Capacitive RF Coupling Structure for Interference Reduction

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Solution Overview

Problem

Existing RF signal coupling devices face challenges in minimizing interference between transmission channels with small frequency spacings and require flexible connection options for various filter types, while also being cost-effective.

Innovation Solution

A capacitive coupling device is designed with a constant coupling capacitance, where RF signals are coupled between coaxial RF connection structures via a line structure and an electrically conductive coupling structure, allowing for flexible connection of different filter types and minimizing interference by maintaining consistent coupling conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If inductive coupling is used to couple filters to the common antenna line, then RF signals can be transmitted through the system, but natural resonances occur between the filter and coupling point that cause interference in certain frequency ranges

Engineering Contradiction:
Improvesignal transmission reliabilityVSAvoidnatural resonance interference
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

A capacitive coupling structure is introduced as an intermediary between the filter and the common antenna line. This capacitor couples the filter output to the antenna line through electrical capacitance, acting as a mediator that prevents direct inductive coupling and the associated resonance problems while still allowing RF signal transmission.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the traditional inductive coupling mechanism with a capacitive coupling mechanism. By substituting the coupling method from inductive to capacitive, the system eliminates the natural resonances that occur with inductive coupling while maintaining effective RF signal transmission between the filter and antenna line.

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

2Manufacturing precision

If matching networks are implemented to improve signal matching in operating channels, then signal propagation is optimized, but the complexity of the device increases

Engineering Contradiction:
Improvesignal matching precisionVSAvoidmatching network complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The capacitive coupling structure is integrated directly into the connection between the filter and the common antenna line, merging the coupling function with the existing signal path. This integration eliminates the need for separate, complex matching networks while maintaining optimal signal matching through the inherent capacitive coupling characteristics.

Inventive Principle:
Principle #5Merging (Combining)

3Adaptability or versatility

If the coupling device needs to accommodate different filter types, then versatility is improved, but the device design becomes more complex

Engineering Contradiction:
Improvefilter type compatibilityVSAvoidcoupling device complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The capacitive coupling structure is designed as a universal interface that can accommodate different filter types (e.g., bandpass filters, low-pass filters, high-pass filters) without requiring design modifications. The same capacitive coupling mechanism works effectively with various filter configurations, providing multi-functionality and broad compatibility.

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

The device effectively couples RF signals onto a common transmission line, reducing interference and allowing for flexible filter connections, while being cost-effective and insensitive to temperature changes.

Implementation Method 1

The line structure is capacitively coupled to an electrically conductive coupling structure, via which the HF signal can be coupled along the signal path

Methodology Applied
Scientific EffectCapacitive coupling: Capacitance

Data Source

PatentEP2533354B1Device for coupling an HF signal along a signal path
Publication Date: 2018.07.04 SPINNER
  • EP2533354B1 patent drawingFigure 1
  • EP2533354B1 patent drawingFigure 2
  • EP2533354B1 patent drawingFigure 3

AI summary

The device (21) has a housing (11) at which coaxial high frequency (HF) connection structures (1, 2) are attached. The structures have inner conductors (3, 4) electrically connected with each other over a line structure (5). The line structure is capacitively coupled with an electrically conductive coupling structure (12). A section of the coupling structure protrudes via a bore or opening (13) that is formed along the line structure. The section and line structure are spaced from each other by an insulator (7), where a HF signal is capacitively coupled between the section and line structure.