Handheld PIM Probe Tuning for Fast External Source Detection

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Solution Overview

Problem

Conventional PIM testing methods are inefficient in locating external PIM sources beyond the antenna, relying on a trial-and-error approach with RF absorbing foam, which is time-consuming and often unsuccessful in identifying non-obvious PIM sources.

Innovation Solution

A handheld PIM probe with a tuned antenna and coaxial cable system, including filters to suppress downlink frequencies and pass PIM frequencies of interest, allowing for precise detection of PIM sources using a signal analyzer, featuring orthogonal PC board or wire loop designs for orientation insensitivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional PIM testing methods using trial-and-error with RF absorbing foam are used, then external PIM sources can be detected, but the process is time-consuming and inefficient

Engineering Contradiction:

ImprovePIM source detection accuracyVSAvoidTime required for PIM source location

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent replaces the mechanical trial-and-error method of covering objects with RF absorbing foam with an electromagnetic field-based detection system. The handheld probe with tuned antenna and signal analyzer uses electromagnetic principles to directly detect and locate PIM sources through systematic scanning, eliminating the need for physical obstruction methods and significantly reducing detection time while maintaining accuracy.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If conventional PIM testing methods are used, then PIM sources can be identified, but the process lacks efficiency and speed

Engineering Contradiction:

ImprovePIM source identification accuracyVSAvoidSpeed of PIM detection process

Core Design Contradiction:

Measurement precisionVSProductivity

Solution Approach 1:

The invention substitutes the slow mechanical process of methodically covering and uncovering objects with RF foam with rapid electromagnetic scanning using a handheld probe. The probe systematically scans the environment and immediately displays PIM source locations on a screen, enabling technicians to identify multiple PIM sources quickly and efficiently without physical obstruction methods.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent creates a visual representation or 'copy' of the electromagnetic field environment by displaying detected PIM sources on a screen interface. This visual copy allows technicians to immediately see the location and strength of PIM sources without physically interacting with each potential source, dramatically increasing detection speed while maintaining identification accuracy.

Inventive Principle:

Principle #26Copying

3Productivity

If handheld PIM probe with tuned antenna is used, then detection speed improves, but device complexity increases

Engineering Contradiction:

ImprovePIM detection speedVSAvoidProbe system complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The handheld probe integrates multiple functions into a single portable device: the tuned antenna detects PIM frequencies, the bandpass filter isolates relevant signals, the signal analyzer processes the electromagnetic data, and the display screen presents results. This multi-functional integration enables rapid PIM detection while consolidating complexity into one unified tool rather than requiring multiple separate pieces of equipment.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enables precise and efficient location of external PIM sources, reducing the time and effort required to identify and mitigate PIM interference, improving the accuracy and speed of PIM detection and mitigation processes.

Implementation Method 1

The PIM antenna is tuned by loop size to receive PIM frequencies of interest generated by downlink broadcast frequencies of a site antenna

Methodology Applied

Scientific EffectElectromagnetic radiation: Electromagnetic Induction

Implementation Method 2

A filter connected to the coaxial cable is configured to suppress the downlink broadcast frequencies and pass the PIM frequencies of interest

Methodology Applied

Scientific EffectFrequency filtering: Filter (electronic)

Data Source

PatentEP3520171B1Passive intermodulation (PIM) probe

Publication Date: 2024.08.28 PIM SOLUTIONS LLC

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AI summary

A PIM probe that includes a PIM antenna carried on a wand sized for positioning by hand. The PIM antenna is tuned by loop size to receive PIM corresponding to uplink reception channels of a site antenna generated by downlink broadcast frequencies F1 and F2 of the duplex antenna. The PIM antenna vanes may include conductors printed on a PC boards or wire loops. A PIM probe system includes a signal analyzer that displays a representation of PIM received by the PIM antenna. The PIM probe system further includes an RF filter for passing the PIM frequencies of interest and suppressing the test frequencies transmitted by the site antenna, such as a cellular base station antenna. When the site antenna is broadcasting the test frequencies, the technician places the PIM antenna in various locations to detect the presence of PIM in those locations.