Practical Measurement
Approaches for Complex Small
Antenna Systems
Derek Skousen
MI Technologies
Industry Trends
• Higher data rates, higher network
congestion
• Denser set of wireless functionality
– Multi-mode, GPS, Bluetooth, WiFi
• Increasing application and UI functionality
• Use cases expanding
– More indoor, off head, off call usage
• Design driven size, cost constraints
Changing Test Environment
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Coupling issues
Power profile issues
Access issues
System vs. antenna test
Coupling
• Multi-antenna coupling
• User (body, clothes, cases etc) coupling
• Chassis and internal electronics coupling
(image: SPEAG)
Air Interface Priority
• Device effectiveness increasingly associated with
antennas and air interface
• Design for diversity, multipath fading
• Average power level vs. peak power levels
Img src: Reuters
Design/Test Processes
• Antenna access
• System vs. antenna test
• Ground plane simulation
Metrics
• Radiation Efficiency
• Resonance Frequency
• Impedance
Metrics cont.
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Gain
Gain Correlation
Directivity
Radiation Pattern
Metrics cont.
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Diversity Gain
Apparent Diversity Gain
Mean Effective Gain (MEG)
Mean Effective Directivities (MED)
Methods: Open Air Tests
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Outdoor
Rooftop
Open sky
Ignore environment
Methods: Anechoic Chamber
Methods: NearNear-field Image Scan
• Hot spot checking
• Image Array Scanner
• Near-Field Scanner in Anechoic Chamber
(Img src: Emscan Corp.)
Methods: Reverberation Chamber
Evolving Diagnostics
Deterministic Pattern
Statistical Profiling
Summary
• Industry trends adding complexity
• Antenna design level gaining visibility
• Today’s antenna tests need to
accommodate new dimensions of variation.
• Value of pattern and impedance
measurements shifting to efficiency and
diversity
• Reference environments now offer
multipath insights.
For More Information:
www.bluetest.se
www.bluetest.us
www.mi-technologies.com/MeasurementApplications/NearField.htm
Long Term Evolution: 3GPP LTE Radio and Cellular Technology (2009)
Chapter 12: Measuring Performance of 3GPP LTE Terminals and Small Base
Stations in Reverberation Chambers (http://www.bluetest.se/download/AU7210_C012.pdf)
Measuring Antennas in Reverberation Chamber
(http://www.bluetest.us/papers/Bluetest-4posters-030810.pdf)
Measuring Diversity Gain in Reverberation Chambers
(http://www.bluetest.us/papers/Diversity_gain_effieciency_TCP_070628.pdf)
Embracing Complexity: MIMO Over-the-Air Testing with the Reverberation
Chamber
(http://www.mwjournal.com/journal/article.asp?HH_ID=AR_9505&tite=Embracing%20Complexity:%20
MIMO%20Over-the-Air%20Testing%20with%20the%20Reverberation%20Chamber)