Multi-mode Dielectric Resonator Filter for Compact Antenna Towers

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Solution Overview

Problem

Conventional single-mode filters are large and costly due to their complex shape and manufacturing requirements, making them unsuitable for compact implementations in microwave telecommunication systems, especially at antenna towers.

Innovation Solution

A multi-mode cavity filter with a simplified resonator body and conductive coupling paths on its surface, allowing coupling to multiple resonance modes without complex shapes or internal protrusions, reducing manufacturing costs and size.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional single-mode filters are built as a cascade of separated physical dielectric resonators with various couplings, then highly selective filtering characteristics are achieved, but the filter size becomes relatively large and manufacturing complexity increases

Engineering Contradiction:
Improvefiltering characteristicsVSAvoidfilter size
Core Design Contradiction:
ReliabilityVSVolume of stationary object

Solution Approach 1:

The patent combines multiple resonant modes (TE101, TE011, TM110) within a single dielectric resonator body, merging the functionality of multiple discrete resonators into one integrated structure. This reduces the overall filter size while maintaining the cascaded resonator filtering characteristics through mode coupling achieved via corner cuts and slots on the resonator surfaces.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent segments the resonator body into distinct regions with different geometrical features (corner cuts on opposite faces, slots on adjacent faces) that selectively couple different resonant modes. Each segmented region acts as an independent coupling mechanism, allowing precise control over mode interaction while maintaining a compact single-body structure.

Inventive Principle:
Principle #1Segmentation

2Volume of stationary object

If multimode filters are implemented by introducing specific defects into the shape of the body to couple energy between modes, then filter size is reduced, but the body shape becomes complicated and manufacturing costs increase

Engineering Contradiction:
Improvefilter sizeVSAvoidmanufacturing costs
Core Design Contradiction:
Volume of stationary objectVSEase of manufacture

Solution Approach 1:

The patent applies local geometrical modifications (corner cuts and slots) at specific locations on the resonator body to achieve mode coupling. Each local feature is optimized for coupling specific resonant modes, allowing the majority of the resonator body to maintain a simple, easily manufacturable shape while achieving complex multimode functionality through localized modifications.

Inventive Principle:
Principle #3Local quality

3Adaptability or versatility

If conventional single-mode filters are implemented with discrete resonators and couplings, then transmission poles can be tuned to provide desired filter response, but the physical complexity and manufacturing costs are increased

Engineering Contradiction:
Improvefilter response tuningVSAvoidphysical complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent enables filter response tuning by modifying geometrical parameters of the resonator body, including the dimensions and positions of corner cuts and slots. These parameter changes affect the coupling between resonant modes, allowing adjustment of transmission poles and filter characteristics without requiring complex reconfiguration of discrete components.

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

The solution results in a smaller, cheaper, and more efficient filter with enhanced filtering characteristics, suitable for compact installations at antenna towers, while maintaining effective frequency response and coupling capabilities.

Implementation Method 1

a resonator body, preferably in the form of a dielectric resonator, having a first resonant frequency f1 and supporting two non-interfering degenerate resonant modes, preferably TE101 and TE011 modes

Methodology Applied
Scientific EffectResonance: Resonance

Implementation Method 2

The reference in this specification to any prior publication (or information derived from it), or to any matter which is known, is not, and should not be taken as an acknowledgment or admission or any form of suggestion that the prior publication (or information derived from it) or known matter forms part of the common general knowledge in the field of endeavour to which this specification relates.

Methodology Applied
Scientific EffectDielectric: Dielectric

Data Source

PatentEP2748887B1Multi-mode filter with dielectric resonator supporting degenerate resonant modes
Publication Date: 2018.08.15 MESAPLEXX
  • EP2748887B1 patent drawingFigure 1A~1C
  • EP2748887B1 patent drawingFigure 1D~1E
  • EP2748887B1 patent drawingFigure 2A~2C

AI summary

A multi-mode cavity filter, comprising a resonator body of dielectric material capable of supporting at least two degenerate electromagnetic standing wave modes and having a face, and a conductive pattern on at least part of the face for coupling a radio frequency signal between the pattern and the resonator body.