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Revision 2 ©copyright 2014 MegiQ BV. All rights reserved.
MegiQ VNA0440e measurements on the VNA Sandbox
This document shows VNA0440e measurements on the circuits contained on the MegiQ VNA
Sandbox. The circuits on this board are designed to show the many possibilities of the VNA0440e.
Introduction to the measurement setup
VNA0440e
The VNA0440e is a professional 4GHz Vector Network Analyzer and comes with a calibration at the
SMA ports. This allows you to directly measure impedances and gains at the connectors without any
user calibration. Further calibration is only required when measuring on-board or connectorized
devices. The device is very stable and does not need any warm-up time.
The VNA0440e also has a built-in Bias Voltage and Current generator. It allows Frequency, Power
and Bias Voltage and Current sweeps to be combined in any combination. This makes it possible to do
several different characterizations on active components in its purest form, without additional
components or programming of external V/I sources.
The software contains a unique Session Manager to easily store several measurements in a Session
File. It makes it easy to build a trail of experiments and retrace your steps. Since all calibration and
measurement data are stored you can go back to an earlier measurement and continue measuring from
there, changing cursor positions, choose another graphical representation etc.
The graphs below are made with the report generator of the VNA0440e software. We printed them in
black here to give a feel of the actual screen. Both screen and reports can be set to white or other
backgrounds with different trace colors.
We varied the choice of graphs and the settings of the graphs for zooming, markers and trace labels to
show the possibilities of the software for a clear presentation of the measurements and to assess the
accuracy of the measurements.
VNA Sandbox The MegiQ VNA Sandbox is a circuit board with many different experiments to demonstrate the
features of VNAs in general and the VNA0440e in particular. It comes with a printed tutorial showing
how to measure and explaining the results you see. It can also be used as a reference to verify the
correct operation of a test setup.
The VNA Sandbox is based on UFL connectors that are also used to measure consumer miniature RF
circuits like mobile phones, Wifi access points etc. it contains a dual calibration kit for quick
calibration, which is supported by the VNA0440e software. This reduces a full 2-port calibration from
12 steps to only 4 steps. The lights on the front panel of the VNA0440e will guide you through the
calibration process.
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Revision 2. ©copyright 2014 MegiQ BV. All rights reserved. 2
The board contains several 1-port impedances, 2-port passive circuits like attenuators and filters, two
antennas and several active circuits that are measured using the bias generator.
Other Calkits Also available from MegiQ are a universal UFL dual Calkit that allows calibration for different print
layer thicknesses, and a Balanced Calkit for measurements on differential circuits and antennas. The
Calkits come with custom SMA adapters and cables necessary for the measurements.
UFL connections The MegiQ VNA Sandbox uses miniature UFL connectors and cables. These connectors and cables
are ideal for measuring small RF devices in the microwave range, but they have the drawback that they
are not so well matched at all frequencies.
These UFL and cable mismatches are calibrated and normalized away by the VNA0440e, but some
artifacts remain in the higher range between 3 and 4 GHz. The same artifacts are also seen on other
high end VNAs. Note that the VNA0440e itself features SMA front panel connectors.
UFL Cable
Here are the bare impedances of two single UFL cables measured with the Port Calibration of the
VNA0440e.
Center 2.20GHz / Span 3.60GHzS11 Z
0.40 0.76 1.12 1.48 1.84 2.20 2.56 2.92 3.28 4.00F [GHz]-60
-40
-20
0
RL
[dB]
Center 2.20GHz / Span 3.60GHzS11 RL
-6-10-15
Center 2.20GHz / Span 3.60GHzS22 Z
1
2
3
1> 0.400GHz: 51.38 + j1.46
2> 2.620GHz: 32.44 - j11.17
3> 4.000GHz: 32.14 + j19.54
0.40 0.76 1.12 1.48 1.84 2.20 2.56 2.92 3.28 4.00F [GHz]-30
-20
-10
0
RL
[dB]
Center 2.20GHz / Span 3.60GHzS22 RL
1
2
3
1> 0.720GHz: -21.47dB
2> 2.620GHz: -12.04dB
3> 4.000GHz: -10.08dB
Impedance
Return Loss
Impedance
Return Loss
VSB measurements\VSB 13: UFL cables w Load 9/14/2014 4:20:11 PM
Measure:
Sw eep:
S11 S22
FrequencySw eep
Frequency:
Pow er:
400 > 4000 MHz 180 steps (20/)
-10 dBm
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Revision 2. ©copyright 2014 MegiQ BV. All rights reserved. 3
Double UFL cable in series
When two cables are connected in series, as in the test setup with the VNA Sandbox, the UFL
impedances are getting quite a bit off.
Center 2.20GHz / Span 3.60GHzS11 Z
Center 2.20GHz / Span 3.60GHzS11 Z
0.40 0.76 1.12 1.48 1.84 2.20 2.56 2.92 3.28 4.00F [GHz]-30
-20
-10
0
RL
[dB]
Center 2.20GHz / Span 3.60GHzS11 RL
1
2 3
1> 0.620GHz: -18.49dB
2> 2.540GHz: -9.93dB
3> 3.920GHz: -9.68dB
0.40 0.76 1.12 1.48 1.84 2.20 2.56 2.92 3.28 4.00F [GHz]
-30
-20
-10
0
10
20
Gain
[dB]
-0.8
0.0
0.8
1.6
2.4
3.2
Tg
[ns]
Center 2.20GHz / Span 3.60GHzS12 Gain Tg
1 2 3
1
1> 0.400GHz: -0.60dB
2> 2.200GHz: -1.58dB
3> 4.000GHz: -2.59dB
1> 0.400GHz: 2.0876ns
Center 2.20GHz / Span 3.60GHzS22 Z
Center 2.20GHz / Span 3.60GHzS22 Z
0.40 0.76 1.12 1.48 1.84 2.20 2.56 2.92 3.28 4.00F [GHz]-50
-40
-30
-20
-10
0
10
Gain
[dB]
-180
-90
0
90
180
Phase
[Deg]
Center 2.20GHz / Span 3.60GHzS21 Gain Phase
0.40 0.76 1.12 1.48 1.84 2.20 2.56 2.92 3.28 4.00F [GHz]0
40
80
120
160
200
|Z|
[Ohm]
-180
-90
0
90
180
Phase
[Deg]
Center 2.20GHz / Span 3.60GHzS22 |Z| Phase
1
2
3
1> 0.400GHz: 49.26Ohm
2> 1.560GHz: 71.68Ohm
3> 3.440GHz: 25.22Ohm
Cal Source Impedance Impedance
Return Loss
Gain
Cal Source Impedance Impedance
Gain
Impedance
VSB measurements\VSB 14: U.FL Through 9/14/2014 3:45:34 PM
Measure:
Sw eep:
S11 S21 S12 S22
Frequency
Frequency:
Pow er:
400 > 4000 MHz 180 steps (20/)
-10 dBm
The total impedance and gain varies quite a bit over the frequency range and the return loss is quite
low on some frequencies. This should be taken into account when applying these cables in an RF
application.
The Group Delay is shown in the bottom left S12 Gain graph. It can be used to estimate the length of
the two cables in series.
MegiQ VNA0440e measurements on the VNA Sandbox www.megiq.com
Revision 2. ©copyright 2014 MegiQ BV. All rights reserved. 4
Calibration The VNA0440e has ‘Port Calibration’ for direct measurements on cables and connectorized antennas,
without further user calibration. The UFL measurements above were made with Port Calibration.
For measurements through cables and fixtures the measurement must be calibrated with reference
impedances at the very point where the device under test is to be connected. A double set of calibration
references is included on the VNA Sandbox which speeds up the calibration process for 2-port
measurements.
For a 2-port measurement we have to make reference measurements with an Open, Short and Load
(50Ohm) on each port, and an Isolation and a Through connection between them.
This graph shows the calibration signals of one half of the 2-port calibration on the VNA Sandbox.
0.40 0.76 1.12 1.48 1.84 2.20 2.56 2.92 4.00F [GHz]-50
-40
-30
-20
-10
0
10
Amp
[dB]
-180
-90
0
90
180
Phase
[Deg]
Center 2.20GHz / Span 3.60GHzS11 Amp Phase
0.40 0.76 1.12 1.48 1.84 2.20 2.56 2.92 4.00F [GHz]-50
-40
-30
-20
-10
0
10
Amp
[dB]
-180
-90
0
90
180
Phase
[Deg]
Center 2.20GHz / Span 3.60GHzS11 Amp Phase
0.40 0.76 1.12 1.48 1.84 2.20 2.56 2.92 4.00F [GHz]-50
-40
-30
-20
-10
0
10
Amp
[dB]
-180
-90
0
90
180
Phase
[Deg]
Center 2.20GHz / Span 3.60GHzS11 Amp Phase
Center 2.20GHz / Span 3.60GHzS11 Z
0.40 0.76 1.12 1.48 1.84 2.20 2.56 2.92 4.00F [GHz]
-60
-50
-40
-30
-20
-10
Amp
[dB]
-180
-90
0
90
Phase
[Deg]
Center 2.20GHz / Span 3.60GHzS12 Amp Phase
0.40 0.76 1.12 1.48 1.84 2.20 2.56 2.92 4.00F [GHz]-50
-40
-30
-20
-10
0
10
Amp
[dB]
-180
-90
0
90
180
Phase
[Deg]
Center 2.20GHz / Span 3.60GHzS12 Amp Phase
Center 2.20GHz / Span 3.60GHzS12 Z
Cal Open
Cal Short
Cal Load
Cal SourceCal Isolation
Cal Through Cal Sink
VSB measurements\VSB Calibration 9/14/2014 4:22:02 PM
Measure:
Sw eep:
S11 S21 S12 S22
Frequency
Frequency:
Pow er:
400 > 4000 MHz 180 steps (20/)
-10 dBm
From the Open-Short-Load calibration (the three graphs on the left), the VNA0440e calculates the
impedance at the reference plane of the calibration. This is the Source impedance with which the
circuit under test is excited.
During the Through-calibration the VNA0440e also measures the impedance that is connected to the
Source. This is the Sink impedance that will terminate the circuit under test.
The ‘imperfect’ Source and Sink impedances – they are not perfectly 50 Ohm – cause errors in the
measurements, both for impedance and for gain results.
The 6 calibrations for each of the 2 ports allow the VNA0440e to perform a 12-term normalization
(Full Normalization) on the measurement to remove these measurement impedances from the results.
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Revision 2. ©copyright 2014 MegiQ BV. All rights reserved. 5
The results then show the device’s characteristics as if it were measured with pure 50 Ohm source and
termination impedances.
We see that there is a significant amount of crosstalk between the UFL cables (Isolation measurement).
This crosstalk is also eliminated in the normalization process.
MegiQ VNA0440e measurements on the VNA Sandbox www.megiq.com
Revision 2. ©copyright 2014 MegiQ BV. All rights reserved. 6
1-port circuits
These are measurements (in pairs) of different series and parallel resonance circuits combined with a
resistor.
Series resonance circuits 22 and 21
Center 2.20GHz / Span 3.60GHzS11 Z
1
2
3
1> 0.420GHz: 44.64 - j15.91
2> 1.760GHz: 1.08 - j0.28
3> 4.000GHz: 38.17 + j19.71
0.40 0.76 1.12 1.48 1.84 2.20 2.56 2.92 3.28 4.00F [GHz]-30
-20
-10
0
RL
[dB]
Center 2.20GHz / Span 3.60GHzS11 RL
1
2
3
1> 0.400GHz: -15.63dB
2> 1.760GHz: -0.37dB
3> 4.000GHz: -11.89dB
Center 2.20GHz / Span 3.60GHzS22 Z
400
1120
1840
2560
3280 4000
0.40 0.76 1.12 1.48 1.84 2.20 2.56 2.92 3.28 4.00F [GHz]0
20
40
60
80
100
120
140
160
180
200
|Z|
[Ohm]
-180
-90
0
90
180
Phase
[Deg]
Center 2.20GHz / Span 3.60GHzS22 |Z| Phase
1
2
3
1> 0.400GHz: 149.60Ohm
2> 1.760GHz: 1.12Ohm
3> 4.000GHz: 83.15Ohm
Impedance
Return Loss
Impedance
Impedance
VSB measurements\VSB 21/22: LCR series 9/14/2014 3:24:31 PM
Measure:
Sw eep:
S11 S22
FrequencySw eep
Frequency:
Pow er:
400 > 4000 MHz 180 steps (20/)
-10 dBm
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Revision 2. ©copyright 2014 MegiQ BV. All rights reserved. 7
Series resonance circuits 24 and 23
Center 2.20GHz / Span 3.60GHzS11 Z
0.40 0.76 1.12 1.48 1.84 2.20 2.56 2.92 3.28 4.00F [GHz]-30
-20
-10
0
RL
[dB]
Center 2.20GHz / Span 3.60GHzS11 RL
Center 2.20GHz / Span 3.60GHzS22 Z
400
1120
1840
2560
3280 4000
1
1> 1.620GHz: 50.60 - j0.54
0.40 0.76 1.12 1.48 1.84 2.20 2.56 2.92 3.28 4.00F [GHz]
-40
-20
0
RL
[dB]
Center 2.20GHz / Span 3.60GHzS22 RL
1
1> 1.620GHz: -41.86dB
0.40 0.76 1.12 1.48 1.84 2.20 2.56 2.92 3.28 4.00F [GHz]0.0
0.5
1.0
1.5
2.0
2.5
3.0
FL
[dB]
Center 2.20GHz / Span 3.60GHzS22 FL
1
1> 1.620GHz: 0.0003dB
Impedance
Return Loss
Impedance Return Loss
Forward Loss
VSB measurements\VSB 23/24: LCR series 9/14/2014 3:25:28 PM
Measure:
Sw eep:
S11 S22
FrequencySw eep
Frequency:
Pow er:
400 > 4000 MHz 180 steps (20/)
-10 dBm
Parallel resonance circuits 32 and 31
Center 2.20GHz / Span 3.60GHzS11 Z
0.40 0.76 1.12 1.48 1.84 2.20 2.56 2.92 3.28 4.00F [GHz]
-40
-20
0
RL
[dB]
Center 2.20GHz / Span 3.60GHzS11 RL
1
1> 2.020GHz: -38.19dB
Center 2.20GHz / Span 3.60GHzS22 Z
400
1120
1840
2560
3280
4000
0.40 0.76 1.12 1.48 1.84 2.20 2.56 2.92 3.28 4.00F [GHz]0
100
200
300
400
500
600
700
800
900
1000
|Z|
[Ohm]
0
450
900
1350
Phase
[Deg]
Center 2.20GHz / Span 3.60GHzS22 |Z| Phase
1
1> 2.000GHz: 874.8Ohm
Impedance
Return Loss
Impedance
Impedance
VSB measurements\VSB 31/32: LCR parallel 9/14/2014 3:26:47 PM
Measure:
Sw eep:
S11 S22
FrequencySw eep
Frequency:
Pow er:
400 > 4000 MHz 180 steps (20/)
-10 dBm
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Revision 2. ©copyright 2014 MegiQ BV. All rights reserved. 8
Parallel resonance circuits 34 and 33
Center 2.20GHz / Span 3.60GHzS11 Z
400
1120
18402560
3280
4000
0.40 0.76 1.12 1.48 1.84 2.20 2.56 2.92 3.28 4.00F [GHz]-30
-20
-10
0
RL
[dB]
Center 2.20GHz / Span 3.60GHzS11 RL
Center 2.20GHz / Span 3.60GHzS22 Z
12
1> 0.400GHz: 50.92 + j8.31
2> 4.000GHz: 51.23 + j12.15
0.40 0.76 1.12 1.48 1.84 2.20 2.56 2.92 3.28 4.00F [GHz]-60
-40
-20
0
RL
[dB]
Center 2.20GHz / Span 3.60GHzS22 RL
Impedance
Return Loss
Impedance
Return Loss
VSB measurements\VSB 33/34: LCR parallel 9/14/2014 3:27:27 PM
Measure:
Sw eep:
S11 S22
FrequencySw eep
Frequency:
Pow er:
400 > 4000 MHz 180 steps (20/)
-10 dBm
Notice that the frequency indications in the Smith chart give a much better insight in the circuit’s
behaviour than the bare lines that other VNAs show. These markers are a unique feature of the
VNA0440e software. In the right Smith chart the measure point markers are turned on.
MegiQ VNA0440e measurements on the VNA Sandbox www.megiq.com
Revision 2. ©copyright 2014 MegiQ BV. All rights reserved. 9
2-port passive circuits
10 dB Pi attenuator
Center 2.20GHz / Span 3.60GHzS11 Z
0.40 0.76 1.12 1.48 1.84 2.20 2.56 2.92 3.28 4.00F [GHz]-60
-40
-20
0
RL
[dB]
Center 2.20GHz / Span 3.60GHzS11 RL
0.40 0.76 1.12 1.48 1.84 2.20 2.56 2.92 3.28 4.00F [GHz]-13
-12
-11
-10
-9
-8
-7
Gain
[dB]
45
54
63
72
Phase
[Deg]
Center 2.20GHz / Span 3.60GHzS12 Gain Phase
1 23
1> 0.400GHz: -10.071dB
2> 3.480GHz: -10.106dB
3> 3.620GHz: -9.898dB
Center 2.200GHz / Span 3.600GHzS22 Z
0.40 0.76 1.12 1.48 1.84 2.20 2.56 2.92 3.28 4.00F [GHz]-60
-40
-20
0
RL
[dB]
Center 2.20GHz / Span 3.60GHzS22 RL
1
2
3
1> 0.400GHz: -49.37dB
2> 2.200GHz: -37.92dB
3> 4.000GHz: -32.94dB
0.40 0.76 1.12 1.48 1.84 2.20 2.56 2.92 3.28 4.00F [GHz]
-20
-15
-10
-5
0
5
Gain
[dB]
0
45
90
135
Phase
[Deg]
Center 2.20GHz / Span 3.60GHzS21 Gain Phase
1 2 3
1 2 3
1> 0.420GHz: -10.067dB
2> 2.200GHz: -10.062dB
3> 4.000GHz: -9.931dB
1> 0.400GHz: 0.505Deg
2> 2.220GHz: 2.851Deg
3> 4.000GHz: 5.643Deg
Impedance
Return Loss
Gain
Impedance
Return Loss
Gain
VSB measurements\VSB 15: 10dB Attenuator 9/14/2014 3:32:09 PM
Measure:
Sw eep:
S11 S21 S12 S22
Frequency
Frequency:
Pow er:
400 > 4000 MHz 180 steps (20/)
-10 dBm
A simple resistor network has very accurate attenuation and matching over the whole band, with only
0.2 dB variation in attenuation.
MegiQ VNA0440e measurements on the VNA Sandbox www.megiq.com
Revision 2. ©copyright 2014 MegiQ BV. All rights reserved. 10
50 Ohm series resistor.
Center 2.20GHz / Span 3.60GHzS11 Z
0.40 0.76 1.12 1.48 1.84 2.20 2.56 2.92 3.28 4.00F [GHz]-15
-10
-5
0
RL
[dB]
Center 2.20GHz / Span 3.60GHzS11 RL
1 2 3
1> 0.400GHz: -9.567dB
2> 2.200GHz: -9.659dB
3> 4.000GHz: -9.831dB
Center 2.200GHz / Span 3.600GHzS22 Z
0.40 0.76 1.12 1.48 1.84 2.20 2.56 2.92 3.28 4.00F [GHz]
-20
-15
-10
-5
0
5
Gain
[dB]
0
45
90
135
Phase
[Deg]
Center 2.20GHz / Span 3.60GHzS21 Gain Phase
1 2 3
1> 0.400GHz: -3.538dB
2> 2.200GHz: -3.526dB
3> 4.000GHz: -3.381dB
0.40 0.76 1.12 1.48 1.84 2.20 2.56 2.92 3.28 4.00F [GHz]50
70
90
110
130
150
|Z|
[Ohm]
-90
-45
0
45
90
Phase
[Deg]
Center 2.20GHz / Span 3.60GHzS11 |Z| Phase
1 23
1> 0.400GHz: 99.76Ohm
2> 2.200GHz: 98.28Ohm
3> 4.000GHz: 95.09Ohm
0.40 0.76 1.12 1.48 1.84 2.20 2.56 2.92 3.28 4.00F [GHz]
-20
-15
-10
-5
0
5
Gain
[dB]
0
45
90
135
Phase
[Deg]
Center 2.20GHz / Span 3.60GHzS12 Gain Phase
1 2 3
1> 0.400GHz: -3.513dB
2> 2.200GHz: -3.480dB
3> 4.000GHz: -3.437dB
Impedance
Return Loss
Impedance
GainImpedance
Gain
VSB measurements\VSB 16: 50R Series resistor 9/14/2014 3:33:31 PM
Measure:
Sw eep:
S11 S21 S12 S22
Frequency
Frequency:
Pow er:
400 > 4000 MHz 180 steps (20/)
-10 dBm
In series with the system impedance of 50 Ohm we measure (nearly) 100 Ohm in total. The circuit has
about 3.5dB attenuation.
MegiQ VNA0440e measurements on the VNA Sandbox www.megiq.com
Revision 2. ©copyright 2014 MegiQ BV. All rights reserved. 11
Filters
3rd order low pass filter
Center 2.20GHz / Span 3.60GHzS11 Z
0.40 0.76 1.12 1.48 1.84 2.20 2.56 2.92 3.28 4.00F [GHz]-60
-40
-20
0
RL
[dB]
Center 2.20GHz / Span 3.60GHzS11 RL
1
1> 1.500GHz: -43.60dB
0.40 0.76 1.12 1.48 1.84 2.20 2.56 2.92 3.28 4.00F [GHz]-50
-40
-30
-20
-10
0
10
Gain
[dB]
-180
-90
0
90
180
Phase
[Deg]
Center 2.20GHz / Span 3.60GHzS12 Gain Phase
1
2
1> 2.200GHz: -6.24dB
2> 4.000GHz: -34.22dB
Center 2.20GHz / Span 3.60GHzS22 Z
0.40 0.76 1.12 1.48 1.84 2.20 2.56 2.92 3.28 4.00F [GHz]-60
-40
-20
0
RL
[dB]
Center 2.20GHz / Span 3.60GHzS22 RL
0.40 0.76 1.12 1.48 1.84 2.20 2.56 2.92 3.28 4.00F [GHz]-50
-40
-30
-20
-10
0
10
Gain
[dB]
-2.0
-1.2
-0.4
0.4
1.2
2.0
Tg
[ns]
Center 2.20GHz / Span 3.60GHzS21 Gain Tg
1
2
1> 2.200GHz: -6.33dB
2> 4.000GHz: -33.50dB
Impedance
Return Loss
Gain
Impedance
Return Loss
Gain
VSB measurements\VSB 25: CLC LPF 9/14/2014 3:34:37 PM
Measure:
Sw eep:
S11 S21 S12 S22
Frequency
Frequency:
Pow er:
400 > 4000 MHz 180 steps (20/)
-10 dBm
3rd order high pass filter
Center 2.20GHz / Span 3.60GHzS11 Z
0.40 0.76 1.12 1.48 1.84 2.20 2.56 2.92 3.28 4.00F [GHz]-30
-20
-10
0
RL
[dB]
Center 2.20GHz / Span 3.60GHzS11 RL
1
2
1> 1.280GHz: -28.91dB
2> 2.000GHz: -9.36dB
Center 2.20GHz / Span 3.60GHzS22 Z
0.40 0.76 1.12 1.48 1.84 2.20 2.56 2.92 3.28 4.00F [GHz]-30
-20
-10
0
RL
[dB]
Center 2.20GHz / Span 3.60GHzS22 RL
0.40 0.76 1.12 1.48 1.84 2.20 2.56 2.92 3.28 4.00F [GHz]-50
-40
-30
-20
-10
0
10
Gain
[dB]
-180
-90
0
90
180
Phase
[Deg]
Center 2.20GHz / Span 3.60GHzS21 Gain Phase
1 21> 1.280GHz: -0.38dB
2> 2.000GHz: -0.85dB
0.40 0.76 1.12 1.48 1.84 2.20 2.56 2.92 3.28 4.00F [GHz]0.0
0.5
1.0
1.5
2.0
2.5
3.0
FL
[dB]
Center 2.20GHz / Span 3.60GHzS11 FL
1
2
1> 1.280GHz: 0.0056dB
2> 2.000GHz: 0.5344dB
Impedance
Return Loss
Impedance
Return Loss
GainForward Loss
VSB measurements\VSB 26: LCL HPF 9/14/2014 3:35:13 PM
Measure:
Sw eep:
S11 S21 S12 S22
Frequency
Frequency:
Pow er:
400 > 4000 MHz 180 steps (20/)
-10 dBm
MegiQ VNA0440e measurements on the VNA Sandbox www.megiq.com
Revision 2. ©copyright 2014 MegiQ BV. All rights reserved. 12
Wifi MLCC band pass filter
Center 2.200GHz / Span 3.600GHzS11 Z
12
1> 2.4000GHz: 39.61 + j8.04
2> 2.5000GHz: 37.78 + j6.40
0.40 0.76 1.12 1.48 1.84 2.20 2.56 2.92 3.28 4.00F [GHz]-30
-20
-10
0
RL
[dB]
Center 2.20GHz / Span 3.60GHzS11 RL
0.40 0.76 1.12 1.48 1.84 2.20 2.56 2.92 3.28 4.00F [GHz]-50
-40
-30
-20
-10
0
10
Gain
[dB]
-180
-90
0
90
180
Phase
[Deg]
Center 2.20GHz / Span 3.60GHzS12 Gain Phase
1 21> 2.400GHz: -1.66dB
2> 2.500GHz: -1.87dB
Center 2.20GHz / Span 3.60GHzS22 Z
0.40 0.76 1.12 1.48 1.84 2.20 2.56 2.92 3.28 4.00F [GHz]-30
-20
-10
0
RL
[dB]
Center 2.20GHz / Span 3.60GHzS22 RL
1
2
1> 2.400GHz: -19.72dB
2> 2.500GHz: -15.56dB
0.40 0.76 1.12 1.48 1.84 2.20 2.56 2.92 3.28 4.00F [GHz]-30
-25
-20
-15
-10
-5
0
Gain
[dB]
-0.6
-0.2
0.2
0.6
1.0
Tg
[ns]
Center 2.20GHz / Span 3.60GHzS21 Gain Tg
1 21> 2.400GHz: -1.626dB
2> 2.500GHz: -1.943dB
Impedance
Return Loss
Gain
Impedance
Return Loss
Gain
VSB measurements\VSB 42: MLCC BPF 9/14/2014 3:36:30 PM
Measure:
Sw eep:
S11 S21 S12 S22
Frequency
Frequency:
Pow er:
400 > 4000 MHz 180 steps (20/)
-10 dBm
This filter has a 0.3dB variation in Insertion Loss and a good Return Loss in the Wifi – Bluetooth –
Zigbee band from 2.4 GHz to 2.5 GHz. The fairly high Group Delay (Gain S21, green trace) may
distort signals and cause symbol errors in an application.
MegiQ VNA0440e measurements on the VNA Sandbox www.megiq.com
Revision 2. ©copyright 2014 MegiQ BV. All rights reserved. 13
Antennas The VNA Sandbox contains two ceramic antennas, one for GPS at 1.575GHz and one for Wifi at
2.5GHz. They are measured here in a 2-port configuration which also shows the coupling between
them. The coupling is of course not optimal since the antennas are made for different frequencies.
The antennas are not very well matched and tuned here. The VNA0440e has the unique possibility to
calculate matching circuits and plot the results after matching. The matching results are simulated in
real-time during measurements.
Center 2.20GHz / Span 3.60GHzS11 Z M-Z
1 1
1> 1.580GHz: 27.00 + j2.51
1> 1.580GHz: 50.00 + j0.01
2.26nH
1.86pF
Zi Zo
match at
1.58GHz
1.12 1.21 1.30 1.39 1.48 1.57 1.66 1.75 2.00F [GHz]-30
-20
-10
0
RL
[dB]
Center 1.55GHz / Span 0.90GHzS11 RL M-RL
1
1> 1.580GHz: -10.45dB
2.26nH
1.86pF
Zi Zo
match at
1.58GHz
0.40 0.76 1.12 1.48 1.84 2.20 2.56 2.92 3.28 4.00F [GHz]-50
-40
-30
-20
-10
0
10
Gain
[dB]
-180
-90
0
90
180
Phase
[Deg]
Center 2.20GHz / Span 3.60GHzS12 Gain Phase
1
1> 1.580GHz: -24.41dB
Center 2.20GHz / Span 3.60GHzS22 Z M-Z
1
1
1> 2.440GHz: 27.70 - j26.35
1> 2.440GHz: 50.00 + j0.01
3.34nH
1.17pF
Zi Zo
match at
2.44GHz
2.11 2.20 2.29 2.38 2.47 2.56 2.65 2.74 3.00F [GHz]-30
-20
-10
0
RL
[dB]
Center 2.55GHz / Span 0.90GHzS22 RL M-RL
1
2
1
2
1> 2.400GHz: -9.32dB
2> 2.500GHz: -5.25dB
1> 2.400GHz: -20.67dB
2> 2.500GHz: -16.83dB
3.34nH
1.17pF
Zi Zo
match at
2.44GHz
0.40 0.76 1.12 1.48 1.84 2.20 2.56 2.92 3.28 4.00F [GHz]-50
-40
-30
-20
-10
0
10
Gain
[dB]
-180
-90
0
90
180
Phase
[Deg]
Center 2.20GHz / Span 3.60GHzS21 Gain Phase
Impedance
Return Loss
Gain
Impedance
Return Loss
Gain
VSB measurements\VSB 44/45: Antennas 9/14/2014 3:37:38 PM
Measure:
Sw eep:
S11 S21 S12 S22
Frequency
Frequency:
Pow er:
400 > 4000 MHz 180 steps (20/)
-10 dBm
Notice that the GPS antenna on the left has a very narrow bandwidth. To visualize this in the Smith
chart we turned measure-point markers on to show how fast the impedance sweeps around the
resonance circle. The VNA0440e can of course also make a much narrower sweep at this frequency.
The Wifi antenna is matched to full Wifi band with a very good return loss. These matching results are
generally well replicated with real-life components in the circuit.
MegiQ VNA0440e measurements on the VNA Sandbox www.megiq.com
Revision 2. ©copyright 2014 MegiQ BV. All rights reserved. 14
Active 2-port circuits The built-in bias generator of the VNA0440e make it possible to measure active circuits like varactors,
PIN diodes and amplifiers in its purest form without biasing components. The bias generator is
Voltage and Current controllable and sweepable and with a range of +/-14V and 100mA it has ample
voltage and current to measure a wide range of devices.
The VNA0440e bias circuit has three configurations for each port:
• Open
• Bias On
• Return to Ground
The Return to Ground setting allows the Bias Current through a component to return to ground without
additional components.
Wideband amplifier
In this measurement the amplifier supply is generated by the bias generator (70mA current source).
There are no additional components on the chip.
Center 2.20GHz / Span 3.60GHzS11 Z
0.40 0.76 1.12 1.48 1.84 2.20 2.56 2.92 3.28 4.00F [GHz]-30
-20
-10
0
RL
[dB]
Center 2.20GHz / Span 3.60GHzS11 RL
0.40 0.76 1.12 1.48 1.84 2.20 2.56 2.92 3.28 4.00F [GHz]
-20
-10
0
10
20
30
Gain
[dB]
0
90
180
270
Phase
[Deg]
Center 2.20GHz / Span 3.60GHzS12 Gain Phase
1 2 3
1> 0.400GHz: -21.42dB
2> 2.200GHz: -21.11dB
3> 4.000GHz: -21.01dB
Center 2.20GHz / Span 3.60GHzS22 Z
0.40 0.76 1.12 1.48 1.84 2.20 2.56 2.92 3.28 4.00F [GHz]-30
-20
-10
0
RL
[dB]
Center 2.20GHz / Span 3.60GHzS22 RL
0.40 0.76 1.12 1.48 1.84 2.20 2.56 2.92 3.28 4.00F [GHz]
-20
-10
0
10
20
30
Gain
[dB]
0
90
180
270
Phase
[Deg]
Center 2.20GHz / Span 3.60GHzS21 Gain Phase
1 2 3
1> 0.400GHz: 18.76dB
2> 2.200GHz: 18.45dB
3> 4.000GHz: 18.52dB
Impedance
Return Loss
Gain
Impedance
Return Loss
Gain
VSB measurements\VSB 41: Amplifier w Bias 9/14/2014 3:42:22 PM
Measure:
Sw eep:
S11 S21 S12 S22
Frequency
Frequency:
Pow er:
400 > 4000 MHz 180 steps (20/)
-10 dBm
Bias voltage:
Bias Current:
10 V
70 mA
The amplifier has a steady gain of 18.5dB which varies by only 0.25 dB up to 4 GHz. The reverse gain
is about -21dB, which shows that the amplifier is stable. The return loss is also around a nice 15dB
over the frequency range.
MegiQ VNA0440e measurements on the VNA Sandbox www.megiq.com
Revision 2. ©copyright 2014 MegiQ BV. All rights reserved. 15
1dB Compression Point
We can combine a power sweep with frequency stepping to determine the 1dB compression point at
different frequencies.
Center -5dBm / Span 20dBmS11Z(VF=1000) Z(VF=2000) Z(VF=3000) Z(VF=4000)
Center -5dBm / Span 20dBmS11Z(VF=1000) Z(VF=2000) Z(VF=3000) Z(VF=4000)
-15 -13 -11 -9 -7 -5 -3 -1 1 5Power [dBm]-30
-20
-10
0
RL
[dB]
Center -5dBm / Span 20dBmS11 RL(VF=1000) RL(VF=2000) RL(VF=3000) RL(VF=4000)
-15 -13 -11 -9 -7 -5 -3 -1 1 5Power [dBm]
-25
-20
-15
-10
-5
0
Gain
[dB]
-45
0
45
90
Phase
[Deg]
Center -5dBm / Span 20dBmS12Phase(VF=1000) Gain(VF=2000) Phase(VF=2000) Gain(VF=3000) Phase(VF=3000) Gain(VF=4000)
Center -5dBm / Span 20dBmS22Z(VF=1000) Z(VF=2000) Z(VF=3000) Z(VF=4000)
Center -5dBm / Span 20dBmS22Z(VF=1000) Z(VF=2000) Z(VF=3000) Z(VF=4000)
-15 -13 -11 -9 -7 -5 -3 -1 1 5Power [dBm]-30
-20
-10
0
RL
[dB]
Center -5dBm / Span 20dBmS22 RL(VF=1000) RL(VF=2000) RL(VF=3000) RL(VF=4000)
-5 -4 -3 -2 -1 0 1 2 3 4 5[dBm]Power
15
16
17
18
19
20
Gain
[dB]
207
216
225
234
Phase
[Deg]
Center 0dBm / Span 10dBmS21Phase(VF=1000) Gain(VF=2000) Phase(VF=2000) Gain(VF=3000) Phase(VF=3000) Gain(VF=4000)
22 2
2
1> -15.0dBm: 18.685dB
2> -3.0dBm: 17.713dB
1> -15.0dBm: 18.469dB
2> -2.5dBm: 17.345dB
1> -15.0dBm: 18.342dB
2> -2.0dBm: 17.280dB
1> -15.0dBm: 18.631dB
2> -0.5dBm: 17.590dB
Cal Source Impedance Impedance
Return Loss
Gain
Cal Source Impedance Impedance
Return Loss
Gain
VSB measurements\VSB 41: Amplifier 1dB Comp 9/14/2014 4:07:01 PM
Measure:
Sw eep:
S11 S21 S12 S22
Frequency-Pow er
Frequency:
Pow er:
1000 > 4000 MHz 3 steps (1000/)
-15 > 5 dBm 80 steps (0.25/)
Bias voltage:
Bias Current:
10 V
70 mA
Bias ports: P1=X P2=V PG=X
We determine the level at which the gain decreases by 1dB by setting a marker at the low frequency
gain (outside the zoomed graph) and finding the point at which this gain is 1dB lower. The
compression point is measured at 1, 2, 3 and 4 GHz.
Notice that the decline in input return loss at 3GHz (RL S11, red trace) causes input power to be lost
and moves the compression point to a higher input power level (Gain S21, red trace).
We could combine this sweep with a stepping of the bias current (2-parameter sweep) to determine the
1dB compression points at different amplifier currents, but this would yield very busy graphs with
many traces.
MegiQ VNA0440e measurements on the VNA Sandbox www.megiq.com
Revision 2. ©copyright 2014 MegiQ BV. All rights reserved. 16
Tunable low pass filter
The Bias Voltage and Current can also be combined with the Frequency sweep to make parametric
measurements, like Frequency sweeps while stepping Bias Voltage, or Bias Voltage sweeps while
stepping Frequency.
This graph shows a Pi low pass filter with two varactor diodes, at several varactor voltages.
Center 2.20GHz / Span 3.60GHzS11 Z(BV=0) Z(BV=1) Z(BV=2) Z(BV=3)
0.40 0.76 1.12 1.48 1.84 2.20 2.56 2.92 3.28 4.00F [GHz]-30
-20
-10
0
RL
[dB]
Center 2.20GHz / Span 3.60GHzS11 RL(BV=0) RL(BV=1) RL(BV=2) RL(BV=3)
0.40 0.76 1.12 1.48 1.84 2.20 2.56 2.92 3.28 4.00F [GHz]-30
-25
-20
-15
-10
-5
0
Gain
[dB]
-45
0
45
90
Phase
[Deg]
Center 2.20GHz / Span 3.60GHzS12Gain(BV=0) Phase(BV=0) Gain(BV=1) Phase(BV=1) Gain(BV=2) Phase(BV=2) Gain(BV=3) Phase(BV=3)
Center 2.20GHz / Span 3.60GHzS22 Z(BV=0) Z(BV=1) Z(BV=2) Z(BV=3)
0.40 0.76 1.12 1.48 1.84 2.20 2.56 2.92 3.28 4.00F [GHz]-60
-40
-20
0
RL
[dB]
Center 2.20GHz / Span 3.60GHzS22 RL(BV=0) RL(BV=1) RL(BV=2) RL(BV=3)
0.40 0.76 1.12 1.48 1.84 2.20 2.56 2.92 3.28 4.00F [GHz]-50
-40
-30
-20
-10
0
10
Gain
[dB]
-180
-90
0
90
180
Phase
[Deg]
Center 2.20GHz / Span 3.60GHzS21Gain(BV=0) Phase(BV=0) Gain(BV=1) Phase(BV=1) Gain(BV=2) Phase(BV=2) Gain(BV=3) Phase(BV=3)
Impedance
Return Loss
Gain
Impedance
Return Loss
Gain
VSB measurements 2\VSB 35: Varicap LPF Bias-Freq 9/14/2014 3:53:03 PM
Measure:
Sw eep:
S11 S21 S12 S22
BiasVolt-Frequency
Frequency:
Pow er:
400 > 4000 MHz 180 steps (20/)
-10 dBm
Bias voltage:
Bias Current:
0 > 3 V 3 steps (1/)
10 mA
Bias ports: P1=G P2=V PG=X
Notice how the impedance in the Smith chart swirls around at different points with different voltages.
MegiQ VNA0440e measurements on the VNA Sandbox www.megiq.com
Revision 2. ©copyright 2014 MegiQ BV. All rights reserved. 17
PIN diode Voltage-Frequency sweep
We can make two different parametric sweeps with the bias voltage: Voltage-Frequency sweep and
Frequency-Voltage sweep.
This is a Voltage-Frequency sweep of a PIN diode: the VNA0440e sweeps through the frequency
range at 4 different bias voltage settings.
Center 2.20GHz / Span 3.60GHzS11 Z(BV=0.1) Z(BV=0.4) Z(BV=0.7) Z(BV=1)
0.40 0.76 1.12 1.48 1.84 2.20 2.56 2.92 3.28 4.00F [GHz]-30
-20
-10
0
RL
[dB]
Center 2.20GHz / Span 3.60GHzS11 RL(BV=0.1) RL(BV=0.4) RL(BV=0.7) RL(BV=1)
1
1
1
1
1> 0.400GHz: -0.12dB
1> 0.400GHz: -2.48dB
1> 0.400GHz: -7.60dB
1> 0.400GHz: -32.23dB
0.40 0.76 1.12 1.48 1.84 2.20 2.56 2.92 3.28 4.00F [GHz]-30
-25
-20
-15
-10
-5
0
Gain
[dB]
-45
0
45
90
Phase
[Deg]
Center 2.20GHz / Span 3.60GHzS12Gain(BV=0.1) Phase(BV=0.1) Gain(BV=0.4) Phase(BV=0.4) Gain(BV=0.7) Phase(BV=0.7) Gain(BV=1) Phase(BV=1)
1
1
1
1
1> 0.400GHz: -29.205dB
1> 0.400GHz: -11.918dB
1> 0.400GHz: -4.925dB
1> 0.400GHz: -0.219dB
Center 2.20GHz / Span 3.60GHzS22 Z(BV=0.1) Z(BV=0.4) Z(BV=0.7) Z(BV=1)
0.40 0.76 1.12 1.48 1.84 2.20 2.56 2.92 3.28 4.00F [GHz]-30
-20
-10
0
RL
[dB]
Center 2.20GHz / Span 3.60GHzS22 RL(BV=0.1) RL(BV=0.4) RL(BV=0.7) RL(BV=1)
0.40 0.76 1.12 1.48 1.84 2.20 2.56 2.92 3.28 4.00F [GHz]-50
-40
-30
-20
-10
0
10
Gain
[dB]
-180
-90
0
90
180
Phase
[Deg]
Center 2.20GHz / Span 3.60GHzS21Gain(BV=0.1) Phase(BV=0.1) Gain(BV=0.4) Phase(BV=0.4) Gain(BV=0.7) Phase(BV=0.7) Gain(BV=1) Phase(BV=1)
Impedance
Return Loss
Gain
Impedance
Return Loss
Gain
VSB measurements\VSB 36: PIN diode Bias-Freq 9/14/2014 3:58:41 PM
Measure:
Sw eep:
S11 S21 S12 S22
BiasVolt-Frequency
Frequency:
Pow er:
400 > 4000 MHz 180 steps (20/)
-10 dBm
Bias voltage:
Bias Current:
0.1 > 1 V 3 steps (0.3/)
2 mA
Bias ports: P1=G P2=V PG=X
At the highest voltage (red traces) the PIN is turned ON and it is a good bypass, connecting the 50
Ohm measuring source directly to the 50 Ohm termination impedance. When the voltage gets lower
(towards the purple traces) the PIN becomes a series resistor. The attenuation is highest at the lower
frequencies.
MegiQ VNA0440e measurements on the VNA Sandbox www.megiq.com
Revision 2. ©copyright 2014 MegiQ BV. All rights reserved. 18
PIN diode Frequency-Voltage sweep
To see the switching behaviour we sweep the bias voltage of the PIN diode at 4 different frequencies:
1, 2, 3 and 4GHz.
Center 0.55V / Span 0.90VS11Z(VF=1000) Z(VF=2000) Z(VF=3000) Z(VF=4000)
Center 0.55V / Span 0.90VS11Z(VF=1000) Z(VF=2000) Z(VF=3000) Z(VF=4000)
0.10 0.19 0.28 0.37 0.46 0.55 0.64 0.73 0.82 1.00Bias [V]-30
-20
-10
0
RL
[dB]
Center 0.55V / Span 0.90VS11 RL(VF=1000) RL(VF=2000) RL(VF=3000) RL(VF=4000)
0.10 0.19 0.28 0.37 0.46 0.55 0.64 0.73 0.82 1.00Bias [V]-30
-25
-20
-15
-10
-5
0
Gain
[dB]
-45
0
45
90
Phase
[Deg]
Center 0.55V / Span 0.90VS12Phase(VF=1000) Gain(VF=2000) Phase(VF=2000) Gain(VF=3000) Phase(VF=3000) Gain(VF=4000)
1
1
11
1> 0.100V: -22.922dB
1> 0.100V: -17.362dB
1> 0.100V: -13.834dB
1> 0.100V: -12.016dB
Center 0.55V / Span 0.90VS22Z(VF=1000) Z(VF=2000) Z(VF=3000) Z(VF=4000)
0.10 0.19 0.28 0.37 0.46 0.55 0.64 0.73 0.82 1.00Bias [V]-30
-25
-20
-15
-10
-5
0
Gain
[dB]
-45
0
45
90
Phase
[Deg]
Center 0.55V / Span 0.90VS21Phase(VF=1000) Gain(VF=2000) Phase(VF=2000) Gain(VF=3000) Phase(VF=3000) Gain(VF=4000)
Center 0.55V / Span 0.90VS12Z(VF=1000) Z(VF=2000) Z(VF=3000) Z(VF=4000)
-30-30-25
-25
-20
-20
-15
-15
-10
-10
-5
-5
Gain
dB
-180
-165
-150
-135
-120-105 -90 -75
-60
-45
-30
-15
0
15
30
45
607590105
120
135
150
165Phase
Deg
S21 Gain(VF=1000) Gain(VF=2000) Gain(VF=3000) Gain(VF=4000)
Cal Source Impedance Impedance
Return Loss
Gain
Impedance
Gain
Cal Sink
Gain
VSB measurements\VSB 36: PIN diode Freq-Bias 9/14/2014 4:02:41 PM
Measure:
Sw eep:
S11 S21 S12 S22
Frequency - BiasVolt
Frequency:
Pow er:
1000 > 4000 MHz 3 steps (1000/)
-10 dBm
Bias voltage:
Bias Current:
0.1 > 1 V 90 steps (0.01/)
10 mA
Bias ports: P1=G P2=V PG=X
We can see how the impedance and attenuation develop over bias voltage, at each of the frequencies.