Network Analysis

Back to Basics

Objectives

Review RF basics (transmission lines, etc.)

Understand what types of measurements are made with vector

network analyzers (VNAs)

Examine architectures of modern VNAs

Provide insight into nonlinear

characterization of amplifiers,

mixers, and converters using a VNA

Understand associated calibrations

Application: Amplifiers test and Fixture

Simulator

Automation VBA example

Network Analysis is NOT.…

Router

Bridge

Repeater

Hub

Your IEEE 802.37 X.25 ASDN switched-packet data stream is running at 547 MBPS with a BER of 1.523 X 10 . . .

-9

What Are Vector Network Analyzers?

Are stimulus-response test systems

Characterize forward and reverse reflection and transmission responses (S-parameters) of RF and microwave components

Quantify linear magnitude and phase

Are very fast for swept measurements

Provide the highest level of measurement accuracy

S21

S12

S11 S22

R1 R2

RF Source

LO

Test port 2

B A

Test port 1

Phase

Magnitude

DUT

Reflection

Transmission

What Types of Devices are Tested?

Device type Active Passive

Inte

gra

tio

n

Hig

h

Lo

w

Antennas

Switches

Multiplexers

Mixers

Samplers

Multipliers

Diodes

Duplexers

Diplexers

Filters

Couplers

Bridges

Splitters, dividers

Combiners

Isolators

Circulators

Attenuators

Adapters

Opens, shorts, loads

Delay lines

Cables

Transmission lines

Resonators

Dielectrics

R, L, C's

RFICs

MMICs

T/R modules

Transceivers

Receivers

Tuners

Converters

VCAs

Amplifiers

VTFs

Modulators

VCAtten’s

Transistors

Device Test Measurement Model

NF

Stimulus type Complex Simple

Co

mp

lex

Re

sp

on

se

to

ol

Sim

ple

DC CW Swept Swept Noise 2-tone Multi-tone Complex Pulsed- Protocol freq power modulation RF

Det/Scope

Param. An.

NF Mtr.

Imped. An.

Power Mtr.

SNA

VNA

SA

VSA

RFIC Testers

TG/SA

Ded. Testers

I-V

Absol.

Power

LCR/Z

Harm. Dist.

LO stability

Image Rej.

Gain/flat.

Phase/GD

Isolation

Rtn loss

Impedance

S-parameters

Compr'n

AM-PM

Mixers

Balance

d

RFIC test

Full call

sequence

Pulsed S-parm.

Pulse profiling

BER

EVM

ACP

Regrowth

Constell.

Eye

Intermodulation

Distortion NF

Measurement plane

Lightwave Analogy to RF Energy

RF

Incident

Reflected

Transmitted

Lightwave

DUT

Why Do We Need to Test Components?

Verify specifications of “building blocks”

for more complex RF systems

Ensure distortionless transmission

of communications signals

• Linear: constant amplitude, linear phase / constant group delay

• Nonlinear: harmonics, intermodulation, compression, X-parameters

Ensure good match when absorbing

power (e.g., an antenna)

KPWR FM 97

The Need for Both Magnitude and Phase

4. Time-domain characterization

Mag

Time

5. Vector-error correction

Error

Measured

Actual

2. Complex impedance

needed to design

matching circuits

3. Complex values

needed for device

modeling

1. Complete characterization

of linear networks

S21

S12

S11 S22

6. X-parameter (nonlinear) characterization

Agenda

• What measurements do we make?

• Network analyzer hardware

• Error models and calibration

• Applications

• Automation RECEIVER / DETECTOR

PROCESSOR / DISPLAY

REFLECTED

(A)

TRANSMITTED

(B) INCIDENT (R)

SIGNAL SEPARATION

SOURCE

Incident

Reflected

Transmitted

DUT

SHORT

OPEN

LOAD

Transmission Line Basics

Low frequencies Wavelengths >> wire length

Current (I) travels down wires easily for efficient power transmission

Measured voltage and current not dependent on position along wire

High frequencies

Wavelength or << length of transmission medium

Need transmission lines for efficient power transmission

Matching to characteristic impedance (Zo) is very important for

low reflection and maximum power transfer

Measured envelope voltage dependent on position along line

+ _

I

Transmission line Zo

Zo determines relationship between voltage and current waves

Zo is a function of physical dimensions and r

Zo is usually a real impedance (e.g. 50 or 75 ohms)

Characteristic impedance for coaxial

airlines (ohms)

10 20 30 40 50 60 70 80 90 100

1.0

0.8

0.7

0.6

0.5

0.9

1.5

1.4

1.3

1.2

1.1

norm

aliz

ed v

alu

es

50 ohm standard

attenuation is

lowest at 77 ohms

power handling capacity

peaks at 30 ohms

Power Transfer Efficiency

RS

RL

For complex impedances, maximum

power transfer occurs when ZL = ZS*

(conjugate match)

Maximum power is transferred when RL = RS

RL / RS

0

0.2

0.4

0.6

0.8

1

1.2

0 1 2 3 4 5 6 7 8 9 10

Lo

ad

Po

we

r

(no

rma

lized

)

Rs

RL

+jX

-jX

Transmission Line Terminated with Zo

For reflection, a transmission line terminated in Zo

behaves like an infinitely long transmission line

Zs = Zo

Zo

Vreflect = 0! (all the incident power

is transferred to and

absorbed in the load)

V inc

Zo = characteristic impedance

of transmission line

Transmission Line Terminated with Short, Open

Zs = Zo

Vreflect

V inc

For reflection, a transmission line terminated in a

short or open reflects all power back to source

In-phase (0o) for open,

out-of-phase (180o) for short

Transmission Line Terminated with 25 Ohms

Vreflect

Standing wave pattern does not

go to zero as with short or open

Zs = Zo

ZL = 25 W

V inc

High-Frequency Device Characterization

Transmitted

Incident

TRANSMISSION

Gain / Loss

S-Parameters

S21, S12

Group

Delay

Transmission

Coefficient

Insertion

Phase

Reflected

Incident

REFLECTION

VSW

R

S-Parameters

S11, S22 Reflection

Coefficient

Impedance,

Admittance

R+jX,

G+jB

Return Loss

G, r T,t

Incident

Reflected

Transmitted R B

A

A

R =

B

R =

Reflection Parameters

dB

No reflection

(ZL = Zo)

r

RL

VSWR

0 1

Full reflection

(ZL = open, short)

0 dB

1

= Reflection

Coefficient =

V reflected

V incident

= r F G

= r G Return loss = -20 log(r ),

Voltage Standing Wave

Ratio

VSWR = Vmax

Vmin =

1 + r

1 - r

Vmax

Vmin

ZL - Zo

ZL + Zo

Smith Chart Review

Smith Chart maps

rectilinear impedance

plane onto polar plane

0 +R

+jX

-jX

Rectilinear impedance plane -90 o

0 o 180

o + -

.2

.4

.6

.8

1.0

90 o

0

Polar plane

Z = Zo L

= 0 G

Constant X

Constant R

Smith chart

G L

Z = 0

= ±180 O

1

(short) Z = L

= 0 O

1 G

(open)

Transmission Parameters

V Transmitted

V Incident

Transmission Coefficient = T = V Transmitted

V Incident

= t

DUT

Gain (dB) = 20 Log V

Trans

V Inc

Insertion Loss (dB) = -20 Log V

Trans

V Inc

= -20 Log(t)

= 20 Log(t)

Linear Versus Nonlinear Behavior

Linear behavior: Input and output frequencies are the

same (no additional frequencies created)

Output frequency only undergoes

magnitude and phase change

Frequency f 1

Time

Sin 360o * f * t

Frequency

A phase shift =

to * 360o * f

1 f

DUT

Time

A

t o

A * Sin 360o * f (t - to)

Input Output

Time

Nonlinear behavior: Output frequency may undergo

frequency shift (e.g. with mixers)

Additional frequencies created

(harmonics, intermodulation)

Frequency f 1

Criteria for Distortionless Transmission

Constant amplitude over

bandwidth of interest

Magnitude

Phase

Frequency

Frequency

Linear phase over

bandwidth of

interest

Linear Networks

Magnitude Variation with Frequency

F(t) = sin wt + 1/3 sin 3wt + 1/5 sin 5wt

Time

Linear Network

Frequency Frequency Frequency

Magnitude

Time

Phase Variation with Frequency

Frequency

Magnitude

Linear Network

Frequency

Frequency

Time

0

-180

-360

°

°

°

Time

F(t) = sin wt + 1 /3 sin 3wt + 1 /5 sin 5wt

Deviation from Linear Phase

Use electrical delay to remove

linear portion of phase response Linear electrical length

added

+ =

Frequency

(Electrical delay function)

Frequency

RF filter response Deviation from linear

phase

Ph

ase

1

/Div

o

Ph

ase

45

/D

iv

o

Frequency

Low resolution High resolution

Group Delay

in radians

in radians/sec

in degrees

f in Hertz (w = 2 p f)

w

Group Delay (tg) =

-d d w

= -1

360 o

d d f *

Frequency

Group delay ripple

Average delay

t o

t g

Phase

D

Frequency (w)

Dw

Group-delay ripple indicates phase distortion

Average delay indicates electrical length of DUT

Aperture (Dw) of measurement is very important

Why Measure Group Delay?

Same peak-peak phase ripple can result in different group delay

Ph

ase

Ph

ase

Gro

up

De

lay

Gro

up

De

lay

-d d w

-d d w

f

f

f

f

Characterizing Unknown Devices

Using parameters (H, Y, Z, S) to characterize devices:

Gives linear behavioral model of our device

Measure parameters (e.g. voltage and current) versus frequency under

various source and load conditions (e.g. short and open circuits)

Compute device parameters from measured data

Predict circuit performance under any source and load conditions

H-parameters

V1 = h11I1 + h12V2

I2 = h21I1 + h22V2

Y-parameters

I1 = y11V1 + y12V2

I2 = y21V1 + y22V2

Z-parameters

V1 = z11I1 + z12I2

V2 = z21I1 + z22I2

h11 = V1

I1 V2=0

h12 = V1

V2 I1=0

(requires short circuit)

(requires open circuit)

Why Use S-Parameters?

Relatively easy to obtain at high frequencies

Measure voltage traveling waves with a vector network analyzer

Don't need shorts/opens (can cause active devices to oscillate or self-destruct)

Relate to familiar measurements (gain, loss, reflection coefficient ...)

Can cascade S-parameters of multiple devices to predict system performance

Can compute H-, Y-, or Z-parameters from S-parameters if desired

Can easily import and use S-parameter files in electronic-simulation tools

Incident Transmitted S 21

S 11 Reflected S 22

Reflected

Transmitted Incident

b 1

a 1 b 2

a 2 S 12

DUT

b 1 = S 11 a 1 + S 12 a 2

b 2 = S 21 a 1 + S 22 a 2

Port 1 Port 2

Measuring S-Parameters

S 22 = Reflected

Incident =

b 2

a 2 a 1 = 0

S 12 = Transmitted

Incident =

b 1

a 2 a 1 = 0

S 11 = Reflected

Incident =

b 1

a 1 a 2 = 0

S 21 = Transmitted

Incident =

b 2

a 1 a 2 = 0

Incident Transmitted S 21

S 11

Reflected b

a 1

b 2

1

Z 0

Load

a 2 = 0

DUT Forward

Incident Transmitted S 12

S 22

Reflected

b 2

a 2

b

a 1 = 0

DUT Z 0

Load Reverse

1

Equating S-Parameters With

Common Measurement Terms

S11 = forward reflection coefficient (input match)

S22 = reverse reflection coefficient (output match)

S21 = forward transmission coefficient (gain or loss)

S12 = reverse transmission coefficient (isolation)

Remember, S-parameters are inherently

complex, linear quantities -- however, we often

express them in a log-magnitude format

Measurements on Nonlinear Components

• Saturation, crossover, intermodulation, and other nonlinear

effects can cause signal distortion

• Effect on system depends on amount and type of distortion

and system architecture

Nonlinear Networks

33

Scattering Parameters – Power Dependence

An early attempt at providing

some power-dependence

was the P2D files used in

ADS.

Unfortunately these files did

not properly capture non-

linear behavior except S11

and S21 compression,

nor did they predict

harmonics and IMD

34

X-parameters come from the

Poly-Harmonic Distortion (PHD) Framework

1 1 11 12 21 22( , , ,..., , ,...)k kB F DC A A A A=

2 2 11 12 21 22( , , ,..., , ,...)k kB F DC A A A A=Port Index Harmonic (or carrier) Index

Spectral map of complex large input phasors to large complex output phasors Black-Box description holds for transistors, amplifiers, RF systems, etc.

2A1A

1B

37

X-parameters Reduce to S-parameters

11

( )

21 11 21| | 0

[ ( )] F

A

X A s

11

( )

21,21 11| | 0

( ) 0T

AX A

-60 -25 -20 -15 -10 -5 0 5 10

|A11| (dBm)

-40

40

20

0

-20

dB

( )

21,21

SX

( )

21,21

TX

( )

21 11/ | |FX A

Reduces to (linear)

S-parameters in the

appropriate limit

11

( )

21,21 11 22| | 0

( )S

AX A s

+

11| |A

( )

21 1

( )

21,21

2 *

21 11

( )

21,21 11 21 1 11 21() )( ) ( )( TF SXB XA A P AAAA XP= + +

Agenda

• What measurements do we make?

• Network analyzer hardware

• Error models and calibration

• Applications

• Automation RECEIVER / DETECTOR

PROCESSOR / DISPLAY

REFLECTED

(A)

TRANSMITTED

(B) INCIDENT (R)

SIGNAL SEPARATION

SOURCE

Incident

Reflected

Transmitted

DUT

SHORT

OPEN

LOAD

Generalized Network Analyzer Block Diagram

(Forward Measurements Shown)

RECEIVER / DETECTOR

PROCESSOR / DISPLAY

REFLECTED

(A)

TRANSMITTED

(B)

INCIDENT

(R)

SIGNAL

SEPARATION

SOURCE

Incident

Reflected

Transmitted

DUT

Source

Supplies stimulus for system

Can sweep frequency or power

Traditionally NAs had one signal source

Modern NAs have the option for a second

internal source and/or the ability to control

external source.

Can control an external source as a local

oscillator (LO) signal for mixers and

converters

Useful for mixer measurements like

conversion loss, group delay

RECEIVER / DETECTOR

PROCESSOR / DISPLAY

REFLECTED

(A)

TRANSMITTED

(B) INCIDENT (R)

SIGNAL

SEPARATION

SOURCE

Incident

Reflected

Transmitted

DUT

Signal Separation

Test Port

Detector directional

coupler

splitter bridge

• Measure incident signal for reference

• Separate incident and reflected signals RECEIVER / DETECTOR

PROCESSOR / DISPLAY

REFLECTED

(A)

TRANSMITTED

(B) INCIDENT (R)

SIGNAL

SEPARATION

SOURCE

Incident

Reflected

Transmitted

DUT

Directivity

Directivity is a measure of how well a directional coupler or

bridge can separate signals moving in opposite directions

Test port

(undesired leakage

signal) (desired reflected

signal)

Directional Coupler

desired leakage

result

Directivity = Isolation (I) - Fwd Coupling (C) - Main Arm Loss (L)

I C

L

Directional Bridge

Test Port

Detector

50 W 50 W

50 W

50-ohm load at test port balances

the bridge -- detector reads zero

Non-50-ohm load imbalances bridge

Measuring magnitude and phase of

imbalance gives complex impedance

"Directivity" is difference between

maximum and minimum balance

Advantage: less loss at low

frequencies

Disadvantages: more loss in main

arm at high frequencies and less

power-handling capability

Interaction of Directivity with the DUT

(Without Error Correction)

Data max

Add in-phase

Device

Directivity

Retu

rn L

oss

Frequency

0

30

60

DUT RL = 40 dB

Add out-of-phase

(cancellation)

De

vic

e

Directivity

Data = vector sum

Dire

ctivity

Devic

e Data min

Detector Types:

Narrowband Detection - Tuned Receiver

Best sensitivity / dynamic range

Provides harmonic / spurious signal rejection

Improve dynamic range by increasing power,

decreasing IF bandwidth, or averaging

Trade off noise floor and measurement speed

10 MHz 26.5 GHz

IF Filter

LO

ADC / DSP RF

RECEIVER / DETECTOR

PROCESSOR / DISPLAY

REFLECTED

(A)

TRANSMITTED

(B) INCIDENT (R)

SIGNAL

SEPARATION

SOURCE

Incident

Reflected

Transmitted

DUT Tuned Receiver Front Ends:

Mixers Versus Samplers

It is cheaper and easier to make

broadband front ends using

samplers instead of mixers, but

dynamic range is considerably less

Mixer-based front end

ADC / DSP

Sampler-based front end

S

Harmonic

generator

f

frequency "comb"

ADC / DSP

Error Due to Interfering Signal

0.001

0.01

0.1

1

10

100

0 -5 -10 -15 -20 -25 -30 -35 -40 -45 -50 -55 -60 -65 -70

Interfering signal or noise (dB)

Err

or

(dB

, d

eg) phase error

magn error

+

-

Dynamic range is

very important for

measurement

accuracy!

Dynamic Range and Accuracy

T/R Versus S-Parameter Test Sets

RF comes out port 1; port 2 is receiver

Forward measurements only

Response, one-port cal available

RF comes out port 1 or port 2

Forward and reverse measurements

Two-port calibration possible

Transmission/Reflection Test Set

Port 1 Port 2

Source

B

R

A

DUT Fwd

S-Parameter Test Set

DUT Fwd Rev

Port 1

Transfer switch

Port 2

Source

B

R1

A

R2

Fwd

Modern VNA Block Diagram (2-Port PNA-X)

DUT

Test port 1

R1

Test port 2

R2

A B

To receivers

LO

Source 2

Output 1

Source 2

Output 2

Pulse generators

rear panel

1

2

3

4

+28V

Noise receivers

10 MHz -

3 GHz

3 –

13.5/

26.5

GHz

Source 1

OUT 1 OUT 2

Pulse

modulator

Source 2

OUT 1 OUT 2

Pulse

modulator

RF jumpers

S-parameter receivers

Mechanical switch noise receivers

J9 J10 J11 J8 J7 J2 J1

Impedance tuner for noise

figure measurements

+

-

RECEIVER / DETECTOR

PROCESSOR / DISPLAY

REFLECTED

(A)

TRANSMITTED

(B)

INCIDENT

(R)

SIGNAL

SEPARATION

SOURCE

Incident

Reflected

Transmitted

DUT

Processor / Display

• Markers

• Limit lines

• Pass/fail indicators

• Linear/log formats

• Grid/polar/Smith charts

• Time-domain transform

• Trace math

Achieving Measurement Flexibility

Channel

Trace Trace Trace Trace Trace Trace

Trace

• Parameter

• Format

• Scale

• Markers

• Trace math

• Electrical delay

• Phase offset

• Smoothing

• Limit tests

• Time-domain transform

Channel

• Sweep type

• Frequencies

• Power level

• IF bandwidth

• Number of points

• Trigger state

• Averaging

• Calibration

Window Window

Window Window

Trace (CH1)

Trace (CH2)

Trace (CH1)

Trace (CH2) Trace (CH3)

Trace (CH4)

Three Channel Example

Window

Window Window

Channel 1

frequency sweep (narrow)

S11 S21

Channel 2

frequency sweep (broad)

S21

Channel 3

power sweep

S21 S11

Agenda

• What measurements do we make?

• Network analyzer hardware

• Error models and calibration

• Applications

• Automation RECEIVER / DETECTOR

PROCESSOR / DISPLAY

REFLECTED

(A)

TRANSMITTED

(B) INCIDENT (R)

SIGNAL SEPARATION

SOURCE

Incident

Reflected

Transmitted

DUT

SHORT

OPEN

LOAD

The Need For Calibration

Why do we have to calibrate?

• It is impossible to make perfect hardware

• It would be extremely difficult and expensive to make hardware good

enough to entirely eliminate the need for error correction

How do we get accuracy?

• With vector-error-corrected calibration

• Not the same as the yearly instrument calibration

What does calibration do for us?

• Removes the largest contributor to measurement

uncertainty: systematic errors

• Provides best picture of true performance of DUT Systematic error

Measurement Error Modeling

Systematic errors

• Due to imperfections in the analyzer and test setup

• Assumed to be time invariant (predictable)

• Generally, are largest sources or error

Random errors

• Vary with time in random fashion (unpredictable)

• Main contributors: instrument noise, switch and connector repeatability

Drift errors

• Due to system performance changing after a calibration has been done

• Primarily caused by temperature variation

Measured

Data

SYSTEMATIC

RANDOM

DRIFT

Errors:

Unknown

Device

Systematic Measurement Errors

A B

Source

Mismatch

Load

Mismatch

Crosstalk Directivity

DUT

Frequency response

Reflection tracking (A/R)

Transmission tracking (B/R)

R

Six forward and six reverse error terms

yields 12 error terms for two-port devices

What is Vector-Error Correction?

Vector-error correction…

• Is a process for characterizing systematic error terms

• Measures known electrical standards

• Removes effects of error terms from subsequent measurements

Electrical standards…

• Can be mechanical or electronic

• Are often an open, short, load, and thru,

but can be arbitrary impedances as well

Errors

Measured

Actual

Using Known Standards to Correct

for Systematic Errors

1-port calibration (reflection measurements)

Only three systematic error terms measured

Directivity, source match, and reflection tracking

Full two-port calibration (reflection and transmission measurements)

Twelve systematic error terms measured

Usually requires 12 measurements on four known standards (SOLT)

Standards defined in cal kit definition file

Network analyzer contains standard cal kit definitions

CAL KIT DEFINITION MUST MATCH ACTUAL CAL KIT USED!

User-built standards must be characterized and entered into user cal-kit

Reflection: One-Port Model

ED = Directivity

ERT = Reflection tracking

ES = Source Match

S11M = Measured

S11A = Actual

To solve for error terms, we

measure 3 standards to generate

3 equations and 3 unknowns

S11M

S11A ES

ERT

ED

1 RF in

Error Adapter

S11M

S11A

RF in Ideal

Assumes good termination at port two if testing two-port devices

If using port two of NA and DUT reverse isolation is low (e.g., filter passband):

Assumption of good termination is not valid

Two-port error correction yields better results

S11M = ED + ERT

1 - ES S11A

S11A

Before and After A One-Port Calibration

Data before 1-port calibration

Data after 1-port calibration

Two-Port Error Correction

Each actual S-parameter is a function of

all four measured S-parameters

Analyzer must make forward and reverse

sweep to update any one S-parameter

Luckily, you don't need to know these

equations to use a network analyzers!!!

Port 1 Port 2 E

S 11

S 21

S 12

S 22

E S E D

E RT

E TT

E L

a 1

b 1

A

A

A

A

X

a 2

b 2

Forward model

= fwd directivity

= fwd source match

= fwd reflection tracking

= fwd load match

= fwd transmission tracking

= fwd isolation

E S

E D

E RT

E TT

E L

E X

= rev reflection tracking

= rev transmission tracking

= rev directivity

= rev source match

= rev load match

= rev isolation

E S'

E D'

E RT'

E TT'

E L'

E X'

Port 1 Port 2

S 11

S

S 12

S 22 E S' E D'

E RT'

E TT'

E L'

a 1

b 1 A

A

A

E X'

21 A

a 2

b 2

Reverse model

S a

S m ED

ERT

S m ED

ERT

ES E L

S m E X

ETT

S m E X

ETT

S m ED'

ERT

ES

S m ED

ERT

ES E L EL

S m E X

ETT

S m E X

ETT

11

111

22 21 12

111

122 21 12

=

-+

--

- -

+-

+-

-- -

( )('

'' ) ( )(

'

')

( )('

'' ) ' ( )(

'

')

S a

S m E X

ETT

S m ED

ERT

ES EL

S m ED

ERT

ES

S m ED

ERT

ES EL

21

21 22

111

122

=

-1 +

--

+-

+-

-

( )('

'( ' ))

( )('

'' ) ' ( )(

'

')EL

S m E X

ETT

S m E X

ETT

21 12- -

'S E S E- -(

')( ( ' ))

( )('

'' ) ' ( )(

'

')

m X

ETT

m D

ERT

ES EL

S m ED

ERT

ES

S m ED

ERT

ES EL E L

S m E X

ETT

S m E X

ETT

S a

121

11

111

122 21 12

12

+ -

+-

+-

-- -

=

('

')(

(

S m ED

ERT

S m ED

ERT

S a

22

111

22

-) ' ( )(

'

')

S m ED

ERT

ES EL

S m E X

ETT

S m E X

ETT

11 21 12--

- -

+-

=

ES

S m ED

ERT

ES EL EL

S m E X

ETT

S m E X

ETT

)('

'' ) ' ( )(

'

')1

22 21 12+

--

- -

1 +

Crosstalk: Signal Leakage Between Test Ports

During Transmission

Can be a problem with:

• High-isolation devices (e.g., switch in open position)

• High-dynamic range devices (some filter stopbands)

Isolation calibration

• Adds noise to error model (measuring near noise floor of system)

• Only perform if really needed (use averaging if necessary)

• If crosstalk is independent of DUT match, use two terminations

• If dependent on DUT match, use two

DUTs with termination on output

DUT

DUT LOAD DUT LOAD

Errors and Calibration Standards

Convenient

Generally not accurate

No errors removed

Easy to perform

Use when highest

accuracy is not

required

Removes frequency

response error

For reflection measurements

Need good termination for

high accuracy with two-port

devices

Removes these errors:

Directivity

Source match

Reflection tracking

Highest accuracy

Removes these

errors:

Directivity

Source, load match

Reflection tracking

Transmission

tracking

Crosstalk

UNCORRECTED RESPONSE 1-PORT

FULL 2-PORT

DUT

DUT

DUT

DUT

thru

thru

ENHANCED-RESPONSE

Combines response and 1-port

Corrects source match for transmission

measurements

SHORT

OPEN

LOAD

SHORT

OPEN

LOAD

SHORT

OPEN

LOAD

Calibration Summary

error cannot be corrected

* enhanced response cal corrects

for source match during

transmission measurements

error can be corrected

SHORT

OPEN

LOAD Reflection tracking

Directivity

Source match

Load match

S-parameter (two-port)

T/R (one-port)

Reflection Test Set (cal type)

Transmission Tracking

Crosstalk

Source match

Load match

S-parameter (two-port)

T/R

(response, isolation) Transmission

Test Set (cal type)

* ( )

Response versus Two-Port Calibration

Uncorrected

After two-port calibration

After response calibration

Measuring filter insertion loss

• Variety of two- and four-port modules cover 300 kHz to 67 GHz

• Nine connector types available, 50 and 75 ohms

• Single-connection calibration

dramatically reduces calibration time

makes calibrations easy to perform

minimizes wear on cables and standards

eliminates operator errors

• Highly repeatable temperature-compensated

characterized terminations provide excellent accuracy

ECal: Electronic Calibration

Microwave modules use a

transmission line shunted

by PIN-diode switches in

various combinations

USB controlled

ECAL User Characterizations

4. VNA stores resulting

characterization data

inside the module.

2. Perform a calibration

using appropriate

mechanical standards.

3. Measure the ECal

module, including

adapters, as though

it were a DUT

1. Select adapters for the

module to match the

connector configuration

of the DUT.

Thru-Reflect-Line (TRL) Calibration

We know about Short-Open-Load-Thru (SOLT) calibration... What is TRL?

A two-port calibration technique

Good for non-coaxial environments (waveguide, fixtures, wafer probing)

Characterizes same 12 systematic errors as the more common SOLT cal

Uses practical calibration standards that

are easily fabricated and characterized

Other variations: Line-Reflect-Match (LRM),

Thru-Reflect-Match (TRM), plus many others

TRL was developed for

non-coaxial microwave

measurements

Network Analyzer Basics

www.agilent.com/find/backtobasics

Unknown-Thru Calibration

Cal Methods are listed in order of

ascending accuracy (least accurate

first):

• Uncharacterized Thru Adapter

• Electronic Calibrator (Ecal)

• Ecal with Unknown Thru

• Mechanical with Unknown Thru

Cal

• Adapter Removal

Analyzer

Port 1 Port 2

Thru Short

Open

Load

Short

Open

Load

DUT

Analyzer

Port 1 Port 2 DUT

Agenda

• What measurements do we make?

• Network analyzer hardware

• Error models and calibration

• Applications

• Automation RECEIVER / DETECTOR

PROCESSOR / DISPLAY

REFLECTED

(A)

TRANSMITTED

(B) INCIDENT (R)

SIGNAL SEPARATION

SOURCE

Incident

Reflected

Transmitted

DUT

SHORT

OPEN

LOAD

76

VNA application examples

– RF amplifier test

– High-power measurement

76

RF amplifier test

The modern VNA is a more suited solution for many parametric tests of RF amplifiers.

Gain compression Sweeps both frequency and

input power level at PxdB

Harmonic Distortion Performs real-time harmonics test

over frequency or input power

Efficiency (PAE) Calculate power-added

efficiency (PAE)

Swept IMD Performs IMD analysis over an

entire range of frequencies

High-power test Performs accurate tests with

high-power input / output of DUT

VNA

Pulsed-RF Characterize pulsed

performance of devices

Stability (K-factor) Calculates stability (K-factor)

from all S-parameters with

equation editor

f1 f2 f3 f1

77

78

What is gain compression?

•Parameter to define the transition between the linear and nonlinear region of an active device.

•The compression point is observed as x dB drop in the gain with VNA’s power sweep.

Output Power (dBm)

Input Power (dBm)

Linear region

Compression

(nonlinear) region

Power is not high enough

to compress DUT.

Gain (S21)

Input Power (dBm)

Sufficient power

level to drive DUT

Enough margin of source power capability

is needed for analyzers.

DUT

78

Modern VNA (Agilent E5072A)

VNA Functions Power sweep range

Legacy VNA (Agilent/ HP 8753ES)

Ex.) RF amplifier - Gain compression point

• Power sweep range is limited within 25 dB

(i.e. -15 to 10 dBm).

• VNA’s output power is NOT high enough to

see compression point of DUT.

• VNA can drive up to +20 dBm, enough to

detect compression point.

8753’s sweep range

(i.e. -15 to +10 dBm)

:

•Wide power sweep range (>65 dB) enables

linear and nonlinear test with a single sweep.

S21

S21

79

DUT

VNA Functions User Interface

Legacy VNA

• Measurement wizard is provided using the VNA’s

built-in automated software environment (i.e. VBA;

Visual Basic for Applications)

• Easy setup for calibration / measurement.

• No external system controller is necessary.

• Manual parameter setup only.

• Customers need to develop their own

software for applications.

Modern VNA

System Controller

80

VNA Functions

Measurement Wizard • Measurement wizard program speeds up measurements of RF amplifiers. • Key parameters of amplifiers: S-parameters, harmonics distortion, gain compression (CW or

Swept frequency), and swept-frequency IMD measurements. • Can be downloaded from www.agilent.com/find/enavba

81

82

VNA application examples

– RF amplifier test

– High-power measurement

82

83

Why high-power measurements?

Diagram of RF interface in wireless communication

Antenna

Rx Filter

Power Amp

Tx Filter

LNA

Duplexer

Combiner

• Components used for transmitting data in wireless communications

need to be tested with high-power signals under conditions similar

to actual operation. (may be beyond the measurement capability of

instruments!)

83

84

Power (initial)

High-power Measurements

Measurement Challenges:

• Power leveling - Eliminating short-term drift of a booster amplifier’s gain;

variation of input power to DUT.

When temperature changes after setup / calibration,

input power levels are changed even out of tolerance!

Temperature drift of a booster amp needs to be considered.

Configuration with a booster amp

SA SG Booster

amp Pin DUT

System Controller Power (drifted)

Input power (dBm)

Frequency (Hz)

tolerance

Target

power

level

DUT’s actual input power (Pin)

Gain

Gain variation from

temperature drift

84

Power (drifted)

High-power Measurements Power leveling

Measurement Challenges:

• Power leveling process takes very long time!

• Test configuration is complicated; necessary to lower overall cost of test systems.

SG’s power

is adjusted

Configuration for input power leveling

SA DUT SG

Power

Sensor

Coupler

e.g. GPIB

System Controller

Booster

amp

Pin

Leveled power

Input power (dBm)

Frequency (Hz)

tolerance Target

power

level

DUT’s actual input power (Pin)

DUT’s input power level should be within a specific target range - power leveling.

* Coupler to detect output

power of a booster amp

85

VNA Function Power leveling

VNA Function - Receiver leveling

• Adjusts the source power level using its receiver measurements.

• Replaces existing test systems for power leveling with reducing test complexity.

SA DUT SG

Power

Sensor

Coupler

e.g. GPIB

System Controller

Leveling with rack & stack system VNA’s receiver leveling

Receiver leveling offers fast and accurate leveling

to compensate a booster amp’s drift with a simple

connection.

Booster

amp Pin DUT

V

Booster

amp

Coupler

ATT

(Optional)

Pin

86

High-power Measurements Power leveling

Leveled Input power (Pin)

DUT’s Pin is accurately adjusted (i.e. within +-0.1 dBm) at

target power level of +43 dBm by using the VNA’s receiver

leveling.

Pin (dBm)

0.1 dBm/div

Receiver leveling ON

Receiver leveling OFF

Note: frequency sweep is performed to monitor Pin over frequency.

R1

DUT Booster amp

Coupler

ATT (Optional)

Pin

+43 dBm

Configuration of Power leveling

87

Fixture Simulator

• Fixture Simulator

– Balanced measurements (Mixed-mode S-parameters)

– (De-)Embedding / port matching

– Setup wizard of fixture simulator

– Port matching utility program

Fixture Simulator

DUT

Measured S-

parameters

Port

Extension

Network De-

embedding

Port reference

Z conversion Port Matching

Unbalanced-

Balanced

Conversion

Differential

Port Z

conversion

Differential

Matching

circuit

Embedding

Single-ended S-parameter

Balanced (Mixed-mode) S-parameter

Single-ended Balanced

Zd

Zc

Data Process

Actual

Calibration Plane

Built-in Balanced Measurement

SAW Filters (Bal-Bal) Baluns

Differential Amplifiers Cable

SAW Filters (Unbal-Bal)

Balanced component examples:

44434241

34333231

24232221

14131211

SSSS

SSSS

SSSS

SSSS

22212221

12111211

22212221

12111211

CCCCCDCD

CCCCCDCD

DCDCDDDD

DCDCDDDD

SSSS

SSSS

SSSS

SSSS

DUT

V1 V2

Vdiff

Vcomm

=

2

1*

,

,

V

V

DC

BA

Vcomm

Vdiff

Measure

Single-ended S-parameters

Simulate Hybrid Balun

to extract differential and common

Obtain

Mixed-mode S-parameters

(Balanced and Common-mode

S-parameters)

Mixed-mode S-parameters

Examples of Mixed-mode S-Parameters

Sdd21

Scc21

Mixed-mode S21 for Bal-Bal

Scd21

Sdc21

Sdc11

Sds21

Scs21

Mixed-mode S21 for Single to Bal

Sss11 Ssd12

Sds21 Sdd22

Scs21

Ssc12

Scd22

Sdc22

Scc22

Sdd11 Mixed-mode S11

Balanced SAW filter measurement example

Embedding

50 50 R+jX R+jX

DUT DUT

Complex Port Z Conversion

Embedding/De-embedding and Port Z Conversion

Measure Simulate

DUT

Measured

S-parameter

Embedded Response

Additional

Network

Additional

Network DUT

De-embedded

Response

Measured

S-parameter

Undesired

Network

Undesired

Network

De-embedding

Embedding / De-embedding

Port 1

Port 2

Port 3

Port 4

Port 1

Port 2

Port 3

Port 4

(De-)Embedding of 2-port circuits

(De-)Embedding of 4-port circuits

DUT

DUT

De-embedding

•Accurate characterization of the DUT is achieved by de-embedding S-

parameter (*.s2p) of a fixture.

Calibrated

system(cal

plane at cable

end)

DUT

Connector

RF Cable

DUT

Calibration

Plane

S11

S12

S21

S22

Fixture

Create an S2p file

and de-embed

Embedding Virtual Networks

• Mathematically embed matching circuits on any ports as required.

• Predefined matching topologies or user defined S-parameters networks can

be embedded.

L1

L2

C1

C1

Zd

Zc

Zi

Bal

SAW

Filter

Virtual matching circuits

Balanced SAW Filter Measurement Example

Single-ended (unbalanced)

9x9 S-parameters, S11 to S33

Balanced S-parameters

(both differential and common modes)

Sss11 Ssd12

Sds21 Sdd22

Scs21

Ssc12

Scd22

Sdc22

Scc22

Agilent Restricted

Measurement Specifications

Connections

• Single-ended : Port 1

• Balanced : Port 2

• Balanced : Port 3

Setup

1. Preset : OK

2. Center : 942.5MHz

3. Span : 200MHz

4. Display : Number of Traces: 9

Allocate Traces: |1|2|3|

|4|5|6|

|7|8|9|

5. Select parameter & format as shown on next page

6. Adjust Scale

Band Pass Filter(Single-ended)

F0 : 947.5MHz

50 ohm 50 ohm

PORT 1 PORT 2

Band Pass Filter(Balanced)

F0 : 942.5MHz

50 ohm

200 ohm

PORT 1

PORT 2

PORT 3

Duplexer F0(Tx) : 1880MHz

F0(Rx) : 1960MHz

50 ohm 50 ohm

50 ohm

PORT 1

PORT 2

PORT 3

R

x

T

x

ANT

s1 Handset Component Demo Kit

E5079A

L2

C1

C1

Zd

Zc

Measure Single-ended S-parameters

Measurement parameters

S11 S12 S13

S21 S22 S23

S31 S32 S33

Zi

Measured

S-parameter

Bal

SAW

Filter

Perform Full 3-port Calibration

Measured

S-parameter

(w/Full-3 Cal)

L2

C1

C1

Zd

Zc

Zi

Bal

SAW

Filter

Measured

S-parameter

(w/Full-3 Cal)

Apply Port Extension

Electrical length

Port 1 : 180ps Port 2 : 280ps Port 3 : 280ps

L2

C1

C1

Zd

Zc

Zi

Bal

SAW

Filter

Apply port

extension

Convert to Mixed-mode S-parameters

Measurement Parameters

Sss11 Ssd12 Ssc12

Sds21 Sdd22 Sdc22

Scs21 Scd22 Scc22

Convert to mixed-mode

S-parameter

L2

C1

C1

Zd

Zc

Zi

Bal

SAW

Filter

Measured

S-parameter

(w/Full-3 Cal)

Apply port

extension

Convert to mixed-

mode S-parameter

Convert port

characteristic

impedance*

Modify Port Characteristic Impedance

Port characteristic impedance

Port 1 : 50 ohms

Port 2 : 100 ohms

Port 3 : 100 ohms

* Differential & common impedance are

automatically calculated from defined

single-ended impedance.

L2

C1

C1

Zd

Zc

Zi

Bal

SAW

Filter

Measured

S-parameter

(w/Full-3 Cal)

Apply port

extension

Apply Port Matching

Matching specifications

Port 1 : none

Port 2 : Shunt L = 28nH

Port 3 : Shunt L = 28nH

Convert to mixed-

mode S-parameter

Convert port

characteristic

impedance*

Apply matching

circuit

L2

C1

C1

Zd

Zc

Zi

Bal

SAW

Filter

Measured

S-parameter

(w/Full-3 Cal)

Apply port

extension

Save “State & Cal”

Agilent Restricted

Measurement Specifications

Band Pass Filter(Single-

ended) F0 : 947.5MHz

50 ohm 50

ohm

PORT 1 PORT 2

Band Pass Filter(Balanced)

F0 : 942.5MHz

50 ohm

200 ohm

PORT 1

PORT 2

PORT 3

Duplexer F0(Tx) :

1880MHz

F0(Rx) :

1960MHz 50 ohm 50 ohm

50 ohm

PORT 1

PORT 2

PORT 3

R

x

T

x

ANT

s1 Handset Component Demo Kit E5079A

Electrical length

Port 1 : 180ps

Port 2 : 280ps

Port 3 : 280ps

Port characteristic impedance

Port 1 : 50 ohms

Port 2 : 100 ohms

Port 3 : 100 ohms

Matching specifications

Port 1 : none

Port 2 : Shunt L = 28nH

Port 3 : Shunt L = 28nH

Setup

1. Preset : OK

2. Center : 942.5MHz

3. Span : 200MHz

Setup Wizard of Fixture Simulator Fast and easy measurements with setup wizard

Available at Agilent website at http://www.agilent.com/find/enavba

Agenda

• What measurements do we make?

• Network analyzer hardware

• Error models and calibration

• Applications

• Automation RECEIVER / DETECTOR

PROCESSOR / DISPLAY

REFLECTED

(A)

TRANSMITTED

(B) INCIDENT (R)

SIGNAL SEPARATION

SOURCE

Incident

Reflected

Transmitted

DUT

SHORT

OPEN

LOAD

Agilent IO Libraries Suite 16 provides

one tool for fast start-up

Suite 16

• Identify and set up LAN,

USB, GPIB, and converter

interfaces

• Identify and communicate

with instruments

• Change addresses and set

interface aliases

• Works with NI-488 software

and NI VISA I/O library

System set-up in

< 15 minutes

Page 109

LAN eXtension for Instrumentation

IP Address

Manufacturer

Model #

Serial #

Firmware rev.

IP Address

Domain name

etc.

Ability to

change the

IP address

LXI devices serve a web page

Page 114

LXI Possibilities

Expert

Troubleshooting

Parallel

operations

Reduce

programming

Long

distance

operations

Internal

network

Timestamp

all data

Higher

throughput

Asset

Management

Flexible

triggering

Smart instruments

No trigger

wires

Eliminate

latency

Software Integration

Agilent ADS

1/26/2011 Page 115

Agilent SystemVue

VEE Pro

Integrated

VBA Programming

Quick Demo Guide

ENA Series Network Analyzer - VBA Programming (UserMenu)

1. Connect DUT to ENA

2. Launch VBA editor, and code VBA program

a. Press [Macro setup] hard key then press VBA Editor soft key

VBA editor

b. Create module and code procedure

Click Insert in the menu bar then click Module

Code as shown below in Module1

c. Save VBA program and exit VBA editor

Click icon of the VBA editor. The Save As dialog box

appears. Specify the file name and location and click Save.

Click icon of the VBA editor.

Procedure overview

1. Connect DUT to ENA

2. Launch VBA editor, and code VBA program

3. Run VBA Macro

4. Add bandwidth search module

5. Apply VBA macro to UserMenu buttons

Required Instrument and fixture

ENA series network analyzer (E5071C or E5061B)

In this demo…

• Code simple VBA macro for bandpass filter measurement

• Apply VBA macro to UserMenu buttons

N-Type Cable

In this demo, we will use BPF (Center frequency =

1.09 GHz) but you can use another filter. Prepare

appropriate cable and adapter to connect between

ENA and DUT.

Figure1. DUT connection DUT

Sub main()

Call Setup

End Sub

Sub Setup()

SCPI.SYSTem.PRESet

SCPI.SENSe.FREQuency.CENTer = “1.09E9”

SCPI.SENSe.FREQuency.SPAN = “200E6”

SCPI.CALCulate.PARameter.Count = 2

SCPI.DISPlay.WINDow.Split = "D12"

SCPI.CALCulate.PARameter(2).DEFine = "S21"

SCPI.SENSe.BANDwidth.RESolution = 1000

MsgBox "Setup done"

SCPI.DISPlay.WINDow.TRACe(1).Y.SCALe.AUTO

SCPI.DISPlay.WINDow.TRACe(2).Y.SCALe.AUTO

End Sub

3. Run VBA macro

Press [Macro Run] Hard key.

The ENA calles main() procedure, and this VBA program will set

up the measurement parameters as shown below. Band pass filter (BPF)

Quick Demo Guide

www.agilent.com/find/ena_vba

4. Add Bandwidth Search Module

a. Open VBA Editor

b. Modify Sub() procedure of Module1 as below code

c. Add below procedure on Module1

d. Save VBA program and run

Click icon, then icon of the VBA editor

Press [Macro Run] hard key.

This code sets the measurement parameter, then make

bandwidth search function as below.

Sub Bandwidth()

SCPI.CALCulate.PARameter(2).SELect

With SCPI.CALCulate.SELected.MARKer

.State = True

.FUNCtion.TYPE = "MAX"

.FUNCtion.EXECute

.BWIDth.State = True

End With

End Sub

Sub Main()

Call Setup

Call Bandwidth

End Sub

5. Apply VBA procedure to UserMenu buttons

a. Open VBA Editor

b. Modify Sub() procedure of Module1 as below code

c. Create UserMenu module

Click E5061B_Objects then Double-Click UserMenu

In the object box in the code window, select UserMenu as

shown below.

d. Code below procedure on UserMenu module

e. Save program and run

Click icon, then icon of the VBA Editor

press [Macro Run] hard key.

Sub Main()

UserMenu.Item(1).enabled = True

UserMenu.Item(2).enabled = True

UserMenu.Item(1).Caption = "Setup"

UserMenu.Item(2).Caption = "Bandwidth"

UserMenu.Show

End Sub

Private Sub UserMenu_OnPress(ByVal ID As

Long)

If ID = 1 Then Module1.Setup

If ID = 2 Then Module1.Bandwidth

UserMenu.Show

End Sub

6. Use UserMenu Buttons

a. Press “Setup” button to run Setup procedure

b. Press “Bandwidth” button to run Bandwidth_Search

procedure

Tips: Command finder Using command finder chapter of the help file, you can easily

find appropriate command for each button. To open help,

press [Help] hard key, then click Programing > Command

Reference > Command Finder.

Sample VBA(s) for the ENA

Page 119 Last update:

Nov 2010

PNA-L World’s most capable value VNA

300 kHz to 6, 13.5, 20 GHz

10 MHz to 40, 50 GHz

ENA-L Low cost VNA

300 kHz to 1.5/3.0 GHz

Agilent VNA Solutions

ENA World’s most popular

economy VNA

9 kHz to 4.5, 8.5 GHz

300 kHz to 20.0 GHz

FieldFox RF Analyzer

5 Hz to 4/6 GHz

PNA-X, NVNA Industry-leading performance

10 MHz to 13.5/26.5/43.5/50/67 GHz

Banded mm-wave to 2 THz

PNA-X

receiver 8530A replacement

Mm-wave

solutions Up to 2 THz

PNA Performance VNA

10 MHz to 20, 40, 50, 67, 110 GHz

Banded mm-wave to 2 THz

Test Accessories

PNA-X Customer Presentation

ENA Series Network Analyzers

9 / 100 kHz to 4.5 / 6.5 / 8.5 GHz

300 kHz to 14 / 20 GHz

5 Hz to 3 GHz

100 kHz to 1.5 / 3 GHz E5061B

E5071C

30 kHz to 4.5 / 8.5 GHz

E5072A

New!

• 2-port

• Wide output power range

• Configurable test set

• 150 dB dynamic range

• Low-freq coverage

• Z-analysis function

• 2-port & 4-port

• Balanced meas.

• Up to 20 GHz

• Option TDR

• Low-cost simple RF NA

• 50 Ω & 75 Ω

E5061B-3L5, LF-RF option

E5061B-115 to 237, RF options

Page 121

Group/Presentation Title

Agilent Restricted

17 December 2012

Accurate Handheld VNA N9923A (4/6 GHz)

◄ Full 2 port vector network Analyzer

◄ CalReady at each test port

◄ Full 2 port QuickCal

◄ O.01 dB/deg C Stability Spec

◄ 100 dB dynamic range

◄ Power meter

◄ Vector Voltmeter (1 – and 2-channel)

◄ Distance to Fault

◄ LAN, USB, mini SD

Quad display CAT Vector volt Meter Power Meter

APPENDIX

122

VNA application examples

– RF amplifier test

– High-power measurement

– Swept IMD measurement

– High-gain amp measurement

12

3

What is intermodulation distortion (IMD)?

• A measure of nonlinearity of amplifiers.

• Two or more tones applied to an amplifier and produce additional intermodulation products.

• The DUT’s output will contain signals at the frequencies: n*F1 +m *F2.

F1 F2 2*F1-F2 2*F2-F1

DeltaF

IM3 relative to

carrier (dBc)

P(F1) P(F2)

P(2*F1-F2)

Frequency

F_IMD = n * F1 + m * F2

ex.)

•Lo F_IM3 = 2 * F1 - F2

•Hi F_IM3 = 2 * F2 - F1

•Lo F_IM5 = 3 * F1 - 2 * F2

•Hi F_IM5 = 3 * F2 - 2 * F1

•Lo F_IM7 = 4 * F1 - 3 * F2

•Hi F_IM7 = 4 * F2 - 3 * F1

12

4

Third-order Intercept Point (IP3)

• The third-order intercept point (IP3) or the third-order intercept (TOI) are often used as figures

of merit for IMD.

F1 F2 2*F1-F2 2*F2-F1

DeltaF

IM3 relative to

carrier (dBc)

P(F1) P(F2)

P(2*F1-F2)

Frequency IP3 can be calculated by the equation using

low-side IM3:

IP3 (dBm) = P(F1) + (P(F2) - P(2*F1-F2)) / 2

When high-side IM3 is used, the equation is:

IP3 (dBm) = P(F2) + (P(F1) - P(2*F2-F1)) / 2

Input power

(dBm)

Output power (dBm)

IIP3

OIP3

Fundamental

(Slope 1:1)

Third-order product

(Slope 1:3)

12

5

P(F1): Power level of low tone

P(F2): Power level of high tone

P(2*F1-F2): Power level of low-side IM3 signal

P(2*F2-F1): Power level of high-side IM3 signal

• ENA with frequency-offset mode (FOM) option

can set different frequencies at the source and

receiver.

• Real-time swept frequency IMD measurements

can be performed.

• Source power calibration and receiver calibration

is available with VNA for accurate absolute power

measurements.

• Using two SGs and a SA with CW signals.

• It requires a controller to synchronize

instruments.

• If many frequencies must be tested, test time

is increased dramatically.

2x SG + SA

Intermodulation Distortion

SG + VNA

12

6

VNA functions

Frequency Offset Mode

• Sets different frequency range for the source and receivers.

• Can be used for harmonics or intermodulation distortion (IMD) measurements with the VNA.

Source and receiver are tuned at the different

frequency range (for harmonics, IMD test etc.)

Source and receiver are tuned at the same

frequency range. (i.e. S-parameter).

Normal Sweep Frequency-offset Sweep

f1

Source

(Port 1) f1

Receiver

(Port 2) f1

Source

(Port 1) f2

Receiver

(Port 2)

12

7

DUT DUT

IMD Measurement

Measurement example (sweep delta)

Power levels of main tones and IM products in

swept frequencies can be monitored with the

VNA’s absolute measurements.

Configuration of IMD measurement with VNA

DUT Combiner

Attenuator

(Optional)

USB/GPIB

Interface 10 MHz REF

SG

VNA

f1

f1 (SG)

f2

f2 (ENA)

f_IM

f_IM

(ENA)

f1 (SG) f2 (ENA)

Lo IM3

12

8

IMD Measurement Wizard for the E5072A

Key Features:

• Measurement macro running on the E5072A with intuitive GUI

• Quick setup of two-tone IMD measurements

• Control all necessary equipments from E5072A

– MXG (connected via GPIB/USB interface)

– Power meter & sensor (connected via GPIB/USB interface)

– USB power sensor (connected directly to the ENA’s USB port)

• Guided calibration wizard

• Various measurement sweep types

– Fixed F1 and Swept F2

– Sweep Fc

– Sweep DeltaF

• Various IMD measurement parameters

– Absolute power of fundamental tones (in dBm)

– Power levels of IMD products (absolute in dBm), Low or High-side IM (3rd, 5th, 7th)

– Calculated third-order intercept point (IP3)

Available at: www.agilent.com/find/enavba

12

9

VNA application examples

– RF amplifier test

– High-power measurement

– Swept IMD measurement

– High-gain amp measurement

13

0

VNA Functions Uncoupled Power

Independent built-in source attenuators to uncouple power level

• Different output power level can be set for port 1 & 2 with independent source attenuators.

• Easy characterization of high-gain power amp without external attenuators on output port.

• More accurate reverse measurement (i.e. S12, S22) with wider dynamic range.

R1

A

R2

B

High-gain amp -85 dBm 0 dBm

ATT = 40 dB

(Port 1) ATT = 0 dB

(Port 2)

Example DUTs:

BTS repeaters, LNA, receivers.

13

1

Coupled power (Port 1 = Port 2 = -40 dBm)

Uncoupled power (Port 1 = -40 dBm, Port 2 = 0 dBm)

High-gain amp measurement

S12

S22

S11

S21

DUT: High-gain (30 dB) RF Power amp

K-factor

S12

S22

S11

S21

K-factor

More accurate S12 measurement with uncoupled

power results in better trace of calculated K-factor.

13

2

Resources

• Configuration Guide (5990-8001EN)

• Data Sheet (5990-8002EN)

• Quick Fact Sheet (5990-8003EN)

• Technical Overview (5990-8004EN)

• Application Note

– High-power measurement using the E5072A (5990-8005EN)

• ENA Series: www.agilent.com/find/ena

• E5072A Product page: www.agilent.com/find/e5072a

• Campaign page: www.agilent.com/find/e5072a_PR

• E5072A on YouTube: www.youtube.com/user/AgilentVNA#p/u/5/cA83A4qFEZU

Campaign page YouTube page

THANK YOU!

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