PIM (Passive Intermodulation) testing basics

This page covers PIM (Passive Intermodulation) testing basics.It mentions PIM tester or PIM Analyzer used to conduct PIM test of the Base station Site. Anritsu PIM Analyzer is one of the popular PIM test equipment.

As we know intermodulation is kind of distortion produced in the wireless system as a result of more than one frequencies getting tapped into amplifier or mixer or connector or cable. Let us understand example of intermodulation with two frequencies as input. The nonlinear active or pasive components generate second and third order products of these two frequencies (i.e. f1 and f2).

Active IM and Passive IM (PIM)

There are two basic types of intermodulation (IM) viz. active IM and Passive IM. The active IM is a result of mixing of more than one frequency signals in the active components such as RF mixer, RF amplifier etc. The passive IM is a result of mixing of frequency signals in the passive components or parts such as loose contacts between cable and connector, broken connectors, broken cables, passive components with poor VSWR from different vendors in a system etc.

Out of second and third Intermodulation, third order distorition is the one creates problem in normal functioning of the wireless system. It is measured by measuring TOI (Third Order Intercept) Point or 1dB compression point. TOI is also known as IP3.

Anritsu PIM Analyzer used as PIM Test Equipment

The test equipment used for PIM testing is known as PIM analyzer. Anritsu corporation has developed MW82119A PIM Master which can be used as PIM test equipment. As it is portable, it is very handy for cellular tower testing requirement.

Following are the features of this PIM analyzer:
• Battery powered (One time charged battery can run for 2.5 Hrs.)
• houses 8.4 inch touchscreen display
• Supports testing of LTE, PCS, DCS, GSM technologies
• Different models supports different frequency bands (700 MHz, 1900 MHz) in the transmit and receive directions
• Allows user to configure two input carrier frequencies (f1,f2), order of intermodulation, output power level, duration of test, upper limit, lower limit etc.
• Provides PIM vs time,distance to PIM and swept PIM measurements

Other PIM tester or PIM Analyzer Equipments

Following table mentions Other PIM analyzer equipments used as PIM tester.

Company Description
Kaelus Portable PIM Test Analyzers (iPA, iTA, iQA models)
AWT Global S1L PIM analyzer for QA and lab testing, TETRA/UHF PIM test equipment etc.
rosenberger Portable PIM analyzer for cellular tower site and fixed one for desktop applications
Boonton PIM tester model: PIM-21
Communication Components Inc. NJ, USA
portable, rack mount tower series of PIM analyzers, developed for LTE, GSM, PCS standard based products

RF test and measurement equipments

RF Vector Signal Generator
Keysight vs Tektronix vs Rigol Spectrum Analyzers
Waveguide Mixer
Sound Level Meter
PIM Analyzer
Noise Figure Meter
Near Field Probe Set