RF Filter Granular Cavity Foam Pressure

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Radio frequency filters with air-filled cavity resonators face challenges in maintaining uniform packing density and avoiding air spaces when filled with dielectric or magnetic powders, leading to instability and inefficiency.

Innovation Solution

Incorporating a layer of compressible foam material between the lid and granular material within the cavity to apply uniform pressure, ensuring controlled density and stability of the dielectric or magnetic material, thereby optimizing the filter's performance and size.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If a cavity resonator is filled with granular dielectric or magnetic material, then the filter size can be reduced and performance improved, but the packing density becomes non-uniform and air spaces form

Engineering Contradiction:
Improvefilter sizeVSAvoidpacking density uniformity
Core Design Contradiction:
Volume of moving objectVSStability of the object's composition

Solution Approach 1:

The patent applies compressive pressure to the granular material, changing its physical state by increasing packing density and eliminating air spaces. This parameter change (applying pressure) transforms the loose, non-uniform granular filling into a dense, uniform configuration that maintains stable electromagnetic properties throughout the cavity resonator.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces a compression mechanism as an intermediary between the cavity resonator walls and the granular material. This intermediary applies controlled compressive force to achieve uniform packing density, mediating between the need for small filter size and the requirement for stable, uniform material composition.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If granular material is packed densely in the cavity, then filter performance improves, but the material becomes unstable and shifts position

Engineering Contradiction:
Improvefilter performanceVSAvoidmaterial position stability
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent applies compressive pressure to change the physical state of the granular material, increasing packing density to improve electromagnetic performance. The controlled compression maintains the material in a stable, high-density configuration that prevents shifting while achieving the desired performance characteristics.

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If air spaces are present in the granular material filling, then manufacturing is easier, but resonating structure stability decreases

Engineering Contradiction:
Improvefilling processVSAvoidresonating structure stability
Core Design Contradiction:
Ease of manufactureVSStability of the object's composition

Solution Approach 1:

The patent applies compressive pressure as a post-filling treatment to eliminate air spaces that would otherwise be present after simple gravity filling. This parameter change (applying compression) removes harmful air gaps while maintaining the ease of the original filling process, achieving stable resonating structures without complicating manufacturing.

Inventive Principle:
Principle #35Parameter changes

4Manufacturing precision

If compressible foam material is added to apply uniform pressure, then density control improves, but device complexity increases

Engineering Contradiction:
Improvedensity controlVSAvoidfilter structure
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent introduces compressible foam material to apply uniform compressive pressure, achieving precise control over granular material density. This addition enables accurate density control to optimize electromagnetic properties, accepting a moderate increase in structural complexity as a trade-off for the significant improvement in manufacturing precision and filter performance.

Inventive Principle:
Principle #35Parameter changes

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 allows for efficient use of powders in radio frequency equipment, enhancing stability, uniformity, and density control, resulting in smaller filter sizes with minimal impact on resonating structures, suitable for applications like metrocell base stations and macrocell active antenna arrays.

Implementation Method 1

a layer of compressible foam material is provided between the lid and the granular material so as to apply a uniform pressure to the granular material

Methodology Applied
Scientific EffectCompression: Compression

Implementation Method 2

the granular material being a dielectric material or magnetic material

Methodology Applied
Scientific EffectDielectric: Dielectric

Data Source

PatentEP2814110B1A radio frequency filter, a method of radio frequency filtering and a method of constructing a radio frequency filter
Publication Date: 2018.04.25 ALCATEL LUCENT SA
  • EP2814110B1 patent drawingFigure 1~3
  • EP2814110B1 patent drawingFigure 4

AI summary

A radio frequency filter 2 is provided comprising at least one resonant chamber 20 that comprises a cavity 20 substantially filled by a granular material 6 and has a lid 10, the granular material being a dielectric material or magnetic material, in which a layer 24 of compressible foam material is provided between the lid and the granular material so as to apply a uniform pressure to the granular material.