obtaining accurate device-only s-parameter data to 15 … · obtaining accurate device-only...
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Copyright A Tyco International Ltd. Company 2004
Circuits & Design
Obtaining Accurate DeviceObtaining Accurate Device--OnlyOnlySS--Parameter Data to 15Parameter Data to 15--20 GHz20 GHz
Using InUsing In--FixtureFixtureMeasurement TechniquesMeasurement Techniques
Chad W. MorganChad W. MorganFebruary 3, 2004February 3, 2004
Technical Session 7-TP1
Copyright A Tyco International Ltd. Company 2004
Circuits & Design2
Presentation Outline
In-FixtureTechnique
Comparison
TRL/LRMCalibration
Success Stories
FrequencyDomain
Considerations
In-FixtureMeasurementTechniques
TRL/LRMCalibration
Implementation
Side FlowchartAlways HighlightsCurrent LocationIn Presentation
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Circuits & Design3
Frequency Domain Considerations
In-FixtureMeasurementTechniques
TRL/LRMCalibration
Implementation
TRL/LRMCalibration
Success Stories
In-FixtureTechnique
Comparison
FrequencyDomain
Considerations
FrequencyDomain
Considerations
• Why Measure in the Frequency Domain?• Why Data to 15-20 GHz?
• Why ‘In-Fixture’ Measurements?
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Circuits & Design4
•• DUTDUT--ONLY measurement capabilityONLY measurement capability–– All test fixture effects removedAll test fixture effects removed
Why Measure in the Frequency Domain?
In-FixtureMeasurementTechniques
TRL/LRMCalibration
Implementation
TRL/LRMCalibration
Success Stories
In-FixtureTechnique
Comparison
FrequencyDomain
Considerations
•• DISTRIBUTED data for highDISTRIBUTED data for high--speed modelsspeed models–– Lumped models inadequate above several GHzLumped models inadequate above several GHz
Insertion Loss
-10.0
-9.0
-8.0
-7.0
-6.0
-5.0
-4.0
-3.0
-2.0
-1.0
0.0
1.0E+08 1.0E+09 1.0E+10Frequency (Hz)
Am
plitu
de R
atio
(dB)
•• FINISHED measurement model for the DUTFINISHED measurement model for the DUT–– Can calculate any electrical valueCan calculate any electrical value–– Can reconstruct time domain signals via IFFTsCan reconstruct time domain signals via IFFTs
•• FULL characterization of Device Under Test (FULL characterization of Device Under Test (DUTDUT))–– Direct display of performance vs. speedDirect display of performance vs. speed–– Easy detection of narrowband resonancesEasy detection of narrowband resonances
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Circuits & Design5
Why Data to 15-20 GHz?
•• Experience shows that 20 GHz data allows good Experience shows that 20 GHz data allows good transforms for 10 Gbps waves & 25 ps edge ratestransforms for 10 Gbps waves & 25 ps edge rates
In-FixtureMeasurementTechniques
TRL/LRMCalibration
Implementation
TRL/LRMCalibration
Success Stories
In-FixtureTechnique
Comparison
FrequencyDomain
Considerations
GHzpsT
Fr
BW 2025
5.05.0 ===Signal Integrity ‘Rule of Thumb’: The majority of a signal’s energy lies below FBW
•• Practical transform approachPractical transform approach
Sampling every 5ps (20 samples/bit) requires data to 100 GHz!! - Difficult to measure (λ in air = 3 mm)
GHzpsT
Fs
1005*21
*21
max ===
•• Rigorous transform approach:Rigorous transform approach:
•• HighHigh--speed serial links are speed serial links are pushing 10 Gbpspushing 10 Gbps
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Circuits & Design6
Why ‘In-Fixture’ Measurements?
In-FixtureMeasurementTechniques
TRL/LRMCalibration
Implementation
TRL/LRMCalibration
Success Stories
In-FixtureTechnique
Comparison
FrequencyDomain
Considerations
•• Uniform standards measurementsUniform standards measurements–– Standards available for many RF interfacesStandards available for many RF interfaces–– Implementation well documentedImplementation well documented
–– NO REMOVAL OF TEST FIXTURE EFFECTSNO REMOVAL OF TEST FIXTURE EFFECTSREF1 REF2
DUT
–– Only removes VNA/cable/adapter effectsOnly removes VNA/cable/adapter effects–– NO REMOVAL OF TEST FIXTURE EFFECTSNO REMOVAL OF TEST FIXTURE EFFECTS
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Circuits & Design7
Why ‘In-Fixture’ Measurements?
In-FixtureMeasurementTechniques
TRL/LRMCalibration
Implementation
TRL/LRMCalibration
Success Stories
In-FixtureTechnique
Comparison
FrequencyDomain
Considerations
REF1 REF2DUT
–– ALLOWS DUTALLOWS DUT--ONLY MEASUREMENTONLY MEASUREMENT
•• ‘‘InIn--Fixture’ measurementsFixture’ measurements–– Standards must be customStandards must be custom--designeddesigned–– Documentation more challenging to findDocumentation more challenging to find
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Circuits & Design8
In-Fixture Measurement Techniques
In-FixtureMeasurementTechniques
TRL/LRMCalibration
Implementation
TRL/LRMCalibration
Success Stories
In-FixtureTechnique
Comparison
TRL/LRM Cal
Normalization
Time Gating
[T] Deembed
FrequencyDomain
Considerations
SOLT Cal
In-FixtureMeasurementTechniques
• SOLT Calibration• TRL/LRM Calibration
• Normalization• Enhanced Time Domain Gating
• [ T ] Matrix Deembedding
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Circuits & Design9
Presentation Terminology
In-FixtureMeasurementTechniques
TRL/LRMCalibration
Implementation
TRL/LRMCalibration
Success Stories
In-FixtureTechnique
Comparison
TRL/LRM Cal
Normalization
Time Gating
[T] Deembed
FrequencyDomain
Considerations
SOLT Cal
•• DeembeddingDeembedding–– Removal of the unwanted measurement portion, GIVEN Removal of the unwanted measurement portion, GIVEN
a known response for the fixture errora known response for the fixture error–– [ T ] matrices & e[ T ] matrices & e--γγll
•• CalibrationCalibration–– Characterization AND removal of the unwanted Characterization AND removal of the unwanted
measurement portion using known standardsmeasurement portion using known standards–– SOLT & TRLSOLT & TRL
•• Note: Many other methods exist Note: Many other methods exist -- only those only those above are being covered in this presentationabove are being covered in this presentation
•• Error CorrectionError Correction–– Removal of the unwanted measurement portion, using Removal of the unwanted measurement portion, using
postpost--calibration mathematical techniquescalibration mathematical techniques–– Normalization, gating, & enhanced gating Normalization, gating, & enhanced gating
Copyright A Tyco International Ltd. Company 2004
Circuits & Design10
SOLT (SHORT-OPEN-LOAD-THRU) Calibration
In-FixtureMeasurementTechniques
TRL/LRMCalibration
Implementation
TRL/LRMCalibration
Success Stories
In-FixtureTechnique
Comparison
TRL/LRM Cal
Normalization
Time Gating
[T] Deembed
FrequencyDomain
Considerations
SOLT Cal
•• Classic technique that most people useClassic technique that most people use•• Makes use of full 12Makes use of full 12--term error modelterm error model
EDF = Forward Directivity
ESF = Forward Source Match
ERF = Forward Reflection Tracking
ETF = Forward Transmission Tracking
ELF = Forward Load Match
EXF= Forward Isolation
EDR = Reverse Directivity
ESR = Reverse Source Match
ERR = Reverse Reflection Tracking
ETR = Reverse Transmission Tracking
ELR = Reverse Load Match
EXR = Reverse Isolation
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Circuits & Design11
SOLT (SHORT-OPEN-LOAD-THRU) Calibration
In-FixtureMeasurementTechniques
TRL/LRMCalibration
Implementation
TRL/LRMCalibration
Success Stories
In-FixtureTechnique
Comparison
TRL/LRM Cal
Normalization
Time Gating
[T] Deembed
FrequencyDomain
Considerations
SOLT Cal
•• Characterization of directivity, source match, Characterization of directivity, source match, and reflection tracking (both directions)and reflection tracking (both directions)
IMPERFECT LOAD, OPEN, & SHORT standards MUST BE CHARACTERIZED!-LOAD must be perfect (or known)-OPEN fringe capacitance must be known-SHORT lead inductance must be known
3453
2362
271
150 )10()10()10()10()( fCfCfCCFCeff
−−−− •+•+•+•=342
3233
224
112
0 )10()10()10()10()( fLfLfLLHLeff−−−− •+•+•+•=
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Circuits & Design12
SOLT (SHORT-OPEN-LOAD-THRU) Calibration
In-FixtureMeasurementTechniques
TRL/LRMCalibration
Implementation
TRL/LRMCalibration
Success Stories
In-FixtureTechnique
Comparison
TRL/LRM Cal
Normalization
Time Gating
[T] Deembed
FrequencyDomain
Considerations
SOLT Cal
Isolation typically omitted since it is below the noise floor of the VNA (unless averaging used)
Must know Zo and Tpd of THRU
LOAD match is the return loss of the THRU, measured with 1-port that is already calibrated (from previous slide)
•• Characterization of transmission tracking, Characterization of transmission tracking, load match, and isolationload match, and isolation
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Circuits & Design13
SOLT (SHORT-OPEN-LOAD-THRU) Calibration
In-FixtureMeasurementTechniques
TRL/LRMCalibration
Implementation
TRL/LRMCalibration
Success Stories
In-FixtureTechnique
Comparison
TRL/LRM Cal
Normalization
Time Gating
[T] Deembed
FrequencyDomain
Considerations
SOLT Cal
•• Once all 12 error terms are known, test fixture Once all 12 error terms are known, test fixture error can be removed from the measurement:error can be removed from the measurement:
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Circuits & Design14
SOLT (SHORT-OPEN-LOAD-THRU) Calibration
In-FixtureMeasurementTechniques
TRL/LRMCalibration
Implementation
TRL/LRMCalibration
Success Stories
In-FixtureTechnique
Comparison
TRL/LRM Cal
Normalization
Time Gating
[T] Deembed
FrequencyDomain
Considerations
SOLT Cal
•• Well known & easily completed with uniform Well known & easily completed with uniform standardsstandards
•• Difficult to implement w/ ‘inDifficult to implement w/ ‘in--fixture’ standardsfixture’ standards–– Must perfect or fully characterize the LOAD at high Must perfect or fully characterize the LOAD at high
frequency (extremely difficult)frequency (extremely difficult)–– Must eliminate or fully characterize the fringe Must eliminate or fully characterize the fringe
capacitance of the OPEN (difficult but achievable)capacitance of the OPEN (difficult but achievable)–– Must eliminate or fully characterize the lead Must eliminate or fully characterize the lead
inductance of the SHORT (difficult but achievable)inductance of the SHORT (difficult but achievable)–– Must characterize impedance and delay of the Must characterize impedance and delay of the
THRU (relatively easy)THRU (relatively easy)
•• Characterization of SOLT standards relies on Characterization of SOLT standards relies on modeling or other test methods (modeling or other test methods (selfself--defeatingdefeating))
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Circuits & Design15
TRL (THRU-REFLECT-LINE) Calibration
In-FixtureMeasurementTechniques
TRL/LRMCalibration
Implementation
TRL/LRMCalibration
Success Stories
In-FixtureTechnique
Comparison
TRL/LRM Cal
Normalization
Time Gating
[T] Deembed
FrequencyDomain
Considerations
SOLT Cal
•• Characterization math of fixture error and Characterization math of fixture error and deembedding of that error is very different deembedding of that error is very different than SOLTthan SOLT
LaunchError
ReceiveError
THRU
REF1 REF2
LaunchError
ReceiveError
LINE(s)
REF1 REF2
REF1 REF2
LaunchError
ReceiveError
REFLECT(SHORT or OPEN)
•• Calibration technique uses standards belowCalibration technique uses standards below
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Circuits & Design16
TRL (THRU-REFLECT-LINE) Calibration
In-FixtureMeasurementTechniques
TRL/LRMCalibration
Implementation
TRL/LRMCalibration
Success Stories
In-FixtureTechnique
Comparison
TRL/LRM Cal
Normalization
Time Gating
[T] Deembed
FrequencyDomain
Considerations
SOLT Cal
•• More recent calibration techniqueMore recent calibration technique
N. R. Franzen & R. A. Speciale, “A New Procedure for System Calibration & Error Removal in Automated S-parameter Measurements”, Proc. 5th European Microwave Conf, Sep, 1975.
–– Sep, 1975: TSD Calibration Technique IntroducedSep, 1975: TSD Calibration Technique Introduced
Glenn Engen and Cletus Hoer, “Thru-Reflect-Line: An Improved Technique for Calibrating the Dual Six-Port Automatic Network Analyzer”, IEEE-MTT Vol. MTT-27, No. 12, Dec, 1979.
–– Dec, 1979: Improvement to TSD; ‘TRL’ first mentionedDec, 1979: Improvement to TSD; ‘TRL’ first mentioned
Renato Pantoja, Michael Howes, John Richardson, and Roger Pollard, “Improved Calibration and Measurement of the Scattering Parameters of Microwave Integrated Circuits”, IEEE-MTT Vol. 37, No. 11, Nov, 1989.
–– Nov, 1989: TRL improved…pretty much as it is used todayNov, 1989: TRL improved…pretty much as it is used today
Michael Rubin, “De-embedding MM-wave MICs with TRL”, Microwave Journal, Jun, 1990.
–– Jun, 1990: Useful, easyJun, 1990: Useful, easy--toto--follow outlining of TRL mathfollow outlining of TRL math
•• Math too long to include here Math too long to include here –– examine examine Rubin article for more detailRubin article for more detail
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Circuits & Design17
TRL (THRU-REFLECT-LINE) Calibration
In-FixtureMeasurementTechniques
TRL/LRMCalibration
Implementation
TRL/LRMCalibration
Success Stories
In-FixtureTechnique
Comparison
TRL/LRM Cal
Normalization
Time Gating
[T] Deembed
FrequencyDomain
Considerations
SOLT Cal
•• TRL advantagesTRL advantages–– THRU: Typically requires no characterizationTHRU: Typically requires no characterization–– REFLECT: No need for characterizationREFLECT: No need for characterization
•• Need only approximate phase (OPEN or SHORT)Need only approximate phase (OPEN or SHORT)•• Needs to be the same for both portsNeeds to be the same for both ports
–– LINEs: Only require ZLINEs: Only require Zoo & T& Tpdpd characterizationcharacterization–– LOAD: None involved!LOAD: None involved!
•• TRL restrictionsTRL restrictions–– THRU: Launch/receive must be same transmission THRU: Launch/receive must be same transmission
line type (directly connectable)line type (directly connectable)–– LINEs: Need several LINEs across frequency LINEs: Need several LINEs across frequency
•• Each LINE has numerical difficulty with some Each LINE has numerical difficulty with some frequenciesfrequencies
•• Low frequency LINEs become too long for practical Low frequency LINEs become too long for practical implementationimplementation
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•• LRM calibration for low frequencyLRM calibration for low frequency–– TRL algorithm with LOAD, instead of LINEsTRL algorithm with LOAD, instead of LINEs–– Convenient routine for low frequencyConvenient routine for low frequency
•• TRL LINEs are too long for practical implementationTRL LINEs are too long for practical implementation•• Accurate LOAD achievable at low frequencyAccurate LOAD achievable at low frequency
–– Combination of TRL/LRM calibration at Combination of TRL/LRM calibration at high/low frequency makes for an accurate, high/low frequency makes for an accurate, realizable inrealizable in--fixture calibration methodfixture calibration method
LRM (LOAD-REFLECT-MATCH) Calibration
In-FixtureMeasurementTechniques
TRL/LRMCalibration
Implementation
TRL/LRMCalibration
Success Stories
In-FixtureTechnique
Comparison
TRL/LRM Cal
Normalization
Time Gating
[T] Deembed
FrequencyDomain
Considerations
SOLT Cal
LaunchError
REF1/2
LOADLaunchError
THRU
REF1 REF2
ReceiveError
LaunchError
REF1/2
REFLECT
LaunchError
LINE(s)
REF1 REF2
ReceiveError
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Circuits & Design19
TRL (THRU-REFLECT-LINE) Calibration
In-FixtureMeasurementTechniques
TRL/LRMCalibration
Implementation
TRL/LRMCalibration
Success Stories
In-FixtureTechnique
Comparison
TRL/LRM Cal
Normalization
Time Gating
[T] Deembed
FrequencyDomain
Considerations
SOLT Cal
•• Uniform TRL standards are availableUniform TRL standards are available–– Typically rated to higher frequency than SOLTTypically rated to higher frequency than SOLT–– Example: Agilent 85052C 3.5mm kitExample: Agilent 85052C 3.5mm kit
•• This presentation focuses on inThis presentation focuses on in--fixture fixture TRL/LRM (building your own standards)TRL/LRM (building your own standards)
•• Variations of TRL/LRM algorithmVariations of TRL/LRM algorithm–– TRL*/LRM* TRL*/LRM* -- Not as efficient in removing Not as efficient in removing
unwanted test fixture resonancesunwanted test fixture resonances–– LRM with LOAD compensation LRM with LOAD compensation –– Extends LRM Extends LRM
technique to higher frequency by characterizing technique to higher frequency by characterizing LOAD inductanceLOAD inductance
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Circuits & Design20
Normalization
–– In linear scale, divide DUT by THRUIn linear scale, divide DUT by THRU
In-FixtureMeasurementTechniques
TRL/LRMCalibration
Implementation
TRL/LRMCalibration
Success Stories
In-FixtureTechnique
Comparison
TRL/LRM Cal
Normalization
Time Gating
[T] Deembed
FrequencyDomain
Considerations
SOLT Cal
−
•• Also referred to as response calibrationAlso referred to as response calibration•• Normalization procedure:Normalization procedure:
REF1 REF2
THRU
–– For two port measurement, measure test fixture For two port measurement, measure test fixture THRU (DUT removed)THRU (DUT removed)
–– In dB scale, subtract THRU from DUTIn dB scale, subtract THRU from DUT
DUTREF1 REF2
–– Calibrate to uniform standardsCalibrate to uniform standards–– Measure the DUT, including test fixturingMeasure the DUT, including test fixturing
÷
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Circuits & Design21
Normalization•• AdvantagesAdvantages
–– Relatively easy to completeRelatively easy to complete–– Corrects for loss and delayCorrects for loss and delay
•• DisadvantagesDisadvantages–– Does NOT correct for fixture reflectionsDoes NOT correct for fixture reflections–– Inaccurate if fixture or DUT have Inaccurate if fixture or DUT have
significant reflectionssignificant reflections•• Often used at low frequencyOften used at low frequency•• Often used for structures like cablesOften used for structures like cables
•• Normalization WILL NOT correct Normalization WILL NOT correct properly for resonances in frequency!properly for resonances in frequency!
In-FixtureMeasurementTechniques
TRL/LRMCalibration
Implementation
TRL/LRMCalibration
Success Stories
In-FixtureTechnique
Comparison
TRL/LRM Cal
Normalization
Time Gating
[T] Deembed
FrequencyDomain
Considerations
SOLT Cal
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Circuits & Design22
Time Domain Gating•• Time domain gating procedure:Time domain gating procedure:
–– Calibrate to uniform standardsCalibrate to uniform standards–– Measure the DUT, including test fixturingMeasure the DUT, including test fixturing–– Transform response to time domain and set gatesTransform response to time domain and set gates–– Transform time response between gates back to Transform time response between gates back to
the frequency domainthe frequency domain–– Test fixture resonances are now removedTest fixture resonances are now removed
In-FixtureMeasurementTechniques
TRL/LRMCalibration
Implementation
TRL/LRMCalibration
Success Stories
In-FixtureTechnique
Comparison
TRL/LRM Cal
Time Gating
Normalization
[T] Deembed
FrequencyDomain
Considerations
SOLT Cal
DUTREF1 REF2
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Circuits & Design23
Enhanced Time Domain Gating•• ‘‘Enhancement’ to time domain gatingEnhancement’ to time domain gating
–– Complete the same procedure from the previous Complete the same procedure from the previous page for the THRU calibration structurepage for the THRU calibration structure
–– In linear scale, divide gated DUT by gated THRUIn linear scale, divide gated DUT by gated THRU–– In dB scale, subtract gated THRU from gated DUTIn dB scale, subtract gated THRU from gated DUT–– Test fixture resonances, loss, and delay are now Test fixture resonances, loss, and delay are now
removed from the measurementremoved from the measurement
In-FixtureMeasurementTechniques
TRL/LRMCalibration
Implementation
TRL/LRMCalibration
Success Stories
In-FixtureTechnique
Comparison
TRL/LRM Cal
Time Gating
Normalization
[T] Deembed
FrequencyDomain
Considerations
SOLT Cal
DUTREF1 REF2 REF1 REF2
THRU
−÷
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Circuits & Design24
Enhanced Time Domain Gating•• AdvantagesAdvantages
–– Only calibration structure is the THRUOnly calibration structure is the THRU–– Data, in general, can be very accurateData, in general, can be very accurate
•• DisadvantagesDisadvantages–– Complex implementationComplex implementation
•• Must complete math on EACH sMust complete math on EACH s--parameterparameter•• Gate placement requires user judgmentGate placement requires user judgment•• Test fixturing must allow inclusion/exclusion timesTest fixturing must allow inclusion/exclusion times•• Care must be taken with transformsCare must be taken with transforms
–– Data can be inaccurate in specific casesData can be inaccurate in specific cases•• Band edges inaccurate due to windowingBand edges inaccurate due to windowing•• Reflection phase is not accurateReflection phase is not accurate
•• NotesNotes–– S21 CAN be obtained without gating a TDT S21 CAN be obtained without gating a TDT
waveformwaveform–– Procedure best for analysis, not for creating standProcedure best for analysis, not for creating stand--
alone DUT modelsalone DUT models
In-FixtureMeasurementTechniques
TRL/LRMCalibration
Implementation
TRL/LRMCalibration
Success Stories
In-FixtureTechnique
Comparison
TRL/LRM Cal
Time Gating
Normalization
[T] Deembed
FrequencyDomain
Considerations
SOLT Cal
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Circuits & Design25
[ T ] Matrix Deembedding•• GIVEN sGIVEN s--parameters for the launch [Sparameters for the launch [SLL], the ], the
receive [Sreceive [SRR], and the DUT], and the DUT--withwith--fixture [Sfixture [SLDRLDR], one ], one can derive the scan derive the s--parameters for the DUT [Sparameters for the DUT [SDD]:]:–– Convert [SConvert [SLL], [S], [SRR], and S[], and S[LDRLDR] to [T] parameters (1)] to [T] parameters (1)–– Determine the [T] matrix for the DUT (2)Determine the [T] matrix for the DUT (2)–– Convert the [TConvert the [TDD] matrix back to s] matrix back to s--parameters [Sparameters [SDD] (3)] (3)
In-FixtureMeasurementTechniques
TRL/LRMCalibration
Implementation
TRL/LRMCalibration
Success Stories
In-FixtureTechnique
Comparison
TRL/LRM Cal
Time Gating
Normalization
[T] Deembed
FrequencyDomain
Considerations
SOLT Cal
DUTREF1 REF2
[ ]LS [ ]DS [ ]RS
[ ]LDRS
−
•−•−
=
2121
22
21
11
21
21122211
1SS
SSS
SSSSS
T(1)
[ ] [ ] [ ][ ] 11 −−= RLDRLD TTTT(2)
−
•−•
=
22
21
22
22
21122211
22
12
1TT
T
TTTTT
TT
S(3)
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Circuits & Design26
•• Advantages:Advantages:–– Relatively simple mathRelatively simple math–– Removes loss, delay, and resonancesRemoves loss, delay, and resonances
•• Disadvantages:Disadvantages:–– Must know [SMust know [SLL] and [S] and [SRR]]
•• Must model or somehow measure preciselyMust model or somehow measure precisely•• (or must be omniscient)(or must be omniscient)
•• Note:Note:–– Matrix conversions can be derived for more than Matrix conversions can be derived for more than
two portstwo ports
[ T ] Matrix Deembedding
In-FixtureMeasurementTechniques
TRL/LRMCalibration
Implementation
TRL/LRMCalibration
Success Stories
In-FixtureTechnique
Comparison
TRL/LRM Cal
Time Gating
Normalization
[T] Deembed
FrequencyDomain
Considerations
SOLT Cal
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Circuits & Design27
In-Fixture Technique Comparison
In-FixtureMeasurementTechniques
TRL/LRMCalibration
Implementation
TRL/LRMCalibration
Success Stories
In-FixtureTechnique
Comparison
TRL/LRM Cal
Normalization
Time Gating
[T] Deembed
FrequencyDomain
Considerations
SOLT Cal
In-FixtureTechnique
Comparison
• SOLT Calibration• TRL/LRM Calibration
• Normalization• Enhanced Time Domain Gating
• [ T ] Matrix Deembedding
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Circuits & Design28
Creating Controlled Comparison
In-FixtureMeasurementTechniques
TRL/LRMCalibration
Implementation
TRL/LRMCalibration
Success Stories
In-FixtureTechnique
Comparison
TRL/LRM Cal
Normalization
Time Gating
[T] Deembed
FrequencyDomain
Considerations
SOLT Cal
•• Test boards built w/ inTest boards built w/ in--fixture standardsfixture standards–– SHORT, OPEN, LOAD, THRU, LINESSHORT, OPEN, LOAD, THRU, LINES–– Multiple transmission line types and lengthsMultiple transmission line types and lengths–– Multiple test point variations (SMAs shown)Multiple test point variations (SMAs shown)
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Circuits & Design29
The ‘knownDUT’ Concept
In-FixtureMeasurementTechniques
TRL/LRMCalibration
Implementation
TRL/LRMCalibration
Success Stories
In-FixtureTechnique
Comparison
TRL/LRM Cal
Normalization
Time Gating
[T] Deembed
FrequencyDomain
Considerations
SOLT Cal
•• Note: For accurate performance prediction:Note: For accurate performance prediction:–– Must measure real geometry (Must measure real geometry (µµsections)sections)–– Must know Must know εεrr and tanand tanδδ vs. frequencyvs. frequency
•• Structure chosen to benchmark methodsStructure chosen to benchmark methods–– Sample performance must be predictableSample performance must be predictable
•• Parametric equationsParametric equations•• Field solversField solvers
–– Sample needs to be lossy and reflectiveSample needs to be lossy and reflective
REF1 REF2
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Circuits & Design30
The ‘knownDUT’ Concept
In-FixtureMeasurementTechniques
TRL/LRMCalibration
Implementation
TRL/LRMCalibration
Success Stories
In-FixtureTechnique
Comparison
TRL/LRM Cal
Normalization
Time Gating
[T] Deembed
FrequencyDomain
Considerations
SOLT Cal
•• Predicted ‘knownDUT’ sPredicted ‘knownDUT’ s--parametersparameters
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Circuits & Design31
The ‘knownDUT’ Concept
In-FixtureMeasurementTechniques
TRL/LRMCalibration
Implementation
TRL/LRMCalibration
Success Stories
In-FixtureTechnique
Comparison
TRL/LRM Cal
Normalization
Time Gating
[T] Deembed
FrequencyDomain
Considerations
SOLT Cal
•• Predicted ‘knownDUT’ Zo profilePredicted ‘knownDUT’ Zo profile
IFFT
Modeled
TDR
Measured
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Circuits & Design32
SOLT (SHORT-OPEN-LOAD-THRU) Calibration
•• InIn--fixture SOLT assumptions:fixture SOLT assumptions:–– Calibration using custom PWB standardsCalibration using custom PWB standards–– No standards correctionNo standards correction
•• Would requires modeling or another methodWould requires modeling or another method•• Will be examined in the futureWill be examined in the future
–– Data shown for test fixture with BEST results for Data shown for test fixture with BEST results for this procedurethis procedure
•• Optimal test pointOptimal test point•• Optimal Tline typeOptimal Tline type•• Optimal Tline lengthOptimal Tline length
In-FixtureMeasurementTechniques
TRL/LRMCalibration
Implementation
TRL/LRMCalibration
Success Stories
In-FixtureTechnique
Comparison
TRL/LRM Cal
Normalization
Time Gating
[T] Deembed
FrequencyDomain
Considerations
SOLT Cal
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Circuits & Design33
SOLT (SHORT-OPEN-LOAD-THRU) Calibration
In-FixtureMeasurementTechniques
TRL/LRMCalibration
Implementation
TRL/LRMCalibration
Success Stories
In-FixtureTechnique
Comparison
TRL/LRM Cal
Normalization
Time Gating
[T] Deembed
FrequencyDomain
Considerations
SOLT Cal
•• SOLT vs. PredictedSOLT vs. Predicted
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Circuits & Design34
TRL (THRU-REFLECT-LINE) Calibration•• InIn--fixture TRL/LRM assumptions:fixture TRL/LRM assumptions:
–– Calibration using custom PWB standardsCalibration using custom PWB standards–– Standards characterizationStandards characterization
•• THRU THRU –– NothingNothing•• REFLECT REFLECT –– NothingNothing•• LOAD LOAD –– Nothing (LRM Nothing (LRM –– Low Frequency)Low Frequency)•• LINEs LINEs –– ZZoo and Tand Tpdpd (TRL (TRL –– High Frequency)High Frequency)
–– Data shown for test fixture with BEST results for Data shown for test fixture with BEST results for this procedurethis procedure
•• Optimal test pointOptimal test point•• Optimal Tline typeOptimal Tline type•• Optimal Tline lengthOptimal Tline length
In-FixtureMeasurementTechniques
TRL/LRMCalibration
Implementation
TRL/LRMCalibration
Success Stories
In-FixtureTechnique
Comparison
TRL/LRM Cal
Normalization
Time Gating
[T] Deembed
FrequencyDomain
Considerations
SOLT Cal
Copyright A Tyco International Ltd. Company 2004
Circuits & Design35
TRL (THRU-REFLECT-LINE) Calibration
In-FixtureMeasurementTechniques
TRL/LRMCalibration
Implementation
TRL/LRMCalibration
Success Stories
In-FixtureTechnique
Comparison
TRL/LRM Cal
Normalization
Time Gating
[T] Deembed
FrequencyDomain
Considerations
SOLT Cal
•• TRL/LRM vs. PredictedTRL/LRM vs. Predicted
Copyright A Tyco International Ltd. Company 2004
Circuits & Design36
Normalization•• Normalization assumptionsNormalization assumptions
–– Calibration using uniform standardsCalibration using uniform standards–– Simple DUT/THRU measurementSimple DUT/THRU measurement–– Data shown for test fixture with BEST results for Data shown for test fixture with BEST results for
this procedurethis procedure•• Optimal test pointOptimal test point•• Optimal Tline typeOptimal Tline type•• Optimal Tline lengthOptimal Tline length
In-FixtureMeasurementTechniques
TRL/LRMCalibration
Implementation
TRL/LRMCalibration
Success Stories
In-FixtureTechnique
Comparison
TRL/LRM Cal
Normalization
Time Gating
[T] Deembed
FrequencyDomain
Considerations
SOLT Cal
Copyright A Tyco International Ltd. Company 2004
Circuits & Design37
Normalization
In-FixtureMeasurementTechniques
TRL/LRMCalibration
Implementation
TRL/LRMCalibration
Success Stories
In-FixtureTechnique
Comparison
TRL/LRM Cal
Normalization
Time Gating
[T] Deembed
FrequencyDomain
Considerations
SOLT Cal
•• Normalization vs. PredictedNormalization vs. Predicted
Copyright A Tyco International Ltd. Company 2004
Circuits & Design38
Enhanced Time Domain Gating•• Enhanced time domain gating assumptionsEnhanced time domain gating assumptions
–– Calibration using uniform standardsCalibration using uniform standards–– Data shown for test fixture with BEST results for Data shown for test fixture with BEST results for
this procedurethis procedure•• Optimal test pointOptimal test point•• Optimal Tline typeOptimal Tline type•• Optimal Tline lengthOptimal Tline length
In-FixtureMeasurementTechniques
TRL/LRMCalibration
Implementation
TRL/LRMCalibration
Success Stories
In-FixtureTechnique
Comparison
TRL/LRM Cal
Time Gating
Normalization
[T] Deembed
FrequencyDomain
Considerations
SOLT Cal
Copyright A Tyco International Ltd. Company 2004
Circuits & Design39
Enhanced Time Domain Gating
In-FixtureMeasurementTechniques
TRL/LRMCalibration
Implementation
TRL/LRMCalibration
Success Stories
In-FixtureTechnique
Comparison
TRL/LRM Cal
Time Gating
Normalization
[T] Deembed
FrequencyDomain
Considerations
SOLT Cal
•• Enhanced Gating vs. PredictedEnhanced Gating vs. Predicted
Copyright A Tyco International Ltd. Company 2004
Circuits & Design40
Microprobe LRM with Deembedding•• LRM with deembedding assumptionsLRM with deembedding assumptions
–– Calibration using microprobe Impedance Substrate Calibration using microprobe Impedance Substrate Standard (ISS)Standard (ISS)
•• LRM with automatic LOAD inductance LRM with automatic LOAD inductance compensationcompensation
•• ISS coplanar waveguide LOAD extremely good to ISS coplanar waveguide LOAD extremely good to high frequency with inductance compensationhigh frequency with inductance compensation
•• Eliminates any need for TRLEliminates any need for TRL–– DUT and test fixture measuredDUT and test fixture measured–– Test fixture modeledTest fixture modeled
•• Full 3D EM SolverFull 3D EM Solver•• Precise geometryPrecise geometry•• Known materialsKnown materials
–– Test fixture deembeddedTest fixture deembedded
In-FixtureMeasurementTechniques
TRL/LRMCalibration
Implementation
TRL/LRMCalibration
Success Stories
In-FixtureTechnique
Comparison
TRL/LRM Cal
[T] Deembed
Normalization
Time Gating
FrequencyDomain
Considerations
SOLT Cal
Copyright A Tyco International Ltd. Company 2004
Circuits & Design41
Microprobe LRM with Deembedding
In-FixtureMeasurementTechniques
TRL/LRMCalibration
Implementation
TRL/LRMCalibration
Success Stories
In-FixtureTechnique
Comparison
TRL/LRM Cal
[T] Deembed
Normalization
Time Gating
FrequencyDomain
Considerations
SOLT Cal
•• Microprobe LRM/Deembed vs. PredictedMicroprobe LRM/Deembed vs. Predicted
Copyright A Tyco International Ltd. Company 2004
Circuits & Design42
Comparison of All Techniques
In-FixtureMeasurementTechniques
TRL/LRMCalibration
Implementation
TRL/LRMCalibration
Success Stories
In-FixtureTechnique
Comparison
TRL/LRM Cal
[T] Deembed
Normalization
Time Gating
FrequencyDomain
Considerations
SOLT Cal
•• Insertion LossInsertion Loss
Copyright A Tyco International Ltd. Company 2004
Circuits & Design43
Comparison of All Techniques
In-FixtureMeasurementTechniques
TRL/LRMCalibration
Implementation
TRL/LRMCalibration
Success Stories
In-FixtureTechnique
Comparison
TRL/LRM Cal
[T] Deembed
Normalization
Time Gating
FrequencyDomain
Considerations
SOLT Cal
•• Return LossReturn Loss
Copyright A Tyco International Ltd. Company 2004
Circuits & Design44
Comparison of All Techniques•• InIn--fixture SOLT inaccurate, without detailed fixture SOLT inaccurate, without detailed
standards characterizationstandards characterization•• InIn--fixture TRL/LRM accurate and easy to fixture TRL/LRM accurate and easy to
implementimplement•• Simple normalization is inaccurate if the DUT Simple normalization is inaccurate if the DUT
has any significant reflectionshas any significant reflections•• Enhanced time domain gating accurate, but:Enhanced time domain gating accurate, but:
–– Reflection phase and band edges are inaccurateReflection phase and band edges are inaccurate–– Heavy user judgment and postHeavy user judgment and post--processing processing
involvedinvolved•• Microprobe LRM cal very accurate, but:Microprobe LRM cal very accurate, but:
–– Still must complete [ T ] matrix deembeddingStill must complete [ T ] matrix deembedding–– Determining error sDetermining error s--parameters can be very parameters can be very
difficultdifficult
In-FixtureMeasurementTechniques
TRL/LRMCalibration
Implementation
TRL/LRMCalibration
Success Stories
In-FixtureTechnique
Comparison
TRL/LRM Cal
[T] Deembed
Normalization
Time Gating
FrequencyDomain
Considerations
SOLT Cal
Copyright A Tyco International Ltd. Company 2004
Circuits & Design45
TRL/LRM Calibration Implementation
In-FixtureMeasurementTechniques
TRL/LRMCalibration
Implementation
TRL/LRMCalibration
Success Stories
In-FixtureTechnique
Comparison
FrequencyDomain
Considerations
T Lines
Test Points
Cal Kit
Measurement
Standards
TRL/LRMCalibration
Implementation
• Choosing RF Test Points• Transmission Line Guidelines
• Making the Measurements• Configuring the Calibration Kit
• Designing PWB Standards
Copyright A Tyco International Ltd. Company 2004
Circuits & Design46
Designing PWB Standards•• Necessary TRL/LRM StandardsNecessary TRL/LRM Standards
In-FixtureMeasurementTechniques
TRL/LRMCalibration
Implementation
TRL/LRMCalibration
Success Stories
In-FixtureTechnique
Comparison
FrequencyDomain
Considerations
T Lines
Test Points
Cal Kit
Measurement
Standards
LOAD dPerfect 50 Ohms
REFLECT dOPEN or SHORT
THRU d d
LINE1 d dLong Length (low frequency)
LINE2 d dMid-Length (mid-frequency)
LINEX d dShort Length
(high frequency)
LAUNCH RECEIVEDUTd d
LAUNCH RECEIVEKnownDUT
d d
Copyright A Tyco International Ltd. Company 2004
Circuits & Design47
Designing PWB Standards•• TEST FIXTURETEST FIXTURE
–– Each must be identical & same as standardsEach must be identical & same as standards•• THRUTHRU
–– Direct connection of launch/receiveDirect connection of launch/receive•• REFLECTREFLECT
–– Can be OPEN or SHORTCan be OPEN or SHORT–– Does NOT need to be perfectDoes NOT need to be perfect–– REFLECT must be the same for both portsREFLECT must be the same for both ports
•• LOADLOAD–– Must be perfect matchMust be perfect match–– Only achievable at low frequencyOnly achievable at low frequency
•• Known DUTKnown DUT–– Used to validate calibrationUsed to validate calibration
In-FixtureMeasurementTechniques
TRL/LRMCalibration
Implementation
TRL/LRMCalibration
Success Stories
In-FixtureTechnique
Comparison
FrequencyDomain
Considerations
T Lines
Test Points
Cal Kit
Measurement
Standards
DUTd d
d d
d
d
KnownDUT
d d
Copyright A Tyco International Ltd. Company 2004
Circuits & Design48
Designing PWB Standards•• LINEsLINEs
–– Any LINE length has invalid frequency rangesAny LINE length has invalid frequency ranges–– Numerical difficulties deriving Numerical difficulties deriving γ γ = = α α + j+ jΒ Β occur occur
when the wave phase at the reference plane when the wave phase at the reference plane approaches n*180approaches n*180oo, where n = 0, 1, 2, 3, …, where n = 0, 1, 2, 3, …
–– For 0For 0--20 GHz, one LINE length will not be enough20 GHz, one LINE length will not be enough–– Must use LOAD at low frequency (LRM)Must use LOAD at low frequency (LRM)–– Must design multiple LINEs for high frequenciesMust design multiple LINEs for high frequencies
In-FixtureMeasurementTechniques
TRL/LRMCalibration
Implementation
TRL/LRMCalibration
Success Stories
In-FixtureTechnique
Comparison
FrequencyDomain
Considerations
T Lines
Test Points
Cal Kit
Measurement
Standards
n=1
n=2
Etc.
Copyright A Tyco International Ltd. Company 2004
Circuits & Design49
Designing PWB Standards•• LINEs LINEs –– Calculating LengthsCalculating Lengths
–– Must know the prop velocity of the LINEs (Must know the prop velocity of the LINEs (vv))–– Must know phase span of interest (Must know phase span of interest (spanspan))
•• 180180o o * n (n=0,1,2,3…) is bad* n (n=0,1,2,3…) is bad•• Keep span < 140Keep span < 140oo (20(20oo--160160oo, 200, 200oo--340340oo, etc.), etc.)•• Tightening the span will increase accuracyTightening the span will increase accuracy
–– Must know one of the following frequencies:Must know one of the following frequencies:•• Low frequency (Low frequency (fflolo))•• Center frequency (Center frequency (ffcc))•• High frequency (High frequency (ffhihi))
In-FixtureMeasurementTechniques
TRL/LRMCalibration
Implementation
TRL/LRMCalibration
Success Stories
In-FixtureTechnique
Comparison
FrequencyDomain
Considerations
T Lines
Test Points
Cal Kit
Measurement
Standards
...5,3,1=n( )
±×
××=
290
90spann
nfflohic
( )
×
±××=
n
spannff c
lohi 90
290
××
=
36090 n
fvxc
Copyright A Tyco International Ltd. Company 2004
Circuits & Design50
Designing PWB Standards•• LINEs LINEs –– LINE length calculation exampleLINE length calculation example
smcv
r
88
105.14103 ×=×==
ε
In-FixtureMeasurementTechniques
TRL/LRMCalibration
Implementation
TRL/LRMCalibration
Success Stories
In-FixtureTechnique
Comparison
FrequencyDomain
Considerations
T Lines
Test Points
Cal Kit
Measurement
Standards
•• Notes:Notes:–– Can iterate example above…next LINE fCan iterate example above…next LINE fhihi=5.72 GHz=5.72 GHz–– Using n=1 will give the widest bandwidth per LINEUsing n=1 will give the widest bandwidth per LINE–– Using n>1 allows longer LINEs to be used at higher frequency…canUsing n>1 allows longer LINEs to be used at higher frequency…can
be more accuratebe more accurate
Assumptions:LINEs in stripline FR4 (εr=4.0), Phase span = 100o, fhi = 20 GHz, n=1
GHzGHzspanff hic 86.12
210090
9020
290
90 =
+×=
+×=
mfvxc
39
8
1092.236090
1086.12105.1
36090 −×=
×
×=
=
GHzGHz
span
ff chi 2090
210090
86.1290
290
=
+×=
+×=GHzGHz
span
ff clo 72.590
210090
86.1290
290
=
−×=
−×=
Copyright A Tyco International Ltd. Company 2004
Circuits & Design51
Transmission Line Guidelines•• TRL calibration cannot recover DUT TRL calibration cannot recover DUT
response if too much information is lostresponse if too much information is lost–– At high frequency, VNA & cables already have At high frequency, VNA & cables already have
some degree of losssome degree of loss–– Must choose launch/receive transmission lines so Must choose launch/receive transmission lines so
that loss is not too much worsethat loss is not too much worse
In-FixtureMeasurementTechniques
TRL/LRMCalibration
Implementation
TRL/LRMCalibration
Success Stories
In-FixtureTechnique
Comparison
FrequencyDomain
Considerations
T Lines
Test Points
Cal Kit
Measurement
Standards
Pre-Calibration
Copyright A Tyco International Ltd. Company 2004
Circuits & Design52
Transmission Line Guidelines•• Rule of Thumb Rule of Thumb –– Design THRU so that insertion Design THRU so that insertion
loss (test pointloss (test point--toto--test point) is no less than 0.707 test point) is no less than 0.707 ((--3 dB) at highest frequency of interest3 dB) at highest frequency of interest–– Keep traces short and use low loss dielectricKeep traces short and use low loss dielectric–– Keep traces wide (also keeps Zo consistent)Keep traces wide (also keeps Zo consistent)
In-FixtureMeasurementTechniques
TRL/LRMCalibration
Implementation
TRL/LRMCalibration
Success Stories
In-FixtureTechnique
Comparison
FrequencyDomain
Considerations
T Lines
Test Points
Cal Kit
Measurement
Standards
Good Cal
Pre-Cal Loss Test for TRL Accuracy:VNA/Cable loss budget: -3 dBTHRU loss budget: + -3 dB“Cutoff frequency (fcut)”: -6 dB
Fcut = frequency above which datawill become invalid for calibration(Typically seen as ‘wavy’ frequencydata…especially in reflected data)
Copyright A Tyco International Ltd. Company 2004
Circuits & Design53
Transmission Line Guidelines•• Allow no coupling between test fixture Allow no coupling between test fixture
transmission linestransmission lines–– Challenging when measuring dense DUTsChallenging when measuring dense DUTs–– Stripline is better than microstripStripline is better than microstrip
•• Design transmission lines to match test Design transmission lines to match test equipment Zo (typically 50 Ohms)equipment Zo (typically 50 Ohms)–– TRL DOES allow measurement in ANY TRL DOES allow measurement in ANY
impedance environmentimpedance environment–– TRL calibration can automatically TRL calibration can automatically
renormalize results to 50 Ohmsrenormalize results to 50 Ohms
In-FixtureMeasurementTechniques
TRL/LRMCalibration
Implementation
TRL/LRMCalibration
Success Stories
In-FixtureTechnique
Comparison
FrequencyDomain
Considerations
T Lines
Test Points
Cal Kit
Measurement
Standards
Copyright A Tyco International Ltd. Company 2004
Circuits & Design54
Choosing RF Test Points•• Intrinsic propertiesIntrinsic properties
–– Density, cost, ease of use, ease of terminationDensity, cost, ease of use, ease of termination
•• Quality of cable interfaceQuality of cable interface–– Zo, IL, moding, variability, & mating cycle lifeZo, IL, moding, variability, & mating cycle life
•• Quality of PWB interfaceQuality of PWB interface–– Zo, IL, moding, & attachment repeatability (solder)Zo, IL, moding, & attachment repeatability (solder)
In-FixtureMeasurementTechniques
TRL/LRMCalibration
Implementation
TRL/LRMCalibration
Success Stories
In-FixtureTechnique
Comparison
FrequencyDomain
Considerations
T Lines
Test Points
Cal Kit
Measurement
Standards
TermCable
Copyright A Tyco International Ltd. Company 2004
Circuits & Design56
Choosing RF Test Points•• Tyco has examined over 50 familiesTyco has examined over 50 families
In-FixtureMeasurementTechniques
TRL/LRMCalibration
Implementation
TRL/LRMCalibration
Success Stories
In-FixtureTechnique
Comparison
FrequencyDomain
Considerations
T Lines
Test Points
Cal Kit
Measurement
Standards
•• Choose your own favorite…Choose your own favorite…
Copyright A Tyco International Ltd. Company 2004
Circuits & Design57
Configuring the Calibration Kit•• Characterizing the standardsCharacterizing the standards
–– Measure transmission line impedances (TDR fine)Measure transmission line impedances (TDR fine)–– Measure each LINE propagation delay (TDT fine)Measure each LINE propagation delay (TDT fine)
•• LINE propagation delay is relative to the THRULINE propagation delay is relative to the THRU–– Calculate the valid frequency range for each LINECalculate the valid frequency range for each LINE
•• Calculated previously when board was designedCalculated previously when board was designed•• ReRe--calculate real values for increased accuracycalculate real values for increased accuracy
In-FixtureMeasurementTechniques
TRL/LRMCalibration
Implementation
TRL/LRMCalibration
Success Stories
In-FixtureTechnique
Comparison
FrequencyDomain
Considerations
T Lines
Test Points
Cal Kit
Measurement
Standards
Example:20ps delay LINE, n=1, span=100o
Ghz
span
Delayfhi 4.19
3602
10090
10201
3602
901
12 =
+
××
=
+
×= −Ghz
span
Delayflo 6.5
3602
10090
10201
3602
901
12 =
−
××
=
−
×= −
( )...5,3,1,
3602
901 =
±×
×= n
spann
Delayf
lohi
Copyright A Tyco International Ltd. Company 2004
Circuits & Design58
Configuring the Calibration Kit•• Preparing the VNA for calibrationPreparing the VNA for calibration
–– Can enter calibration constants directly into VNACan enter calibration constants directly into VNA–– Can use Cal Kit Manager to load from PCCan use Cal Kit Manager to load from PC
•• Freeware from Freeware from www.vnahelp.comwww.vnahelp.com
In-FixtureMeasurementTechniques
TRL/LRMCalibration
Implementation
TRL/LRMCalibration
Success Stories
In-FixtureTechnique
Comparison
FrequencyDomain
Considerations
T Lines
Test Points
Cal Kit
Measurement
Standards
Copyright A Tyco International Ltd. Company 2004
Circuits & Design59
Configuring the Calibration Kit•• Defining the standardsDefining the standards
–– C0C0--C3 and LOC3 and LO--L3 ARE NOT USED for TRL!L3 ARE NOT USED for TRL!–– ZZoo should be the same for each standardshould be the same for each standard
In-FixtureMeasurementTechniques
TRL/LRMCalibration
Implementation
TRL/LRMCalibration
Success Stories
In-FixtureTechnique
Comparison
FrequencyDomain
Considerations
T Lines
Test Points
Cal Kit
Measurement
Standards
Copyright A Tyco International Ltd. Company 2004
Circuits & Design60
Configuring the Calibration Kit•• Mapping standards to class assignmentsMapping standards to class assignments
–– Standard numbers are just arbitrary definitionsStandard numbers are just arbitrary definitions–– Must map standard numbers to known definitionsMust map standard numbers to known definitions
In-FixtureMeasurementTechniques
TRL/LRMCalibration
Implementation
TRL/LRMCalibration
Success Stories
In-FixtureTechnique
Comparison
FrequencyDomain
Considerations
T Lines
Test Points
Cal Kit
Measurement
Standards
Copyright A Tyco International Ltd. Company 2004
Circuits & Design61
Configuring the Calibration Kit•• Setting reference impedance and planesSetting reference impedance and planes
–– Line Zo relative to line, system Zo renormalizedLine Zo relative to line, system Zo renormalized–– THRU reference plane more accurateTHRU reference plane more accurate
In-FixtureMeasurementTechniques
TRL/LRMCalibration
Implementation
TRL/LRMCalibration
Success Stories
In-FixtureTechnique
Comparison
FrequencyDomain
Considerations
T Lines
Test Points
Cal Kit
Measurement
Standards
Copyright A Tyco International Ltd. Company 2004
Circuits & Design62
Making the Measurements•• Complete calibrationComplete calibration
–– Load calibration kit into the VNALoad calibration kit into the VNA–– Measure standards, as instructed by VNAMeasure standards, as instructed by VNA
•• Verify calibrationVerify calibration–– ReRe--measure standards to test repeatabilitymeasure standards to test repeatability–– Measure knownDUT to test accuracyMeasure knownDUT to test accuracy
•• Take measurementsTake measurements–– Connect two ports to desired DUT portsConnect two ports to desired DUT ports–– Terminate all other coupled portsTerminate all other coupled ports
In-FixtureMeasurementTechniques
TRL/LRMCalibration
Implementation
TRL/LRMCalibration
Success Stories
In-FixtureTechnique
Comparison
FrequencyDomain
Considerations
T Lines
Test Points
Cal Kit
Measurement
Standards
for 0 where, jkaabS k
j
iij ≠==
bi is output wave on port iaj is incident wave on port jIncident waves on all other non-j ports is zero(meaning they are all matched impedance)
Terminate Terminate
Copyright A Tyco International Ltd. Company 2004
Circuits & Design63
Making the Measurements•• Importance of terminationsImportance of terminations
–– Sharp error resonances will occur when coupled Sharp error resonances will occur when coupled paths in the DUT are not terminated properlypaths in the DUT are not terminated properly
–– Spikes caused by high reflections that take a long Spikes caused by high reflections that take a long time to return to the measurement porttime to return to the measurement port
•• Anything long in time is narrow in frequencyAnything long in time is narrow in frequency•• Anything short in time is broad in frequencyAnything short in time is broad in frequency
In-FixtureMeasurementTechniques
TRL/LRMCalibration
Implementation
TRL/LRMCalibration
Success Stories
In-FixtureTechnique
Comparison
FrequencyDomain
Considerations
T Lines
Test Points
Cal Kit
Measurement
Standards
Copyright A Tyco International Ltd. Company 2004
Circuits & Design64
TRL/LRM Success Stories
In-FixtureMeasurementTechniques
TRL/LRMCalibration
Implementation
TRL/LRMCalibration
Success Stories
In-FixtureTechnique
Comparison
FrequencyDomain
Considerations
TRL/LRMCalibration
Success Stories
• Tyco HM-Zd PWB Footprint
•Tyco HM-Zd Connector•Tyco PT Connector (SFP/XFP Standard)
Copyright A Tyco International Ltd. Company 2004
Circuits & Design65
Tyco HM-Zd PWB Footprint
In-FixtureMeasurementTechniques
TRL/LRMCalibration
Implementation
TRL/LRMCalibration
Success Stories
In-FixtureTechnique
Comparison
FrequencyDomain
Considerations
•• Modeled vs. Measured (TRL/LRM)Modeled vs. Measured (TRL/LRM)
Copyright A Tyco International Ltd. Company 2004
Circuits & Design66
Tyco PT Connector (SFP/XFP Standard)
In-FixtureMeasurementTechniques
TRL/LRMCalibration
Implementation
TRL/LRMCalibration
Success Stories
In-FixtureTechnique
Comparison
FrequencyDomain
Considerations
•• Modeled vs. Measured (TRL/LRM)Modeled vs. Measured (TRL/LRM)
Copyright A Tyco International Ltd. Company 2004
Circuits & Design67
Tyco PT Connector (SFP/XFP Standard)
In-FixtureMeasurementTechniques
TRL/LRMCalibration
Implementation
TRL/LRMCalibration
Success Stories
In-FixtureTechnique
Comparison
FrequencyDomain
Considerations
•• Time Domain: Measured TDR vs. Measured Time Domain: Measured TDR vs. Measured TRL/LRM TransformTRL/LRM Transform
TDR
IFFT
VNA
Copyright A Tyco International Ltd. Company 2004
Circuits & Design68
Tyco HM-Zd Connector
In-FixtureMeasurementTechniques
TRL/LRMCalibration
Implementation
TRL/LRMCalibration
Success Stories
In-FixtureTechnique
Comparison
FrequencyDomain
Considerations
•• Modeled vs. Measured (TRL/LRM)Modeled vs. Measured (TRL/LRM)
Copyright A Tyco International Ltd. Company 2004
Circuits & Design69
Tyco HM-Zd Connector
In-FixtureMeasurementTechniques
TRL/LRMCalibration
Implementation
TRL/LRMCalibration
Success Stories
In-FixtureTechnique
Comparison
FrequencyDomain
Considerations
•• Time Domain: Measured TDR vs. Measured Time Domain: Measured TDR vs. Measured TRL/LRM TransformTRL/LRM Transform
TDR
IFFT
VNA
Copyright A Tyco International Ltd. Company 2004
Circuits & Design70
A Final Thought
•• Full 3D EM modeling becoming more prevalentFull 3D EM modeling becoming more prevalent–– Multiple packages can be purchasedMultiple packages can be purchased–– Having a tool DOES NOT guarantee accuracyHaving a tool DOES NOT guarantee accuracy
•• SS--parameter test data is becoming standardparameter test data is becoming standard–– Obtaining high frequency DUT data is challengingObtaining high frequency DUT data is challenging–– TRL/LRM calibration combines accuracy & practicalityTRL/LRM calibration combines accuracy & practicality
•• CAN ONLY BE SURE OF RESULTS WHEN MEASURED CAN ONLY BE SURE OF RESULTS WHEN MEASURED AND MODELED DATA OVERLAY!!!AND MODELED DATA OVERLAY!!!
Copyright A Tyco International Ltd. Company 2004
Circuits & Design71
Further Information•• Presentation copies can be obtained from:Presentation copies can be obtained from:
– Chad Morgan, (717) 986-3342, chad.morgan@tycoelectronics.com
– Dave Helster, (717) 986-5686, dave.helster@tycoelectronics.com
– Alex Sharf, (717) 986-5447, alex.sharf@tycoelectronics.com
•• Tyco Electronics Circuits & DesignTyco Electronics Circuits & Design
Connector modeling & design
High-speed measurement & analysis
Gigabit system simulation & optimization
• For further information, email modeling@tycoelectronics.com or go to www.tycoelectronics.com/products/simulation
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