Non-Uniform Polymeric Cable Hanger Structure to Minimize PIM
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Solution Overview
Problem
Metallic cable hangers near antennas on cell sites cause unwanted passive intermodulation (PIM) in the radio frequency environment and are costly, necessitating non-metallic, non-magnetic solutions for cable management on small cell telecommunications towers that are easy to install and reduce technical performance concerns like PIM.
Innovation Solution
A flexible cable holding device made of polymeric material with a wrapping and mounting portion, featuring non-uniform undulations and apertures, and a securing feature with barbs that can be secured to a mounting structure, designed to circumscribe cables and reduce stress concentrations for improved elongation and flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If metallic cable hangers are used to hold cables on cell sites, then the cables are securely held and mounted, but unwanted passive intermodulation (PIM) is generated in the radio frequency environment
Solution Approach 1:
The patent removes metallic components from the cable hanger design and replaces them with non-metallic polymeric materials. This extraction of the harmful metallic element eliminates the source of PIM while preserving the cable holding function through the polymeric body with wrapping and mounting portions.
Solution Approach 2:
The patent employs composite material construction using polymeric materials instead of traditional metallic components. The polymeric body provides both structural integrity for cable holding and electromagnetic compatibility by being non-metallic, thus resolving the PIM issue while maintaining mechanical performance.
2Object-generated harmful factors
If non-metallic cable hangers are used to reduce PIM, then PIM is minimized, but the structural strength and durability may be compromised
Solution Approach 1:
The patent applies local quality by varying the thickness of the polymeric body in different regions. The body is thicker at the wrapping portion to provide strength for cable containment and at the mounting portion for secure attachment, while maintaining non-metallic composition throughout to eliminate PIM.
Solution Approach 2:
The patent incorporates undulations (curved features) in the polymeric body structure. These curved features distribute stress more evenly throughout the material, preventing stress concentration that could lead to failure, thereby compensating for the lower inherent strength of polymeric materials compared to metals.
3Ease of manufacture
If uniform undulations are used in the polymeric body, then manufacturing is simplified, but stress concentrations occur leading to cracking
Solution Approach 1:
The patent employs asymmetric undulation patterns where the height, width, and spacing of undulations vary along the length of the polymeric body. This asymmetry prevents stress concentration at specific locations by distributing mechanical loads more evenly, thereby reducing the likelihood of cracking while remaining manufacturable.
Solution Approach 2:
The patent applies local quality by varying the dimensions of undulations at different locations along the polymeric body. Specific undulations have different heights and widths tailored to local stress requirements, with greater variation in regions experiencing higher mechanical loads, thus preventing cracking while maintaining manufacturing feasibility.
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
The device achieves significant elongation and stress distribution uniformity, reducing the likelihood of cracking and accommodating various cable sizes, while minimizing PIM and installation costs by using polymeric materials that are non-metallic and non-magnetic.
Implementation Method 1
The device achieves significant elongation and stress distribution uniformity, reducing the likelihood of cracking
Data Source
AI summary
A device adapted for holding one or more discrete cables includes: a flexible main body formed of a polymeric material having a length, a width, a thickness, and a longitudinal axis, the main body including a wrapping portion and a mounting portion, wherein the wrapping portion is configured to be wrapped such that the main body circumscribes the one or more discrete cables, and wherein a plurality of undulations are present between the mounting portion and the wrapping portion; a securing feature attached to or integral with the mounting portion of the main body and configured to be secured to a mounting structure; and a plurality of apertures along the longitudinal axis of the wrapping portion of the main body. The securing feature is configured to be received through one of the plurality of apertures when the main body is wrapped around the one or more discrete cables. At least one of the undulations varies in height, width and/or thickness from at least one of the other undulations.