Cavity RF Filter Tuning Screw for Reversible Frequency Adjustment

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Solution Overview

Problem

Conventional cavity-type radio frequency filters require complex and irreversible frequency tuning processes, involving external embossing machines and conventional coupling structures, which are costly and difficult to reverse, limiting their compactness and manufacturing efficiency.

Innovation Solution

A radio frequency filter design featuring a frequency tuning screw with a resilient fixing member, such as a ring-shaped or tapered resilient protrusion, that allows reversible frequency tuning by adjusting the capacitance between the screw and resonant element, eliminating the need for conventional fastening nuts and external embossing machines.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If conventional coupling structures (tuning screws and fastening nuts) are used for frequency tuning, then frequency tuning can be achieved, but the structure becomes complex and the tuning process becomes irreversible and difficult

Engineering Contradiction:
Improvefrequency tuning operationVSAvoidcoupling structure
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent removes the fastening nut component from the conventional tuning screw assembly, extracting only the essential tuning function. The tuning screw is directly integrated into the cover without requiring separate fastening hardware, simplifying the coupling structure while maintaining frequency tuning capability

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The tuning screw and cover are merged into a unified structure where the tuning screw is directly embedded in the cover. This integration eliminates the need for separate fastening nuts and reduces the number of components, making the structure simpler and the tuning operation more reversible

Inventive Principle:
Principle #5Merging (Combining)

2Manufacturing precision

If external embossing machines are used to form dot peen structures, then frequency tuning can be achieved, but manufacturing cost increases and the process becomes irreversible

Engineering Contradiction:
Improvefrequency tuning precisionVSAvoidmanufacturing process
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The tuning screw structure serves its own fixing function through direct integration into the cover, eliminating the need for external embossing machines or dot peen structures. The design is self-sufficient, requiring no additional manufacturing steps for frequency tuning

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The complex mechanical system of external embossing machines and dot peen structures is replaced with a simpler integrated tuning screw mechanism. The frequency tuning function is achieved through the tuning screw's direct mechanical adjustment rather than through embossing operations

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

3Reliability

If conventional fastening nuts are used, then secure fixation is achieved, but the filter structure becomes heavier and larger

Engineering Contradiction:
Improvefixation stabilityVSAvoidfilter structure
Core Design Contradiction:
ReliabilityVSWeight of stationary object

Solution Approach 1:

The fastening nut is extracted from the assembly, removing unnecessary weight and volume. The tuning screw achieves secure fixation through its direct integration into the cover without requiring additional fastening components

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The fixation function and tuning function are merged into a single integrated tuning screw structure. This eliminates the need for separate fastening nuts, reducing both weight and structural complexity while maintaining reliable fixation

Inventive Principle:
Principle #5Merging (Combining)

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 design enables simpler, more compact, and lighter radio frequency filters with reversible frequency tuning, reducing manufacturing costs and improving operational efficiency by allowing repeated adjustments of filtering characteristics.

Implementation Method 1

a resilient fixing member, such as a ring-shaped or tapered resilient protrusion, that allows reversible frequency tuning by adjusting the capacitance between the screw and resonant element

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3621145B1Cavity-type radio frequency filter
Publication Date: 2024.07.10 KMW INC
  • EP3621145B1 patent drawingFigure 1A~1B
  • EP3621145B1 patent drawingFigure 1C~2B
  • EP3621145B1 patent drawingFigure 2C~3B

AI summary

A cavity-type radio frequency filter is disclosed. the radio frequency filter having a cavity structure including an enclosure, a resonant element, a cover, a frequency tuning screw, and a resilient fixing member. The enclosure has a hollow inside and an open surface on one side to have a cavity. The resonant element is positioned in the hollow of the enclosure. The cover has a screw hole having a preset diameter at a position corresponding to the resonant element, and is configured to seal the open surface of the enclosure. The frequency tuning screw is configured to be screwed into the screw hole of the cover, and it has an upper end formed at least partially with a latching abutment that protrudes outwardly.