Coaxial Connector Ingress Reduction Shield Waveguide

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Solution Overview

Problem

Conventional F-Type coaxial cable connectors fail to effectively reduce RF ingress when left open, leading to signal interference in cable television and satellite television systems, with existing solutions being either expensive, impractical, or mechanically unreliable.

Innovation Solution

The implementation of electromagnetic radiation shields, such as waveguides with specific geometries and materials, is used to restrict RF ingress into coaxial cable connectors, even when they are open, by redistributing electric charges and attenuating unwanted frequencies.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If traditional connector shielding is used, then RF ingress is reduced to some extent, but the shielding effectiveness is insufficient and connectors remain vulnerable when left open

Engineering Contradiction:
ImproveRF ingressVSAvoidconnector performance when open
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

A waveguide barrier is introduced as an intermediary element between the external environment and the connector internals. This waveguide acts as a mediator that selectively blocks RF ingress while allowing the connector to remain open for normal operation. The waveguide creates an electromagnetic barrier without requiring physical enclosure of the connector.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The electrical parameters of the connector environment are changed by introducing the waveguide barrier, which modifies the electromagnetic field distribution. The waveguide changes the effective impedance and shielding characteristics of the open connector, transforming it from a vulnerable state to a protected state while maintaining operational functionality.

Inventive Principle:
Principle #35Parameter changes

2Object-affected harmful factors

If multi-braid coaxial cables are used, then RF ingress is reduced, but cable flexibility and installation ease are compromised

Engineering Contradiction:
ImproveRF ingressVSAvoidcable installation
Core Design Contradiction:
Object-affected harmful factorsVSEase of operation

Solution Approach 1:

The RF protection function is extracted from the cable structure itself and relocated to the connector interface. Instead of relying on the cable's multi-braid construction, the waveguide barrier is placed at the connector to provide shielding, allowing the cable to maintain its standard flexible single-braid construction for easy installation.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The waveguide barrier serves as an intermediary shielding element at the connector interface, separating the cable from the connector internals. This intermediary provides the necessary RF protection without requiring changes to the cable construction, thereby preserving cable flexibility and installation ease.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Object-affected harmful factors

If high pass filters are installed, then low frequency RF ingress is limited, but system complexity and cost increase

Engineering Contradiction:
Improvelow frequency RF ingressVSAvoidconnector structure
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The filtering function is extracted from separate electronic filter components and integrated into the mechanical waveguide structure. The waveguide's geometry itself provides the frequency-selective blocking action, eliminating the need for additional electronic high pass filter components and reducing overall system complexity.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

Electronic filtering components are replaced with a mechanical waveguide structure that provides equivalent or superior frequency-selective blocking. The waveguide's physical dimensions and geometry create the necessary electromagnetic filtering effect, substituting mechanical design for electronic filtering circuitry.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Object-affected harmful factors

If connector aperture is reduced to block RF ingress, then shielding effectiveness improves, but signal transmission capability is degraded

Engineering Contradiction:
ImproveRF ingressVSAvoidsignal transmission
Core Design Contradiction:
Object-affected harmful factorsVSLoss of energy

Solution Approach 1:

The aperture is segmented into two functional zones: an outer region occupied by the waveguide barrier that blocks RF ingress, and an inner region that maintains the necessary opening for signal transmission. The waveguide creates an annular blocking structure that preserves the central transmission path, allowing signal passage while blocking harmful RF frequencies.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the aperture are given different functional qualities. The waveguide occupies the outer aperture region to provide RF blocking, while the inner aperture region maintains open quality for signal transmission. This local differentiation allows simultaneous RF protection and signal passage without compromising either function.

Inventive Principle:
Principle #3Local quality

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 approach significantly reduces RF ingress by 20-40 dB at frequencies below 100 MHz while maintaining a nominal 75 ohm impedance, effectively addressing the issue of signal interference in CATV and satellite TV systems without significant degradation of the connector's operational performance.

Implementation Method 1

electromagnetic radiation shields, such as waveguides with specific geometries and materials, is used to restrict RF ingress into coaxial cable connectors, even when they are open, by redistributing electric charges and attenuating unwanted frequencies

Methodology Applied
Scientific EffectElectromagnetic radiation shielding: Faraday Cage

Implementation Method 2

waveguides with specific geometries and materials, is used to restrict RF ingress into coaxial cable connectors... attenuating unwanted frequencies

Methodology Applied
Scientific EffectWaveguide filtering: Waveguide

Data Source

PatentEP2745358B1Coaxial connector with ingress reduction shield
Publication Date: 2019.07.10 HOLLAND MICHAEL
  • EP2745358B1 patent drawingFigure 1~2
  • EP2745358B1 patent drawingFigure 3A~3C
  • EP2745358B1 patent drawingFigure 4~5

AI summary

The present invention relates to s coaxial connector having a technical feature of a shield against unwanted radio frequency transfer in coaxial cable installations. Effective shields include perforated structures such as screens, fabrics, perforated plates, and perforated disks. In effect, these shields are waveguides tending to attenuate and/or reject passage of certain frequencies. An embodiment of the invention provides a smaller entry hole of 2 to 3.5 mm with a nominal thickness of between 0.5 to 1.5 mm. This combination of hole size and thickness acts as a waveguide to restrict ingress of low frequencies, typically under 100Mhz by 20-40dB of that of an open-ended F port.