Mobile Phone Testing using Impedance Tuners · Mobile Phone Testing using Impedance Tuners ......

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1 Mobile Phone Testing using Impedance Tuners Roman Meierer and Steve Dudkiewicz Your Complete Measurement & Modeling Solutions Partner

Transcript of Mobile Phone Testing using Impedance Tuners · Mobile Phone Testing using Impedance Tuners ......

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Mobile Phone Testing using Impedance Tuners

Roman Meierer and Steve Dudkiewicz

Your Complete Measurement & Modeling Solutions Partner

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We Live in a 50Ω World

The components have been designed for ideal 50Ω operation!

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When are we not at 50Ω?

1) Antennas are not always 50Ω by design How much mismatch between phone and antenna can be tolerated?

2) Non-ideal reception conditions mimic non-50Ω conditions

Driving inside tunnel Talking inside elevator

Broken antenna

How much mismatch between phone and antenna/outside-world can be tolerated?

How can we even test outside of 50Ω?

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Mobile Phone Testing Beyond 50Ω

It is not enough to test a phone at ideal 50Ω, it must be tested under realistic conditions!

Agilent 8960 - Acts as base station

- Sets active channel and power levels - Measures power, BER, ACPR …

Maury MT98x Tuner - Sets non-50Ω impedance

Maury AMTS Software - Controls 8960 and tuner

- De-embeds VSWR and power levels to DUT reference

- Controls variable DC supply to mimic battery voltages

- Automates measurements

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What is the Agilent 8960?

Note: 8960 testing is at 50Ω condition only

“The Agilent 8960 is your one-box solution for wireless device development, manufacturing and repair - today and tomorrow “ – Agilent Technologies

Important Tests using 8960:

TX Power Test at specific PCL levels

RX Sensitivity BER testing

ACPR

Output Spectrum

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Tuner emulates mismatched antenna

In order to emulate all non-50Ω conditions, we remove the antenna from the phone and replace with cable connected to impedance tuner.

Impedance tuners can create any VSWR magnitude between 1:1 and ~10-200:1 and phase between 0-360°

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Easily Reproducible Test Conditions

No anechoic chamber or reference antenna needed Compact laboratory desktop setup results in easily reproducible test systems and results

Test multiple modules under identical conditions in a fraction of the time, at multiple site locations!

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The SLIDE-SCREW TUNER

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Automatic Tuner or Manual Tuner ?

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0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 Tuner Reflection

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dB

) Phone Power Tuner Loss 8960 Power

Maximum Phone Power

Maximum 8960 Power

Tuner Loss

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The Pre-Calibrated Automated Tuner

Motor 1 (Carriage)

Motors 2 & 3 (Probes)

Slabline

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Maury Repeatability Data a b c

� a) specification b) Worst case repeatability c) average repeatability

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dB

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Tuner Characterization (Calibration)

S-parameters are recorded for various X-Y positions of the tuner at each frequency of interest loss is calculated in real-time instant DUT de-embedding

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Fixed Source Power LP

Vds = 5.0 V Idsq = 150 mA Freq = 835 MHz

At maximum power of 38 dBm the PAE is 51%

At maximum PAE of 70% the power is 33 dBm

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AMTS Software for Agilent 8960

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TX Power Testing -  Set Frequency/Channel -  Set PCL transmit power level

-  Set VSWR magnitude and phase -  Set DC voltage

Measure power delivered to antenna port as function of VSWR magnitude and phase

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RX Sensitivity Testing -  Set Frequency/Channel -  Set required BER (2% or other)

-  Set VSWR magnitude and phase -  Set DC voltage

Measure sensitivity of phone for given BER as function of VSWR magnitude and phase

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Automation through Scripting

Pre-define list of frequencies/channels, power levels, battery voltages, VSWR settings

Automatically measure each line as a separate test intelligent sequencing

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What do we do with the results?

1) Antennas are not always 50Ω by design Tell the antenna designer how much mismatch is acceptable based on real-life tests (did 2:1 VSWR at all phases meet requirements? 3:1?...)

2) Non-ideal reception conditions mimic non-50Ω conditions - Did our mobile phone pass minimum requirements under pre-defined VSWR and voltage conditions? -  After a large VSWR sweep plan, does the phone return to same performance at 1:1 VSWR? (performance may degrade 0.5-1.0 dB!) -  Are there thermal stability issues? (performance may degrade 0.5-1.0 dB inside burst check for “smooth” curves) -  Is the phone design acceptable or must we redesign a component? -  Is this a batch manufacturing issue?

These are only suggestions on how to analyze the data, the possibilities are endless!

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Mobile Phone Test System