Keysight 86205A Service manual

Keysight 86205A
Directional Bridge
Operating and
Service Manual

2 Keysight 86205A Operating and Service Manual
Notices
Copyright Notice
© Keysight Technologies 1992 - 2019
No part of this manual may be reproduced in
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storage and retrieval or translation into a for-
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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 hardware 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.
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and for other Keysight products may be down-
loaded from the Web. Go to http://www.key-
sight.com/go/conformity. You can then search
by product number to find the latest Declara-
tion of Conformity.
U.S. Government Rights
The Software is “commercial computer soft-
ware,” as defined by Federal Acquisition Regu-
lation (“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-
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require or permit, among other things, that
Keysight: (1) Furnish technical information
related to commercial computer software or
commercial computer software documenta-
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public; or (2) Relinquish to, or otherwise pro-
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documentation. No additional government
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elsewhere in the EULA. Keysight shall be
under no obligation to update, revise or other-
wise modify the Software. With respect to any
technical data as defined by FAR 2.101, pursu-
ant 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 DOCU-
MENT IS PROVIDED “AS IS,” AND IS SUBJECT
TO BEING CHANGED, WITHOUT NOTICE, IN
FUTURE EDITIONS. FURTHER, TO THE MAXI-
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REGARD TO THIS MANUAL AND ANY INFOR-
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BUT NOT LIMITED TO THE IMPLIED WARRAN-
TIES OF MERCHANTABILITY AND FITNESS
FOR A PARTICULAR PURPOSE. KEYSIGHT
SHALL NOT BE LIABLE FOR ERRORS OR FOR
INCIDENTAL OR CONSEQUENTIAL DAMAGES
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MENT OR OF ANY INFORMATION CONTAINED
HEREIN. SHOULD KEYSIGHT AND THE USER
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WITH WARRANTY TERMS COVERING THE
MATERIAL IN THIS DOCUMENT THAT CON-
FLICT WITH THESE TERMS, THE WARRANTY
TERMS IN THE SEPARATE AGREEMENT
SHALL CONTROL.
Safety Information
CAUTION
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 pro-
ceed beyond a CAUTION notice until the indi-
cated conditions are fully understood and met.
WARNING
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.

Keysight 86205A Operating and Service Manual 3
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)

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Keysight 86205A Operating and Service Manual 5
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
3PerformanceTests
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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Keysight 86205A Operating and Service Manual 7
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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Keysight 86205A Operating and Service Manual 9
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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Keysight 86205A Directional Bridge
Operating and Service Manual
11
1 General Information
Manual Overview 12
Initial Inspection 13
This manual contains information for operating, testing, and servicing 86205A bridge.

1 General Information
12 Keysight 86205A Operating and Service Manual
Manual Overview
Product description
86205A is a high performance 50Wdirectional 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.

General Information 1
Keysight 86205A Operating and Service Manual 13
Initial Inspection
1Check the shipping container and packaging material for damage.
2Check the shipment for completeness.
3Check the connectors and bridge body for mechanical damage.
4Check 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
–failedelectricaltest
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.

1 General Information
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Operation 2
Keysight 86205A Operating and Service Manual 15
2 Operation
Overview 16
Bridge Operation 17
Bridge Features 18
Operating Precautions 19
Measurement Configurations 20

2Operation
16 Keysight 86205A Operating and Service Manual
Overview
This chapter includes the following information on Keysight 86205A directional bridge:
– bridge operation
– bridge features
– operating precautions
– measurement configurations

Operation 2
Keysight 86205A Operating and Service Manual 17
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.
Figure 2-1 86205A bridge ports and measurement paths
Table 2-1 Port orientation with corresponding application
Part number Application
Reflection measurement Power monitoring/leveling
1 Test port Input
2 Input port Output
3 Coupled Coupled level

2Operation
18 Keysight 86205A Operating and Service Manual
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

Operation 2
Keysight 86205A Operating and Service Manual 19
Operating Precautions
– 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).
CAUTION
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.

2Operation
20 Keysight 86205A Operating and Service Manual
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
1Connect the equipment as shown in Figure 2-3.
Figure 2-3 Remote directivity measurement setup
2Set the parameters on the analyzer to measure with an external detector by pressing:
CHAN 1, Det Options Broadband External Y/R*
3With nothing connected to the bridge, make a normalization of the measurement setup by
pressing:
CAL, Normalize
4Connect the DUT to the bridge and adjust the scale/division under the DISPLAY key.
NOTE
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.
KEYSIGHT 8711A
NETWORK ANALYZER
KEYSIGHT
86200A SCALAR
KEYSIGHT 86205A
DIRECTIONAL BRIDGE