Impedance measurement with E5061B LF-RF Network Analyzer · Page 1 Impedance measurement with E5061B LF-RF Network Analyzer Rev.100408 Agilent Technologies April 2010

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Impedance measurement with

E5061B LF-RF Network Analyzer

Rev.100408

Agilent Technologies

April 2010

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© Copyright 2010 Agilent Technologies

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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

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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

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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

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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)

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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)


Test fixture

Home-made fixture

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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.

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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)

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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



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].


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.



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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

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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.



4) Select the mode “S11 1-port (with Open/Short/Load cal)”, and click on [Start measurement].


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),





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.



4) Select the mode “S11 1-port (with O/S/L cal + Open/Short compen)”, and click on [Start measurement].


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),


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.



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


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)



(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),




(Label Kit), type in user cal kit's name, for example “SMD 50 ohm", (Return).

Page 22


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)



(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),




(Label Kit), type in user cal kit's name, for example “ZA 7 mm", (Return).

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Impedance measurement with E5061B LF-RF Network Analyzer · Page 1 Impedance measurement with E5061B LF-RF Network Analyzer Rev.100408 Agilent Technologies April 2010