Coherent RF Feeds for Uniform Electromagnetic Cooking

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Solution Overview

Problem

Conventional microwave ovens using a single, non-coherent magnetron source for cooking result in nonuniform heating due to the lack of tunability and narrowband frequency emission, leading to inefficient cooking processes.

Innovation Solution

An electromagnetic cooking device employing multiple coherent radio frequency feeds with independently controlled frequency, phase, and amplitude settings to create dynamic electromagnetic wave patterns within an enclosed cavity, ensuring coherent interference and uniform heating.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single magnetron source is used for microwave generation, then the device complexity is reduced, but the heating uniformity deteriorates

Engineering Contradiction:
Improvedevice complexityVSAvoidheating uniformity
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The single magnetron source is divided into multiple independent magnetron sources (first magnetron and second magnetron), each capable of generating microwave signals independently. This segmentation allows for better distribution of electromagnetic energy throughout the cavity, improving heating uniformity while maintaining manageable device complexity through modular architecture

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Multiple magnetron sources are combined within a single cavity space, with their outputs merged through waveguides and power dividers. The coherent combination of signals from multiple sources creates more uniform standing wave patterns, resolving the heating uniformity issue without requiring a complete redesign of the system

Inventive Principle:
Principle #5Merging (Combining)

2Ease of manufacture

If a non-tunable magnetron source is used, then the ease of manufacture is improved, but the adaptability deteriorates

Engineering Contradiction:
Improveease of manufactureVSAvoidadaptability
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The system transitions from static, fixed-frequency magnetron operation to dynamic, tunable frequency control. Each magnetron can be independently tuned to different frequencies, and the system can adaptively adjust operating parameters based on food type, quantity, and desired heating patterns, greatly enhancing adaptability while maintaining ease of manufacture through standard magnetron components

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system enables changes in key operating parameters including frequency, phase, and amplitude for each magnetron source. By varying these parameters dynamically, the system can optimize heating performance for different cooking scenarios without requiring different hardware configurations, achieving high adaptability with conventional components

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If mechanical stirrers and turntables are used for even heating, then the heating uniformity is improved, but the device complexity increases

Engineering Contradiction:
Improveheating uniformityVSAvoiddevice complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent replaces mechanical stirring and rotating mechanisms with an electromagnetic field-based solution. Multiple coherent microwave sources create controlled interference patterns and standing waves that naturally distribute energy more uniformly throughout the cavity, eliminating the need for mechanical stirrers and turntables while achieving comparable or superior heating uniformity

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

Solution Approach 2:

Instead of mechanical motion, the system uses electromagnetic wave interference and resonance to achieve uniform energy distribution. The coherent sources create dynamic field patterns that effectively 'stir' the electromagnetic energy distribution without physical movement, reducing mechanical complexity while maintaining heating effectiveness

Inventive Principle:
Principle #18Mechanical vibration

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 enables precise control over the electromagnetic field distribution, resulting in more even and efficient heating patterns, maximizing the coupling of RF power with the food and allowing for the determination and classification of resonant modes within the cavity.

Implementation Method 1

employing multiple coherent radio frequency feeds with independently controlled frequency, phase, and amplitude settings to create dynamic electromagnetic wave patterns within an enclosed cavity, ensuring coherent interference

Methodology Applied
Scientific EffectCoherent interference: Interference

Implementation Method 2

A sub-band of the radio frequency spectrum, microwave frequencies at or around 2.45 GHz cause dielectric heating primarily by absorption of energy in water

Methodology Applied
Scientific EffectDielectric heating: Dielectric Heating

Implementation Method 3

determination and classification of resonant modes within the cavity

Methodology Applied
Scientific EffectResonance: Resonance

Data Source

PatentEP3305019B1Method and device for electromagnetic cooking
Publication Date: 2023.07.19 WHIRLPOOL CORP
  • EP3305019B1 patent drawingFigure 1
  • EP3305019B1 patent drawingFigure 2
  • EP3305019B1 patent drawingFigure 3

AI summary

An electromagnetic cooking device includes an enclosed cavity; a set of radio frequency feeds configured to introduce electromagnetic radiation into the enclosed cavity to heat up and prepare food; a set of high-power radio frequency amplifiers coupled to the set of radio frequency feeds, each high-power amplifier comprising at least one amplifying stage configured to output a signal that is amplified in power with respect to an input radio frequency signal; a signal generator coupled to the set of high- power radio frequency amplifiers for generating the input radio frequency signal, and a controller. The controller can be configured to, among other things, cause the signal generator and selected ones of the set of high-power amplifiers to output a radio frequency signal, select from a set of phase values of radio frequency electromagnetic waves, and identify the resonant modes excited within the enclosed cavity.