Page 1
Keysight 86205A
Directional Bridge
Operating and
Service Manual
Page 2
Notices
CAUTION
WARNING
Copyright Notice
© Keysight Technologies 1992 - 2019
No part of this manual may be reproduced in
any form or by any means (including electronic
storage and retrieval or translation into a foreign language) without prior agreement and
written consent from Keysight Technologies as
governed by United States and international
copyright laws.
Manual Part Number
86205-90001
Edition
Edition 2, March 12, 2019
Printed in:
Printed in Malaysia
Published by:
Keysight Technologies
Bayan Lepas Free Industrial Zone,
11900 Penang, Malaysia
Technology Licenses
The hard ware and/or software described in
this document are furnished under a license
and may be used or copied only in accordance
with the terms of such license.
Declaration of Conformity
Declarations of Conformity for this product
and for other Keysight products may be downloaded from the Web. Go to http://www.key-
sight.com/go/conformity. You can then search
by product number to find the latest Declaration of Conformity.
U.S. Government Rights
The Software is “commercial computer software,” as defined by Federal Acquisition Regulation (“FAR”) 2.101. Pursuant to FAR 12.212
and 27.405-3 and Department of Defense FAR
Supplement (“DFARS”) 227.7202, the U.S.
government acquires commercial computer
software under the same terms by which the
software is customarily provided to the public.
Accordingly, Keysight provides the Software to
U.S. government customers under its standard
commercial license, which is embodied in its
End User License Agreement (EULA), a copy of
which can be found at http://www.key-
sight.com/find/sweula. The license set forth in
the EULA represents the exclusive authority by
which the U.S. government may use, modify,
distribute, or disclose the Software. The EULA
and the license set forth therein, does not
require or permit, among other things, that
Keysight: (1) Furnish technical information
related to commercial computer software or
commercial computer software documentation that is not customarily provided to the
public; or (2) Relinquish to, or otherwise provide, the government rights in excess of these
rights customarily provided to the public to
use, modify, reproduce, release, perform, d isplay, or disclose commercial computer software or commercial computer software
documentation. No additional government
requirements beyond those set forth in the
EULA shall apply, except to the extent that
those terms, rights, or licenses are explicitly
required from all providers of commercial computer software pursuant to the FAR and the
DFARS and are set forth specifically in writing
elsewhere in the EULA. Keysight shall be
under no obligation to update, revise or otherwise modify the Software. With respect to any
technical data as defined by FAR 2.101, pursuant to FAR 12.211 and 27.404.2 and DFARS
227.7102, the U.S. government acquires no
greater than Limited Rights as defined in FAR
27.401 or DFAR 227.7103-5 (c), as applicable
in any technical data.
Warranty
THE MATERIAL CONTAINED IN THIS DOCUMENT IS PROVIDED “AS IS,” AND IS SUBJECT
TO BEING CHANGED, WITHOUT NOTICE, IN
FUTURE EDITIONS. FURTHER, TO THE MAXIMUM EXTENT PERMITTED BY APPLICABLE
LAW, KEYSIGHT DISCLAIMS ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, WITH
REGARD TO THIS MANUAL AND ANY INFORMATION CONTAINED HEREIN, INCLUDING
BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
FOR A PARTICULAR PURPOSE. KEYSIGHT
SHALL NOT BE LIABLE FOR ERRORS OR FOR
INCIDENTAL OR CONSEQUENTIAL DAMAGES
IN CONNECTION WITH THE FURNISHING,
USE, OR PERFORMANCE OF THIS DOCUMENT OR OF ANY INFORMATION CONTAINED
HEREIN. SHOULD KEYSIGHT AND THE USER
HAVE A SEPARATE WRITTEN AGREEMENT
WITH WARRANTY TERMS COVERING THE
MATERIAL IN THIS DOCUMENT THAT CONFLICT WITH THESE TERMS, THE WARRANTY
TERMS IN THE SEPARATE AGREEMENT
SHALL CONTROL.
Safety Information
A CAUTION notice denotes a hazard. It calls
attention to an operating procedure, practice,
or the like that, if not correctly performed or
adhered to, could result in damage to the
product or loss of important data. Do not proceed beyond a CAUTION notice until the indicated conditions are fully understood and met.
A WARNING notice denotes a hazard. It calls
attention to an operating procedure, practice,
or the like that, if not correctly performed or
adhered to, could result in personal injury or
death. Do not proceed beyond a WARNING
notice until the indicated conditions are fully
understood and met.
2 Keysight 86205A Operating and Service Manual
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Waste Electrical and Electronic Equipment (WEEE) Directive
This instrument complies with the WEEE Directive marking requirement. This affixed product label
indicates that you must not discard this electrical or electronic product in domestic household
waste.
Product category:
With reference to the equipment types in the WEEE directive Annex 1, this instrument is classified
as a “Monitoring and Control Instrument” product.
The affixed product label is as shown below.
Do not dispose in domestic household waste.
To return this unwanted instrument, contact your nearest Keysight Service Center, or visit http://
about.keysight.com/en/companyinfo/environment/takeback.shtml for more information.
Sales and Technical Support
To contact Keysight for sales and technical support, refer to the support links on the following
Keysight websites:
– www.keysight.com/find/mta
(product-specific information and support, software and documentation updates)
– www.keysight.com/find/assist
(worldwide contact information for repair and service)
Keysight 86205A Operating and Service Manual 3
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4 Keysight 86205A Operating and Service Manual
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Table of Contents
Waste Electrical and Electronic Equipment (WEEE) Directive . . . . . . . . . . . . . . . . . . . . 3
Product category: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Sales and Technical Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
List of Figures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
List of Tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
1 General Information
Manual Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Product description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Instruments covered by this manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Initial Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
2Operation
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Bridge Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Bridge Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Operating Precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Measurement Configurations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Remote reflection measurement configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Vector impedance measurement configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
External power leveling configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Reflection measurement configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
3Performance Tests
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Performance test record . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Function Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Recommended equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
In case of failure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Return Loss Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Recommended equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
In case of failure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
Directivity Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
Recommended equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
In case of failure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
4 Maintenance
Mating Connectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
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List of Figures
Figure 2-1 86205A bridge ports and measurement paths . . . . . . . . . . . . . . . . . . 17
Figure 2-2 Location of threaded mounting holes . . . . . . . . . . . . . . . . . . . . . . . . . 18
Figure 2-3 Remote directivity measurement setup . . . . . . . . . . . . . . . . . . . . . . . . 20
Figure 2-4 Vector impedance measurement setup . . . . . . . . . . . . . . . . . . . . . . . . 21
Figure 2-5 External power leveling configuration . . . . . . . . . . . . . . . . . . . . . . . . . 22
Figure 2-6 Reflection measurement setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Figure 3-1 Equipment setup for a thru measurement calibration . . . . . . . . . . . . 27
Figure 3-2 Equipment setup for insertion loss measurement . . . . . . . . . . . . . . . . 28
Figure 3-3 Equipment setup for coupling loss measurement . . . . . . . . . . . . . . . . 29
Figure 3-4 Equipment setup for a 522 1-port measurement calibration . . . . . . . 31
Figure 3-5 Equipment setup for return loss measurement on port 1 . . . . . . . . . . 32
Figure 3-6 Equipment setup for return loss measurement on port 3 . . . . . . . . . . 33
Figure 3-7 Equipment setup for return loss measurement on port 2 . . . . . . . . . . 33
Figure 3-8 Equipment setup for S22 1-port measurement calibration . . . . . . . . 36
Figure 3-9 86205A test record (1 of 3) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
Figure 3-10 86205A test record (2 of 3) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
Figure 3-11 86205A test record (3 of 3) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
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List of Tables
Table 2-1 Port orientation with corresponding application . . . . . . . . . . . . . . . . . 17
Table 3-1 Recommended equipment for function test . . . . . . . . . . . . . . . . . . . . 27
Table 3-2 Recommended equipment for return loss test . . . . . . . . . . . . . . . . . . 30
Table 3-3 Recommended equipment for directivity test . . . . . . . . . . . . . . . . . . . 35
Table 4-1 Environmental requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
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10 Keysight 86205A Operating and Service Manual
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Keysight 86205A Directional Bridge
Operating and Service Manual
1 General Information
Manual Overview 12
Initial Inspection 13
This manual contains information for operating, testing, and servicing 86205A bridge.
11
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1 General Information
Manual Overview
Product description
86205A is a high performance 50W directional bridge designed for high quality reflection
measurements and external source leveling applications over an RF frequency range of 300 kHz to
6 GHz. The bridge achieves a low through loss of 1.5 dB and a high coupling factor of 16 dB. These
characteristics make it useful in applications requiring directional couplers, such as power
monitoring and closed-loop leveling applications.
Instruments covered by this manual
Each bridge has a unique serial number. The contents of this manual apply directly to bridges with
serial number 3140A00101 and above.
12 Keysight 86205A Operating and Service Manual
Page 13
Initial Inspection
1 Check the shipping container and packaging material for damage.
2 Check the shipment for completeness.
3 Check the connectors and bridge body for mechanical damage.
4 Check the bridge electrically.
Refer to the Chapter 3, "Performance Tests" for procedures that check the bridge electrically.
If any of the following conditions exist, notify your nearest Keysight office:
– incomplete shipment
– mechanical damage or defect
–failed electrical test
If you find damage or signs of stress to the shipping container or the cushioning material, keep
them for the carrier's inspection. Keysight does not wait for a claim settlement before arranging for
repair or replacement.
General Information 1
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1 General Information
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2 Operation
Overview 16
Bridge Operation 17
Bridge Features 18
Operating Precautions 19
Measurement Configurations 20
Operation 2
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2Operation
Overview
This chapter includes the following information on Keysight 86205A directional bridge:
– bridge operation
– bridge features
– operating precautions
– measurement configurations
16 Keysight 86205A Operating and Service Manual
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Bridge Operation
Table 2-1 and Figure 2-1 illustrate the bridge operation. The table shows the port orientation in a
reflection measurement and in a power monitoring or leveling configuration. The figure identifies
the paths and ports of the bridge and shows the electrical characteristics of each path.
Table 2-1 Port orientation with corresponding application
Operation 2
Part number
Reflection measurement Power monitoring/leveling
1 Test port Input
2 Input port Output
3 Coupled Coupled level
Application
Figure 2-1 86205A bridge ports and measurement paths
Keysight 86205A Operating and Service Manual 17
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2Operation
Bridge Features
– Frequency range from 300kHz to 6 GHz
– High directivity
– Insertion loss of 1.5 dB (nominal)
– Coupled arm flatness of ±0.2 dB from nominal
86205A operates over an RF frequency range of 300 kHz to 6 GHz and has excellent directivity for
high quality reflection measurements. Additionally, the bridge has a very low insertion loss of
1.5 dB which means more power to the device under test; this is especially important in the
measurement of high power solid state amplifiers and TWTs. The bridge also features a ±0.2 dB
flatness from the nominal 16 dB coupled arm. This capability is valuable in external leveling
applications where a power meter or diode detector is used to level the power remotely from the
source. Power variations are then minimized, which is important when measuring input-sensitive
devices.
DC bias may be applied to a DUT through the main arm of the bridge. (DO NOT apply bias to the
coupled port of the bridge.)
Threaded mounting holes (3.5 mm x 0.5 mm) are located under pre-punched holes in the model
number label, as shown in Figure 2-2. Since the bridge package is brass, appropriate caution must
be taken to avoid damaging the threaded holes.
Figure 2-2 Location of threaded mounting holes
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Operating Precautions
CAUTION
– Read and observe all cautions.
– Tighten the bridge connectors with fingers only.
– If you must use a wrench, use a torque wrench set at 9.2 cm-kg (12 lb-in).
Electrostatic discharge (ESD) can damage the highly sensitive microcircuits in this device; an ESD
as low as 1000V can destroy your bridge.
ESD damage occurs most often as you connect or disconnect a device. Use the bridge at a
static-safe workstation and wear a grounding strap. Never touch the input connector center
contacts, or the contact pins of a connecting cable.
Do not apply more than +25 dBm RF CW power, or more than 1 amp DC or 0 VDC to port 3 or
30 VDC to port 1 or 2 of the bridge. Higher current/power/voltage can electrically damage the
bridge.
Before you connect a cable to the bridge, always discharge the cable's center conductor static
electricity to instrument-ground.
Do not drop the bridge or subject it to mechanical shock.
Operation 2
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2Operation
NOTE
KEYSIGHT 8711A
NETWORK ANAL YZER
KEYSIGHT
86200A SCALAR
KEYSIGHT 86205A
DIRECTIONAL BRIDGE
Measurement Configurations
This section shows 86205A directional bridge in the following configurations:
– remote reflection measurement using 8711 network analyzer
– vector impedance measurement using two bridges and 8753 network analyzer
– external power leveling with or without a controller
– reflection measurement using a spectrum analyzer and tracking generator
Remote reflection measurement configuration
You can use remote sensing in applications where your DUT is not easily accessible. For example:
when measuring the reflection coefficient of an antenna that is located on a tower.
To set up the measurement
1 Connect the equipment as shown in Figure 2-3.
The cable length from the analyzer source to the bridge does not affect directivity, but may affect
source match. However, you may put an attenuator between the cable and bridge to improve
source match.
Connect the DUT either directly to the bridge or as close as possible.
Figure 2-3 Remote directivity measurement setup
2 Set the parameters on the analyzer to measure with an external detector by pressing:
CHAN 1, Det Options Broadband External Y/R*
3 With nothing connected to the bridge, make a normalization of the measurement setup by
pressing:
CAL, Normalize
4 Connect the DUT to the bridge and adjust the scale/division under the DISPLAY key.
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Vector impedance measurement configuration
NOTE
KEYSIGHT 8753C
NETWORK ANALYZER
KEYSIGHT 86205A
KEYSIGHT 86205A
DIRECTIONAL BRIDGE
This configuration provides a low-cost custom test system when full 2-port measurements are not
needed.
To set up the measurement
1 Connect the equipment as shown in Figure 2-4.
You may connect the analyzer input signal to either the A or B input port. Use an A/R or B/R ratio
measurement to improve the source match.
Operation 2
Keysight 86205A Operating and Service Manual 21
Figure 2-4 Vector impedance measurement setup
2 Choose the following parameters on the analyzer:
PRESET
MEAS, A/R (or B/R if you connected the analyzer input signal to the B input port)
MENU, POWER then enter the power value and press x1
NUMBER OF POINTS then enter the desired number
START then enter the start frequency and press x1
STOP then enter the stop frequency and press x1
3 Make a measurement calibration by pressing one of the following key sequences:
CAL
Cal Kit, N 50W
Return, Calibrate menu
RESPONSE connect either an open or short calibration device to the reference plane and press
the corresponding OPEN (F) or SHORT (F) key.
Page 22
2Operation
KEYSIGHT 86205A
DIRECTIONAL BRIDGE
KEYSIGHT 8360A
SYNTHESIZED SWEEPER
KEYSIGHT 438A
POWER METER
4 Connect the DUT to the reference plane and adjust the scale/division under the SCALE REF key.
External power leveling configuration
The measurement configuration shown in Figure 2-5 provides precision power levels to a remote
DUT. With a power meter and bridge, the source power can be monitored and automatically
adjusted.
8753 and 8625 sources can alternatively be used in this automated measurement configuration.
By substituting a frequency counter for the power meter, this configuration can be used for signal
monitoring.
To set up the measurement
or
CAL, Calibrate Menu
(for A/R) S11 1-PORT
(for B/R) S22 1-PORT
Connect an open, short, and load calibration device to the reference plane while pressing the
corresponding key for measurement.
1 Connect the equipment as shown in Figure 2-5.
Figure 2-5 External power leveling configuration
2 Zero and calibrate the power meter/sensor.
3 Enter the appropriate power sensor calibration factors into the power meter. (Can only be done
with 438A or 437B.)
refer to its operating manual.
4 Enable the power meter/ sensor cal factor array. For operating information on the power meter
5 Connect the power sensor to the bridge as shown in Figure 2-5.
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Operation 2
NOTE
6 Set up the synthesizer parameters by pressing:
PRESET
START then enter the desired start frequency
STOP then enter the desired stop frequency
7 Set up the user flatness correction by pressing:
MENU, Fltness Menu
Delete Menu, Delete All
PRIOR
Auto Fill Start and entered the desired start frequency value
Auto Fill Stop and entered the desired stop frequency value
Auto Fill Incr and entered the desired increment frequency value
8 Set the power meter under synthesizer control to perform the sequence of steps necessary to
generate the correction information at each frequency point by pressing:
Mtr Meas Menu, Measure Corr All
9 When a message is displayed, indicating the operation is complete, apply the flatness
correction array to your measurement setup by pressing:
FLTNESS ON/OFF (the amber LED should be on)
The power produced at the point where the power meter/sensor was disconnected is now
calibrated at the frequencies and power level specified above.
10 On 8360, press:
ALC, Leveling Point ExtDet
11 Set the coupling factor by pressing:
Coupling Factor, -14.5, dB(m)
The 16 dB coupling factor is partially compensated by the through loss (1.5 dB) to give a 14.5 dB
effective coupling factor (relative to the bridge output port).
The bridge coupling flatness has as good as 0.1 dB/GHz power level roll-off with <±0.2 dB error.
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2Operation
KEYSIGHT 86205A
DIRECTIONAL BRIDGE
KEYSIGHT 8590A
SPECTRUM
ANALYZER OPTION 10
Reflection measurement configuration
To set up the measurement
1 Connect the equipment as shown in Figure 2-6.
Figure 2-6 Reflection measurement setup
2 On the tracking generator, press:
AUX CTRL
TRACK GEN, SRC PWR ON
3 Set the desired center frequency and span to view the DUT.
4 Replace the DUT with a short circuit.
5 Normalize the trace by pressing:
TRACE
TRACE B, CLEAR WRITE B
BLANK B, MORE 1 OF 3, NORMALIZE ON
6 Measure the DUT by connecting it to port 1 of the bridge.Terminate the second port of a
two-port DUT.
7 Press MKR and position the marker with the front panel knob to measure the return loss at the
frequency of interest.
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3 Performance Tests
Introduction 26
Function Test 27
Return Loss Test 30
Directivity Test 35
Performance Tests 3
Keysight 86205A Operating and Service Manual 25
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3 Performance Tests
Introduction
Use the procedures in this chapter to test the bridge's electrical performance. None of the tests
require you to access the interior of the bridge. The procedures, and an explanation of what they
check, are listed below.
– The functional test checks the bridge's typical operation.
– The return loss test verifies that the bridge operates within the return loss specification.
– The directivity test verifies that the bridge operates within the directivity specification.
Performance test record
Record the results of the performance tests on the test record that is located at the end of this
chapter.
Tables are also provided for recording the results of the functional test and connector pin depth
measurements.
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Function Test
KEYSIGHT 8753C
NETWORK
ANALYZER
The functional test confirms your bridge is operating correctly. The procedure checks the nominal
insertion loss and coupling of the bridge.
Recommended equipment
Table 3-1 Recommended equipment for function test
1 Connect the equipment as shown in Figure 3-1.
Performance Tests 3
Equipment Recommended model
Network analyzer 8753C (or 8753A with 85046A)
S-parameter test set 85046A or 85047A
50W type-N (m) load 909F option 012
Type-N cable part number 8120-4781
Adapters 7 mm to type-N (f) 11524A
Figure 3-1 Equipment setup for a thru measurement calibration
2 To perform a thru measurement calibration, press the following keys on 8753.
PRESET
MEAS, S21
CAL, CALIBRATE MENU
RESPONSE, THRU, DONE:RESPONSE
3 Connect the equipment as shown in Figure 3-2.
Keysight 86205A Operating and Service Manual 27
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3 Performance Tests
KEYSIGHT 8753C
NETWORK
ANALYZER
KEYSIGHT 86205A
DIRECTIONAL
BRIDGE
Figure 3-2 Equipment setup for insertion loss measurement
4 To measure the insertion loss, press the following keys.
SCALE, 1, x1
MKR FCTN, MARKER SEARCH, MAX
The insertion loss shown on the display should be between 0 and 3 dB. Write the maximum
insertion loss on the test record located at the end of this chapter.
5 Press MIN to find the minimum value and record it also.
6 Connect the equipment as shown in Figure 3-3.
28 Keysight 86205A Operating and Service Manual
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Performance Tests 3
KEYSIGHT 8753C
NETWORK
ANALYZER
KEYSIGHT 86025A
DIRECTIONAL
BRIDGE
Figure 3-3 Equipment setup for coupling loss measurement
7 To measure the coupling loss, press the following keys.
SCALE, 5, x1
MKR FCTN, MARKER SEARCH, MAX
The value should be between -14 dB and -18 dB. Write the maximum coupling loss on the test
record located at the end of this chapter.
In case of failure
Check connectors for damage. Clean and gage connectors.
Verify that the calibration kit devices are within their tolerances. Check adapters and cables to
make sure that they are not broken.
If the bridge appears to be bad, it must be replaced. It can only be repaired at the factory.
Keysight 86205A Operating and Service Manual 29
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3 Performance Tests
NOTE
Return Loss Test
Recommended equipment
Tab le 3-2 Recommended equipment for return loss test
Equipment Recommended model
Network analyzer 8753C (or 8753A with 85046A)
S-parameter test set 85046A or 85047A
50W type-N calibration kit 85032B
50W type-N (m) load 909F option 012
Type-N cable part number 8120-4781
Adapters 7 mm to type-N (m) 11524A (p/o 85032B)
Procedure
1 Set the IF bandwidth to 100 Hz and select S22 as the measurement parameter, by pressing the
following keys on 8753:
PRESET
MEAS, S22
AVG, IF BW, 100, x1
2 Set the stop frequency to 2 GHz and select a log frequency sweep, by pressing:
STOP, 2, G/n
MENU, TRIGGER MENU, SINGLE
MENU, SWEEP TYPE MENU, LOG FREQ
3 Set the power to 20 dBm, by pressing:
MENU
POWER, 20, x1
4 Perform a one-port calibration on port 2, by pressing:
CAL
CAL KIT, N 50 ohm
RETURN, CALIBRATE MENU, S22 1-PORT
5 When prompted, connect the standards as shown in Figure 3-4.
When measuring the open and short devices, select OPEN (m) and SHORT (m) on the analyzer.
The selection must correspond to the test port, not the device being measured.
30 Keysight 86205A Operating and Service Manual
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Performance Tests 3
KEYSIGHT 8753C
NETWORK
ANALYZER
NOTE
Figure 3-4 Equipment setup for a 522 1-port measurement calibration
6 Save the calibration in a register by pressing:
SAVE, REG 1
7 Set a linear frequency sweep from 2 to 3 GHz, by pressing:
CH2
MEAS, S22
MENU, COUPLED CH OFF
SWEEP TYPE MENU LIN FREQ
START, 2, G/n
STOP, 3, G/n
8 Repeat steps 4 and 5 to perform a one-port calibration on port 2.
9 Save the calibration in a register by pressing:
SAVE, REG 2
10 Connect the equipment as shown in Figure 3-5 to measure the return loss.
Do not use a female load with a type-N adapter, since an adapter has poor return loss and may
affect the measurement.
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3 Performance Tests
KEYSIGHT 8753C
NETWORK
ANALYZER
KEYSIGHT 86025A
DIRECTIONAL
BRIDGE
Figure 3-5 Equipment setup for return loss measurement on port 1
11 Trigger a new sweep, by pressing:
CHI
MENU, MEASURE RESTART
12 Find the worst-case return loss from 300 kHz to 2 GHz, by pressing:
MKR FCTN
MARKER SEARCH, MAX
Write the value on the test record located at the end of this chapter.
13 Trigger a new sweep, by pressing:
CH2
MENU, MEASURE RESTART
14 Find the worst-case return loss from 2 to 3 GHz, by pressing:
MKR FCTN
MARKER SEARCH, MAX
Write the value on the test record located at the end of this chapter.
15 Connect the equipment as shown in Figure 3-6 and repeat steps 11 through 14 to find the
return loss on port 3.
32 Keysight 86205A Operating and Service Manual
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Performance Tests 3
KEYSIGHT 8753C
NETWORK
ANALYZER
KEYSIGHT 86025A
DIRECTIONAL BRIDGE
KEYSIGHT 8753C
NETWORK
ANALYZER
KEYSIGHT 86025A
DIRECTIONAL
BRIDGE
Figure 3-6 Equipment setup for return loss measurement on port 3
16 Connect the equipment as shown in Figure 3-7 and repeat steps 11 through 14 to find the
return loss on port 2.
Figure 3-7 Equipment setup for return loss measurement on port 2
Keysight 86205A Operating and Service Manual 33
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3 Performance Tests
In case of failure
Check connectors for damage. Clean and gage connectors.
Verify that the calibration kit devices are within their tolerances. Check adapters and cables to
make sure that they are not broken.
If the bridge appears to be bad, it must be replaced. It can only be repaired at the factory.
34 Keysight 86205A Operating and Service Manual
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Directivity Test
Recommended equipment
Table 3-3 Recommended equipment for directivity test
Equipment Recommended model
Network analyzer 8753C (or 8753A with 85046A)
S-parameter test set 85046A or 85047A
50W type-N calibration kit 85032B
50W type-N (m) load 909F option 012
Type-N cable part number 8120-4781
Procedure
1 Switch the RF output to port 2 on the test set to prevent the test set from switching the test
Performance Tests 3
port power during the calibration, by pressing:
PRESET
MEAS, S12
INPUT PORTS, A/R
2 Set the IF bandwidth to 30 Hz and the analyzer power to 20 dBm, by pressing:
AVG
IF BW, 30, x1
MENU
POWER, 20, x1
3 Put the analyzer into hold mode and move the reference line up so that the data trace can be
seen, by pressing:
RETURN, TRIGGER MENU, HOLD
SCALE/REF
REFERENCE POSITION, 8, x1
4 Set up a log frequency sweep from 300 kHz to 5 MHz, by pressing:
STOP, 5, M/m
MENU
SWEEP TYPE MENU, LOG FREQ
5 Make a S22 one-port calibration (to calibrate A/R, even though test port appears to be port 2),
by pressing:
CAL
CAL KIT, N 50 ohm
RETURN, CALIBRATE MENU, S22 1-PORT
Keysight 86205A Operating and Service Manual 35
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3 Performance Tests
NOTE
KEYSIGHT 8753C
NETWORK
ANALYZER
KEYSIGHT 86025A
DIRECTIONAL
BRIDGE
6 When prompted, connect the calibration devices to port 1 of the bridge as shown in Figure 3-8
(measure the load last).
When measuring the open and short devices, select OPEN (f) and SHORT (f) on the analyzer. The
selection made must correspond to the test port not the device being measured.
Measure the open and short circuit devices; then measure the load.
36 Keysight 86205A Operating and Service Manual
Figure 3-8 Equipment setup for S22 1-port measurement calibration
7 Load the frequency response error term into memory when the calibration is done, by pressing:
SYSTEM
SERVICE MENU, TESTS
34, x1, EXECUTE TEST
DISPLAY, DATA/MEM
CAL, CORRECTION OFF
The resulting display is the uncorrected load data (the last measurement taken during the
calibration), normalized to the frequency response of the system.
8 Find the worst-case directivity value, by pressing:
MKR FCTN
MARKER SEARCH MAX
Page 37
Record this value in the test record located at the end of this chapter.
9 Set up a linear frequency sweep from 5 MHz to 3 GHz, by pressing:
START, 5, M/m
STOP, 3, G/n
MENU, SWEEP TYPE MENU, LIN FREQ
10 Repeat steps 5 through 8. You will need to use the marker manually to find the worst case value
in one of the two remaining frequency spans.
In case of failure
Check connectors for damage. Clean and gage connectors.
Verify that the calibration kit devices are within their specifications. Check adapters and cables to
make sure that they are not broken.
Performance Tests 3
Keysight 86205A Operating and Service Manual 37
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3 Performance Tests
Figure 3-9 86205A test record (1 of 3)
38 Keysight 86205A Operating and Service Manual
Page 39
Performance Tests 3
Figure 3-10 86205A test record (2 of 3)
The measurement uncertainty is quoted for these performance tests using only the recommended
models specified at the beginning of each test. The measurement uncertainty quoted represents
limits of ±3 times the equivalent standard deviation (3s) and is intended to represent a 99%
confidence level.
Keysight 86205A Operating and Service Manual 39
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3 Performance Tests
Figure 3-11 86205A test record (3 of 3)
40 Keysight 86205A Operating and Service Manual
Page 41
Keysight 86205A Directional Bridge
Operating and Service Manual
4 Maintenance
Mating Connectors 42
Environment 43
41
Page 42
4 Maintenance
CAUTION
Mating Connectors
The Microwave Connector Care Manual (part number 08510-90064) provides information on the
proper maintenance, inspection, and gaging of connectors.
When tightening a connector, do not apply more than 9.2 cm-kg (12 lb-in) of torque. Greater
torque can deform the mating surfaces.
42 Keysight 86205A Operating and Service Manual
Page 43
Environment
Maintenance 4
Operate the bridges only in environments within the limits listed. Storage and shipment
environments must meet the conditions shown.
Table 4-1 Environmental requirements
Parameter Required values/ranges
Temperature
–Operating
– Storage and shipment
Humidity
–Operating
– Storage and shipment
Altitude
–Operating
– Storage and shipment
0 to +55 °C
-25 to +75 °C
Up to 95%. Protect the bridge from temperature extremes, which can cause
condensation.
Up to 95%. Protect the bridge from temperature extremes, which can cause
condensation.
Up to 7,620m (25,000 feet)
Up to 7,620m (25,000 feet)
Keysight 86205A Operating and Service Manual 43
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4 Maintenance
THIS PAGE HAS BEEN INTENTIONALLY LEFT BLANK.
44 Keysight 86205A Operating and Service Manual
Page 45
This information is subject to change
without notice. Always refer to the
Keysight website for the latest
revision.
© Keysight Technologies 1992 - 2019
Edition 2, March 12, 2019
Printed in Malaysia
*86205-90001*
86205-90001
www.keysight.com
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