Radiated PIM Testing Standard Expected From IEC

Characterizing the Passive Intermodulation (PIM) performance of mechanical objects like brackets has presented designers with a new radiated PIM testing and measurement challenge. How do you verify if a bracket design is low PIM when a bracket does not have Radio Frequency (RF) connectors for injecting PIM test signals?

A working group within the International Electrotechnical Commission (IEC) has taken on this challenge and has developed a new specification for Radiated PIM Testing. This new PIM testing standard, IEC-62037-8, is in the final stages of release and should be published by the IEC later this year.

The New Radiated PIM Testing Procedure IEC 62037-8

The new radiated PIM testing procedure requires devices under test (DUT) to be radiated with two high-power test signals while applying a dynamic stimulus. The DUT is radiated on four sides using two different polarization transmit signals for a total of eight radiated PIM tests per frequency band.

For items deployed near cell sites, it is a good idea to run the test at a low frequency such as 700 MHz and then repeat the tests at a high frequency such as 1900 MHz to better simulate the range of frequencies encountered in the field. This comes to a total of 16 individual radiated PIM tests per design to verify it will not generate passive intermodulation when radiated by RF energy.

PIM Shield® Low PIM Products Meet IEC PIM Test Standards

We use the new PIM testing standard outlined in IEC 62037-8 to validate the PIM performance of every PIM Shield® product promoted as low PIM. Even after 4 years of developing low PIM products we are still occasionally surprised by failing results during this PIM test. Things that look like they should be low PIM sometimes are not! The only way to know for sure if a product is low PIM is to perform the test according to the most up-to-date PIM testing guidelines.

Operators should not take chances when approving products for use in the high-risk PIM zone near antennas. Claims that a product is "low PIM" are meaningless unless backed up with test data. Radiated PIM Test Reports for every ConcealFab PIM Shield® low PIM product is available to download from the individual product pages on the ConcealFab website. Learn more about our poles, attachments, and interference mitigation products by browsing this website.