was measured in three propagation environments and 10 real user scenarios. The results indicate that AIM can improve MIMO capacity by up to 42% equivalent to 3.5 dB of multiplexing efficiency (ME) gain. Taking into account the measured losses of 1 dB... (More)
It is well known that user proximity introduces absorption and impedance mismatch losses that severely degrade multiple-input multiple-output (MIMO) performance of handset antennas. In this work, we experimentally verified the potential of adaptive impedance matching (AIM) to mitigate user interaction effects and identified the main AIM gain mechanism in realistic systems. A practical setup including custom-designed CMOS silicon-on-insulator (SOI) impedance tuners implemented on a MIMO handset was measured in three propagation environments and 10 real user scenarios. The results indicate that AIM can improve MIMO capacity by up to 42% equivalent to 3.5 dB of multiplexing efficiency (ME) gain. Taking into account the measured losses of 1 dB in the integrated tuners, the maximum net ME gain is 2.5 dB suggesting applicability in practical systems. Variations in ME gains of up to 1.5 dB for different hand-grip styles were mainly due to differences in impedance mismatch and tuner loss distribution. The study also confirmed earlier results on the significant differences in mismatch and absorption between phantoms and real users, in which the phantoms underestimated user effects and therefore AIM gains. Finally, propagation environments of different angular spreads were found to give only minor ME gain variations. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
in press
subject
keywords
CMOS ICs, impedance matching, antennas and propagation, MIMO and cellular systems
in
IEEE Transactions on Microwave Theory and Techniques
volume
64
issue
5
pages
1622 - 1622
publisher
IEEE--Institute of Electrical and Electronics Engineers Inc.
external identifiers
  • Scopus:84963685609
ISSN
0018-9480
DOI
10.1109/TMTT.2016.2546244
project
EIT_Optantsys Novel Antenna System Design Paradigm for High Performance Mobile Communications
EIT_ANTCHN Antenna-Channel Harmonization for Throughput Enhancement in Advanced Mobile Terminals
language
English
LU publication?
yes
id
e2a7a8ba-bcd5-4360-a87d-28a8493ea314 (old id 8821314)
date added to LUP
2016-03-01 11:31:46
date last changed
2016-07-04 04:12:52
@misc{e2a7a8ba-bcd5-4360-a87d-28a8493ea314,
  abstract     = {It is well known that user proximity introduces absorption and impedance mismatch losses that severely degrade multiple-input multiple-output (MIMO) performance of handset antennas. In this work, we experimentally verified the potential of adaptive impedance matching (AIM) to mitigate user interaction effects and identified the main AIM gain mechanism in realistic systems. A practical setup including custom-designed CMOS silicon-on-insulator (SOI) impedance tuners implemented on a MIMO handset was measured in three propagation environments and 10 real user scenarios. The results indicate that AIM can improve MIMO capacity by up to 42% equivalent to 3.5 dB of multiplexing efficiency (ME) gain. Taking into account the measured losses of 1 dB in the integrated tuners, the maximum net ME gain is 2.5 dB suggesting applicability in practical systems. Variations in ME gains of up to 1.5 dB for different hand-grip styles were mainly due to differences in impedance mismatch and tuner loss distribution. The study also confirmed earlier results on the significant differences in mismatch and absorption between phantoms and real users, in which the phantoms underestimated user effects and therefore AIM gains. Finally, propagation environments of different angular spreads were found to give only minor ME gain variations.},
  author       = {Vasilev, Ivaylo and Lindstrand, Jonas and Plicanic, Vanja and Sjöland, Henrik and Lau, Buon Kiong},
  issn         = {0018-9480},
  keyword      = {CMOS ICs,impedance matching,antennas and propagation,MIMO and cellular systems},
  language     = {eng},
  number       = {5},
  pages        = {1622--1622},
  publisher    = {ARRAY(0x83a7790)},
  series       = {IEEE Transactions on Microwave Theory and Techniques},
  title        = {Experimental investigation of adaptive impedance matching for a MIMO terminal with CMOS SOI tuners},
  url          = {http://dx.doi.org/10.1109/TMTT.2016.2546244 },
  volume       = {64},
  year         = {2016},
}