impedance measurement with e5061b lf-rf network analyzer · page 1 impedance measurement with...
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Page 1Page 1
Impedance measurement with
E5061B LF-RF Network Analyzer
Rev.100408
Agilent Technologies
April 2010
Page 2
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Page 3
Targets of this solution
• Simple Z measurement solution for circuit designers / component users(= Series-thru & Reflection methods)
Measure components’ impedance parameters such as C and L
in 2-element impedance models with “good enough accuracy”.
Not suitable for accurately measuring smaller part of impedance vector.(= Small loss of capacitors and inductors: D, Q, Rs, Rp, etc)
• Solution for PDN component characterization(= Shut-thru method)
Measure impedance parameters of small-Z PDN components (bypass capacitors, etc)
in 2-element impedance models.
X=-1/(2*pi*f*Cs)
Rs
Z
2-element impedance models Impedance vector
D=1/Q=Rs/X
Cp
Rp
Cs Rs
Ls Rs
Page 4
VBA program for measuring impedance parameters
with E5061B-3L5
• Application sample program
• Impedance parameters are calculated and plotted with equation editor function.
• VBA program just assists users to set equations for impedance calculations.
• Series-thru #1, Shut-thru, and Reflection methods are possible.
NOTE #1: At gain-phase test port (~30 MHz), with open/short/load cal
Selectable parameters:Cs Series capacitance
Cp Parallel capacitance
Ls Series inductance
Lp Parallel inductance
|Z| Impedance magnitude |Z| (in ohm, linear scale)
|Z|_dB 20*Log |Z| (in dB)
|Y| Admittance magnitude |Y| (in ohm linear scale)
|Y|_dB 20*Log |Y| (in dB)
Zphase Impedance phase (in deg)
Yphase Admittance phase (in deg)
R Resistance
X Reactance
G Conductance
B Susceptance
Rs Series resistance
Rp Parallel resistance
Q Quality factor
D Dissipation factor
Page 5
Limitations
The following functions are not supported by this program.
• 3 and 4-element equivalent circuit analysis
• Saving measured impedance parameters to memory traces
• Open/Short fixture compensation #1
• Power sweep #2, DC-bias sweep #2, and Time-domain measurements
NOTES #1: Only a simplified open/short compensation by using the memory traces is possible in the reflection method.
Open admittance and short impedance are fixed to zero. Not possible to define these values.
#2: To measure frequency-dependent impedance parameters such as capacitance and inductance
in the power sweep and DC-bias sweep, manually modify the term “xAxis” of the equation to the CW value.
Page 6
VBA program overview
1.0312 nU 1.0312 nF
Capacitance
43.652 U 43.652 dB|Z|_dB
= 20*Log|Z|
Z parameters are calculated with equation editor
and displayed with unit “U”.
Select measurement mode.
Setup stimulus conditions, perform calibration,
and select three Z parameters to be measured.
Page 7
Summary of major VNA-based Z measurement methods(case of 50 ohm receivers)
ZdutVT VR
50
50
50
50
50
S21=VT/VR
ZdutVT VR
50
50
50
50
50
S11=VT/VR
VT VR
50
50
50
50
50S21=VT/VR
Zdut
Shunt-thru method* For small-Z DUTs
* Zdut = 50 x S21/(2 x (1-S21))
Reflection method* For middle-Z DUTs
* Zdut = 50 x (1+S11)/(1-S11)
Series-thru method* For middle to large-Z DUTs
* Not applicable to grounded DUTs
* Zdut = 50 x 2 x (1-S21)/S21
Shunt-thru
Series-thru
50ohm
10 kohm
0.1ohm
|Zdut|
Measured AC voltage at VT
Shunt-thru
Reflection
Series-thru
Se
nsitiv
e
ran
ge
Reflection
VT significantly varies:
High-sensitivity for Z measurement
Page 8
Frequency (Hz)
Recommended Z measurement methods with E5061B-3L5Im
pe
da
nce
|Z
| (
oh
m)
1 10 100 1K 10K 100K 1M 10M 100M 1G
10M
1M
100K
10K
1K
100
10
1
100m
10m
1m
Series-thru methodwith gain-phase test port
Shunt-thru method
Reflection method
Page 9Page 9
Series-thru method with gain-phase test port (up to 30 MHz)
VT
50
Zdut
VR
+
Internal DC bias
applicable to
capacitive DUTs
P/N 0699-2014Axial-lead 50 ohm (ESL = approx. 14 nH
with minimum lead length)
P/N 0699-2829SMD 50 ohm
50 ohmresistor
Calibration
open
short
16047E 4TP fixture
4-Terminal-Pair type fixture
• For middle to large Z-range (Zdut=1 ohm to >100 kohm)
• Need Open/Short/Load cal at fixture( implemented with 1-port full cal + S11-to-Z conversion for T/R port)
HcHpLc Lp
Examples of load:
( Load’s ESL=14 nH can be set with the following load definitions;
Offset Z0=500 ohm, Offset delay=14 nH / 500 ohm = 28 psec )
Zin=50 ohm Zin=1 Mohm 1 nF capacitor measurementTest freq=100 Hz to 30 MHzSource=7 dBm, IFBW=Auto / 20 Hz-limit
20*log |Z| [dB]
Cp [farad]
|Z| [ohm]
100 kohm
100 dB(=100 kohm)
1 nF
T R LF OUT
Lp terminal of fixture is
not connected.
Configuration example
Page 10
Series-thru method with gain-phase test port (up to 30 MHz)
Test fixture
Some 4-Terminal-Pair (4TP) type fixtures for LCR meters/Z-analyzers can be utilized
for connecting DUTs with series-thru connection at gain-phase test port.
Applicable 4TP fixtures:• 2-terminal contact fixtures (4-terminal contact fixtures such as 16047A and 16044A are not applicable.)
• Need a good contact repeatability (for accurately performing the Open/Short/Load cal at the fixture)
For leaded DUTs:
16047E, 16047C (discontinued)
Example of load device …. P/N 0699-2014 axial-lead 50 ohm resistor
For Surface Mount Devices:
16034E, 16034G
Example of load device …. P/N 0699-2829 SMD 50 ohm resistor, or
P/N 0699-2488 SMD 100 ohm resistor ( supplied with 16034G)
Page 11
Terminal block
BNC(f) receptacle
Copper board (GND)
50 ohmresistorshort
wire
Open/Short/Load cal
DUT
From LF OUT
To R-port (Zin=1 Mohm)
To T-port (Zin=50 ohm)
Series-thru method with gain-phase test port (up to 30 MHz)
Test fixture
Home-made fixture
Page 12
Series-thru method with gain-phase test port (up to 30 MHz)
Example of measurement procedure
1) Connect the fixture to the gain-phase test port.
2) Preset the E5061B.
3) Load & Run the VBA program “LF-RF_Zmeas_xxxx.vba”.
4) Select the mode “T/R (with Open/Short/Load cal, T:50 ohm, R:1 Mohm)”, and click on [Start measurement].
5) Setup stimulus conditions (Start, Stop, Sweep type, IFBW, Source power, etc) by using front keys.
6) Perform the Open/Short/Load cal (1-port full cal) by using front keys.
Press [Cal], (Cal Kit), and select your user-defined cal kit,
press (Calibrate), (1-Port Cal), leave the fixture open, and press (Open),
short the fixture, and press (Short),
connect a 50 ohm resistor to the fixture, and press (Load),
press (Done) to complete the calibration.
7) Connect the DUT to the fixture.
8) Select impedance parameters, and click on [Select parameters].
The E5061B will start the impedance measurement.
Page 13
T: Zin=50 ohmR: Zin=50 ohm
Shunt-thru methods
Cal: SOLT (2-port full), or
Response thruCal: Response thru, or
Open/Short/Load
Method-1:
With S-param. test port (~3 GHz)
For most of bypass capacitors
Method-2:
With gain-phase test port, Zin=50 ohm (~ 30 MHz)
For very-large capacitors (mF order)
• For small Z-range (down to milliohms / sub-milliohms)
• Calibration method depending onmeasurement configuration and test freq
Test board(user prepared)
Page 14
Open
Short
Load
VR
Ri
50
+
VT
T: Zin=1 MohmR: Zin=1 Mohm
Ri=10 to 50 ohm
Or use power splitter
T-connector50
DUTBuilt-in DC bias source
R (Zin=1 Mohm)T (Zin=1 Mohm)
50 ohm
Open/Short/Load cal (using 1-port full cal function
and S11-to-Z conv.)
Shunt-thru methods
Ri
Cs [farad]
ESR [ohm]
|Z| [ohm]
(Linear scale)
37 uF @10 kHz
29 uF @10 kHz
Apply 3 Vdc bias.
DC-biased MLCC measurementTest freq=100 Hz to 10 MHz
DC bias=0 V & 3 V, T&R receiver ATT=20 dB
Bias=0 Vdc
Bias=3 Vdc
Method-3:
With gain-phase test port, Zin=1 Mohm (~ 30 MHz)
For DC-biased MLCC measurements
Page 15
Shunt-thru methodsExample of measurement procedure
1) Preset the E5061B.
2) Load & Run the VBA program “LF-RF_Zmeas_xxxx.vba”.
3) Select one of the following measurement mode, depending on your connection and calibration methods;
Method-1: “S21 Shunt-thru (with 2-port full or Thru cal)”
Method-2: “TR Shunt-thru (with Thru cal)”, or “TR (with Open/Short/Load cal, T:Zin=50 ohm, R:Zin=50 ohm)
Method-3: “TR (with Open/Short/Load cal, T:Zin=1 Mohm, R:Zin=1 Mohm)”
and click on [Start measurement].
4) Setup stimulus conditions (Start, Stop, Sweep type, IFBW, Source power, etc) by using front keys.
If necessary, set the T-port attenuator to 0 dB to improve the measurement SNR for milliohm measurements
( [Meas], “Gain-phase setup”, “T Attenuator” ).
5) Perform the calibration.
6) Connect the DUT.
7) Select impedance parameters, and click on [Select parameters].
The E5061B will start the impedance measurement.
Page 16
Reflection method
7 mm to 3.5 mm(f) adapter
(P/N 1250-1747
fits to 04287-60121)
SMA(m)-SMA(m)
semi-rigid cable (50cm)
7 mm fixture stand
(P/N 04287-60121)
16092A fixture (~ 500 MHz)
• For middle Z-range (Zdut=0.1 ohm to 1 kohm)
• Need Open/Short/Load cal
DUT
N(m)-SMA(f) adapter
(P/N 1250-2879)
20*log |Z| [dB]
Ls [henry]
|Z| [ohm]
60 dB(=1 kohm)
1 kohm
10 uH
10 uH inductor measurementTest freq=100 kHz to 100 MHzSource= -10 dBm, IFBW=Auto / 100 Hz-limit
NOTE: Re-perform the calibration if you changed the source power setting, especially when measuring >1 kohm ranges and
setting the source power to >0 dBm.
Configuration example
P/N 0699-2829SMD 50 ohm
short
Open/Short/Load cal at fixture
Page 17
Applicable 7 mm fixtures:16092A (~500 MHz, for SMDs and leaded DUTs),
16192A (~1.8 GHz, for SMDs),
16191A (~1.8 GHz, for SMDs),
Example of load device …. P/N 0699-2829 SMD 50 ohm resistor
Reflection methodTest fixture
SMA receptacle
Home-made fixture:
DUT (soldered between
center pin and GND)
Copper foil (GND)
Cal devices
Open Short Load50 ohmresistor
ToPort-1
Page 18
Reflection methodExample of measurement procedure:
With Open/Short/Load cal at the fixture
1) Connect the 7 mm type test fixture to the Port-1 via a semi rigid cable and adapters.
2) Preset the E5061B.
3) Load & Run the VBA program “LF-RF_Zmeas_xxxx.vba”.
4) Select the mode “S11 1-port (with Open/Short/Load cal)”, and click on [Start measurement].
5) Setup stimulus conditions (Start, Stop, Sweep type, IFBW, Source power, etc) by using front keys.
6) Perform the Open/Short/Load cal (1-port full cal) by using front keys #1 #2.
Press [Cal], (Cal Kit), and select your user-defined cal kit,
press (Calibrate), (1-Port Cal), leave the fixture open, and press (Open),
short the fixture, and press (Short),
connect a 50 ohm resistor to the fixture, and press (Load),
press (Done) to complete the calibration.
7) Connect the DUT to the fixture.
8) Select impedance parameters, and click on [Select parameters].
The E5061B will start the impedance measurement.
NOTE #1: Re-perform the Open/Short/Load cal when you changed the source power setting.
NOTE #2: User cal kit definition must be done before performing the calibration.
Page 19
Reflection methodExample of measurement procedure:
With Open/Short/Load cal at 7 mm plane, and Open/Short compensation at fixture
1) Connect a 7 mm type test fixture to the Port-1 via a semi rigid cable and adapters.
2) Preset the E5061B.
3) Load & Run the VBA program “LF-RF_Zmeas_xxxx.vba”.
4) Select the mode “S11 1-port (with O/S/L cal + Open/Short compen)”, and click on [Start measurement].
5) Setup stimulus conditions (Start, Stop, Sweep type, IFBW, Source power, etc) by using front keys.
6) Perform Open/Short/Load cal (1-port full cal) by using front keys.
Press [Cal], (Cal Kit), and select your user-defined 7 mm cal kit,
press (Calibrate), (1-Port Cal), connect the 7 mm open termination, and press (Open),
connect the 7 mm short termination to the fixture, and press (Short),
connect the 7 mm 50 ohm termination, and press (Load),
press (Done) to complete the calibration.
7) Connect the 7 mm type fixture to the 7 mm plane.
8) Leave the fixture open, and click on [Open meas]. The open measurement data will be stored into the memory trace-1.
9) Short the short bar to the fixture, and click on [Short meas]. The short meas. data will be stored into the memory trace-2.
10) Connect the DUT to the fixture.
11) Select impedance parameters, and click on [Select parameters].
The E5061B will measure impedance with the fixture compensation data stored in the memory trace 1 & 2.
(NOTE: Not possible to define open admittance and short impedance.)
For 4195A/41951A users who have its 7 mm cal kit
and prefer coax Open/Short/Load cal + fixture compensation
Page 20
How to define user cal kit
Defining user cal kit for P/N 0699-2014 axial lead 50 ohm resistor
(Load = 50 ohm + about 14 nH #1, Open = 0 S + 0 F, Short = 0 ohm + 0 H)
[Cal], (Cal Kit), (User), (Modify Cal Kit), (Define STDs),
(1.No name), (Label), type in "short", (Std Type), (Short), (Return),
(2.No name), (Label), type in "open", (Std Type), (Open), (Return),
(3.No name), (Label), type in "load", (Std Type), (Arbitrary),
(Arb. Impedance), set to “50 ohm”, (Offset Z0), set to “500 ohm”, (Offset delay), set to “14 nH / 500 ohm = 28 psec” #1,
(Return), (Return),
(Specify CLSs),
(Open), (Port 1), (2.open), (Port 2), (2.open), (GP Port), (2.open), (Return),
(Short), (Port 1), (1.short), (Port 2), (1.short), (GP Port), (1.short), (Return),
(Load), (Port 1), (3.load), (Port 2), (3.load), (GP Port), (3.load), (Return),
(Label Kit), type in user cal kit's name, for example “Lead 50 ohm", (Return).
NOTES #1:
* The load device is defined with a simple R+jwL model, which is good enough for the measurements up to 30 MHz.
* Series inductance L (=about 14 nH) can be approximately defined by setting Offset Z0 to a large value,
and Offset delay = (14 nH / Offset Z0).
* Need to connect the load device with a minimal lead length.
50 ohmload
Fixture
Page 21
How to define user cal kit
Defining user cal kit for P/N 0699-2829 SMD 50 ohm resistor
(Load = 50 ohm + 0 H, Open = 0 S + 0 F, Short = 0 ohm + 0 H)
[Cal], (Cal Kit), (User), (Modify Cal Kit), (Define STDs),
(1.No name), (Label), type in "short", (Std Type), (Short), (Return),
(2.No name), (Label), type in "open", (Std Type), (Open), (Return),
(3.No name), (Label), type in "load", (Std Type), (Arbitrary),
(Arb. Impedance), set to “50 ohm”, (Return), (Return),
(Specify CLSs),
(Open), (Port 1), (2.open), (Port 2), (2.open), (GP Port), (2.open), (Return),
(Short), (Port 1), (1.short), (Port 2), (1.short), (GP Port), (1.short), (Return),
(Load), (Port 1), (3.load), (Port 2), (3.load), (GP Port), (3.load), (Return),
(Label Kit), type in user cal kit's name, for example “SMD 50 ohm", (Return).
Page 22
How to define user cal kit
Defining user cal kit for 7 mm coaxial cal kit of 41951A and 43961A
(Load = 50 ohm + 0 H, Open = 0 S + 82 fF, Short = 0 ohm + 0 H)
[Cal], (Cal Kit), (User), (Modify Cal Kit), (Define STDs),
(1.No name), (Label), type in "short", (Std Type), (Short), (Return),
(2.No name), (Label), type in "open", (Std Type), (Open), (C0), set to “82e-15 F”, (Return),
(3.No name), (Label), type in "load", (Std Type), (Load), (Return), (Return),
(Specify CLSs),
(Open), (Port 1), (2.open), (Port 2), (2.open), (GP Port), (2.open), (Return),
(Short), (Port 1), (1.short), (Port 2), (1.short), (GP Port), (1.short), (Return),
(Load), (Port 1), (3.load), (Port 2), (3.load), (GP Port), (3.load), (Return),
(Label Kit), type in user cal kit's name, for example “ZA 7 mm", (Return).