Magnetron λ/4 Choke Structure for Harmonic Suppression

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Solution Overview

Problem

Conventional magnetrons for microwave ovens struggle to effectively suppress higher harmonic wave components, particularly those in higher order modes and the medium band, leading to radio interference and increased costs due to the need for additional choke structures.

Innovation Solution

A magnetron design incorporating a λ/4 type choke structure that simultaneously suppresses both fundamental and higher order mode harmonic wave components within a single choke groove, utilizing specific dimensions and configurations to achieve effective suppression without increasing device size or cost.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple separate λ/4 type choke structures are provided to suppress different higher harmonic wave components, then the suppression effectiveness is improved, but the device complexity and cost increase

Engineering Contradiction:
Improvesuppression effectivenessVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines multiple λ/4 type choke structures into a single integrated structure that can suppress multiple higher harmonic wave components simultaneously. The choke groove is designed with specific dimensional relationships to achieve suppression of both fundamental mode and higher order mode harmonic waves, thereby reducing device complexity while maintaining suppression effectiveness.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The single choke groove structure is designed to perform multiple functions: suppressing fundamental mode harmonic waves and higher order mode harmonic waves. By setting specific dimensional relationships (L1, L2, R1, R2), the structure achieves multi-functionality in harmonic wave suppression without requiring separate dedicated structures for each mode.

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

2Reliability

If additional choke structures are added to suppress higher order mode harmonic waves, then the suppression completeness is improved, but the manufacturing cost increases

Engineering Contradiction:
Improvesuppression completenessVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent merges the functionality of multiple choke structures into a single integrated choke groove, eliminating the need for separate manufacturing processes for multiple components. This reduces manufacturing complexity and cost while achieving comprehensive suppression of higher harmonic wave components including higher order modes.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The single choke groove structure is designed with universal suppression capability for both fundamental and higher order mode harmonic waves, making it a cost-effective solution that eliminates the need for additional specialized structures for each mode.

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

3Device complexity

If conventional choke structures are used, then the device simplicity is maintained, but higher order mode harmonic waves cannot be effectively suppressed

Engineering Contradiction:
Improvedevice simplicityVSAvoidsuppression effectiveness
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent modifies the parameters of the choke groove structure (lengths L1 and L2, radii R1 and R2) to achieve effective suppression of higher order mode harmonic waves. By setting specific dimensional relationships, the structure maintains simplicity while enhancing suppression effectiveness for both fundamental and higher order modes.

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 proposed design ensures comprehensive suppression of higher harmonic wave components in both fundamental and higher order modes, preventing leakage and reducing unnecessary radiation, while maintaining productivity and stability, thus addressing the limitations of conventional designs.

Implementation Method 1

a magnetron that outputs a high frequency wave, e.g. a magnetron for microwave oven... generates a microwave with a frequency band of e.g. 2450 MHz. At this time, higher harmonic wave components are generated simultaneously with the fundamental wave component.

Methodology Applied
Scientific EffectElectromagnetic wave interference: Interference

Implementation Method 2

Conventional magnetrons for microwave oven are provided with a λ/4 type choke structure in, for example, the output part thereof in order to suppress generation of the higher harmonic wave components

Methodology Applied
Scientific EffectChoke structure:

Data Source

PatentEP1814364B1Magnetron
Publication Date: 2019.08.21 TOSHIBA HOKUTO ELECTRONICS CORP
  • EP1814364B1 patent drawingFigure 1
  • EP1814364B1 patent drawingFigure 2
  • EP1814364B1 patent drawing

AI summary

Problems: To provide a magnetron having a λ/4 type choke structure suppressing higher harmonic wave components propagated in a higher order mode or suppressing an unnecessary radiation of the medium band interposed between two higher harmonic waves having frequencies of integer multiples of the fundamental wave. Means for solving the problems: In a magnetron comprising a high frequency wave generating part 11 generating a high frequency wave, an antenna 24 extracting the high frequency wave, a cylindrical metallic envelope 18 surrounding the antenna 24 and a λ/4 type choke structure C2 suppressing a higher harmonic wave component propagated in a fundamental mode in the metallic envelope 18, another λ/4 type choke structure C1 suppressing a higher harmonic wave component propagated in a higher order mode in the metallic envelope has been provided.