1EZ70
Multi-port calibration by using
a two port calibration unit
Application Note
Products:
®
ı
R&S ZVA
ı
R&S ZNB
ı
R&S ZVT
®
®
Performing a multi-port calibration of a vector
network analyzer (VNA) is straight forward by using
either a calibration unit with the corresponding
numbers of ports or single calibration standards.
V.Herrmann / T. Bednorz
1.2013 - 1EZ70
Application Note
This paper shows how to perform a n-port multi-port
calibration by using calibration unit with a lower
number of ports than available of the vector network
analyzer.
Table of Contents
Table of Contents
1 Introduction......................................................................................... 3
2 Multi-port calibration steps................................................................ 4
2.1
Using the R&S®ZVA with multi-port calibration.......................................................4
2.2
Using the R&S®ZNB with multiport calibration........................................................6
3 Ordering Information .......................................................................... 8
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Introduction
Using the R&S®ZVA with multi-port calibration
1 Introduction
The system error correction (SEC) calibration is a fundamental step in using a vector
network analyzer (VNA). In particular for multi-port measurement with a higher number
of ports, it is highly recommended to use a calibration unit instead of single calibration
standards to reduce the time and to avoid manually operating mistakes. The purpose
of this paper is to illustrate how to perform a multi-port calibration by using a calibration
unit with less numbers of ports than VNA test ports.
The pictures below show fundamental examples of multi-port calibration applications.
Figure 1-1 shows a four-port VNA and Figure 1-2 shows a two-port VNA connected to
a 16 port switch matrix. Both VNAs have to be calibrated by e.g. a two port calibration
unit.
Fig. 1-1: Four port R&S®ZVA
Fig. 1-2: Two port R&S®ZNB + switch matrix
To perform a full n-port calibration by a calibration unit with a lower number of ports, it
is obvious that the calibration unit has to get connected to each physical port of the
VNA. The vector network analyzer provides an optimized connection proposal to
reduce the number of THRU connections. Hence, the required number of
reconnections will also be reduced. Instead of measuring the THRU connection
between each individual port, the error correction data of the missing transmissions are
calculated based on the available system error correction data.
In case that the recommended connection procedure is not suitable for the used
application, of course it is possible to change the connection sequence manually. The
ZVA also allows adding and deleting of additional assignments whereas at the ZNB,
the proposed number of connections cannot be changed.
The total number of connections is related on the used ports of the vector network
analyzer, the ports of the calibration unit and the selected calibration type.
For a segmented sweep, the n-port calibration procedure includes each segment. It is
not necessary to calibrate the segments individually.
The number of ports which can be calibrated e.g. by a two port calibration unit is only
limited by the physical ports of the vector network analyzer or the connected switch
matrix. The support of the switch matrix is only available on the R&SZNB and requires
firmware version up from 1.7.
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Multi-port calibration steps
Using the R&S®ZVA with multi-port calibration
2 Multi-port calibration steps
The calibration process is described by the following steps:
Set up of stimulus data and sweep settings
Open the Calibration menu
Select the used ports and calibration type
Set the connection sequence
Perform the calibration including reconnection of the calibration unit
The following sections show a step-by-step instruction of the R&S®ZVA and
R&S®ZNB. In the examples, a four-port vector network analyzer has to be calibrated
by a two-port calibration unit. In case of a higher number of ports, the number of
connections will be increased but the procedure works similar.
2.1 Using the R&S®ZVA with multi-port calibration
Set up of stimulus data and sweep settings
Channel > Stimulus > Start
Frequency…
Channel > Stimulus > Stop Frequency…
Channel > Stimulus > Power…
Channel > Sweep > Number of Points…
Instead of number of points, it is possible
to use
Channel > Sweep > Frequency Step
Size…
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Multi-port calibration steps
Using the R&S®ZVA with multi-port calibration
Open the calibration menu
Channel > Calibration > Start Cal >
Calibration Unit…
The ZVA performs an auto detection to
detect the assignment of VNA ports to the
calibration unit. The input power into the
calibration unit has to be at least -40 dBm
to ensure a correct result of the auto
detection algorithm. If the result is
incorrect, the connections should be
verified and the ports have to be assigned
manually.
Select the used ports and calibration type
Press the Modify Calibration Settings…
button
The affected ports have to be selected,
e.g. port 1 and 2.
Select the Calibration Type
Set the connection sequence
Press the Default button
The vector network analyzer creates an
optimized connection sequence to ensure
the minimum number of connections to
perform a precise calibration.
To set up a connection sequence
manually, those assignments can be
created by the Add button and deleted by
the Delete Button.
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Multi-port calibration steps
Using the R&S®ZNB with multi-port calibration
Perform the calibration including reconnection of the calibration unit
Press the Start button
The table shows the current status of
connection sequence.
If a calibration step is finished, the
software displays a green checkmark. The
next connection has to be set up and the
Start button has to be pressed again.
2.2 Using the R&S®ZNB with multi-port calibration
Set up of stimulus sweep settings
Channel > Stimulus > Start
Frequency…
Channel > Stimulus > Stop
Frequency…
Channel > Stimulus > Power
Bandwidth Average > Power…
Channel > Sweep > Number of
Points…
Open the calibration menu
Channel > Start Cal >
Start Cal…(Cal Unit)
The ZNB performs an auto
detection to get the assignment of
VNA ports to the calibration
unit.
If the result is incorrect, the
connections should be verified and
the ports have to be assigned
manually. Like with the ZVA, the
input power into the calibration has
to be min. -40 dBm to ensure a
correct result of the auto detection
algorithm.
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Multi-port calibration steps
Using the R&S®ZNB with multi-port calibration
Select the used ports and the calibration type
Select the used ports by
using the ZNB touchscreen and
choose the calibration type.
Set the connection sequence
The ZNB creates an optimized
connection sequence to ensure the
minimum number of connection to
perform a precise calibration.
The order can be changed
manually but in difference to the
ZVA, the number of steps is fixed
and cannot be increased.
Perform the calibration including reconnection of the calibration unit
The picture shows which VNA
port has to get connected to the
calibration unit.
Press the Start Cal Sweep
button
After the next connection, the
Start Cal Sweep button starts the
next calibration step.
.
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Ordering Information
Using the R&S®ZNB with multi-port calibration
3 Ordering Information
Designation
Type
Order No.
300 kHz - 8 GHz, 4 Ports
R&S®ZVA8
1145.1110.10
10 MHz - 24 GHz, 4 Ports
R&S®ZVA24
1145.1110.26
10 MHz - 40 GHz, 4 Ports
R&S®ZVA40
1145.1110.42
10 MHz - 50 GHz, 4 Ports
R&S®ZVA50
1145.1110.52
10 MHz - 67 GHz, 4 Ports
R&S®ZVA67
1312.7002.04
9 kHz - 4.5 GHz, 4 Ports
R&S®ZNB4
1311.6010.24
9 kHz - 8.5 GHz, 4 Ports
R&S®ZNB8
1311.6010.44
300 kHz - 8 GHz, up to 8 Ports
R&S®ZVT8
1300.0000.08
10 MHz - 20 GHz, up to 6 Ports
R&S®ZVT20
1300.0000.20
300 kHz to 8 GHz, Four Ports, 3.5 mm (f)
R&S®ZV-Z51
1164.0515.30
300 kHz to 8 GHz, Four Ports, N (f)
R&S®ZV-Z51
1164.0515.70
10 MHz to 24 GHz, Four Ports, 3.5 mm (f)
R&S®ZV-Z52
1164.0521.30
300 kHz to 18 GHz, Four Ports, N (f)
R&S®ZV-Z53
1164.0473.72
300 kHz to 24 GHz, Two Ports, 3.5 mm (f)
R&S®ZV-Z53
1164.0473.32
10 MHz - 40 GHz, 2 Ports, 2.92mm (f)
R&S®ZV-Z54
1164.0467.92
300 kHz - 8 GHz, 8 Ports, N (f)
R&S®ZV-Z58
1164.0638.78
10 MHz - 20 GHz, 6 Ports, 3.5 mm (f)
R&S®ZV-Z59
1164.0450.36
50 MHz - 24 GHz, 2 to 5 Ports, 2.92 mm (f)
R&S®ZV-Z81
5200.6790.05
50 MHz - 24 GHz, 2 to 9 Ports, 2.92 mm (f)
R&S®ZV-Z81
5200.6790.09
50 MHz - 24 GHz, 2 to 16 Ports, N (f)
R&S®ZV-Z81
5200.6790.66
50 MHz - 24 GHz, 4 to 10 Ports, 2.92 mm (f)
R&S®ZV-Z82
5200.6860.10
Vector Network Analyzers
Calibration Units:
Switch Matrix
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About Rohde & Schwarz
Regional contact
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