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

2 We Live in a 50Ω World The components have been designed for ideal 50Ω operation!

3 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?

4 Mobile Phone Testing Beyond 50Ω It is not enough to test a phone at ideal 50Ω, it must be tested under realistic conditions! Agilent 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

5 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

6 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°

7 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!

8 The SLIDE-SCREW TUNER

9 Automatic Tuner or Manual Tuner ?

10 The Pre-Calibrated Automated Tuner Motor 1 (Carriage) Motors 2 & 3 (Probes) Slabline

11 Maury Repeatability Data a bc a) specification b) Worst case repeatabilityc) average repeatability dB

12 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

13 Fixed Source Power LP V ds = 5.0 V I dsq = 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

14 AMTS Software for Agilent 8960

15 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

16 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

17 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

18 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 dB!) - Are there thermal stability issues? (performance may degrade 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!

19 Mobile Phone Test System