RF Filter Cover Assembly for Reduced Size and Weight

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Solution Overview

Problem

Conventional RF filters are bulky and heavy due to thick exterior and interior walls required for screw attachments and O-rings, which limits their size reduction and weight optimization.

Innovation Solution

The use of adhesive tape to attach the outer cover to the housing without screws, and soldering the tuning cover to the interior wall instead of screws, along with non-debris tuning elements and press-in standoffs to reduce weight and size, and incorporate cleaning holes for maintenance without disassembly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If thick walls are used for screw attachments and O-rings, then structural strength and reliability are improved, but filter size and weight increase

Engineering Contradiction:
Improvestructural strengthVSAvoidfilter weight
Core Design Contradiction:
StrengthVSWeight of stationary object

Solution Approach 1:

The patent replaces the mechanical screw attachment system with an adhesive bonding system. The adhesive tape provides sufficient structural strength to hold the outer cover and tuning cover in place without requiring thick walls for screw holes, thereby reducing filter weight while maintaining structural integrity.

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

Solution Approach 2:

The patent uses thin adhesive tape films to bond the covers to the housing. This thin film approach eliminates the need for thick structural walls required for mechanical fasteners, achieving weight reduction while maintaining adequate structural strength through the adhesive bonding mechanism.

Inventive Principle:
Principle #30Flexible shells and thin films

2Reliability

If thick walls are used for screw attachments and O-rings, then structural reliability is improved, but filter volume increases

Engineering Contradiction:
Improvestructural reliabilityVSAvoidfilter volume
Core Design Contradiction:
ReliabilityVSVolume of stationary object

Solution Approach 1:

The patent replaces the mechanical screw attachment system with an adhesive bonding system. The adhesive tape provides sufficient structural reliability to hold the outer cover and tuning cover in place without requiring thick walls for screw holes, thereby reducing filter volume while maintaining structural integrity.

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

3Strength

If screws and O-rings are used for attachments, then structural strength is improved, but manufacturing complexity increases

Engineering Contradiction:
Improveattachment strengthVSAvoidmanufacturing simplicity
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The patent replaces the mechanical screw and O-ring attachment system with a simpler adhesive bonding system. This eliminates the need for precision machining of screw holes, threading operations, and O-ring installation, significantly simplifying the manufacturing process while maintaining adequate attachment strength through adhesive bonding.

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

Solution Approach 2:

The patent uses thin adhesive tape films to bond the covers to the housing. This approach eliminates complex mechanical fastening operations and simplifies manufacturing by using a straightforward adhesive application process that requires less precision and fewer assembly steps.

Inventive Principle:
Principle #30Flexible shells and thin films

4Ease of repair

If cleaning holes are added to the cover, then maintenance ease is improved, but structural integrity may be compromised

Engineering Contradiction:
Improvecleaning accessibilityVSAvoidcover structural integrity
Core Design Contradiction:
Ease of repairVSStrength

Solution Approach 1:

The patent uses thin adhesive tape films for bonding covers, and the tuning cover itself is designed as a thin structure with cleaning holes. The adhesive bonding provides the necessary structural integrity while allowing the thin cover with holes to be attached without compromising overall strength, as the adhesive distributes loads across the bonding area rather than requiring a solid continuous cover.

Inventive Principle:
Principle #30Flexible shells and thin films

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 results in a significantly reduced filter size and weight, improved compactness for small cell applications, and reduced passive intermodulation distortion, while maintaining performance metrics like insertion loss and return loss.

Implementation Method 1

The filter device includes adhesive tape that attaches the outer cover to the housing

Methodology Applied
Scientific EffectAdhesive: Adhesive

Implementation Method 2

One type of filter for RF applications is a resonator filter comprising a group of coaxial resonators. The overall transfer function of the resonator filter is a function of the responses of the individual resonators as well as the electromagnetic coupling between different pairs of resonators within the group

Methodology Applied
Scientific EffectElectromagnetic resonance: Resonance

Data Source

PatentEP4032142B1Radio frequency filters having reduced size
Publication Date: 2024.11.06 OUTDOOR WIRELESS NETWORKS LLC
  • EP4032142B1 patent drawingFigure 1
  • EP4032142B1 patent drawingFigure 2A
  • EP4032142B1 patent drawingFigure 2B

AI summary

Filter devices are provided herein. In some embodiments, a filter device includes resonators and a cover that is attached by adhesive tape to a housing that includes the resonators. In some embodiments, the filter device includes a tuning cover that overlaps the resonators and has cleaning holes therein. Moreover, in some embodiments, the filter device includes a wall inside the housing between a first of the resonators and a second of the resonators, and an average thickness of the wall is 3.0 millimeters or thinner. Related methods of manufacturing filter devices are also provided.