Solid-State RF Oven Context Awareness Through Reflected Power

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Solution Overview

Problem

Microwave ovens suffer from uneven heating due to indiscriminate energy application, while solid state RF ovens offer fine-tuned control but lack context awareness for optimized cooking.

Innovation Solution

An oven utilizing solid state RF energy with closed-loop feedback systems to detect RF signatures, enabling context awareness and responsive cooking adjustments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If solid state RF energy is used for heating, then heating control precision is improved, but context awareness capability deteriorates

Engineering Contradiction:
Improveheating control precisionVSAvoidcontext awareness capability
Core Design Contradiction:
Manufacturing precisionVSLoss of information

Solution Approach 1:

The patent implements a feedback mechanism by monitoring reflected RF power and comparing it against expected values to detect context changes in the cooking chamber. The system continuously measures the RF signature and uses this information to adjust heating parameters, thereby maintaining both precise heating control and context awareness through closed-loop control.

Inventive Principle:
Principle #23Feedback

2Productivity

If RF signatures are monitored for context awareness, then cooking control is optimized, but system complexity increases

Engineering Contradiction:
Improvecooking control optimizationVSAvoidsystem complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The system performs self-diagnosis by automatically analyzing reflected RF power patterns to detect context changes such as food presence, container type, and cooking stage. This self-service capability enables the oven to autonomously optimize cooking parameters without requiring external sensors or complex user input, thereby improving cooking control while minimizing additional system complexity.

Inventive Principle:
Principle #25Self-service

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

Achieves precise and efficient cooking by monitoring RF signatures for context-aware cooking control, ensuring uniform heating and optimal energy usage.

Implementation Method 1

an RF heating system that uses solid state electronic components to generate controllable RF energy and apply the RF energy into the cooking chamber

Methodology Applied
Scientific EffectDielectric heating: Dielectric Heating

Implementation Method 2

a context awareness engine that includes processing circuitry to receive RF signature data including measurements of at least forward power and reflected power and determine context information about the cooking chamber based on the RF signature data

Methodology Applied
Scientific EffectElectromagnetic radiation detection: Radar

Data Source

PatentEP3987887B1Solid state RF oven with context awareness
Publication Date: 2025.08.06 ILLINOIS TOOL WORKS INC
  • EP3987887B1 patent drawingFigure 1
  • EP3987887B1 patent drawingFigure 2
  • EP3987887B1 patent drawingFigure 3

AI summary

An oven may include a cooking chamber configured to receive a food product, a radio frequency (RF) heating system configured to provide RF energy into the cooking chamber using solid state electronic components to heat the food product, and a context awareness engine. The context awareness engine may include processing circuitry configured to receive RF signature data (including measurements of at least forward power and reflected power) associated with provision of RF energy into the cooking chamber, and to correlate an RF signature with a phenomenon observed with respect to the food product to define a signature profile for the phenomenon observed.