High-Band Resonator Filter Layout Using Negative Coupling

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Solution Overview

Problem

Conventional approaches to achieving a stopband below the passband in RF combiners often result in increased mechanical complexity, higher costs, and sensitivity to mechanical tolerances due to the need for close coupling between resonators, which can be challenging to tune effectively.

Innovation Solution

The use of exclusively negative couplings between high-band resonators, achieved through specific shaping and topology, allows for a robust high-band channel filter with improved mechanical tolerance and reduced size and complexity, while maintaining effective stopband rejection and insertion losses.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional approaches are used to achieve stopband below passband, then stopband rejection is improved, but mechanical complexity increases

Engineering Contradiction:
Improvestopband rejectionVSAvoidmechanical complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent changes the coupling parameter from mixed (inductive and capacitive) to exclusively capacitive coupling between resonators. This parameter change enables stopband rejection below the passband while avoiding the mechanical complexity of close inductive coupling, as capacitive coupling can be achieved through field interactions without requiring physically close resonator structures.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces mechanical inductive coupling (which requires close physical proximity and precise mechanical alignment) with electromagnetic capacitive coupling. This substitution eliminates the need for tight mechanical tolerances and complex mechanical structures, achieving stopband rejection through field-based coupling instead of mechanical coupling.

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

2Reliability

If conventional approaches are used to achieve stopband below passband, then stopband rejection is improved, but cost increases

Engineering Contradiction:
Improvestopband rejectionVSAvoidcost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

By changing the coupling mechanism to exclusively capacitive coupling, the patent simplifies the manufacturing process. Capacitive coupling structures are generally easier and less costly to manufacture than inductive coupling structures that require precise mechanical assembly, thereby reducing production costs while maintaining stopband rejection performance.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If conventional approaches are used to achieve stopband below passband, then stopband rejection is improved, but sensitivity to mechanical tolerances increases

Engineering Contradiction:
Improvestopband rejectionVSAvoidsensitivity to mechanical tolerances
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent substitutes mechanical inductive coupling with electromagnetic capacitive coupling. Since capacitive coupling relies on electric field interactions rather than direct mechanical contact or precise physical alignment, the resulting structure is significantly less sensitive to mechanical tolerances and manufacturing variations, thereby improving robustness while maintaining stopband rejection.

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

4Reliability

If close coupling between resonators is used, then stopband rejection is improved, but tuning effectiveness decreases

Engineering Contradiction:
Improvestopband rejectionVSAvoidtuning effectiveness
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent changes the coupling type from inductive to capacitive. Capacitive coupling allows for easier and more effective tuning because it can be adjusted through electrical means (such as variable capacitors or tuning screws) without requiring mechanical disassembly or repositioning of closely coupled resonators, thereby improving tuning effectiveness while maintaining stopband rejection.

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 enables a high-band channel filter with optimal performance, reduced sensitivity to mechanical tolerances, and lower insertion losses, while maintaining effective stopband rejection, by using only negative couplings between high-band resonators, which are arranged and shaped to provide capacitive couplings without inductive coupling.

Implementation Method 1

adjacent and non-adjacent ones of the high-band resonators are capacitively coupled to one another

Methodology Applied
Scientific EffectCapacitive coupling: Capacitance

Implementation Method 2

The high-band resonators are arranged and shaped to provide negative coupling between the resonators, which provides a stopband below a passband of the high-band channel filter

Methodology Applied
Scientific EffectNegative coupling:

Implementation Method 3

a resonator filter comprising a group of coaxial resonators

Methodology Applied
Scientific EffectResonance: Resonance

Data Source

PatentEP3667810B1Filters having resonators with negative coupling
Publication Date: 2024.03.13 COMMSCOPE ITAL SRL
  • EP3667810B1 patent drawingFigure 1A
  • EP3667810B1 patent drawingFigure 1B
  • EP3667810B1 patent drawingFigure 1C

AI summary

Filter devices are provided herein. A filter device includes a plurality of low-band resonators and a plurality of high-band resonators. In some embodiments, adjacent ones of the plurality of high-band resonators are spaced farther apart from each other than adjacent ones of the plurality of low-band resonators are spaced apart from each other.