IEC 62037-6-2021 pdf free download – Passive RF and microwave devices, intermodulation level measurement – Part 6: Measurement of passive intermodulation in antennas.
The antenna consists of a number of parts or components.These components include, but arenot limited to,one or many radiating elements,one or many RF interfaces, a distribution orcombining feed network,internal support structures，devices which control or adjust theamplitude/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.Thesecomponents can include, but are not limited to, mounting brackets,mounting hardware, radome,radome fasteners, thermal insulation and grounding hardware.
4.2Antenna 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).
4.3Active antenna
An active antenna incorporates active devices such as low noise amplifiers (LNAs), high poweramplifiers (HPAs), phase shifters,etc. An active antenna has the additional concern of activeintermodulation (AIM) which is typically at a much higher level than PIM.The measurement ofPIM in the presence of AIM is not within the scope of this document. lf required，the PIMmeasurement of an active antenna shall be performed on the passive portion of the antenna only.
4.4Antenna PIM
The antenna PIM is defined as the PIM that is generated by the antenna assembly itself at areference plane or RF interface. The PlM 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 PIMperformance of an antenna or antenna system.The effect of ferromagnetic materials,dissimilarmetallic junctions which are part of neighbouring hardware,such as other antennas， towerstructures,aircraft fuselage components，spacecraft thermal control hardware，DC and ESDgrounding hardware，non-high pressure mechanical connections,etc.,can potentially have adetrimental effect on the PIM performance of the communication system.
5.2Antenna interface connection
Any interface that is exposed to RF is a potential PIM source and shall be designed to be lowPIM. 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 protrudingmaterial,and other potential contaminates. Any coaxial connections shall be torqued to themanufacturer’s specifications to ensure proper metal-to-metal contact pressure is achieved. lfwaveguide is used, then the flange bolts shall be torqued to the recommended manufacturer’sspecifications. Careful attention shall be paid to the alignment of the mating coaxial connectorsor waveguide flanges.
The materials and combination of materials used in the connectors，including plating,areimportant for the PlIM performance.The use of a soft plating material (e.g. gold, silver, etc.) ofsufficient thickness (several skin depths) over a hard-base material (brass,BeCu, etc.) is usuallypreferable.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 PIMgeneration. More information about coaxial connectors can be found in lEC 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.IEC 62037-6 pdf download.