Rotatable Coaxial Connector PIM Reduction
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Solution Overview
Problem
Rotational forces during coaxial cable installation can damage the connector and cable integrity, leading to unacceptable levels of passive intermodulation distortion (PIM) due to non-uniform circumferential contact between the spring contact and the connector surfaces.
Innovation Solution
A coupling arrangement where the primary electrical contact between the spring contact and the contact groove occurs along the connector end sidewall, with a groove design that prevents contact with the groove bottom, ensuring uniform circumferential contact and using a bias gasket to maintain contact during rotation, eliminating the need for a grip ring mechanical interconnection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a flared end of the outer conductor is clamped against an annular wedge surface via a coupling nut, then secure mechanical interconnection is achieved, but rotational forces during installation can damage the connector and cable integrity
Solution Approach 1:
The connector separates the mechanical retention function from the electrical contact function. The grip ring with grip surfaces provides mechanical retention without clamping, allowing rotation. The spring contact provides electrical contact independently. This segmentation eliminates the damage caused by rigid clamping during rotation while maintaining secure mechanical interconnection.
Solution Approach 2:
The spring contact is designed to be resilient and adaptable, allowing it to maintain uniform circumferential contact during rotation. The dynamic spring mechanism compensates for rotational movements and maintains reliable electrical connection without requiring rigid mechanical clamping that would prevent rotation.
2Strength
If the spring contact contacts the groove bottom, then mechanical support is provided, but non-uniform circumferential contact paths cause high PIM
Solution Approach 1:
The contact groove is designed with specific geometric characteristics where the sidewall contact provides the primary electrical contact path. The groove geometry is optimized so that contact occurs at specific locations (sidewall rather than bottom) to ensure uniform circumferential contact. This local quality control of the contact geometry eliminates non-uniform contact paths and reduces PIM while maintaining mechanical support.
3Reliability
If a grip ring mechanical interconnection is used, then rotational retention is achieved, but device complexity increases
Solution Approach 1:
The grip ring is integrated into the connector body as a single piece rather than being a separate component. The grip surfaces are formed directly on the connector structure. This merging of functions reduces the number of parts and assembly steps while maintaining rotational retention capability.
Solution Approach 2:
The connector structure performs multiple functions: the grip surfaces provide mechanical retention during rotation, the spring contact provides electrical connection, and the overall structure allows rotational movement. This multi-functionality eliminates the need for separate grip ring components while achieving rotational retention.
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
This configuration enhances PIM performance by maintaining uniform electrical interconnection and preventing deformation-induced non-uniform contact paths, thereby reducing PIM and ensuring reliable connectivity during rotation.
Implementation Method 1
a bias gasket to maintain contact during rotation
Data Source
AI summary
A coupling arrangement between a coaxial connector body and an outer conductor of a coaxial cable that includes an annular contact groove provided in a bore of the connector body. The contact groove has a groove bottom, a connector end sidewall and a cable end sidewall. The connector end sidewall is angled to transition between a groove bottom width that is less than a groove top width. A spring contact has a non-deformed state width seated within the contact groove. The non-deformed state width is greater than the groove bottom width and less than the groove top width. In a non-deformed state the spring contact contacts the connector end sidewall, without contacting the groove bottom.