IEC 62037-6:2021
(Main)Passive RF and microwave devices, intermodulation level measurement - Part 6: Measurement of passive intermodulation in antennas
Passive RF and microwave devices, intermodulation level measurement - Part 6: Measurement of passive intermodulation in antennas
IEC 62037-6:2021 defines the test fixtures and procedures recommended for measuring levels of passive intermodulation generated by antennas, typically used in wireless communication systems. The purpose is to define qualification and acceptance test methods for antennas for use in low intermodulation (low IM) applications. This second edition cancels and replaces the first edition published in 2013. This edition includes the following significant technical changes with respect to the previous edition:
a. dynamic testing requirements updated to define impact energy and locations to apply impacts to devices under test
Dispositifs RF et à micro-ondes passifs, mesure du niveau d'intermodulation - Partie 6: Mesure de l'intermodulation passive dans les antennes
L'IEC 62037-6:2021 définit les dispositifs et les procédures d’essai recommandés pour mesurer les niveaux d’intermodulation passive générés par des antennes, généralement utilisées dans des systèmes de communication sans fil. L’objectif est de définir des méthodes d’essai de qualification et d’acceptation pour des antennes destinées à être utilisées dans des applications de faible intermodulation (faible IM). Cette seconde édition annule et remplace la première édition parue en 2013. Cette édition inclut les modifications techniques majeures suivantes par rapport à l'édition précédente:
a. mise à jour des exigences relatives aux essais dynamiques afin de définir l’énergie des chocs et la position où ils sont appliqués sur les dispositifs soumis à essai.
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Passive RF and microwave devices, intermodulation level measurement –
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IEC 62037-6 ®
Edition 2.0 2021-11
REDLINE VERSION
INTERNATIONAL
STANDARD
colour
inside
Passive RF and microwave devices, intermodulation level measurement –
Part 6: Measurement of passive intermodulation in antennas
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 33.040.20 ISBN 978-2-8322-5120-1
– 2 – IEC 62037-6:2021 RLV © IEC 2021
CONTENTS
FOREWORD . 3
1 Scope . 5
2 Normative references . 5
3 Terms, definitions and abbreviated terms . 5
3.1 Terms and definitions . 5
3.2 Abbreviated terms . 5
4 Definitions of antenna as it pertains to PIM . 6
4.1 Antenna . 6
4.2 Antenna under test . 6
4.3 Active antenna . 6
4.4 Antenna PIM . 6
5 Antenna design and field installation considerations . 6
5.1 Environmental effects on PIM performance . 6
5.2 Antenna interface connection. 6
5.3 Mounting considerations to avoid PIM generation . 7
5.4 Neighbouring sources of interference . 7
5.5 Standard practices and guidelines for material selection . 7
6 PIM measurement considerations . 7
6.1 Quality assurance process and handling procedures . 7
6.2 Measurement accuracy . 7
6.3 Test environment . 8
6.4 Safety . 8
6.5 Test set-up. 8
6.5.1 Coaxial test cable assemblies . 8
6.5.2 Defining a good low PIM reference load . 8
6.5.3 Test set-up and test site baseline PIM verification . 9
6.6 PIM test configurations . 9
6.7 Combined environmental and PIM testing . 11
6.7.1 General . 11
6.7.2 Mechanical considerations . 11
6.7.3 Test system cables and connectors . 11
6.8 PIM test chamber design . 11
6.8.1 General . 11
6.8.2 RF absorber materials . 12
6.8.3 Supporting structures and walls . 12
6.8.4 RF shielding . 12
7 Dynamic PIM measurement considerations . 13
7.1 General . 13
7.2 Dynamic testing methodology . 13
7.3 Shocks test . 13
Bibliography . 15
Figure 1 – Antenna reverse PIM test set-up . 10
Figure 2 – Antenna forward PIM test set-up . 10
Figure 3 – Hammer description . 14
INTERNATIONAL ELECTROTECHNICAL COMMISSION
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PASSIVE RF AND MICROWAVE DEVICES,
INTERMODULATION LEVEL MEASUREMENT –
Part 6: Measurement of passive intermodulation in antennas
FOREWORD
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– 4 – IEC 62037-6:2021 RLV © IEC 2021
IEC 62037-6 has been prepared by IEC technical committee 46: Cables, wires, waveguides, RF
connectors, RF and microwave passive components and accessories. It is an International
Standard.
This second edition cancels and replaces the first edition published in 2013. This edition
constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) dynamic testing requirements updated to define impact energy and locations to apply
impacts to devices under test;
The text of this International Standard is based on the following documents:
Draft Report on voting
46/838/FDIS 46/859/RVD
Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
The language used for the development of this International Standard is English.
This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
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at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are
described in greater detail at www.iec.ch/standardsdev/publications.
A list of all the parts in the IEC 62037 series, published under the general title Passive RF and
microwave devices, intermodulation level measurement can be found on the IEC website.
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PASSIVE RF AND MICROWAVE DEVICES,
INTERMODULATION LEVEL MEASUREMENT –
Part 6: Measurement of passive intermodulation in antennas
1 Scope
This part of IEC 62037 defines the test fixtures and procedures recommended for measuring
levels of passive intermodulation generated by antennas, typically used in wireless
communication systems. The purpose is to define qualification and acceptance test methods for
antennas for use in low intermodulation (low IM) applications.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and
are indispensable for its application. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments)
applies.
IEC 62037-1:2012, Passive r.f. and microwave devices, intermodulation level measurement –
Part 1: General requirements and measuring methods
IEC 62037-3, Passive r.f. and microwave devices, intermodulation level measurement – Part 3:
Measurement of passive intermodulation in coaxial connectors
There are no normative references in this document.
3 Terms, definitions and abbreviated terms
3.1 Terms and definitions
No terms and definitions are listed in this document.
ISO and IEC maintain terminological databases for use in standardization at the following
addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
3.2 Abbreviated terms
AIM Active intermodulation
AUT Antenna under test
ESD Electrostatic discharge
HPA High power amplifier
IM Intermodulation
LNA Low noise amplifier
PIM Passive intermodulation
RF Radio frequency
– 6 – IEC 62037-6:2021 RLV © IEC 2021
4 Definitions of antenna as it pertains to PIM
4.1 Antenna
An antenna is that part of a radio transmitting or receiving system which is designed to provide
the required coupling between a transmitter or a receiver and the medium in which the radio
wave propagates.
The antenna consists of a number of parts or components. These components include, but are
not limited to, one or many radiating elements, one or many RF interfaces, a distribution or
combining feed network, internal support structures, devices which control or adjust the
amplitude/phase response and distribution to the radiating element(s), filters, diplexers,
orthomode transducers, polarizers, waveguides, coaxial cables or printed circuits. In addition,
peripheral components could also influence the PIM performance of the antenna. These
components may can include, but are not limited to, mounting brackets, mounting hardware,
radome, radome fasteners, thermal insulation and grounding hardware.
4.2 Antenna under test
The antenna hardware can have an effect on the overall antenna PIM performance. Therefore,
it is necessary to specify the hardware which is to be part of the antenna under test (AUT).
4.3 Active antenna
An active antenna incorporates active devices such as low noise amplifiers (LNAs), high power
amplifiers (HPAs), phase shifters, etc. An active antenna has the additional concern of active
intermodulation (AIM) which is typically at a much higher level than PIM. The measurement of
PIM in the presence of AIM is not within the scope of this document. If required, the PIM
measurement of an active antenna shall be performed on the passive portion of the antenna only.
4.4 Antenna PIM
The antenna PIM is defined as the PIM that is generated by the antenna assembly itself at a
reference plane or RF interface. The PIM can be measured in a radiated or conducted
(transmissive or reflective) mode.
5 Antenna design and field installation considerations
5.1 Environmental effects on PIM performance
Any hardware located in the nearby environment can significantly influence the PIM
performance of an antenna or antenna system. The effect of ferromagnetic materials, dissimilar
metallic junctions which are part of neighbouring hardware, such as other antennas, tower
structures, aircraft fuselage components, spacecraft thermal control hardware, DC and ESD
grounding hardware, non-high pressure mechanical connections, etc., can potentially have a
detrimental effect on the PIM performance of the communication system.
5.2 Antenna interface connection
Any interface that is exposed to RF is a potential PIM source and shall be designed to be low
PIM. Care shall be taken to ensure that all the mating surfaces are clean. The connections,
whether coaxial or waveguide, should be inspected for dirt, metallic filings, sharp protruding
material, and other potential contaminates. Any coaxial connections shall be torqued to the
manufacturer’s specifications to assure ensure proper metal-to-metal contact pressure is
achieved. If waveguide is used, then the flange bolts shall be torqued to the recommended
manufacturer’s specifications. Careful attention shall be paid to the alignment of the mating
coaxial connectors or waveguide flanges.
The materials and combination of materials used in the connectors, including plating, are
important for the PIM performance. The use of a soft plating material (e.g. gold, silver, etc.) of
sufficient thickness (several skin depths) over a hard-base material (brass, BeCu, etc.) is usually
preferable. The number of interfaces (coaxial connectors and adapters) should be minimized.
This will reduce the number of metal-to-metal junctions and, thus, the possibility of PIM
generation. More information about coaxial connectors can be found in IEC 62037-3.
5.3 Mounting considerations to avoid PIM generation
The antenna shall be properly secured to its mounting bracket. All bolts and holding harnesses
used to secure the antenna to its support structure shall be tightened and torqued according to
the manufacturer’s specifications. The coaxial or waveguide transmission line(s) leading to the
antenna input port(s) shall also be well-secured and prohibited from rubbing or moving.
Care should be taken in the antenna placement by pointing it towards a clear sky view and to
isolate it from all possible neighbouring sources of interference such as tower structures, near-
by antennas, buildings, walls, aircraft fuselage, spacecraft platform, etc.
5.4 Neighbouring sources of interference
Knowledge of the RF environment in which the antenna is to be installed is important. Care should
be taken in the antenna placement to isolate it from all possible neighbouring sources of
interference. For instance, structures having low contact pressure or corroding parts should be
avoided. Additionally, other antennas radiating in a similar band or in bands whose harmonics
could fall within the receive frequency band of the antenna being installed also require
consideration. Other electric or electronic devices may can emit interfering RF signals that fall
into the receive frequency band of the antenna.
5.5 Standard practices and guidelines for material selection
IEC 62037-1:20122021, Clause 6 serves as a guide for the design, selection of materials, and
handling of components that may can be susceptible to PIM generation. It is very important to
consider the application of the antenna, as there are large differences in acceptable PIM levels
between space applications and terrestrial applications.
6 PIM measurement considerations
6.1 Quality assurance process and handling procedures
The purpose of Clause 6 is to provide guidance in the areas of quality control as it pertains to the
performance of PIM testing of antenna products. Procedures are included to enhance the
accuracy and ensure safety when performing PIM measurements on antenna products. The
following guidelines will help minimize errors induced within the test system.
6.2 Measurement accuracy
The accuracy of PIM tests performed on antenna products may can be severely affected by a
multitude of sources that may can be either external or internal to the test system. Some of the
sources which can affect the results of PIM tests performed on antenna products include, but
are not limited to, the following:
a) objects comprising parts made of electrically conductive materials that are exposed to the
electromagnetic fields radiated by the AUT;
b) loose, damaged or corroded mounting hardware attached to the AUT;
c) loose or corroded hardware exposed to the radiated RF fields from the AUT;
d) radio frequency signals generated by external sources;
e) faulty or poorly performing coaxial interface cables;
f) dirty/contaminated/worn interface connections;
– 8 – IEC 62037-6:2021 RLV © IEC 2021
g) improperly mated interface connections;
h) poorly shielded RF interface connections;
i) inadequately filtered AIM from the test set-up;
j) consideration should be given to of input transmission line losses;
k) contaminated absorbers.
6.3 Test environment
When applicable, PIM measurements may can be accomplished outdoors. In performing such a
test, it is important to ensure that government regulations pertaining to the maximum authorized
RF radiation levels are met. Also, the RF energy radiated from the AUT may can generate PIM in
surrounding structures that may couple back into the antenna resulting in invalid PIM test results.
Additionally, external sources of RF radiation may can interfere with the test measurements. A
survey of the frequencies locally in use is recommended prior to testing. Many of the external
sources of PIM may can be minimized or eliminated by performing the PIM testing of antennas
within an anechoic test chamber providing a low PIM test environment. More information on the
construction of anechoic test chambers suitable for PIM testing is provided in 6.8.
6.4 Safety
Performing PIM tests on antenna products can be dangerous. Potentially high voltages and high
levels of RF energy may can be present both within the AUT and within the test environment. The
AUT should be positioned such that personnel will not be exposed to electromagnetic fields
exceeding the acceptable levels specified by government agencies.
6.5 Test set-up
6.5.1 Coaxial test cable assemblies
A problem with PIM test set-ups using coaxial cable interfaces is the need to repeatedly
connect/disconnect coaxial connectors. The following are some recommendations on test set-
up procedures.
a) Sealing O-rings at connector interfaces should be thoroughly cleaned or should preferably
be avoided if possible. These O-rings accumulate metal filings, which can become a source
of PIM.
b) Inspect connectors, dielectric and interface mating surfaces or flanges for contamination,
especially metallic debris, just prior to mating the interface. Also inspect connector mating
surfaces for burrs, scratches, dents, and loss of plating. Proper installation and torquing of
the hardware will minimize the generation of PIM within interface connections.
c) Clean compressed air should be used to blow potential metal particles from the connector
interfaces after each connect-disconnect cycle.
d) Great care shall be taken to ensure that the cables have not been stressed or fatigued to the
point of cracking. The inner and outer conductors can crack under the insulating cable jacket
and not be detectable by visual inspection. This will cause intermittent PIM signals to be
generated. One way to test for this is to flex or tap on the cable while performing a baseline
test. If there are fluctuations in the PIM signal, the cable may can be damaged and should be
replaced.
6.5.2 Defining a good low PIM reference load
A good low PIM load can be made using a long section of high quality coaxial cable terminated
with a high quality (low PIM) connector. This connector should be soldered to the coaxial cable
on both the inner and outer conductors. The length of cable should be held in a fixture so that
no fatigue is placed on the connector or cable. When soldering coaxial cables, it should be done
very carefully to avoid melting or deforming the insulation, which can cause impedance changes.
6.5.3 Test set-up and test site baseline PIM verification
Prior to the testing of the antenna, perform a baseline PIM test set-up noise floor verification.
To verify the test set-up itself, a low PIM termination may be used. Check the cables and
connections for sensitivity to flexure, mechanical stress and configuration during the baseline
test.
The test site should also be evaluated to ensure that it does not generate unacceptable levels of
PIM or to identify any potential extraneous interfering RF sources. The test site could be an
anechoic test enclosure or a chosen outdoor site. If an anechoic chamber is used, special design
considerations are needed as outlined in 6.8. During the site verification, if possible, use a low
PIM reference antenna having a radiation pattern and gain comparable to that of the AUT in
order to ensure that the test environment is exposed to representative flux densities as for the
AUT test.
The actual antenna PIM test should be performed using the same set-up as for the baseline test:
minimize movements of components, do not add components, minimize changes in the
environment, etc. After the antenna PIM test is completed or as required during the test, compare
the baseline test results with previous set-up verification results for any sign of degradation in
the test system.
6.6 PIM test configurations
A typical test set-up for antenna reverse (reflected) PIM testing is shown in Figure 1 and one
another for antenna forward (transmitted) PIM is shown in Figure 2. It should be noted that the
dynamic range between the two test configurations should be examined to assess the
appropriate choices to use. In both cases, the test should take place in either a well-designed
low PIM anechoic chamber or outdoors, which would allow the full range of antenna movement.
For the antenna forward (transmitted) PIM test, a low PIM antenna on the receiver side of the
test set-up is required. Also, for this test, the environment may can be first verified by using two
low PIM antennas.
Whenever possible, the diplexer (Figure 1) and the filter (Figure 2), both of which should be low
PIM, shall be placed as close as possible to the AUT input port to minimize PIM generated by
the test set-up. The overall cable or waveguide lengths should be minimized to deliver maximum
power to the AUT. Also, coaxial and waveguide adapters should be avoided as much as possible.
– 10 – IEC 62037-6:2021 RLV © IEC 2021
Figure 1 – Antenna reverse PIM test set-up
Each set-up has two synthesized sources, amplified separately to avoid AIM (active
intermodulation). The two-tone-test results in discrete intermodulation products, whose levels
are to be measured. These PIM products are typically first amplified by one or two stages of
LNAs before detection by the spectrum analyzer or digital receiver. This is in order to increase
the sensitivity of the set-up.
Figure 2 – Antenna forward PIM test set-up
6.7 Combined environmental and PIM testing
6.7.1 General
Whenever possible and practical, each AUT should be measured for PIM while being exposed
to representative environmental operating conditions. If it is not possible, the AUT may be
measured for PIM before and after exposure to representative environmental conditions.
6.7.2 Mechanical considerations
A loose mechanical joint is likely to cause PIM. Materials expand and contract due to temperature
changes. Different materials expand and contract at different rates. This difference can cause
varying amounts of stress to be induced in any mechanical joint of the antenna components. The
differences in expansion and contraction can even cause the parts to move so much as to loosen
a mechanical joint. A bolted joint that was torqued to its specified value can loosen to the point
where the required clamping force is no longer being produced. Evaluation of mechanical
connections may be accomplished by performing PIM testing during thermal cycling.
Vibrations can produce detrimental effects similar to those from thermal environments.
For terrestrial applications, extreme temperature cycling occurs only in specific geographical
areas and is more applicable to aeronautical and space applications. Wind-induced vibrations
occur in most terrestrial and aeronautical applications but never for space applications. However,
vibrations are induced on space-borne antennas during platform manoeuvres. For space and
aeronautical applications, it is recommended that PIM testing be performed during thermal
cycling before and after vibration testing.
6.7.3 Test system cables and connectors
The test cables connected to the antenna under test are exposed to the same test environments
as the antenna itself. Therefore, great care shall be taken in selecting cables suitable for PIM
testing in the specific test environment. The entire test set-up, including the cables, shall be
verified under the same test conditions as for the AUT testing.
6.8 PIM test chamber design
6.8.1 General
The purpose of 6.8 is to provide guidance for the construction of test chambers suitable for the
performance of PIM testing on antennas.
Evaluation of antenna products for PIM presents additional challenges not found with other non-
radiating components. The antenna will be connected to an RF source and will radiate RF
energy during the PIM test. This energy shall not be allowed to excite potential PIM sources in
the test environment. It is also sometimes not practical to perform these tests in an outdoor
environment since the radiated RF energy should preferably be contained. To successfully
perform PIM testing on antennas, it may can be desirable to construct an RF anechoic chamber
specially designed for PIM testing.
The main components of an RF anechoic test chamber are:
a) RF absorber materials;
b) supporting structures and walls;
c) RF shielding.
Each of these components will be discussed in 6.8.2 to 6.8.4.
– 12 – IEC 62037-6:2021 RLV © IEC 2021
6.8.2 RF absorber materials
RF absorber materials are commonly manufactured from a carbon impregnated foam. This
material offers attenuation to radio frequency signals as they pass through it. This attenuation of
the signal (absorption of energy) serves in essence as a "load" to the antenna.
RF absorber materials are available in many styles and sizes. The selection of style and size is
dependent on the frequency of operation and the placement within the test chamber. Proper
selection of the RF absorbers may can be the most critical factor in the construction of a PIM test
chamber. Recommendations that may can help in the selection process are as follows:
a) Select an absorber with an incident RF attenuation greater than 30 dB.
b) For good results, place pyramidal absorber panels in the field of the antenna radiation
pattern, preferably with normal incidence to the beam peak. However, best results can be
achieved when the interior of the test chamber is completely covered with RF absorber
material.
c) As a minimum, ensure there are enough panels to avoid back reflections.
For safety purposes, select an absorber that contains fire retardant materials and is rated for the
anticipated maximum power dissipation required.
6.8.3 Supporting structures and walls
The supporting structure and walls for the PIM test chamber shall provide a suitable inner surface
for attachment of the RF absorber material. In some applications, the supporting structure and
walls may can also be required to assist in the control of the temperature, the pressure, the
humidity level, or other environmental conditions for the test.
The materials and methods of construction will vary greatly depending on the specific application.
For many applications, simple lumber and plywood provide very good results. Cement block
construction also provides excellent support but at a much greater expense. Some general
considerations in designing the support structure and walls are as follows:
a) The use of metal shielding in the outer structure improves the isolation of the anechoic
chamber and is recommended when RF shielding needs to be high (see 6.8.4). However, it is
critical to ensure that the design does not include metal-to-metal junctions that themselves
have poor PIM performance. Examples of this would include overlapping metal plates or the
use of metal hardware going through sheet metal parts that are exposed.
b) Wood supports can be successfully joined using screws. Screws are stronger than nails and
it is easier to control their final location. Do not allow metal fasteners to contact each other,
even within the framework.
c) Make sure that the actual dimensions of absorber panels are known before completing the
design of the structure as they do not usually have the exact size advertised.
d) The size of the test chamber should be large enough to allow the test antenna to be sufficiently
far from any RF absorber to avoid mutual coupling between the radiating antenna and the
absorber material.
e) Hinges, fasteners, light fixtures, fire sprinklers, mounting hardware, etc., should all be
evaluated for potential PIM generation.
6.8.4 RF shielding
RF shielding may or may not be required, depending on the particular application. The purpose
of RF shielding may can be for security, to maintain a low RF noise floor in the test facility or may
can be required to ensure personnel safety. A method of identifying the need for RF shielding is
based on the calculated power densities. From such calculations, it may can be found that RF
levels behind the RF absorber are extremely low and therefore safe. It is always recommended
that an RF survey of the area surrounding the chamber be performed prior to the approval of the
final test plan or procedure.
Methods of RF shielding also vary depending on the application. One method providing good
results for most applications is to apply thin aluminium sheets or panels to the exterior surface
of the test chamber structure. The sheets can be securely attached using adhesive products.
Placing a plastic insulating material on the edge of each panel will prevent any direct contact
between panels. A small gap between the panels will not pass RF energy except at extremely
small wavelengths compared to the gap size. Although RF power levels may can be extremely
low at the RF shield, it would still be advisable to avoid materials which may can generate PIM
such as wire mesh fabrics.
7 Dynamic PIM measurement considerations
7.1 General
In real operating conditions, an antenna is submitted to varying amounts of stress, like
temperature changes and vibrations. Since PIM sources are often caused by loose metal-to-
metal contacts, whenever possible and practical, each antenna should be measured for PIM
while being exposed to representative operating conditions.
It is not possible to define a single test representing all the possible operating conditions for
any antenna but defining some guidelines to apply some stresses during PIM test can be done.
This is the goal of the "dynamic testing methodology" proposed in Clause 7, "dynamic" meaning
here with mechanical stresses.
7.2 Dynamic testing methodology
There are several methods to apply stress on an antenna. Nevertheless, the PIM dynamic test
shall be done in an acceptable time frame, in a practical and pragmatic manner, shall not cause
irreversible damages on the AUT and shall take into account that antennas can have different
various forms. The stress applied during the PIM dynamic tests should be able to detect
potential instabilities within the antenna.
Methodologies permitting to apply a shock sequence are compatible with these inputs and goals.
The report should document the type, description and conditions of the test and the PIM values
prior to each dynamic test, during dynamic test, and after dynamic test. If the PIM cannot be
measured during the stress, the results shall be compared before and after the test sequence.
7.3 Shocks test
A shocking sequence is applied along the antenna, every 30 cm at least, preferably on its rear
face. Shock should not be applied on potential AUT accessories or other fragile parts.
At each location, two consecutive impacts are applied.
The impact energy value shall be 1 J. The impact force can be applied by using a spring hammer
or automated impact hammer. A description of related tools and methodology can be found in
IEC 60068-2-75.
It is preferable that an impactor is made from polyamide (hardness range between 85 HRR and
100 HRR Rockwell hardness according to ISO 2039-2) in order to ensure the energy transfer
and to prevent PIM generation by the impactor due to metal-to-metal contact with the AUT (see
Figure 3 for the hammer description). The surface impact should be sufficiently wide not to
damage the AUT.
It is preferable that impact locations are a structural part of the product, solid enough to
withstand a mechanical shock without damage.
– 14 – IEC 62037-6:2021 RLV © IEC 2021
Figure 3 – Hammer description
Bibliography
IEC 60068-2-75, Environmental testing – Part 2-75: Tests – Test Eh: Hammer tests
IEC 62037-1, Passive RF. and microwave devices, intermodulation level measurement – Part 1:
General requirements and measuring methods
IEC 62037-3, Passive RF and microwave devices, intermodulation level measurement – Part 3:
Measurement of passive intermodulation in coaxial connectors
ISO 2039-2, Plastics – Determination of hardness – Part 2: Rockwell hardness
____________
IEC 62037-6 ®
Edition 2.0 2021-11
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Passive RF and microwave devices, intermodulation level measurement –
Part 6: Measurement of passive intermodulation in antennas
Dispositifs RF et à micro-ondes passifs, mesure du niveau d’intermodulation –
Partie 6: Mesure de l’intermodulation passive dans les antennes
– 2 – IEC 62037-6:2021 © IEC 2021
CONTENTS
FOREWORD . 3
1 Scope . 5
2 Normative references . 5
3 Terms, definitions and abbreviated terms . 5
3.1 Terms and definitions . 5
3.2 Abbreviated terms . 5
4 Definitions of antenna as it pertains to PIM . 5
4.1 Antenna . 5
4.2 Antenna under test . 6
4.3 Active antenna . 6
4.4 Antenna PIM . 6
5 Antenna design and field installation considerations . 6
5.1 Environmental effects on PIM performance . 6
5.2 Antenna interface connection. 6
5.3 Mounting considerations to avoid PIM generation . 7
5.4 Neighbouring sources of interference . 7
5.5 Standard practices and guidelines for material selection . 7
6 PIM measurement considerations . 7
6.1 Quality assurance process and handling procedures . 7
6.2 Measurement accuracy . 7
6.3 Test environment . 8
6.4 Safety . 8
6.5 Test set-up. 8
6.5.1 Coaxial test cable assemblies . 8
6.5.2 Defining a good low PIM reference load . 8
6.5.3 Test set-up and test site baseline PIM verification . 8
6.6 PIM test configurations . 9
6.7 Combined environmental and PIM testing .
...
IEC 62037-6 ®
Edition 2.1 2025-12
INTERNATIONAL
STANDARD
CONSOLIDATED VERSION
Passive RF and microwave devices, intermodulation level measurement -
Part 6: Measurement of passive intermodulation in antennas
ICS 33.040.20 ISBN 978-2-8327-0923-8
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CONTENTS
FOREWORD . 2
INTRODUCTION to Amendment . 4
1 Scope . 5
2 Normative references . 5
3 Terms, definitions and abbreviated terms . 5
3.1 Terms and definitions. 5
3.2 Abbreviated terms . 5
4 Definitions of antenna as it pertains to PIM . 5
4.1 Antenna . 5
4.2 Antenna under test . 5
4.3 Active antenna . 6
4.4 Antenna PIM . 6
5 Antenna design and field installation considerations . 6
5.1 Environmental effects on PIM performance . 6
5.2 Antenna interface connection . 6
5.3 Mounting considerations to avoid PIM generation . 6
5.4 Neighbouring sources of interference . 6
5.5 Standard practices and guidelines for material selection . 7
6 PIM measurement considerations . 7
6.1 Quality assurance process and handling procedures . 7
6.2 Measurement accuracy . 7
6.3 Test environment . 7
6.4 Safety . 8
6.5 Test set-up . 8
6.5.1 Coaxial test cable assemblies . 8
6.5.2 Defining a good low PIM reference load . 8
6.5.3 Test set-up and test site baseline PIM verification . 8
6.6 PIM test configurations . 9
6.7 Combined environmental and PIM testing . 10
6.7.1 General . 10
6.7.2 Mechanical considerations . 10
6.7.3 Test system cables and connectors . 10
6.8 PIM test chamber design . 11
6.8.1 General . 11
6.8.2 RF absorber materials . 11
6.8.3 Supporting structures and walls . 11
6.8.4 RF shielding . 12
7 Dynamic PIM measurement considerations . 12
7.1 General . 12
7.2 Dynamic testing methodology . 13
7.3 Shocks test . 13
Bibliography . 14
Figure 1 – Antenna reverse PIM test set-up . 9
Figure 2 – Antenna forward PIM test set-up . 10
Figure 3 – Hammer description . 13
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
Passive RF and microwave devices, intermodulation level measurement -
Part 6: Measurement of passive intermodulation in antennas
FOREWORD
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This consolidated version of the official IEC Standard and its amendment has been prepared
for user convenience.
IEC 62037-6 edition 2.1 contains the second edition (2021-11) [documents 46/838/FDIS and
46/859/RVD] and its amendment 1 (2025-12) [documents 46/1030/CDV and 46/1056/RVC].
In this Redline version, a vertical line in the margin shows where the technical content is
modified by amendment 1. Additions are in green text, deletions are in strikethrough red text.
A separate Final version with all changes accepted is available in this publication.
IEC 62037-6 has been prepared by IEC technical committee 46: Cables, wires, waveguides, RF
connectors, RF and microwave passive components and accessories. It is an International
Standard.
This second edition cancels and replaces the first edition published in 2013. This edition
constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) dynamic testing requirements updated to define impact energy and locations to apply
impacts to devices under test;
The text of this International Standard is based on the following documents:
Draft Report on voting
46/838/FDIS 46/859/RVD
Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
The language used for the development of this International Standard is English.
This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available
at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are
described in greater detail at www.iec.ch/standardsdev/publications.
A list of all the parts in the IEC 62037 series, published under the general title Passive RF and
microwave devices, intermodulation level measurement can be found on the IEC website.
The committee has decided that the contents of this document and its amendment will remain
unchanged until the stability date indicated on the IEC website under webstore.iec.ch in the
data related to the specific document. At this date, the document will be
– reconfirmed,
– withdrawn, or
– revised.
INTRODUCTION to Amendment
The purpose of this amendment is:
– to improve Clause 5 Antenna design and field installation considerations, 5.3 Mounting
considerations to avoid PIM generation, paragraph 2: change "towards a clear sky view and
to isolate it" to "from".
– to correct Clause 7 Dynamic PIM measurement considerations, 7.2 Dynamic testing,
methodology paragraph 3: to add "maximum" to the PIM values to be reported.
1 Scope
This part of IEC 62037 defines the test fixtures and procedures recommended for measuring
levels of passive intermodulation generated by antennas, typically used in wireless
communication systems. The purpose is to define qualification and acceptance test methods for
antennas for use in low intermodulation (low IM) applications.
2 Normative references
There are no normative references in this document.
3 Terms, definitions and abbreviated terms
3.1 Terms and definitions
No terms and definitions are listed in this document.
ISO and IEC maintain terminological databases for use in standardization at the following
addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
3.2 Abbreviated terms
AIM Active intermodulation
AUT Antenna under test
ESD Electrostatic discharge
HPA High power amplifier
IM Intermodulation
LNA Low noise amplifier
PIM Passive intermodulation
RF Radio frequency
4 Definitions of antenna as it pertains to PIM
4.1 Antenna
An antenna is that part of a radio transmitting or receiving system which is designed to provide
the required coupling between a transmitter or a receiver and the medium in which the radio
wave propagates.
The antenna consists of a number of parts or components. These components include, but are
not limited to, one or many radiating elements, one or many RF interfaces, a distribution or
combining feed network, internal support structures, devices which control or adjust the
amplitude/phase response and distribution to the radiating element(s), filters, diplexers,
orthomode transducers, polarizers, waveguides, coaxial cables or printed circuits. In addition,
peripheral components could also influence the PIM performance of the antenna. These
components can include, but are not limited to, mounting brackets, mounting hardware, radome,
radome fasteners, thermal insulation and grounding hardware.
4.2 Antenna under test
The antenna hardware can have an effect on the overall antenna PIM performance. Therefore,
it is necessary to specify the hardware which is to be part of the antenna under test (AUT).
4.3 Active antenna
An active antenna incorporates active devices such as low noise amplifiers (LNAs), high power
amplifiers (HPAs), phase shifters, etc. An active antenna has the additional concern of active
intermodulation (AIM) which is typically at a much higher level than PIM. The measurement of
PIM in the presence of AIM is not within the scope of this document. If required, the PIM
measurement of an active antenna shall be performed on the passive portion of the antenna only.
4.4 Antenna PIM
The antenna PIM is defined as the PIM that is generated by the antenna assembly itself at a
reference plane or RF interface. The PIM can be measured in a radiated or conducted
(transmissive or reflective) mode.
5 Antenna design and field installation considerations
5.1 Environmental effects on PIM performance
Any hardware located in the nearby environment can significantly influence the PIM
performance of an antenna or antenna system. The effect of ferromagnetic materials, dissimilar
metallic junctions which are part of neighbouring hardware, such as other antennas, tower
structures, aircraft fuselage components, spacecraft thermal control hardware, DC and ESD
grounding hardware, non-high pressure mechanical connections, etc., can potentially have a
detrimental effect on the PIM performance of the communication system.
5.2 Antenna interface connection
Any interface that is exposed to RF is a potential PIM source and shall be designed to be low
PIM. Care shall be taken to ensure that all the mating surfaces are clean. The connections,
whether coaxial or waveguide, should be inspected for dirt, metallic filings, sharp protruding
material, and other potential contaminates. Any coaxial connections shall be torqued to the
manufacturer’s specifications to ensure proper metal-to-metal contact pressure is achieved. If
waveguide is used, then the flange bolts shall be torqued to the recommended manufacturer’s
specifications. Careful attention shall be paid to the alignment of the mating coaxial connectors
or waveguide flanges.
The materials and combination of materials used in the connectors, including plating, are
important for the PIM performance. The use of a soft plating material (e.g. gold, silver, etc.) of
sufficient thickness (several skin depths) over a hard-base material (brass, BeCu, etc.) is usually
preferable. The number of interfaces (coaxial connectors and adapters) should be minimized.
This will reduce the number of metal-to-metal junctions and, thus, the possibility of PIM
generation. More information about coaxial connectors can be found in IEC 62037-3.
5.3 Mounting considerations to avoid PIM generation
The antenna shall be properly secured to its mounting bracket. All bolts and holding harnesses
used to secure the antenna to its support structure shall be tightened and torqued according to
the manufacturer’s specifications. The coaxial or waveguide transmission line(s) leading to the
antenna input port(s) shall also be well-secured and prohibited from rubbing or moving.
Care should be taken in the antenna placement by pointing it towards a clear sky view and to
isolate it away from all possible neighbouring sources of interference such as tower structures,
near-by nearby antennas, buildings, walls, aircraft fuselage, spacecraft platform, etc.
5.4 Neighbouring sources of interference
Knowledge of the RF environment in which the antenna is to be installed is important. Care should
be taken in the antenna placement to isolate it from all possible neighbouring sources of
interference. For instance, structures having low contact pressure or corroding parts should be
avoided. Additionally, other antennas radiating in a similar band or in bands whose harmonics
could fall within the receive frequency band of the antenna being installed also require
consideration. Other electric or electronic devices can emit interfering RF signals that fall into
the receive frequency band of the antenna.
5.5 Standard practices and guidelines for material selection
IEC 62037-1:2021, Clause 6 serves as a guide for the design, selection of materials, and
handling of components that can be susceptible to PIM generation. It is very important to
consider the application of the antenna, as there are large differences in acceptable PIM levels
between space applications and terrestrial applications.
6 PIM measurement considerations
6.1 Quality assurance process and handling procedures
The purpose of Clause 6 is to provide guidance in the areas of quality control as it pertains to the
performance of PIM testing of antenna products. Procedures are included to enhance the
accuracy and ensure safety when performing PIM measurements on antenna products. The
following guidelines will help minimize errors induced within the test system.
6.2 Measurement accuracy
The accuracy of PIM tests performed on antenna products can be severely affected by a
multitude of sources that can be either external or internal to the test system. Some of the
sources which can affect the results of PIM tests performed on antenna products include, but
are not limited to, the following:
a) objects comprising parts made of electrically conductive materials that are exposed to the
electromagnetic fields radiated by the AUT;
b) loose, damaged or corroded mounting hardware attached to the AUT;
c) loose or corroded hardware exposed to the radiated RF fields from the AUT;
d) radio frequency signals generated by external sources;
e) faulty or poorly performing coaxial interface cables;
f) dirty/contaminated/worn interface connections;
g) improperly mated interface connections;
h) poorly shielded RF interface connections;
i) inadequately filtered AIM from the test set-up;
j) consideration of input transmission line losses;
k) contaminated absorbers.
6.3 Test environment
When applicable, PIM measurements can be accomplished outdoors. In performing such a test,
it is important to ensure that government regulations pertaining to the maximum authorized RF
radiation levels are met. Also, the RF energy radiated from the AUT can generate PIM in
surrounding structures that may couple back into the antenna resulting in invalid PIM test results.
Additionally, external sources of RF radiation can interfere with the test measurements. A survey
of the frequencies locally in use is recommended prior to testing. Many of the external sources
of PIM can be minimized or eliminated by performing the PIM testing of antennas within an
anechoic test chamber providing a low PIM test environment. More information on the
construction of anechoic test chambers suitable for PIM testing is provided in 6.8.
6.4 Safety
Performing PIM tests on antenna products can be dangerous. Potentially high voltages and high
levels of RF energy can be present both within the AUT and within the test environment. The AUT
should be positioned such that personnel will not be exposed to electromagnetic fields exceeding
the acceptable levels specified by government agencies.
6.5 Test set-up
6.5.1 Coaxial test cable assemblies
A problem with PIM test set-ups using coaxial cable interfaces is the need to repeatedly
connect/disconnect coaxial connectors. The following are some recommendations on test set-
up procedures.
a) Sealing O-rings at connector interfaces should be thoroughly cleaned or should preferably
be avoided if possible. These O-rings accumulate metal filings, which can become a source
of PIM.
b) Inspect connectors, dielectric and interface mating surfaces or flanges for contamination,
especially metallic debris, just prior to mating the interface. Also inspect connector mating
surfaces for burrs, scratches, dents, and loss of plating. Proper installation and torquing of
the hardware will minimize the generation of PIM within interface connections.
c) Clean compressed air should be used to blow potential metal particles from the connector
interfaces after each connect-disconnect cycle.
d) Great care shall be taken to ensure that the cables have not been stressed or fatigued to the
point of cracking. The inner and outer conductors can crack under the insulating cable jacket
and not be detectable by visual inspection. This will cause intermittent PIM signals to be
generated. One way to test for this is to flex or tap on the cable while performing a baseline
test. If there are fluctuations in the PIM signal, the cable can be damaged and should be
replaced.
6.5.2 Defining a good low PIM reference load
A good low PIM load can be made using a long section of high quality coaxial cable terminated
with a high quality (low PIM) connector. This connector should be soldered to the coaxial cable
on both the inner and outer conductors. The length of cable should be held in a fixture so that
no fatigue is placed on the connector or cable. When soldering coaxial cables, it should be done
very carefully to avoid melting or deforming the insulation, which can cause impedance changes.
6.5.3 Test set-up and test site baseline PIM verification
Prior to the testing of the antenna, perform a baseline PIM test set-up noise floor verification.
To verify the test set-up itself, a low PIM termination may be used. Check the cables and
connections for sensitivity to flexure, mechanical stress and configuration during the baseline
test.
The test site should also be evaluated to ensure that it does not generate unacceptable levels of
PIM or to identify any potential extraneous interfering RF sources. The test site could be an
anechoic test enclosure or a chosen outdoor site. If an anechoic chamber is used, special design
considerations are needed as outlined in 6.8. During the site verification, if possible, use a low
PIM reference antenna having a radiation pattern and gain comparable to that of the AUT in
order to ensure that the test environment is exposed to representative flux densities as for the
AUT test.
The actual antenna PIM test should be performed using the same set-up as for the baseline test:
minimize movements of components, do not add components, minimize changes in the
environment, etc. After the antenna PIM test is completed or as required during the test, compare
the baseline test results with previous set-up verification results for any sign of degradation in
the test system.
6.6 PIM test configurations
A typical test set-up for antenna reverse (reflected) PIM testing is shown in Figure 1 and another
for antenna forward (transmitted) PIM is shown in Figure 2. It should be noted that the dynamic
range between the two test configurations should be examined to assess the appropriate choices
to use. In both cases, the test should take place in either a well-designed low PIM anechoic
chamber or outdoors, which would allow the full range of antenna movement. For the antenna
forward (transmitted) PIM test, a low PIM antenna on the receiver side of the test set-up is
required. Also, for this test, the environment can be first verified by using two low PIM antennas.
Whenever possible, the diplexer (Figure 1) and the filter (Figure 2), both of which should be low
PIM, shall be placed as close as possible to the AUT input port to minimize PIM generated by
the test set-up. The overall cable or waveguide lengths should be minimized to deliver maximum
power to the AUT. Also, coaxial and waveguide adapters should be avoided as much as possible.
Figure 1 – Antenna reverse PIM test set-up
Each set-up has two synthesized sources, amplified separately to avoid AIM (active
intermodulation). The two-tone-test results in discrete intermodulation products, whose levels
are to be measured. These PIM products are typically first amplified by one or two stages of
LNAs before detection by the spectrum analyzer or digital receiver. This is in order to increase
the sensitivity of the set-up.
Figure 2 – Antenna forward PIM test set-up
6.7 Combined environmental and PIM testing
6.7.1 General
Whenever possible and practical, each AUT should be measured for PIM while being exposed
to representative environmental operating conditions. If it is not possible, the AUT may be
measured for PIM before and after exposure to representative environmental conditions.
6.7.2 Mechanical considerations
A loose mechanical joint is likely to cause PIM. Materials expand and contract due to temperature
changes. Different materials expand and contract at different rates. This difference can cause
varying amounts of stress to be induced in any mechanical joint of the antenna components. The
differences in expansion and contraction can even cause the parts to move so much as to loosen
a mechanical joint. A bolted joint that was torqued to its specified value can loosen to the point
where the required clamping force is no longer being produced. Evaluation of mechanical
connections may be accomplished by performing PIM testing during thermal cycling.
Vibrations can produce detrimental effects similar to those from thermal environments.
For terrestrial applications, extreme temperature cycling occurs only in specific geographical
areas and is more applicable to aeronautical and space applications. Wind-induced vibrations
occur in most terrestrial and aeronautical applications but never for space applications. However,
vibrations are induced on space-borne antennas during platform manoeuvres. For space and
aeronautical applications, it is recommended that PIM testing be performed during thermal
cycling before and after vibration testing.
6.7.3 Test system cables and connectors
The test cables connected to the antenna under test are exposed to the same test environments
as the antenna itself. Therefore, great care shall be taken in selecting cables suitable for PIM
testing in the specific test environment. The entire test set-up, including the cables, shall be
verified under the same test conditions as for the AUT testing.
6.8 PIM test chamber design
6.8.1 General
The purpose of 6.8 is to provide guidance for the construction of test chambers suitable for the
performance of PIM testing on antennas.
Evaluation of antenna products for PIM presents additional challenges not found with other non-
radiating components. The antenna will be connected to an RF source and will radiate RF
energy during the PIM test. This energy shall not be allowed to excite potential PIM sources in
the test environment. It is also sometimes not practical to perform these tests in an outdoor
environment since the radiated RF energy should preferably be contained. To successfully
perform PIM testing on antennas, it can be desirable to construct an RF anechoic chamber
specially designed for PIM testing.
The main components of an RF anechoic test chamber are:
a) RF absorber materials;
b) supporting structures and walls;
c) RF shielding.
Each of these components will be discussed in 6.8.2 to 6.8.4.
6.8.2 RF absorber materials
RF absorber materials are commonly manufactured from a carbon impregnated foam. This
material offers attenuation to radio frequency signals as they pass through it. This attenuation of
the signal (absorption of energy) serves in essence as a "load" to the antenna.
RF absorber materials are available in many styles and sizes. The selection of style and size is
dependent on the frequency of operation and the placement within the test chamber. Proper
selection of the RF absorbers can be the most critical factor in the construction of a PIM test
chamber. Recommendations that can help in the selection process are as follows:
a) Select an absorber with an incident RF attenuation greater than 30 dB.
b) For good results, place pyramidal absorber panels in the field of the antenna radiation
pattern, preferably with normal incidence to the beam peak. However, best results can be
achieved when the interior of the test chamber is completely covered with RF absorber
material.
c) As a minimum, ensure there are enough panels to avoid back reflections.
For safety purposes, select an absorber that contains fire retardant materials and is rated for the
anticipated maximum power dissipation required.
6.8.3 Supporting structures and walls
The supporting structure and walls for the PIM test chamber shall provide a suitable inner surface
for attachment of the RF absorber material. In some applications, the supporting structure and
walls can also be required to assist in the control of the temperature, the pressure, the humidity
level, or other environmental conditions for the test.
The materials and methods of construction will vary greatly depending on the specific application.
For many applications, simple lumber and plywood provide very good results. Cement block
construction also provides excellent support but at a much greater expense. Some general
considerations in designing the support structure and walls are as follows:
a) The use of metal shielding in the outer structure improves the isolation of the anechoic
chamber and is recommended when RF shielding needs to be high (see 6.8.4). However, it is
critical to ensure that the design does not include metal-to-metal junctions that themselves
have poor PIM performance. Examples of this would include overlapping metal plates or the
use of metal hardware going through sheet metal parts that are exposed.
b) Wood supports can be successfully joined using screws. Screws are stronger than nails and
it is easier to control their final location. Do not allow metal fasteners to contact each other,
even within the framework.
c) Make sure that the actual dimensions of absorber panels are known before completing the
design of the structure as they do not usually have the exact size advertised.
d) The size of the test chamber should be large enough to allow the test antenna to be sufficiently
far from any RF absorber to avoid mutual coupling between the radiating antenna and the
absorber material.
e) Hinges, fasteners, light fixtures, fire sprinklers, mounting hardware, etc., should all be
evaluated for potential PIM generation.
6.8.4 RF shielding
RF shielding may or may not be required, depending on the particular application. The purpose
of RF shielding can be for security, to maintain a low RF noise floor in the test facility or can be
required to ensure personnel safety. A method of identifying the need for RF shielding is based
on the calculated power densities. From such calculations, it can be found that RF levels behind
the RF absorber are extremely low and therefore safe. It is always recommended that an RF
survey of the area surrounding the chamber be performed prior to the approval of the final test
plan or procedure.
Methods of RF shielding also vary depending on the application. One method providing good
results for most applications is to apply thin aluminium sheets or panels to the exterior surface
of the test chamber structure. The sheets can be securely attached using adhesive products.
Placing a plastic insulating material on the edge of each panel will prevent any direct contact
between panels. A small gap between the panels will not pass RF energy except at extremely
small wavelengths compared to the gap size. Although RF power levels can be extremely low at
the RF shield, it would still be advisable to avoid materials which can generate PIM such as wire
mesh fabrics.
7 Dynamic PIM measurement considerations
7.1 General
In real operating conditions, an antenna is submitted to varying amounts of stress, like
temperature changes and vibrations. Since PIM sources are often caused by loose metal-to-
metal contacts, whenever possible and practical, each antenna should be measured for PIM
while being exposed to representative operating conditions.
It is not possible to define a single test representing all the possible operating conditions for
any antenna but defining some guidelines to apply some stresses during PIM test can be done.
This is the goal of the "dynamic testing methodology" proposed in Clause 7, "dynamic" meaning
here with mechanical stresses.
7.2 Dynamic testing methodology
There are several methods to apply stress on an antenna. Nevertheless, the PIM dynamic test
shall be done in an acceptable time frame, in a practical and pragmatic manner, shall not cause
irreversible damages on the AUT and shall take into account that antennas can have different
various forms. The stress applied during the PIM dynamic tests should be able to detect
potential instabilities within the antenna.
Methodologies permitting to apply a shock sequence are compatible with these inputs and goals.
The report should document the type, description and conditions of the test and the maximum
PIM values prior to each dynamic test, during dynamic test, and after dynamic test. If the PIM
cannot be measured during the stress, the results shall be compared before and after the test
sequence.
7.3 Shocks test
A shocking sequence is applied along the antenna, every 30 cm at least, preferably on its rear
face. Shock should not be applied on potential AUT accessories or other fragile parts.
At each location, two consecutive impacts are applied.
The impact energy value shall be 1 J. The impact force can be applied by using a spring hammer
or automated impact hammer. A description of related tools and methodology can be found in
IEC 60068-2-75.
It is preferable that an impactor is made from polyamide (hardness range between 85 HRR and
100 HRR Rockwell hardness according to ISO 2039-2) in order to ensure the energy transfer
and to prevent PIM generation by the impactor due to metal-to-metal contact with the AUT (see
Figure 3 for the hammer description). The surface impact should be sufficiently wide not to
damage the AUT.
It is preferable that impact locations are a structural part of the product, solid enough to
withstand a mechanical shock without damage.
Figure 3 – Hammer description
Bibliography
IEC 60068-2-75, Environmental testing – Part 2-75: Tests – Test Eh: Hammer tests
IEC 62037-1, Passive RF. and microwave devices, intermodulation level measurement – Part 1:
General requirements and measuring methods
IEC 62037-3, Passive RF and microwave devices, intermodulation level measurement – Part 3:
Measurement of passive intermodulation in coaxial connectors
ISO 2039-2, Plastics – Determination of hardness – Part 2: Rockwell hardness
____________
CONTENTS
FOREWORD . 2
INTRODUCTION to Amendment . 4
1 Scope . 5
2 Normative references . 5
3 Terms, definitions and abbreviated terms . 5
3.1 Terms and definitions. 5
3.2 Abbreviated terms . 5
4 Definitions of antenna as it pertains to PIM . 5
4.1 Antenna . 5
4.2 Antenna under test . 5
4.3 Active antenna . 6
4.4 Antenna PIM . 6
5 Antenna design and field installation considerations . 6
5.1 Environmental effects on PIM performance . 6
5.2 Antenna interface connection . 6
5.3 Mounting considerations to avoid PIM generation . 6
5.4 Neighbouring sources of interference . 6
5.5 Standard practices and guidelines for material selection . 7
6 PIM measurement considerations . 7
6.1 Quality assurance process and handling procedures . 7
6.2 Measurement accuracy . 7
6.3 Test environment . 7
6.4 Safety . 8
6.5 Test set-up . 8
6.5.1 Coaxial test cable assemblies . 8
6.5.2 Defining a good low PIM reference load . 8
6.5.3 Test set-up and test site baseline PIM verification . 8
6.6 PIM test configurations . 9
6.7 Combined environmental and PIM testing . 10
6.7.1 General . 10
6.7.2 Mechanical considerations .
...
IEC 62037-6 ®
Edition 2.0 2021-11
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Passive RF and microwave devices, intermodulation level measurement –
Part 6: Measurement of passive intermodulation in antennas
Dispositifs RF et à micro-ondes passifs, mesure du niveau d’intermodulation –
Partie 6: Mesure de l’intermodulation passive dans les antennes
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IEC 62037-6 ®
Edition 2.0 2021-11
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Passive RF and microwave devices, intermodulation level measurement –
Part 6: Measurement of passive intermodulation in antennas
Dispositifs RF et à micro-ondes passifs, mesure du niveau d’intermodulation –
Partie 6: Mesure de l’intermodulation passive dans les antennes
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 33.040.20 ISBN 978-2-8322-1049-3
– 2 – IEC 62037-6:2021 © IEC 2021
CONTENTS
FOREWORD . 3
1 Scope . 5
2 Normative references . 5
3 Terms, definitions and abbreviated terms . 5
3.1 Terms and definitions . 5
3.2 Abbreviated terms . 5
4 Definitions of antenna as it pertains to PIM . 5
4.1 Antenna . 5
4.2 Antenna under test . 6
4.3 Active antenna . 6
4.4 Antenna PIM . 6
5 Antenna design and field installation considerations . 6
5.1 Environmental effects on PIM performance . 6
5.2 Antenna interface connection. 6
5.3 Mounting considerations to avoid PIM generation . 7
5.4 Neighbouring sources of interference . 7
5.5 Standard practices and guidelines for material selection . 7
6 PIM measurement considerations . 7
6.1 Quality assurance process and handling procedures . 7
6.2 Measurement accuracy . 7
6.3 Test environment . 8
6.4 Safety . 8
6.5 Test set-up. 8
6.5.1 Coaxial test cable assemblies . 8
6.5.2 Defining a good low PIM reference load . 8
6.5.3 Test set-up and test site baseline PIM verification . 8
6.6 PIM test configurations . 9
6.7 Combined environmental and PIM testing . 10
6.7.1 General . 10
6.7.2 Mechanical considerations . 10
6.7.3 Test system cables and connectors . 10
6.8 PIM test chamber design . 11
6.8.1 General . 11
6.8.2 RF absorber materials . 11
6.8.3 Supporting structures and walls . 11
6.8.4 RF shielding . 12
7 Dynamic PIM measurement considerations . 12
7.1 General . 12
7.2 Dynamic testing methodology . 13
7.3 Shocks test . 13
Bibliography . 14
Figure 1 – Antenna reverse PIM test set-up . 9
Figure 2 – Antenna forward PIM test set-up . 10
Figure 3 – Hammer description . 13
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
PASSIVE RF AND MICROWAVE DEVICES,
INTERMODULATION LEVEL MEASUREMENT –
Part 6: Measurement of passive intermodulation in antennas
FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote international
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8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of patent
rights. IEC shall not be held responsible for identifying any or all such patent rights.
IEC 62037-6 has been prepared by IEC technical committee 46: Cables, wires, waveguides, RF
connectors, RF and microwave passive components and accessories. It is an International
Standard.
This second edition cancels and replaces the first edition published in 2013. This edition
constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) dynamic testing requirements updated to define impact energy and locations to apply
impacts to devices under test;
– 4 – IEC 62037-6:2021 © IEC 2021
The text of this International Standard is based on the following documents:
Draft Report on voting
46/838/FDIS 46/859/RVD
Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
The language used for the development of this International Standard is English.
This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available
at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are
described in greater detail at www.iec.ch/standardsdev/publications.
A list of all the parts in the IEC 62037 series, published under the general title Passive RF and
microwave devices, intermodulation level measurement can be found on the IEC website.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under webstore.iec.ch in the data related to the
specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
PASSIVE RF AND MICROWAVE DEVICES,
INTERMODULATION LEVEL MEASUREMENT –
Part 6: Measurement of passive intermodulation in antennas
1 Scope
This part of IEC 62037 defines the test fixtures and procedures recommended for measuring
levels of passive intermodulation generated by antennas, typically used in wireless
communication systems. The purpose is to define qualification and acceptance test methods for
antennas for use in low intermodulation (low IM) applications.
2 Normative references
There are no normative references in this document.
3 Terms, definitions and abbreviated terms
3.1 Terms and definitions
No terms and definitions are listed in this document.
ISO and IEC maintain terminological databases for use in standardization at the following
addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
3.2 Abbreviated terms
AIM Active intermodulation
AUT Antenna under test
ESD Electrostatic discharge
HPA High power amplifier
IM Intermodulation
LNA Low noise amplifier
PIM Passive intermodulation
RF Radio frequency
4 Definitions of antenna as it pertains to PIM
4.1 Antenna
An antenna is that part of a radio transmitting or receiving system which is designed to provide
the required coupling between a transmitter or a receiver and the medium in which the radio
wave propagates.
– 6 – IEC 62037-6:2021 © IEC 2021
The antenna consists of a number of parts or components. These components include, but are
not limited to, one or many radiating elements, one or many RF interfaces, a distribution or
combining feed network, internal support structures, devices which control or adjust the
amplitude/phase response and distribution to the radiating element(s), filters, diplexers,
orthomode transducers, polarizers, waveguides, coaxial cables or printed circuits. In addition,
peripheral components could also influence the PIM performance of the antenna. These
components can include, but are not limited to, mounting brackets, mounting hardware, radome,
radome fasteners, thermal insulation and grounding hardware.
4.2 Antenna under test
The antenna hardware can have an effect on the overall antenna PIM performance. Therefore,
it is necessary to specify the hardware which is to be part of the antenna under test (AUT).
4.3 Active antenna
An active antenna incorporates active devices such as low noise amplifiers (LNAs), high power
amplifiers (HPAs), phase shifters, etc. An active antenna has the additional concern of active
intermodulation (AIM) which is typically at a much higher level than PIM. The measurement of
PIM in the presence of AIM is not within the scope of this document. If required, the PIM
measurement of an active antenna shall be performed on the passive portion of the antenna only.
4.4 Antenna PIM
The antenna PIM is defined as the PIM that is generated by the antenna assembly itself at a
reference plane or RF interface. The PIM can be measured in a radiated or conducted
(transmissive or reflective) mode.
5 Antenna design and field installation considerations
5.1 Environmental effects on PIM performance
Any hardware located in the nearby environment can significantly influence the PIM
performance of an antenna or antenna system. The effect of ferromagnetic materials, dissimilar
metallic junctions which are part of neighbouring hardware, such as other antennas, tower
structures, aircraft fuselage components, spacecraft thermal control hardware, DC and ESD
grounding hardware, non-high pressure mechanical connections, etc., can potentially have a
detrimental effect on the PIM performance of the communication system.
5.2 Antenna interface connection
Any interface that is exposed to RF is a potential PIM source and shall be designed to be low
PIM. Care shall be taken to ensure that all the mating surfaces are clean. The connections,
whether coaxial or waveguide, should be inspected for dirt, metallic filings, sharp protruding
material, and other potential contaminates. Any coaxial connections shall be torqued to the
manufacturer’s specifications to ensure proper metal-to-metal contact pressure is achieved. If
waveguide is used, then the flange bolts shall be torqued to the recommended manufacturer’s
specifications. Careful attention shall be paid to the alignment of the mating coaxial connectors
or waveguide flanges.
The materials and combination of materials used in the connectors, including plating, are
important for the PIM performance. The use of a soft plating material (e.g. gold, silver, etc.) of
sufficient thickness (several skin depths) over a hard-base material (brass, BeCu, etc.) is usually
preferable. The number of interfaces (coaxial connectors and adapters) should be minimized.
This will reduce the number of metal-to-metal junctions and, thus, the possibility of PIM
generation. More information about coaxial connectors can be found in IEC 62037-3.
5.3 Mounting considerations to avoid PIM generation
The antenna shall be properly secured to its mounting bracket. All bolts and holding harnesses
used to secure the antenna to its support structure shall be tightened and torqued according to
the manufacturer’s specifications. The coaxial or waveguide transmission line(s) leading to the
antenna input port(s) shall also be well-secured and prohibited from rubbing or moving.
Care should be taken in the antenna placement by pointing it towards a clear sky view and to
isolate it from all possible neighbouring sources of interference such as tower structures, near-
by antennas, buildings, walls, aircraft fuselage, spacecraft platform, etc.
5.4 Neighbouring sources of interference
Knowledge of the RF environment in which the antenna is to be installed is important. Care should
be taken in the antenna placement to isolate it from all possible neighbouring sources of
interference. For instance, structures having low contact pressure or corroding parts should be
avoided. Additionally, other antennas radiating in a similar band or in bands whose harmonics
could fall within the receive frequency band of the antenna being installed also require
consideration. Other electric or electronic devices can emit interfering RF signals that fall into
the receive frequency band of the antenna.
5.5 Standard practices and guidelines for material selection
IEC 62037-1:2021, Clause 6 serves as a guide for the design, selection of materials, and
handling of components that can be susceptible to PIM generation. It is very important to consider
the application of the antenna, as there are large differences in acceptable PIM levels between
space applications and terrestrial applications.
6 PIM measurement considerations
6.1 Quality assurance process and handling procedures
The purpose of Clause 6 is to provide guidance in the areas of quality control as it pertains to the
performance of PIM testing of antenna products. Procedures are included to enhance the
accuracy and ensure safety when performing PIM measurements on antenna products. The
following guidelines will help minimize errors induced within the test system.
6.2 Measurement accuracy
The accuracy of PIM tests performed on antenna products can be severely affected by a
multitude of sources that can be either external or internal to the test system. Some of the
sources which can affect the results of PIM tests performed on antenna products include, but
are not limited to, the following:
a) objects comprising parts made of electrically conductive materials that are exposed to the
electromagnetic fields radiated by the AUT;
b) loose, damaged or corroded mounting hardware attached to the AUT;
c) loose or corroded hardware exposed to the radiated RF fields from the AUT;
d) radio frequency signals generated by external sources;
e) faulty or poorly performing coaxial interface cables;
f) dirty/contaminated/worn interface connections;
g) improperly mated interface connections;
h) poorly shielded RF interface connections;
i) inadequately filtered AIM from the test set-up;
j) consideration of input transmission line losses;
k) contaminated absorbers.
– 8 – IEC 62037-6:2021 © IEC 2021
6.3 Test environment
When applicable, PIM measurements can be accomplished outdoors. In performing such a test,
it is important to ensure that government regulations pertaining to the maximum authorized RF
radiation levels are met. Also, the RF energy radiated from the AUT can generate PIM in
surrounding structures that may couple back into the antenna resulting in invalid PIM test results.
Additionally, external sources of RF radiation can interfere with the test measurements. A survey
of the frequencies locally in use is recommended prior to testing. Many of the external sources
of PIM can be minimized or eliminated by performing the PIM testing of antennas within an
anechoic test chamber providing a low PIM test environment. More information on the
construction of anechoic test chambers suitable for PIM testing is provided in 6.8.
6.4 Safety
Performing PIM tests on antenna products can be dangerous. Potentially high voltages and high
levels of RF energy can be present both within the AUT and within the test environment. The AUT
should be positioned such that personnel will not be exposed to electromagnetic fields exceeding
the acceptable levels specified by government agencies.
6.5 Test set-up
6.5.1 Coaxial test cable assemblies
A problem with PIM test set-ups using coaxial cable interfaces is the need to repeatedly
connect/disconnect coaxial connectors. The following are some recommendations on test set-
up procedures.
a) Sealing O-rings at connector interfaces should be thoroughly cleaned or should preferably
be avoided if possible. These O-rings accumulate metal filings, which can become a source
of PIM.
b) Inspect connectors, dielectric and interface mating surfaces or flanges for contamination,
especially metallic debris, just prior to mating the interface. Also inspect connector mating
surfaces for burrs, scratches, dents, and loss of plating. Proper installation and torquing of
the hardware will minimize the generation of PIM within interface connections.
c) Clean compressed air should be used to blow potential metal particles from the connector
interfaces after each connect-disconnect cycle.
d) Great care shall be taken to ensure that the cables have not been stressed or fatigued to the
point of cracking. The inner and outer conductors can crack under the insulating cable jacket
and not be detectable by visual inspection. This will cause intermittent PIM signals to be
generated. One way to test for this is to flex or tap on the cable while performing a baseline
test. If there are fluctuations in the PIM signal, the cable can be damaged and should be
replaced.
6.5.2 Defining a good low PIM reference load
A good low PIM load can be made using a long section of high quality coaxial cable terminated
with a high quality (low PIM) connector. This connector should be soldered to the coaxial cable
on both the inner and outer conductors. The length of cable should be held in a fixture so that
no fatigue is placed on the connector or cable. When soldering coaxial cables, it should be done
very carefully to avoid melting or deforming the insulation, which can cause impedance changes.
6.5.3 Test set-up and test site baseline PIM verification
Prior to the testing of the antenna, perform a baseline PIM test set-up noise floor verification.
To verify the test set-up itself, a low PIM termination may be used. Check the cables and
connections for sensitivity to flexure, mechanical stress and configuration during the baseline
test.
The test site should also be evaluated to ensure that it does not generate unacceptable levels of
PIM or to identify any potential extraneous interfering RF sources. The test site could be an
anechoic test enclosure or a chosen outdoor site. If an anechoic chamber is used, special design
considerations are needed as outlined in 6.8. During the site verification, if possible, use a low
PIM reference antenna having a radiation pattern and gain comparable to that of the AUT in
order to ensure that the test environment is exposed to representative flux densities as for the
AUT test.
The actual antenna PIM test should be performed using the same set-up as for the baseline test:
minimize movements of components, do not add components, minimize changes in the
environment, etc. After the antenna PIM test is completed or as required during the test, compare
the baseline test results with previous set-up verification results for any sign of degradation in
the test system.
6.6 PIM test configurations
A typical test set-up for antenna reverse (reflected) PIM testing is shown in Figure 1 and another
for antenna forward (transmitted) PIM is shown in Figure 2. It should be noted that the dynamic
range between the two test configurations should be examined to assess the appropriate choices
to use. In both cases, the test should take place in either a well-designed low PIM anechoic
chamber or outdoors, which would allow the full range of antenna movement. For the antenna
forward (transmitted) PIM test, a low PIM antenna on the receiver side of the test set-up is
required. Also, for this test, the environment can be first verified by using two low PIM antennas.
Whenever possible, the diplexer (Figure 1) and the filter (Figure 2), both of which should be low
PIM, shall be placed as close as possible to the AUT input port to minimize PIM generated by
the test set-up. The overall cable or waveguide lengths should be minimized to deliver maximum
power to the AUT. Also, coaxial and waveguide adapters should be avoided as much as possible.
Figure 1 – Antenna reverse PIM test set-up
Each set-up has two synthesized sources, amplified separately to avoid AIM (active
intermodulation). The two-tone-test results in discrete intermodulation products, whose levels
are to be measured. These PIM products are typically first amplified by one or two stages of
LNAs before detection by the spectrum analyzer or digital receiver. This is in order to increase
the sensitivity of the set-up.
– 10 – IEC 62037-6:2021 © IEC 2021
Figure 2 – Antenna forward PIM test set-up
6.7 Combined environmental and PIM testing
6.7.1 General
Whenever possible and practical, each AUT should be measured for PIM while being exposed
to representative environmental operating conditions. If it is not possible, the AUT may be
measured for PIM before and after exposure to representative environmental conditions.
6.7.2 Mechanical considerations
A loose mechanical joint is likely to cause PIM. Materials expand and contract due to temperature
changes. Different materials expand and contract at different rates. This difference can cause
varying amounts of stress to be induced in any mechanical joint of the antenna components. The
differences in expansion and contraction can even cause the parts to move so much as to loosen
a mechanical joint. A bolted joint that was torqued to its specified value can loosen to the point
where the required clamping force is no longer being produced. Evaluation of mechanical
connections may be accomplished by performing PIM testing during thermal cycling.
Vibrations can produce detrimental effects similar to those from thermal environments.
For terrestrial applications, extreme temperature cycling occurs only in specific geographical
areas and is more applicable to aeronautical and space applications. Wind-induced vibrations
occur in most terrestrial and aeronautical applications but never for space applications. However,
vibrations are induced on space-borne antennas during platform manoeuvres. For space and
aeronautical applications, it is recommended that PIM testing be performed during thermal
cycling before and after vibration testing.
6.7.3 Test system cables and connectors
The test cables connected to the antenna under test are exposed to the same test environments
as the antenna itself. Therefore, great care shall be taken in selecting cables suitable for PIM
testing in the specific test environment. The entire test set-up, including the cables, shall be
verified under the same test conditions as for the AUT testing.
6.8 PIM test chamber design
6.8.1 General
The purpose of 6.8 is to provide guidance for the construction of test chambers suitable for the
performance of PIM testing on antennas.
Evaluation of antenna products for PIM presents additional challenges not found with other non-
radiating components. The antenna will be connected to an RF source and will radiate RF
energy during the PIM test. This energy shall not be allowed to excite potential PIM sources in
the test environment. It is also sometimes not practical to perform these tests in an outdoor
environment since the radiated RF energy should preferably be contained. To successfully
perform PIM testing on antennas, it can be desirable to construct an RF anechoic chamber
specially designed for PIM testing.
The main components of an RF anechoic test chamber are:
a) RF absorber materials;
b) supporting structures and walls;
c) RF shielding.
Each of these components will be discussed in 6.8.2 to 6.8.4.
6.8.2 RF absorber materials
RF absorber materials are commonly manufactured from a carbon impregnated foam. This
material offers attenuation to radio frequency signals as they pass through it. This attenuation of
the signal (absorption of energy) serves in essence as a "load" to the antenna.
RF absorber materials are available in many styles and sizes. The selection of style and size is
dependent on the frequency of operation and the placement within the test chamber. Proper
selection of the RF absorbers can be the most critical factor in the construction of a PIM test
chamber. Recommendations that can help in the selection process are as follows:
a) Select an absorber with an incident RF attenuation greater than 30 dB.
b) For good results, place pyramidal absorber panels in the field of the antenna radiation
pattern, preferably with normal incidence to the beam peak. However, best results can be
achieved when the interior of the test chamber is completely covered with RF absorber
material.
c) As a minimum, ensure there are enough panels to avoid back reflections.
For safety purposes, select an absorber that contains fire retardant materials and is rated for the
anticipated maximum power dissipation required.
6.8.3 Supporting structures and walls
The supporting structure and walls for the PIM test chamber shall provide a suitable inner surface
for attachment of the RF absorber material. In some applications, the supporting structure and
walls can also be required to assist in the control of the temperature, the pressure, the humidity
level, or other environmental conditions for the test.
– 12 – IEC 62037-6:2021 © IEC 2021
The materials and methods of construction will vary greatly depending on the specific application.
For many applications, simple lumber and plywood provide very good results. Cement block
construction also provides excellent support but at a much greater expense. Some general
considerations in designing the support structure and walls are as follows:
a) The use of metal shielding in the outer structure improves the isolation of the anechoic
chamber and is recommended when RF shielding needs to be high (see 6.8.4). However, it is
critical to ensure that the design does not include metal-to-metal junctions that themselves
have poor PIM performance. Examples of this would include overlapping metal plates or the
use of metal hardware going through sheet metal parts that are exposed.
b) Wood supports can be successfully joined using screws. Screws are stronger than nails and
it is easier to control their final location. Do not allow metal fasteners to contact each other,
even within the framework.
c) Make sure that the actual dimensions of absorber panels are known before completing the
design of the structure as they do not usually have the exact size advertised.
d) The size of the test chamber should be large enough to allow the test antenna to be sufficiently
far from any RF absorber to avoid mutual coupling between the radiating antenna and the
absorber material.
e) Hinges, fasteners, light fixtures, fire sprinklers, mounting hardware, etc., should all be
evaluated for potential PIM generation.
6.8.4 RF shielding
RF shielding may or may not be required, depending on the particular application. The purpose
of RF shielding can be for security, to maintain a low RF noise floor in the test facility or can be
required to ensure personnel safety. A method of identifying the need for RF shielding is based
on the calculated power densities. From such calculations, it can be found that RF levels behind
the RF absorber are extremely low and therefore safe. It is always recommended that an RF
survey of the area surrounding the chamber be performed prior to the approval of the final test
plan or procedure.
Methods of RF shielding also vary depending on the application. One method providing good
results for most applications is to apply thin aluminium sheets or panels to the exterior surface
of the test chamber structure. The sheets can be securely attached using adhesive products.
Placing a plastic insulating material on the edge of each panel will prevent any direct contact
between panels. A small gap between the panels will not pass RF energy except at extremely
small wavelengths compared to the gap size. Although RF power levels can be extremely low at
the RF shield, it would still be advisable to avoid materials which can generate PIM such as wire
mesh fabrics.
7 Dynamic PIM measurement considerations
7.1 General
In real operating conditions, an antenna is submitted to varying amounts of stress, like
temperature changes and vibrations. Since PIM sources are often caused by loose metal-to-
metal contacts, whenever possible and practical, each antenna should be measured for PIM
while being exposed to representative operating conditions.
It is not possible to define a single test representing all the possible operating conditions for
any antenna but defining some guidelines to apply some stresses during PIM test can be done.
This is the goal of the "dynamic testing methodology" proposed in Clause 7, "dynamic" meaning
here with mechanical stresses.
7.2 Dynamic testing methodology
There are several methods to apply stress on an antenna. Nevertheless, the PIM dynamic test
shall be done in an acceptable time frame, in a practical and pragmatic manner, shall not cause
irreversible damages on the AUT and shall take into account that antennas can have different
various forms. The stress applied during the PIM dynamic tests should be able to detect
potential instabilities within the antenna.
Methodologies permitting to apply a shock sequence are compatible with these inputs and goals.
The report should document the type, description and conditions of the test and the PIM values
prior to each dynamic test, during dynamic test, and after dynamic test. If the PIM cannot be
measured during the stress, the results shall be compared before and after the test sequence.
7.3 Shocks test
A shocking sequence is applied along the antenna, every 30 cm at least, preferably on its rear
face. Shock should not be applied on potential AUT accessories or other fragile parts.
At each location, two consecutive impacts are applied.
The impact energy value shall be 1 J. The impact force can be applied by using a spring hammer
or automated impact hammer. A description of related tools and methodology can be found in
IEC 60068-2-75.
It is preferable that an impactor is made from polyamide (hardness range between 85 HRR and
100 HRR Rockwell hardness according to ISO 2039-2) in order to ensure the energy transfer
and to prevent PIM generation by the impactor due to metal-to-metal contact with the AUT (see
Figure 3 for the hammer description). The surface impact should be sufficiently wide not to
damage the AUT.
It is preferable that impact locations are a structural part of the product, solid enough to
withstand a mechanical shock without damage.
Figure 3 – Hammer description
– 14 – IEC 62037-6:2021 © IEC 2021
Bibliography
IEC 60068-2-75, Environmental testing – Part 2-75: Tests – Test Eh: Hammer tests
IEC 62037-1, Passive RF. and microwave devices, intermodulation level measurement – Part 1:
General requirements and measuring methods
IEC 62037-3, Passive RF and microwave devices, intermodulation level measurement – Part 3:
Measurement of passive intermodulation in coaxial connectors
ISO 2039-2, Plastics – Determination of hardness – Part 2: Rockwell hardness
____________
– 16 – IEC 62037-6:2021 © IEC 2021
SOMMAIRE
AVANT-PROPOS . 18
1 Domaine d’application . 20
2 Références normatives . 20
3 Termes, définitions et termes abrégés . 20
3.1 Termes et définitions . 20
3.2 Termes abrégés . 20
4 Définitions d’une antenne dans le contexte de l’intermodulation passive . 20
4.1 Antenne . 20
4.2 Antenne soumise à essai . 21
4.3 Antenne active . 21
4.4 Intermodulation passive dans l’antenne . 21
5 Considérations relatives à la conception de l’antenne et à son installation sur le
terrain . 21
5.1 Effets de l’environnement sur les performances de l’intermodulation passive . 21
5.2 Connexion d’interface de l’antenne . 21
5.3 Considérations relatives au montage pour éviter la génération
d’intermodulation passive. 22
5.4 Sources de perturbations dans le voisinage . 22
5.5 Pratiques de référence et cadre directeur pour le choix des matériaux . 22
6 Considérations relatives à la mesure de l’intermodulation passive . 22
6.1 Pr
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