Coaxial Resonator Filter with Nested Ring for Multi-Band RF

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Solution Overview

Problem

Conventional resonators are limited to filtering signals at a single specific frequency, requiring separate devices for each frequency band, which increases size and complexity, especially in RF front ends that need to handle multiple frequency bands.

Innovation Solution

A resonator assembly that incorporates a conductive resonance post and a conductive resonance ring within the same cavity, allowing simultaneous filtering of signals at two distinct frequency bands, with the ring element being electrically isolated to facilitate independent resonance and reduce coupling between frequency bands.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional resonators are used for each frequency band, then filtering performance is achieved, but device size and complexity increase

Engineering Contradiction:
Improvefiltering performanceVSAvoidnumber of resonator devices
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies multi-functionality by designing a single resonator structure that can operate at multiple frequency bands. The resonator includes a conductive enclosure with a resonance post and multiple resonance ring elements, where each ring element is configured to resonate at a different frequency band. This allows one resonator to perform the filtering function for multiple frequency bands simultaneously, replacing what would traditionally require multiple separate resonator devices.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent implements nesting by placing multiple resonance ring elements inside the same conductive enclosure. The resonance ring elements are positioned concentrically or in nested arrangements within the enclosure, with each ring element operating independently at its designated frequency band. This nested configuration allows multiple resonating structures to coexist in a compact space, reducing the overall device size while maintaining filtering performance across multiple bands.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Adaptability or versatility

If multiple resonator devices are used for different frequency bands, then filtering coverage is improved, but weight increases

Engineering Contradiction:
Improvefrequency band coverageVSAvoidresonator assembly weight
Core Design Contradiction:
Adaptability or versatilityVSWeight of stationary object

Solution Approach 1:

The patent merges multiple resonator functions into a single integrated structure. By combining multiple resonance ring elements and a resonance post within one conductive enclosure, the design consolidates what would traditionally be separate resonator devices into one unified assembly. This merging approach maintains comprehensive frequency band coverage while significantly reducing the total weight compared to using multiple discrete resonator devices.

Inventive Principle:
Principle #5Merging (Combining)

3Strength

If resonance ring element is electrically connected to enclosure, then structural support is provided, but coupling between frequency bands increases

Engineering Contradiction:
Improvestructural supportVSAvoidfrequency band isolation
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent introduces an electrical insulator as an intermediary element between the resonance ring elements and the conductive enclosure. This insulator provides the necessary mechanical support and positioning for the resonance ring elements while simultaneously preventing direct electrical connection to the enclosure. By using this intermediary material, the design maintains structural integrity while ensuring electrical isolation between the resonance elements and the enclosure, thereby preventing unwanted coupling between different frequency bands.

Inventive Principle:
Principle #24Intermediary (Mediator)

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

Enables the construction of smaller, more lightweight resonators that can filter multiple frequency bands concurrently, reducing the need for multiple devices and minimizing insertion losses, while maintaining high Q-factor performance for high-frequency filtering.

Implementation Method 1

a resonator having a conductive resonance post surrounded by a conductive enclosure defining a cavity, the conductive resonance post being operable to filter a signal within a first frequency band, and a conductive resonance ring element positioned around the conductive resonance post, the conductive resonance ring element being operable to filter a signal within a second frequency band concurrently

Methodology Applied
Scientific EffectElectromagnetic resonance: Resonance

Data Source

PatentEP2894709B1Coaxial resonator filter
Publication Date: 2019.05.01 ALCATEL LUCENT SA
  • EP2894709B1 patent drawingFigure 1
  • EP2894709B1 patent drawingFigure 2(A)~2(C)
  • EP2894709B1 patent drawingFigure 3(A)~4(B)

AI summary

A resonant assembly is disclosed. The resonator assembly, comprises: a resonator having a conductive resonance post surrounded by a conductive enclosure defining a cavity, the conductive resonance post being operable to filter a signal within a first frequency band, and a conductive resonance ring element positioned around the conductive resonance post, the conductive resonance ring element being operable to filter a signal within a second frequency band concurrently with the conductive resonance post filtering the signal within the first frequency band. Through this approach, it is possible to provide a single device which implements more than one independent resonance or filtering at the same time within the same cavity volume, allowing significantly smaller cavity filters to be built, which avoids the need to provide separate devices, one for each frequency. This is particularly convenient in resonant assemblies used in RF front ends which will often be required to receive signals at two or more different frequencies.