Coaxial RF Connector Interface with Insulated Centering Sleeve
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Solution Overview
Problem
Existing coaxial RF connectors face challenges in achieving low passive intermodulation (PIM) and reliable grounding, especially in multi-connector assemblies and radiation fields, due to RF currents flowing through non-conductive paths and difficulties in maintaining high contact forces across all components.
Innovation Solution
A coaxial RF connector system with galvanic contact between inner and outer conductors, using centering devices with insulating materials to prevent RF currents from flowing through non-conductive paths, ensuring a low ohmic resistance and capacitive coupling for improved shielding and reduced PIM, and incorporating features like slits and spring-loaded contact elements for enhanced contact forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If dielectric coated surfaces are used between connectors, then galvanic contact is avoided, but grounding quality deteriorates
Solution Approach 1:
The connector interface is segmented into distinct functional zones: a galvanic contact zone for the outer conductors (providing grounding path) and a non-galvanic zone for the inner conductors (reducing PIM generation). This segmentation allows each zone to optimize its function independently.
Solution Approach 2:
Different contact qualities are applied locally: the outer conductor interface uses galvanic contact with metal-to-metal contact for grounding, while the inner conductor interface uses dielectric-coated surfaces for reduced PIM. This local differentiation resolves the contradiction by allowing both contact types to coexist in appropriate locations.
2Object-generated harmful factors
If high contact forces are applied between plug and socket connectors, then passive intermodulation is reduced, but device complexity increases
Solution Approach 1:
The spring-loaded outer connector mechanism is extracted and applied specifically to the plug connector, allowing it to provide the necessary contact force independently. This extraction enables the precision contact design to be implemented without requiring complex structures in both connectors.
Solution Approach 2:
The connector uses dynamic spring-loaded contact elements that automatically adjust contact force based on mating conditions. This dynamic mechanism maintains optimal contact force for low PIM while simplifying the overall structure compared to rigid precision positioning systems.
3Reliability
If galvanic contact is provided between outer conductors, then grounding is improved, but RF currents may flow through non-conductive paths, increasing PIM
Solution Approach 1:
The electrical contact paths are segmented into conductive paths (outer conductors for grounding) and non-conductive paths (inner conductors with dielectric coatings). This segmentation ensures RF currents follow intended paths through the galvanic outer conductor contact while preventing unwanted current flow through non-conductive paths.
Solution Approach 2:
Dielectric materials serve as intermediaries between the inner conductors, preventing direct galvanic contact and thus blocking RF current flow through non-conductive paths. Meanwhile, the outer conductors provide direct galvanic contact for grounding without such intermediaries, resolving the contradiction through selective use of intermediaries.
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 solution effectively reduces PIM by ensuring RF currents flow only through intended paths, maintaining low ohmic resistance and characteristic impedance, and allowing the connectors to be used in radiation fields without generating intermodulation from external signals.
Implementation Method 1
at least one means for electrically insulating the first centering device from the second centering device, when the coaxial RF connector and the coaxial RF counter connector are mated to each other
Implementation Method 2
The RF connector system provides a galvanic contact, when the coaxial RF connector is mated to the coaxial RF counter connector
Implementation Method 3
A coaxial RF connector with capacitive coupling
Data Source
Figure 1
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AI summary
A coaxial RF connector system comprises RF connectors with inner and outer conductors providing a galvanic contact. An outer conductor of a first connector has a plurality of longitudinal slits forming a plurality of spring loaded contact elements which contact a solid outer conductor of a second connector. The first connector has a centering sleeve which is one part with the outer conductor for centering the solid outer conductor of the second connector. An insulation sleeve is provided between the centering sleeve and the solid outer conductor. This prevents a galvanic contact and improves PIM.