Network Analysis Back to Basics

Network Analysis Back to Basics
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
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
-9
a BER of 1.523 X 10 . . .
What Are Vector Network Analyzers?
S21
Transmission
DUT
S11
S22
Reflection
Are stimulus-response test systems
S12
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
Magnitude
Provide the highest level
of measurement accuracy
RF Source
Phase
LO
R1
A
Test port 1
R2
B
Test port 2
Low
Integration
High
What Types of Devices are Tested?
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
Passive
RFICs
MMICs
T/R modules
Transceivers
Receivers
Tuners
Converters
Antennas
VCAs
Amplifiers
Switches
Multiplexers
Mixers
Samplers
Multipliers
VTFs
Modulators
VCAtten’s
Diodes
Transistors
Device type
Active
Complex
Device Test Measurement Model
RFIC Testers
Ded. Testers
VSA
SA
Response tool
RFIC test
Harm. Dist.
LO stability
Image Rej.
VNA
SNA
NF Mtr.
Full call
sequence
Pulsed S-parm.
Pulse profiling
NF
Imped. An.
Simple
Intermodulation
Distortion
Gain/flat. Compr'n
Phase/GD AM-PM
Isolation Mixers
Rtn loss Balance
Impedance d
S-parameters
TG/SA
Param. An.
NF
BER
EVM
ACP
Regrowth
Constell.
Eye
LCR/Z
I-V
Measurement plane
Absol.
Power
Power Mtr.
Det/Scope
DC
CW
Simple
Swept
Swept
freq
power
Noise
2-tone
Multi-tone
Complex
modulation
Stimulus type
Pulsed-
Protocol
RF
Complex
Lightwave Analogy to RF Energy
Incident
Reflected
Transmitted
Lightwave
DUT
RF
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
S21
1. Complete characterization
of linear networks
S11
S22
S12
4. Time-domain characterization
2. Complex impedance
needed to design
matching circuits
Mag
Time
3. Complex values
needed for device
modeling
5. Vector-error correction
Error
Measured
Actual
6. X-parameter (nonlinear) characterization
Agenda
•
•
•
•
•
What measurements do we make?
Network analyzer hardware
Error models and calibration
Applications
Automation
Incident
Transmitted
DUT
SOURCE
Reflected
SIGNAL
SEPARATION
INCIDENT (R)
REFLECTED
(A)
TRANSMITTED
(B)
RECEIVER / DETECTOR
PROCESSOR / DISPLAY
SHORT
OPEN
LOAD
Transmission Line Basics
Low frequencies
+
_
I
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 (Z ) is very important for
o
low reflection and maximum power transfer
Measured envelope voltage dependent on position along line
Transmission line Zo
Zo determines relationship between voltage and current waves
Zo is a function of physical dimensions and εr
Zo is usually a real impedance (e.g. 50 or 75 ohms)
1.5
Twisted-pair
attenuation is
lowest at 77 ohms
1.4
Waveguide
1.3
b
Coaxial
εr
h
h
normalized values
1.2
a
1.1
50 ohm standard
1.0
0.9
0.8
0.7
power handling capacity
peaks at 30 ohms
0.6
w1
w2
Coplanar
w
Microstrip
0.5
10
20
30
40
50
60 70 80 90 100
Characteristic impedance for coaxial
airlines (ohms)
Power Transfer Efficiency
RS
For complex impedances, maximum
power transfer occurs when ZL = ZS*
(conjugate match)
RL
Rs
+jX
Load Power
(normalized)
1.2
-jX
1
0.8
RL
0.6
0.4
0.2
0
0
1
2
3
4
5
6
7
8
9
10
RL / RS
Maximum power is transferred when RL = RS
Transmission Line Terminated with Zo
Zs = Zo
Zo = characteristic impedance
of transmission line
Zo
Vinc
Vreflect = 0! (all the incident power
is transferred to and
absorbed in the load)
For reflection, a transmission line terminated in Zo
behaves like an infinitely long transmission line
Transmission Line Terminated with Short, Open
Zs = Zo
V inc
o
Vreflect In-phase (0 ) for open,
o
out-of-phase (180 ) for short
For reflection, a transmission line terminated in a
short or open reflects all power back to source
Transmission Line Terminated with 25 Ohms
Zs = Zo
ZL = 25 Ω
Vinc
Vreflec
t
Standing wave pattern does not
go to zero as with short or open
High-Frequency Device Characterization
Incident
R
Transmitted
B
Reflected
A
TRANSMISSION
REFLECTION
Reflected
Incident
=
VSW
R
S-Parameters
S11, S22
Reflection
Coefficient
Γ, ρ
A
Transmitted
R
Incident
Return
Loss
Impedance,
Admittance
R+jX,
G+jB
=
B
R
Group
Delay
Gain / Loss
S-Parameters
S21, S12
Transmission
Coefficient
Τ,τ
Insertion
Phase
Reflection Parameters
Reflection
Coefficient
Γ
Vreflected
=
=
Vincident
ρ
Return loss = -20 log(ρ ), ρ
=
Φ
=
ZL - Zo
ZL + Zo
Γ
Vmax
Vmin
Voltage Standing Wave
Ratio
Vmax
VSWR =
Vmin
=
1+ρ
1-ρ
Full reflection
(ZL = open, short)
No reflection
(ZL = Zo)
0
ρ
1
∞ dB
RL
0 dB
1
VSWR
∞
Smith Chart Review
Polar plane
90
o
+jX
1.0
.8
.6
.4
0
+ 180o
-
+R ∞ →
o
.2
0
∞
0
-jX
-90 o
Rectilinear impedance plane
Constant X
Constant R
Z L = Zo
Smith Chart maps
rectilinear impedance
plane onto polar plane
Γ=
0
Z L = 0 (short)
Γ= 1
±180
O
Smith chart
ZL =
(open)
Γ =1
0
O
Transmission Parameters
V Incident
V Transmitted
DUT
Transmission Coefficient =
Insertion Loss (dB) = -20 Log
Τ
=
V Incident
VTrans
V Inc
Gain (dB) = 20 Log
V Trans
V Inc
V Transmitted
= -20 Log(τ)
= 20 Log(τ)
=
τ∠φ
Linear Versus Nonlinear Behavior
A * Sin 360o * f (t - to)
A
Linear behavior:
Time
to
Sin 360o * f * t
A
phase shift =
to * 360o * f
Time
f
1
DUT
Input
Input and output frequencies are the
same (no additional frequencies created)
Output frequency only undergoes
magnitude and phase change
Frequency
Output
Nonlinear behavior:
f
1
Frequency
Time
f
1
Frequency
Output frequency may undergo
frequency shift (e.g. with mixers)
Additional frequencies created
(harmonics, intermodulation)
Criteria for Distortionless Transmission
Linear Networks
Linear phase over
bandwidth of
interest
Magnitude
Constant amplitude over
bandwidth of interest
Phase
Frequency
Frequency
Magnitude Variation with Frequency
F(t) = sin wt + 1/3 sin 3wt + 1/5 sin 5wt
Time
Time
Magnitude
Linear Network
Frequency
Frequency
Frequency
Phase Variation with Frequency
F(t) = sin wt + 1 /3 sin 3wt + 1 /5 sin 5wt
Linear Network
Time
Magnitude
Time
Frequency
0°
Frequency
-180°
-360 °
Frequency
Deviation from Linear Phase
Use electrical delay to remove
linear portion of phase response
Linear electrical length
added
RF filter response
Deviation from linear
phase
Phase 1 /Div
=
+
Frequency
Low resolution
o
o
Phase 45 /Div
(Electrical delay function)
Frequency
Frequency
High resolution
Group Delay
Frequency (ω)
tg
Group delay ripple
∆ω
to
Phase φ
Average delay
∆φ
Frequency
Group Delay=(tg)
−d φ
dω
φ
ω
φ
=
−1
360 o
*
dφ
df
in radians
in radians/sec
in degrees
f in Hertz (ω = 2 π f)
Group-delay ripple indicates phase distortion
Average delay indicates electrical length of DUT
Aperture (∆ω) of measurement is very important
Phase
Phase
Why Measure Group Delay?
f
f
−d φ
dω
Group
Delay
Group
Delay
−d φ
dω
f
f
Same peak-peak phase ripple can result in different group delay
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
(requires short circuit)
h12 = V1
V2
I1=0
(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
a1
S 21
Incident
b2
S11
Reflected
b1
Transmitted
DUT
Port 1
Transmitted
Port 2
S12
S22
Reflected
a2
Incident
b1 = S11 a1 + S12 a 2
b 2 = S21 a1 + S22 a 2
Measuring S-Parameters
a1
Forward
S 21 =
b1
Incident
a2 = 0
b1
= a
1
b
a2 = 0
2
= a
1
a2 = 0
a1 = 0
Z0
DUT
Load
b1
Load
DUT
Reflected
Transmitted
b2
Transmitted
21
Z0
S 11
Reflected
Incident
S 11 =
S
Incident
Transmitted
S 12
S 22 =
S 12 =
Reflected
Incident
Transmitted
Incident
S 22
b2
= a
2
b
1
= a
2
a1 = 0
b2
Reverse
Reflected
a2
Incident
a1 = 0
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
Nonlinear Networks
• Saturation, crossover, intermodulation, and other nonlinear
effects can cause signal distortion
• Effect on system depends on amount and type of distortion
and system architecture
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 nonlinear behavior except S11
and S21 compression,
nor did they predict
harmonics and IMD
33
X-parameters come from the
Poly-Harmonic Distortion (PHD) Framework
A2
A1
B1
B2
B1 k = F1 k ( D C , A11 , A12 , ..., A21 , A22 , ...)
B 2 k = F2 k ( D C , A11 , A12 , ..., A21 , A22 , ...)
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.
34
How X-Parameters extend S-parameters:
•X-parameters capture the power dependent behavior of large-signal
S-parameters
•This power dependence needs a new term, a conjugate term, to be
mathematically correct. This means that X-parameters extend Sparameters by adding a duplicate set (XS11-> XT11, XS21-> XT21…)
that captures this conjugate behavior
•Additionally, this large signal response can include the generation of
harmonics as a function of the large input signal, as well as the
harmonic-to-harmonic cross generation
•Finally, in addition to depending on input power, they can also
depend on other parameters such as bias voltage, control voltage
and temperature
35
Expanding S-Parameters to Non-Linear Systems
b1 = S11a1 + S12 a2
bi = ∑ Sij ( a11 ) ⋅ a j
(
b2 = S21a1 + S22 a2
j
Start with 2-port
Express as a Sum
Now make it a proper non-linear
X-parameter, with conjugate (T) portion:
Make them
Power
Dependent
2
bi =1−>2 = ∑ ( Sij ⋅ a j )
)
bi = ∑ ( X ijS ( a11 ) ⋅ a j ,l + X iTj ( a11 ) ⋅ a *j ,l )
j
j =1
Finally, repeat for each harmonic
and cross harmonic interaction
Move to Multiport
Definitions
bi = ∑ ( Sij ⋅ a j )
j
• i = output port index
• j = input port index
• k = output frequency index
bi , k = ∑ ( X ijS,kl ( a11 ) P k −l ⋅ a j ,l + X iTj ,kl ( a11 ) P k +l ⋅ a*j ,l )
j ,l
• l = input frequency index
36
X-parameters Reduce to S-parameters
B21 ( A11 ) = X
dB
40
20
X
(F )
21
(F )
21
( A11 ) P + X
(S)
21,21
( A11 ) A21 + X
2
*
21
( A11 ) P A
[ X 21( F ) ( A11 )] → s21
/ | A11 |
| A11 |
(S )
X 21,21
0
(T )
21,21
| A11 | → 0
(S )
X 21,21
( A11 ) → s22
| A11 | → 0
-20
-40
-60
-25
X
-20 -15 -10
(T )
X 21,21
( A11 ) → 0
(T )
21,21
|A11| (dBm)
-5
| A11 | → 0
0
5
10
Reduces to (linear)
S-parameters in the
appropriate
limit
+
37
Agenda
•
•
•
•
•
What measurements do we make?
Network analyzer hardware
Error models and calibration
Applications
Automation
Incident
Transmitted
DUT
SOURCE
Reflected
SIGNAL
SEPARATION
INCIDENT (R)
REFLECTED
(A)
TRANSMITTED
(B)
RECEIVER / DETECTOR
PROCESSOR / DISPLAY
SHORT
OPEN
LOAD
Generalized Network Analyzer Block Diagram
(Forward Measurements Shown)
Incident
Transmitted
DUT
SOURCE
Reflected
SIGNAL
SEPARATION
INCIDENT
(R)
REFLECTED
(A)
TRANSMITTED
(B)
RECEIVER / DETECTOR
PROCESSOR / DISPLAY
Source
Incident
Transmitted
DUT
Reflected
SOURCE
SIGNAL
SEPARATION
INCIDENT (R)
REFLECTED
(A)
TRANSMITTED
(B)
RECEIVER / DETECTOR
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
PROCESSOR / DISPLAY
Signal Separation
Incident
Transmitted
DUT
Reflected
SOURCE
SIGNAL
SEPARATION
• Measure incident signal for reference
INCIDENT (R)
REFLECTED
(A)
TRANSMITTED
(B)
• Separate incident and reflected signals
RECEIVER / DETECTOR
PROCESSOR / DISPLAY
splitter
bridge
directional
coupler
Detector
Test Port
Directivity
Directivity is a measure of how well a directional coupler or
bridge can separate signals moving in opposite directions
(undesired leakage
signal)
(desired reflected
signal)
I
leakage
desired
C
result
Test port
L
Directional Coupler
Directivity = Isolation (I) - Fwd Coupling (C) - Main Arm Loss (L)
Directional Bridge
50 Ω
50 Ω
Detector
50 Ω
Test Port
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)
0
Data max
Directivity
30
Add in-phase
Device
60
Frequency
Data min
Add out-of-phase
(cancellation)
Device
Device
Directivity
Directivity
Return Loss
DUT RL = 40 dB
Data = vector sum
Detector Types
Incident
Transmitted
DUT
Diode
Scalar broadband
(no phase information)
Reflected
SOURCE
SIGNAL
SEPARATION
INCIDENT (R)
DC
REFLECTED
(A)
TRANSMITTED
(B)
RECEIVER / DETECTOR
RF
AC
PROCESSOR / DISPLAY
Tuned Receiver
RF
IF = F LO ± F RF
ADC / DSP
IF Filter
LO
Vector narrowband
(magnitude and phase)
Broadband Diode Detection
Easy to make broadband
Inexpensive compared to tuned receiver
Good for measuring frequency-translating devices
Improve dynamic range by increasing power
Medium sensitivity / dynamic range
10 MHz
26.5 GHz
Narrowband Detection - Tuned Receiver
RF
ADC / DSP
IF Filter
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
LO
10 MHz
26.5 GHz
Comparison of Receiver Techniques
Broadband
(diode) detection
Narrowband
(tuned-receiver) detection
0 dB
0 dB
-50 dB
-50 dB
-100 dB
-100 dB
-60 dBm Sensitivity
Higher noise floor
False responses
< -100 dBm Sensitivity
High dynamic range
Harmonic immunity
Dynamic range = maximum receiver power - receiver noise floor
Tuned Receiver Front Ends:
Mixers Versus Samplers
Incident
Transmitted
DUT
Reflected
SOURCE
SIGNAL
SEPARATION
INCIDENT (R)
REFLECTED
(A)
TRANSMITTED
(B)
RECEIVER / DETECTOR
PROCESSOR / DISPLAY
Sampler-based front end
ADC / DSP
S
ADC / DSP
Mixer-based front end
It is cheaper and easier to make
broadband front ends using
samplers instead of mixers, but
dynamic range is considerably less
Harmonic
generator
f
frequency "comb"
Dynamic Range and Accuracy
Error Due to Interfering Signal
100
-
10
Error (dB, deg)
+
phase error
1
Dynamic range is
very important for
measurement
accuracy!
magn error
0.1
0.01
0.001
0
-5
-10
-15
-20
-25
-30
-35
-40
-45
-50
Interfering signal or noise (dB)
-55
-60
-65
-70
T/R Versus S-Parameter Test Sets
S-Parameter Test Set
Transmission/Reflection Test Set
Source
Source
Transfer switch
R1
R
A
B
A
B
R2
Port 1
Port 2
Fwd
DUT
Port 1
Fwd
Fwd
RF comes out port 1; port 2 is receiver
Forward measurements only
Response, one-port cal available
Port 2
DUT
Rev
RF comes out port 1 or port 2
Forward and reverse measurements
Two-port calibration possible
Modern VNA Block Diagram (2-Port E5072A)
Source
Solid-state
Attenuator
(65 dB)
SPDT Switch
R1
R2
Mechanical
Step Attenuator
(60 dB,
10 dB step)
A
B
Mechanical
Step Attenuator
(60 dB,
10 dB step)
RCVR R2 IN
SOURCE OUT
Port 2
SOURCE OUT
CPLR ARM
RCVR B IN
RCVR A IN
Port 1
CPLR ARM
CPLR THRU
SOURCE OUT
SOURCE OUT
RCVR R1 IN
REF 1
CPLR THRU
Bias-Tee
Bias-Tee
REF 2
Processor / Display
Incident
Transmitted
DUT
SOURCE
Reflected
SIGNAL
SEPARATION
INCIDENT
(R)
REFLECTED
(A)
TRANSMITTED
(B)
RECEIVER / DETECTOR
PROCESSOR / DISPLAY
• Markers
• Limit lines
• Pass/fail indicators
• Linear/log formats
• Grid/polar/Smith charts
• Time-domain transform
• Trace math
Achieving Measurement Flexibility
Channel
Channel
Trace
Trace
Trace
Trace
Trace
Trace
Window
Window
Trace (CH1)
Trace (CH1)
Trace (CH2)
Window
Window
Trace (CH3)
Trace (CH2)
Trace (CH4)
•
•
•
•
•
•
•
•
Trace
•
•
•
•
•
•
•
•
•
•
Parameter
Format
Scale
Markers
Trace math
Electrical delay
Phase offset
Smoothing
Limit tests
Time-domain transform
Sweep type
Frequencies
Power level
IF bandwidth
Number of points
Trigger state
Averaging
Calibration
Three Channel Example
Channel 1
Channel 2
Channel 3
frequency sweep (narrow)
frequency sweep (broad)
power sweep
S21
S21
S11
S11
Window
Window
S21
Window
Agenda
•
•
•
•
•
What measurements do we make?
Network analyzer hardware
Error models and calibration
Applications
Automation
Incident
Transmitted
DUT
SOURCE
Reflected
SIGNAL
SEPARATION
INCIDENT (R)
REFLECTED
(A)
TRANSMITTED
(B)
RECEIVER / DETECTOR
PROCESSOR / DISPLAY
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
Errors:
SYSTEMATIC
Measured
Data
RANDOM
DRIFT
Unknown
Device
Systematic Measurement Errors
R
A
B
Crosstalk
Directivity
DUT
Frequency response
Reflection tracking (A/R)
Transmission tracking (B/R)
Source
Mismatch
Load
Mismatch
Six forward and six reverse error terms
yields 12 error terms for two-port devices
Types of Error Correction
Response (normalization)
Simple to perform
thru
Only corrects for tracking (frequency response) errors
Stores reference trace in memory, then does data divided by memory
Vector
Requires more calibration standards
Requires an analyzer that can measure phase
Accounts for all major sources of systematic error
–
–
–
–
–
–
SHORT
OPEN
S11a
thru
S11 m
LOAD
What is Vector-Error Correction?
Errors
Measured
Actual
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
Using Known Standards to Correct
for Systematic Errors
1-port calibration (reflection measurements)
Full two-port calibration (reflection and transmission measurements)
Only three systematic error terms measured
Directivity, source match, and reflection tracking
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
RF in
Ideal
Error Adapter
RF in
S11A
S11M
1
ES
ED
S11M
ERT
To solve for error terms, we
measure 3 standards to generate
3 equations and 3 unknowns
ED = Directivity
S11A
ERT = Reflection tracking
ES = Source Match
S11M = Measured
S11A = Actual
S11A
S11M = ED + ERT
1 - ES S11A
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
Before and After A One-Port Calibration
Data after 1-port calibration
Data before 1-port calibration
Two-Port Error Correction
Reverse model
Port 1
Port 2
E RT'
Forward model
Port 1
a1
ED
EX
ES
S11A
b1
E RT
S22 A
ETT
EL
S22 A
E S'
ED'
S12 A
EX'
S 12
A
ED' = rev directivity
E S' = rev source match
E RT' = rev reflection tracking
EL' = rev load match
ETT' = rev transmission tracking
EX' = rev isolation
A
b2
A
a2
EL = fwd load match
ETT = fwd transmission tracking
EX = fwd isolation
S11
E TT'
b2
ED = fwd directivity
ES = fwd source match
ERT = fwd reflection tracking
E L'
b1
Port 2
S21A
S21
a1
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!!!
S11a =
− ED
− ED '
− E X S12 m − E X '
S
S
S
( 11m
)(1 + 22m
E S ' ) − E L ( 21m
)(
)
E RT
E RT '
E TT
E TT '
S
S
S
− E D'
− ED '
− E X S12 m − E X '
(1 + 11m
E S )(1 + 22m
E S ' ) − E L ' E L ( 21m
)(
)
E RT
E RT '
E TT
ETT '
(
S21a =
S21m − E X
E TT
)(1 +
S22 m − E D '
E RT '
( E S '− E L ))
S
S
S
− ED
− ED'
− E X S12 m − E X '
E S )(1 + 22m
E S ' ) − E L ' E L ( 21m
(1 + 11m
)(
)
E RT
E RT '
E TT
ETT '
S12a =
S
− EX '
S
− ED
( 12m
)(1 + 11m
( E S − E L ' ))
E TT '
E RT
S
− ED
S
− ED'
S
− E X S12m − E X '
(1 + 11m
E S )(1 + 22m
E S ' ) − E L ' E L ( 21m
)(
)
E RT
E RT '
E TT
E TT '
S22a =
S 22m − E D '
S11m − E D
S21m − E X S12m − E X '
)( 1 +
ES ) − E L ' (
)(
)
E RT '
E RT
E TT
E TT '
S
− ED
S
− ED'
S
− E X S12m − E X '
(1 + 11m
E S )(1 + 22m
E S ' ) − E L ' E L ( 21m
)(
)
E RT
E RT '
E TT
ETT '
(
a2
Crosstalk: Signal Leakage Between Test Ports
During Transmission
DUT
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
LOAD
DUT
DUT
LOAD
Errors and Calibration Standards
UNCORRECTED
FULL 2-PORT
RESPONSE
1-PORT
SHORT
DUT
OPEN
thru
Convenient
Generally not accurate
No errors removed
LOAD
SHORT
OPEN
OPEN
LOAD
LOAD
DUT
Easy to perform
Use when highest
accuracy is not
required
Removes frequency
response error
DUT
ENHANCED-RESPONSE
Combines response and 1-port
Corrects source match for transmission
measurements
SHORT
For reflection measurements
Need good termination for
high accuracy with two-port
devices
Removes these errors:
Directivity
Source match
Reflection tracking
thru
DUT
Highest accuracy
Removes these
errors:
Directivity
Source, load match
Reflection tracking
Transmission
tracking
Crosstalk
Calibration Summary
SHORT
Reflection
Test Set (cal type)
T/R
(one-port)
Reflection tracking
Directivity
Source match
Load match
S-parameter
OPEN
(two-port)
LOAD
Test Set (cal type)
Transmission
T/R
(response, isolation) (two-port)
error can be corrected
Transmission Tracking
Crosstalk
Source match
Load match
error cannot be corrected
*
enhanced response cal corrects
for source match during
transmission measurements
(
S-parameter
* )
Response versus Two-Port Calibration
Measuring filter insertion loss
After two-port calibration
After response calibration
Uncorrected
ECal: Electronic Calibration
• Variety of two- and four-port modules cover 300 kHz to 67 GHz
• Nine connector types available, 50 and 75 ohms
USB controlled
• 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
Microwave modules use a
transmission line shunted
by PIN-diode switches in
various combinations
ECAL User Characterizations
1. Select adapters for the
module to match the
connector configuration
of the DUT.
2. Perform a calibration
using appropriate
mechanical standards.
3. Measure the ECal
module, including
adapters, as though
it were a DUT
4. VNA stores resulting
characterization data
inside the module.
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
Unknown-Thru Calibration
Analyzer
Port 1
DUT
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
Port 2
•
•
•
•
Analyzer
Port 1
Short
Open
Load
DUT
Thru
Port 2
Short
Open
Load
www.agilent.com/find/backtobasics
Network Analyzer Basics
Agenda
•
•
•
•
•
What measurements do we make?
Network analyzer hardware
Error models and calibration
Applications
Automation
Incident
Transmitted
DUT
SOURCE
Reflected
SIGNAL
SEPARATION
INCIDENT (R)
REFLECTED
(A)
TRANSMITTED
(B)
RECEIVER / DETECTOR
PROCESSOR / DISPLAY
SHORT
OPEN
LOAD
High-power measurement with E5072A
(ENA with configurable test set)
Contents
• Introduction
• Configurations of High-power Measurements
1. Standard 2-port Configuration
2. Measurement using a Booster Amplifier
3. Direct Receiver Access with a Booster Amplifier
• Features of the E5072A
– Power calibration
– Receiver leveling
– Power handling capability
• Summary
Why high-power measurements?
• 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!)
Diagram of RF interface in wireless communication
LNA Rx Filter
Antenna
Power Amplifier
Duplexer
Tx Filter Combiner
Why high-power measurements?
High-power network analysis is often required.
(1) Long-distance test
(2) Antenna test
Network analyzer
DUT
DUT
Long RF cable
Network analyzer
•Due to loss associated with long RF
cables, necessary to boost power to
DUT’s input in the field or anechoic
chambers.
f_meas
f
•Antenna under test (AUT) has to be located in
the field where unexpected high-power
interference signals are transmitted from other
antennas.
• Need to boost power source output power to
gain S/N ratio for measurements.
f
Challenges of High-power Measurements
High-power network analysis:
1. Output power level of a network analyzer is not sufficient for measurements.
2. Input power level to receivers of a network analyzer exceeds the maximum
allowable level.
Not Enough
Power for DUT!
DUT
Need protection
from damage of
high-power!
Configuration 1
Standard 2-port Configuration
• Uses a network analyzer as a standard test set.
• Simple 2-port measurement is performed within power level available.
Benefits
• Simple setup
• Eliminates additional cost associated with extra
booster amplifier
• Provides good impedance match with error
correction
DUT
Issues
• Only performs measurements within the output
power level capability of a network analyzer.
…How much can the latest network analyzer boost output power?
Configuration 1
Standard 2-port Configuration
Agilent new E5072A can output as high as +20 dBm!
•
•
Maximum output power up to +20 dBm is available at the test port. (300 k to 1 GHz)
Wide power sweep (> 65 dB) can be done for full characterization of active components
with a single sweep.
Output power level comparison
-85 to +8 dBm
8753ES
Opt.014
-55 to +10 dBm
E5071C
-85 to +16 dBm (*1)
E5072A
-109 to +20 dBm (*2)
*1 Specification, *2 Settable power range.
>65 dB wide power sweep
Configuration 1
Standard 2-port Configuration
High output power (max +20 dBm)
•
•
Maximum output power up to +20 dBm is available at the test port. (300 k to 1 GHz)
Wide power sweep (> 65 dB) can be done for full characterization of active components
with a single sweep.
Max Output power level
Comparison E5071C vs. E5072A
Performance data of E5072A
…What if we need more than +20 dBm?
Configuration 2
Measurements using a booster amplifier
• Uses a preamplifier to boost the power prior to the DUT.
• Inputs power level to DUT higher than the network analyzer’s source can
provides.
Benefits
• High input power to DUT beyond instrument’s
capability.
• Can place the amplifier physically closer to DUT,
reducing cable loss for higher input.
Booster
amplifier
DUT
Issues
• Temperature drift of a booster amplifier can not be
removed.
• High-reverse isolation of a booster amplifier
prevents accurate reflection measurements.
Note: An optional isolator can be added between the booster
amplifier and the DUT to improve the source match and protect
the amplifier against high levels of reflected power.
Configuration 2
Measurements using a booster amplifier
Issues:
Accurate reflection measurement (i.e. S11) is NOT possible because of
high reverse isolation of the booster amp.
Measurement Results
Configuration
S11
Booster
amplifier
RF amplifier
(DUT)
S2
1
Large trace noise..
Configuration 2
Measurements using a booster amplifier
Issues:
Accurate reflection measurement (i.e. S11) is NOT possible because of high reverse
isolation of the booster amp.
Configuration
Block Diagram of Network Analyzer
R1
A
R2
B
Booster
amplifier
Bias-tee
RF amplifier
(DUT)
Very low signal is detected in receiver A
of port 1, resulting in large trace noise
with S11 (= A/R1) and S12 (= A/R2).
Port 1
Bias-tee
Port 2
How can we solve
this problem?
Configuration 3
Direct receiver access with a booster amplifier
• Setup using a direct receiver access capability by removing jumper
cables on front panel of a network analyzer.
Benefits
• Very accurate reflection measurement
with high-power.
• Cancels (ratios out) the drift effect of a
booster amplifier
Booster
amplifier
High-power
couplers
DUT
Note: An optional isolator can be added between the booster
amplifier and the DUT to improve the source match and protect
the amplifier against high levels of reflected power.
Issues
• Complicated configuration is needed.
• External accessories such as
attenuators are required. (for protection of
receivers)
Configuration 3
Direct receiver access with a booster amplifier
• Each test port of Agilent network analyzers with configurable test set option is associated
with six SMA connectors.
• The network analyzer should include direct access to the internal source and receivers so
that the test configuration can be modified to handle high-power.
Configuration 3
Direct receiver access with a booster amplifier
•The incident signal can be measured in receiver R1 after the booster amplifier rather than
before, which cancels the effect of temperature drift of the booster amplifier.
•The reflected signal from the DUT is detected at the test receiver A for S11 (=A/R1) without
degrading S/N ratio.
Block Diagram of Network Analyzer
Configuration
R1
R2
A
B
Booster
amplifier
High-power
couplers
Port 1
Port 2
Configuration 3
Direct receiver access with a booster amplifier
• Measurement accuracy is improved by using direct receiver access.
• Essential to have the capability for accurate high-power network analysis.
Measurement Results
S11
S11
S21
S21
Standard configuration
using a booster amplifier
Direct receiver access
with a booster amplifier
Comparison of configurations
Configuration
Benefits
Issues
Standard 2-port
Configuration
• Simple setup
• No additional cost (Booster
amp etc.)
• Only within power level of
network analyzers.
Measurement using a
booster amplifier
• High power level beyond
network analyzer’s capability
• Can place the amp
physically closer to DUT for
higher power.
• Temperature drift effect
can not be removed.
• Not accurate
measurements because of
high reverse isolation of a
booster amplifier
Direct Receiver Access
with a booster amplifier
• The most accurate
measurements with highpower.
• Complicated setup
• External attenuators are
required for protection of
receivers.
Power calibration of VNA
1. Source power calibration
•
•
The VNA’s source power level is calibrated using a
power sensor to get accurate power level at the
calibration plane.
Power level accuracy is directly dependent on the
accuracy of the power sensor used.
2. Receiver calibration
•
•
•
Necessary for absolute measurements in dBm.
Must have a power-calibrated source at the same
frequency range.
Mathematically removes frequency response in the
receiver path and adjusts the VNA’s reading to the
same as power level in dBm at the calibration plane.
Thru
3. Receiver leveling
•
•
•
Before each measurement sweep, background
sweeps are performed to measure power at the
receiver.
Power measurements at the receiver are used to
adjust the VNA’s source power level.
Accurate power level adjustment by using high
receiver linearity of VNA.
Receivers
Source power adjusted
E5072A Features
Source power calibration
• You can expect the power at the point of calibration to be within the range of the uncertainty
of the power sensor used.
• At each data point, power is measured using the power meter and the source power level is
adjusted until the reading of the power sensor is within the tolerance or the max iteration has
been met.
Measured Port Power at cal
plane (in dBm)
Uncorrected power
Corrected power
Target Power Level
Num of Readings: Sets the number of power
level measurements. (Averaging factor)
Tolerance: Maximum desired deviation from
the specified target power.
Loss Compen: Compensates for losses when
using an attenuator to connect the power sensor.
Power Offset: A gain or Loss to account for
components between the port and cal plane. For
example, the positive value is set if a booster amp
is inserted for high-power measurements.
Source power + Power offset = Target Power
E5072A Features
Receiver leveling
• Receiver leveling function adjusts the source power level across a frequency or power sweep
using its receiver measurements.
• Eliminating short-term drift of a booster amplifier.
• You can achieve greater source power level accuracy with faster throughput compared to
conventional method using a power meter and power sensor.
PC
GPIB
Power Sensor
SG
DUT
Booster
Amp
SA
Booster
Amp
DUT
Setup Procedure of High-power Measurements
Accurate power level at DUT’s input is achieved by the E5072A’s calibration features.
1. Perform source power cal
2. Perform receiver cal with receiver R1 of port 1.
3. Enable receiver leveling with receiver R1.
4. Perform enhanced response calibration.
5. Perform high-power measurements. (S11 = A/R1, S21 = B/R1)
1
4
2 3
R1
A
R1
S/O/L
5
Thru
A
B
R1
DUT
Note: Refer to the Agilent application note, “High-power
Measurement using the E5072A” (part number 5990-8005EN)
for more details.
E5072A Features
Robust design to reduce external damage
• The E5072A have adopted a robust design for its internal architecture, both hardware and software.
• Protection circuits inside the instrument protect from electronic stress thus dramatically reduce down time
and repair cost.
• Agilent performs strict qualification test against external damage to all RF interfaces of the E5072A.
• Damage levels of the E5072A’s RF interfaces are listed in the data sheet, part number 5990-8002EN.
Power trip
• E5072A has a power trip function that monitors input signal at the internal receivers.
• Once the excessive levels are detected, output power from the source is turned OFF automatically.
Power limit
• Max power limit sets a maximum power level from the E5072A’s source for each port.
• Once the max power limit is set, the power level can only be set below the desired max power limit.
User preset
• As a default, presetting the E5072A will preset the output power level to 0 dBm, which may result in
damaging the DUT in the test system or the E5072A itself with high-power input.
•Setup user preset to recall a pre-defined state file with the power level lower than factory preset condition.
Power Handling Capability
As high power levels can damage the instrument and it is costly to repair, it is important to
understand the power handling capability of each component in the VNA’s signal path.
Ex.) E5072A port performance
Connector
RF Damage
Level (Typ.)
DC Damage
Level (Typ.)
0.1 dB Compression Level
(SPD*)
Test Port 1 & 2
+26 dBm
+-35 VDC
+6 dBm (30 k to 300 kHz)
+16 dBm (300 k to 2 GHz)
+14 dBm (2 G to 6 GHz)
+10 dBm (6 G to 8.5 GHz)
CPLR ARM
+15 dBm
0 VDC
-
RCVR A IN, RCVR
B IN
+15 dBm
+-16 VDC
-15 dBm (30 k to 300 kHz)
-10 dBm (300 k to 8.5 GHz)
SOURCE OUT
(Port 1 & 2)
+26 dBm
0 VDC
-
CPLR THRU (Port
1 & 2)
+26 dBm
+-35 VDC
-
REF 1/2 SOURCE
OUT
+15 dBm
0 VDC
-
RCVR R1 IN,
RCVR R2 IN
+15 dBm
+-16 VDC
-15 dBm (30 k to 300 kHz)
-10 dBm (300 k to 8.5 GHz)
* SPD or supplemental performance data represents the value of a parameter that is most likely to
occur, not guaranteed bay the product warranty.
Summary
• High-power network analysis can be challenging because:
1. Output power level of a network analyzer is not sufficient for
measurements.
2. Input power level to receivers of a network analyzer exceeds
the maximum allowable level.
• Highly recommended to include direct receiver access with
configurable test set option of a network analyzer to perform highpower measurements.
• Important to understand the power handling capability of the
network analyzer and each component in the signal path.
Resources
E5072A information
• ENA series web page: http://www.agilent.com/find/ena
• E5072A web page: http://www.agilent.com/find/e5072a
• E5072A Configuration Guide: Part number 5990-8001EN
• E5072A Data Sheet: Part number 5990-8002EN
• E5072A Quick Fact Sheet: Part number 5990-8003EN
• E5072A Technical Overview: Part number 5990-8004EN
Application Note
• Using a Network Analyzer to Characterize High-Power Components
(Application Note 1287-6, part number 5966-3319E)
• Recommendations for Testing High-Power Measurements (Application
Note 1408-10, part number 5989-1349EN)
• High-power Measurement using the E5072A (Part Number 5990-8005EN)
Low-power S-parameter Measurements
using the E5072A
(ENA with configurable test set)
Why low-power measurements?
• To characterize components in the receiver path such as bandpass filters or low-noise
amplifiers, it is often required to measure S-parameters using very low signals to simulate
real conditions.
(ex.) Measurements of linear behavior of high-gain amplifiers when low-power level is
supplied to the input of DUT.
Diagram of RF interface in wireless communication
LNA
Rx Filter
Antenna
Duplexer
Tx Filter
Combiner
Power Amplifier
What’s E5072A?
E5072A - ENA with Configurable Test Set
New addition to the ENA series with a more flexible platform to exceed
measurement capability of current RF network analyzers.
• 2-port, 30 k to 4.5 GHz & 8.5 GHz
• Configurable test set
• Wide output power range (spec: -85 to +16 dBm *1, SPD: up to +20 dBm *2)
• High receiver sensitivity (extended dynamic range up to -151 dB)
• Enhanced functions (receiver leveling, independent source ATTs, reverse
sweep, etc)
• Compatibility with E5071C & 8753 (command, box size, U/I, etc)
*1: specification for 300 k to 3 GHz.
*2: SPD or supplemental performance data for 300 k to 1 GHz.
E5072A Features
Wide Output Power Range
•
•
Maximum output power up to +20 dBm is available at the test port. (300 k to 1 GHz)
The built-in source attenuators enable low-power measurement down to specified -85 dBm;
The power level of the E5072A can be set as low as -109 dBm.
Output power level comparison
-85 to +8 dBm
8753ES
Opt.014
-55 to +10 dBm
E5071C
-85 to +16 dBm (*1)
E5072A
-109 to +20 dBm (*2)
*1 Specification, *2 Settable power range.
>65 dB power sweep
E5072A Features & Benefits
E5072A Key Features for low-power measurements:
1. Accurate measurement with very low signals
•
•
Because of the built-in source attenuators installed between internal bridges in the
E5072A, accurate reflection measurements (i.e. S11 or S22) can be performed with
low output power.
No need to add an external attenuator to reduce power level at DUT input.
2. Uncoupled power
•
•
•
Different output power level can be set for port 1 & 2.
Easy characterization of high-gain power amplifier without an external attenuator on
output port. (i.e. power level of port 1 = -85 dBm and port 2 = 0 dBm.)
More accurate reverse measurement (i.e. S12) with wider dynamic range.
E5072A Features & Benefits
1. Accurate measurement with very low signals
•
•
Because of the built-in source attenuators installed between internal bridges in the E5072A,
accurate reflection measurements (i.e. S11 or S22) can be performed with low output
power.
No need to add an external attenuator to reduce power level at DUT input.
Ex. Low-power measurement (-75 dBm at DUT input)
E5072A
E5071C
Power = -55 dBm
(min. power of E5071C)
Power = -15 dBm
~-40 dBm
R1
<-70 dBm
R1
Port 1
ATT = 20 dB
A
R2
B
A
Port 2
DUT
-75 dBm
An external attenuator is necessary to lower the
output power below the E5071C’s minimum output
power of -55 dBm.
ATT = 60 dB
(10 dB step,
Max 60 dB)
R2
~-90 dBm
<-135 dBm
B
Port 1
Port 2
DUT
-75 dBm
Built-in attenuators makes more accurate measurement
with better S/N ratio at receivers, R1 or A.
E5072A Features & Benefits
1. Accurate measurement with very low signals
•
•
Because of the built-in source attenuators installed between internal bridges in the E5072A,
accurate reflection measurements (i.e. S11 or S22) can be performed with low output
power.
No need to add an external attenuator to reduce power level at DUT input.
Ex. Low-power measurement (-75 dBm at DUT input)
E5071C
E5072A
(Power = -55 dBm, w/ 20 dB external ATT)
(Power = -75 dBm, w/ built-in ATT of 60 dB)
S11
S11
S21
S21
E5072A Features & Benefits
2. Uncoupled power
•
•
•
Different output power level can be set for port 1 & 2 with independent source
attenuators.
Easy characterization of high-gain power amp without an external attenuator on
output port.
More accurate reverse measurement (i.e. S12, S22) with wider dynamic range.
R1
R2
A
B
ATT = 40 dB
(Port 1)
ATT = 0 dB
(Port 2)
0 dBm
-85 dBm
High-gain amp
E5072A Features & Benefits
2. Uncoupled power
•
•
•
Different output power level can be set for port 1 & 2 with independent source
attenuators.
Easy characterization of high-gain power amp without an external attenuator on
output port.
More accurate reverse measurement (i.e. S12, S22) with wider dynamic range.
ex.) S-parameters of high-gain amplifier
S11
S12
S11
S22
S22
S21
S12
S21
Coupled power
Uncoupled power
(Port 1 = Port 2 = -40 dBm)
(Port 1 = -40 dBm, Port 2 = 0 dBm)
Power calibration of VNA
1. Power calibration
•
•
The VNA’s source power level is calibrated using a
power sensor to get accurate power level at the
calibration plane.
Power level accuracy is directly dependent on the
accuracy of the power sensor used.
2. Receiver calibration
•
•
•
Necessary for absolute measurements in dBm.
Must have a power-calibrated source at the same
frequency range.
Mathematically removes frequency response in the
receiver path and adjusts the VNA’s reading to the
same as power level in dBm at the calibration plane.
Thru
3. Receiver leveling
•
•
•
Before each measurement sweep, background
sweeps are performed to measure power at the
receiver.
Power measurements at the receiver are used to
adjust the VNA’s source power level.
Accurate power level adjustment by using high
receiver linearity of VNA.
Receivers
Source power adjusted
E5072A Features & Benefits
Receiver leveling
• Receiver leveling adjusts the source power level using its receiver
•
measurements.
Since the E5072A’s receiver linearity is better than source linearity, power accuracy is
improved for low-power measurement by using receiver leveling.
2
2. Automatically adjust
source power level.
1
1. Monitor
power level
at a receiver
R1
R2
A
B
Port 1
Port 2
DUT
32. Accurate power level
at DUT’s input.
E5072A Features & Benefits
Receiver leveling
The accurate low-power level is achieved by using the receiver leveling.
Receiver leveling ON (data)
Receiver leveling OFF (memory)
Ref = -60 dBm, 20 mdB/div. 10 M to 6 GHz, IFBW = 100 Hz, 201 pts.
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
Fixture Simulator
Contents
• Fixture Simulator
– Balanced measurements (Mixed-mode S-parameters)
– (De-)Embedding / port matching
– Setup wizard of fixture simulator
– Port matching utility program
Fixture Simulator
Actual
Calibration Plane
Zd
DUT
Zc
Data Process
Measured Sparameters
Port
Extension
Network Deembedding
Port reference
Z conversion
Port Matching
UnbalancedBalanced
Conversion
Differential
Port Z
conversion
Differential
Matching
circuit
Embedding
Balanced (Mixed-mode) S-parameter
Single-ended S-parameter
Single-ended
Balanced
Built-in Balanced Measurement
Balanced component examples:
SAW Filters (Unbal-Bal)
Baluns
SAW Filters (Bal-Bal)
Differential Amplifiers
Cable
Mixed-mode S-parameters
 S 11

 S 21
 S 31

 S 41
Measure
Single-ended S-parameters
S 12
S 22
S 13
S 23
S 32
S 33
S 42
S 43
S 14 

S 24 
S 34 

S 44 
Simulate Hybrid Balun
to extract differential and common
DUT
Vdiff
Vcomm
Obtain
Mixed-mode S-parameters
(Balanced and Common-mode
S-parameters)
V1
 S DD11
S
 DD 21
 SCD11

 SCD 21
V2
S DD12
S DD 22
S DC11
S DC 21
SCD12
SCD 22
SCC11
SCC 21
S DC12 
S DC 22 
SCC12 

SCC 22 
Vdiff   A, B  V 1 

 = 
 *  
Vcomm   C , D  V 2 
Examples of Mixed-mode S-Parameters
Mixed-mode S21 for Bal-Bal
Sdd21
Sdc21
Mixed-mode S11
Sdd11
Mixed-mode S21 for Single to Bal
Scd21
Sds21
Scc21
Scs21
Sss11
Sds21
Ssd12
Sdd22
Ssc12
Sdc22
Sdc11
Scs21
Scd22
Scc22
Balanced SAW filter measurement example
Embedding/De-embedding and Port Z Conversion
Embedding
De-embedding
Measured
S-parameter
Measured
S-parameter
Additional
Network
Additional
Network
DUT
Undesired
Network
Undesired
Network
DUT
De-embedded
Response
Embedded Response
Complex Port Z Conversion
50
Measure
Simulate
DUT
DUT
50
R+jX
R+jX
Embedding / De-embedding
(De-)Embedding of 2-port circuits
Port 3
Port 1
DUT
Port 2
Port 4
(De-)Embedding of 4-port circuits
Port 1
Port 3
DUT
Port 2
Port 4
De-embedding
•Accurate characterization of the DUT is achieved by de-embedding Sparameter (*.s2p) of a fixture.
DUT
Connector
S21
Calibrated
system(cal
plane at cable
end)
RF Cable
Calibration
Plane
S11
S22
S12
Fixture
Create an S2p file
and de-embed
DUT
Embedding Virtual Networks
Virtual matching circuits
C1
Bal
SAW
Filter
Zi
L2
Zd
L1
C1
Zc
• Mathematically embed matching circuits on any ports as required.
• Predefined matching topologies or user defined S-parameters networks can
be embedded.
Balanced SAW Filter Measurement Example
Single-ended (unbalanced)
9x9 S-parameters, S11 to S33
Balanced S-parameters
(both differential and common modes)
Sss11
Ssd12
Ssc12
Sds21
Sdd22
Sdc22
Scs21
Scd22
Scc22
Measurement Specifications
Connections
Setup
• Single-ended : Port 1
1. Preset :
OK
• Balanced :
Port 2
2. Center :
942.5MHz
• Balanced :
Port 3
3. Span :
200MHz
4. Display :
Number of Traces: 9
Allocate Traces: |1|2|3|
|4|5|6|
|7|8|9|
Band Pass Filter(Singleended)
F0 : 947.5MHz
PORT 2
PORT 1
50 ohm
Duplexer
PORT 1
F0(Tx) :
1880MHz
F0(Rx) :
ANT 50 ohm 1960MHz
50
ohm
PORT 2
50 ohm
R
x
PORT 3
5. Select parameter & format as shown on next page
PORT 2
6. Adjust Scale
50 ohm
T
x
Band Pass Filter(Balanced)
F0 : 942.5MHz
PORT 1
50 ohm
200 ohm
PORT 3
E5079A
A
Handset Component Demo Kit
Agilent Restricted
Measure Single-ended S-parameters
Measurement parameters
S11
S21
S31
S12
S22
S32
S13
S23
S33
C1
Zi
Bal
SAW
Filter
L2
Zd
C1
Zc
Measured
S-parameter
Perform Full 3-port Calibration
C1
Zi
Bal
SAW
Filter
L2
Zd
C1
Zc
Measured
S-parameter
(w/Full-3 Cal)
Apply Port Extension
Electrical length
Port 1 : 180ps
Port 2 : 280ps
Port 3 : 280ps
C1
Zi
Bal
SAW
Filter
L2
Zd
C1
Zc
Apply port
extension
Measured
S-parameter
(w/Full-3 Cal)
Convert to Mixed-mode S-parameters
Measurement Parameters
Sss11
Sds21
Scs21
Ssd12
Sdd22
Scd22
C1
Ssc12
Sdc22
Scc22
Zi
Bal
SAW
Filter
L2
Zd
C1
Zc
Apply port
extension
Measured
S-parameter
(w/Full-3 Cal)
Convert to mixed-mode
S-parameter
Modify Port Characteristic Impedance
Port characteristic impedance
Port 1 : 50 ohms
Port 2 : 100 ohms
Port 3 : 100 ohms
C1
Zi
Bal
SAW
Filter
L2
Zd
C1
Zc
Apply port
extension
Measured
S-parameter
(w/Full-3 Cal)
Convert port
characteristic
impedance*
Convert to mixedmode S-parameter
* Differential & common impedance are
automatically calculated from defined
single-ended impedance.
Apply Port Matching
Matching specifications
Port 1 : none
Port 2 : Shunt L = 28nH
Port 3 : Shunt L = 28nH
C1
Zi
Bal
SAW
Filter
L2
Zd
C1
Zc
Apply port
extension
Apply matching Convert port
characteristic
circuit
impedance*
Measured
S-parameter
Convert to mixed(w/Full-3 Cal)
mode S-parameter
Save “State & Cal”
Measurement Specifications
Setup
Electrical length
1. Preset :
OK
2. Center :
942.5MHz
3. Span :
200MHz
Band Pass Filter(Singleended)
F0 : 947.5MHz
PORT 2
PORT 1
50 ohm
Duplexer
PORT 1
F0(Tx) :
1880MHz
F0(Rx) :
ANT 50 ohm 1960MHz
50
ohm
Port 1 : 180ps
Port 2 : 280ps
Port 3 : 280ps
Port characteristic impedance
Port 1 : 50 ohms
Port 2 : 100 ohms
Port 3 : 100 ohms
PORT 2
50 ohm
Matching specifications
R
x
PORT 3
50 ohm
T
x
Band Pass Filter(Balanced)
PORT 2
F0 : 942.5MHz
PORT 1
50 ohm
200 ohm
PORT 3
Port 1 : none
Port 2 : Shunt L = 28nH
Port 3 : Shunt L = 28nH
E5079A
A
Handset Component Demo Kit
Agilent Restricted
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
Incident
Transmitted
DUT
SOURCE
Reflected
SIGNAL
SEPARATION
INCIDENT (R)
REFLECTED
(A)
TRANSMITTED
(B)
RECEIVER / DETECTOR
PROCESSOR / DISPLAY
SHORT
OPEN
LOAD
Agilent IO Libraries Suite 16 provides
one tool for fast start-up
Suite 16
System set-up in
< 15 minutes
• 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
LAN eXtension for Instrumentation
LXI devices serve a web page
IP Address
Manufacturer
Model #
Serial #
Firmware rev.
IP Address
Domain name
etc.
Ability to
change the
IP address
Page 134
ENA LXI Web control example
Select
ENA
Web
Control
Back to Basics Seminar
135
ENA LXI Web control example
Back to Basics Seminar
136
ENA LXI Web control example
Get Image
Right click
to save
picture.
Back to Basics Seminar
137
ENA LXI Web control example
Get Data
Right click
for save to
Excel
menu.
Back to Basics Seminar
138
LXI Possibilities
Long
distance
operations
Higher
throughput
Flexible
triggering
No trigger
wires
Expert
Troubleshooting
Timestamp
all data
Parallel
operations
Eliminate
latency
Smart instruments
Asset
Management
Internal
network
Reduce
programming
Page 139
Software Integration
VEE Pro
Integrated
VBA Programming
Agilent SystemVue
Page 140
Agilent ADS
1/26/2011
Quick Demo Guide
ENA Series Network Analyzer - VBA Programming (UserMenu)
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)
N-Type Cable
In this demo…
• Code simple VBA macro for bandpass filter measurement
• Apply VBA macro to UserMenu buttons
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
Sub main()
Call Setup
End Sub
Band pass filter (BPF)
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.
1. Connect DUT to ENA
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
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.
DUT
Figure1. DUT connection
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.
Quick Demo Guide
4. Add Bandwidth Search Module
5. Apply VBA procedure to UserMenu buttons
6. Use UserMenu Buttons
a. Open VBA Editor
b. Modify Sub() procedure of Module1 as below code
a. Open VBA Editor
b. Modify Sub() procedure of Module1 as below code
a. Press “Setup” button to run Setup procedure
b. Press “Bandwidth” button to run Bandwidth_Search
procedure
Sub Main()
Call Setup
Call Bandwidth
End Sub
c. Add below procedure on Module1
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()
UserMenu.Item(1).enabled
UserMenu.Item(2).enabled
UserMenu.Item(1).Caption
UserMenu.Item(2).Caption
UserMenu.Show
End Sub
=
=
=
=
True
True
"Setup"
"Bandwidth"
c. Create UserMenu module
Click E5061B_Objects then Double-Click UserMenu
In the object box in the code window, select UserMenu as
shown below.
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.
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.
d. Code below procedure on UserMenu module
Private Sub UserMenu_OnPress(ByVal ID As
Long)
If ID = 1 Then Module1.Setup
If ID = 2 Then Module1.Bandwidth
UserMenu.Show
End Sub
e. Save program and run
Click
icon, then
icon of the VBA Editor
press [Macro Run] hard key.
www.agilent.com/find/ena_vba
Sample VBA(s) for the ENA
Resources
E5071C information
• ENA series web page: http://www.agilent.com/find/ena
• E5071C web page: http://www.agilent.com/find/e5071C
• E5071C Configuration Guide: Part number 5989-5480EN
• E5071C Data Sheet: Part number 5989-5479EN
• E5071C Technical Overview: Part number 5989-9806EN
Application Note
• Introduction to the Fixture Simulator Function of the ENA Series RF
Network Analyzers (Product Note E5070/71-1, part number 5988-4923EN)
• Accurate Mixer Measurements with ENA Frequency-Offset Mode (AN
1463-6), part number 5989-1420EN)
THANK YOU!
145
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