TM Dual-Mode Filter With Gradient Aperture Coupling

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Solution Overview

Problem

Current TM dual mode filters for wireless communication systems lack the capability to achieve two transmission zeros between four resonance modes due to complex electromagnetic conditions, which are crucial for rigorous and precise out-band attenuation.

Innovation Solution

A TM dual-mode filter design featuring an enclosure with two cavities separated by a wall, including gradient apertures and capacity coupling pins, allows for the formation of two transmission zeros by controlling coupling between dual-mode resonators, with adjustable frequency positioning through aperture angle and pin placement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If traditional TM dual mode filter design is used, then the filter structure is simple, but it cannot achieve two transmission zeros between four resonance modes due to complex electromagnetic conditions

Engineering Contradiction:
Improveout-band attenuation precisionVSAvoidfilter structure complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The filter is divided into two separate cavities, each containing a TM dual-mode resonator. This segmentation allows independent control of resonance modes in each cavity while achieving two transmission zeros through coordinated coupling between cavities, resolving the contradiction between precision and complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A coupling structure is introduced as an intermediary between the two cavities to control the coupling of TM dual-mode resonators. This intermediary element enables precise control of transmission zeros without directly complicating the resonator structures themselves.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If gradient aperture with adjustable angle and position is used, then transmission zero frequency positioning is flexible, but the manufacturing complexity increases

Engineering Contradiction:
Improvefrequency tuning rangeVSAvoidaperture fabrication difficulty
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The gradient aperture's angle, length, and position are used as adjustable parameters to control coupling strength and transmission zero frequency. By changing these geometric parameters, flexible frequency positioning is achieved while maintaining a relatively simple aperture structure that can be manufactured.

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If capacity coupling pin is added to control coupling, then transmission zero positioning is improved, but the device complexity increases

Engineering Contradiction:
Improvetransmission zero positioning accuracyVSAvoidnumber of components
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The coupling control function is extracted into a separate capacity coupling pin component, allowing independent optimization of the resonators while achieving precise transmission zero positioning through the adjustable pin. This separation reduces overall system complexity by modularizing the control mechanism.

Inventive Principle:
Principle #2Taking out (Extraction)

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 design enables flexible and stringent attenuation beyond the passband, providing a wide tuning range for transmission zeros, enhancing the filter's topology and performance.

Implementation Method 1

a gradient aperture having an angle, a length, a position and a direction, formed in the wall for coupling between the two TM dual-mode resonators. The gradient aperture is configured to control the coupling and to determine a position of transmission zeros relative to the passband.

Methodology Applied
Scientific EffectElectromagnetic coupling: Electromagnetic Induction

Implementation Method 2

a first transverse magnetic, TM, dual-mode resonator and a second TM dual-mode resonator, each TM dual-mode resonator having two modes

Methodology Applied
Scientific EffectElectromagnetic resonance: Resonance

Data Source

PatentEP3507854B1Tm dual mode filter
Publication Date: 2022.10.05 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP3507854B1 patent drawingFigure 1
  • EP3507854B1 patent drawingFigure 2
  • EP3507854B1 patent drawingFigure 3

AI summary

The present disclosure provides a filter comprises an enclosure having two cavities separated by a wall; a first TM dual-mode resonator and a second TM dual-mode resonator, each TM dual-mode resonator having two modes and comprising a body having a central portion with a plurality of arms extending outwardly from the central portion; a gradient aperture formed in the wall for coupling between two TM dual-mode resonators. The filter is capable of forming two transmission zeros between four resonances modes.