Multi-Level Electrode Design for Uniform RF Defrosting and Heating
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Solution Overview
Problem
Conventional capacitive food defrosting systems using large planar electrodes often result in uneven electromagnetic fields, leading to uneven defrosting and hot spots that can undesirably cook portions of the load.
Innovation Solution
The use of multi-level electrodes in a thermal increase system, where the electrodes have portions at different heights within the cavity, creating a more uniform electromagnetic field for even defrosting or heating by adjusting the impedance matching network to optimize RF power absorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional planar electrodes are used in capacitive food defrosting systems, then the system structure is simple, but the electromagnetic field becomes uneven resulting in uneven defrosting and hot spots
Solution Approach 1:
The patent introduces multi-level electrodes with different heights (z-dimension variation) to create a more uniform electromagnetic field distribution. The first electrode has a first height and the second electrode has a second height different from the first, adding vertical dimensionality to the previously planar (2D) electrode structure. This dimensional change allows the electrodes to better match the load geometry and distribute the electromagnetic field more evenly throughout the heating compartment, eliminating hot spots while maintaining defrosting effectiveness.
2Reliability
If multi-level electrodes with different heights are used, then the electromagnetic field becomes more uniform, but the device structure becomes more complex
Solution Approach 1:
The patent applies local quality by making different portions of the electrode structure have different heights tailored to specific regions. The first electrode has a first height in a first region and a second height in a second region, allowing each region to be optimized for its local requirements. This localized variation in electrode height creates appropriate electromagnetic field intensity in different areas of the heating compartment, ensuring consistent defrosting across the entire load without requiring complete redesign of the entire electrode system.
3Object-affected harmful factors
If conventional electrodes are used, then the system is easier to manufacture, but hot spots are generated that undesirably cook portions of the load
Solution Approach 1:
The patent changes the geometric parameters of the electrodes by introducing multiple height levels. The first electrode has a first height and the second electrode has a second height, creating a stepped or multi-level configuration. This parameter change in electrode geometry fundamentally alters the electromagnetic field distribution pattern, preventing the concentration of energy that causes hot spots. The manufactured electrodes, while slightly more complex, provide controlled and uniform energy distribution that prevents unwanted cooking of food portions.
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 approach ensures more uniform and even defrosting or heating of loads by maintaining optimal RF power transfer and minimizing hot spots, improving the efficiency and consistency of the thermal increase operation.
Implementation Method 1
low power electromagnetic energy is supplied to the electrodes to produce an electromagnetic field in the heating compartment, which gently warms the food load
Implementation Method 2
After a food load is placed between the electrodes, low power electromagnetic energy is supplied to the electrodes to produce an electromagnetic field
Implementation Method 3
adjusting the impedance matching network to optimize RF power absorption
Data Source
AI summary
A thermal increase system includes one or more multi-level electrodes configured to radiate electromagnetic energy into a cavity in response to receiving a radio frequency (RF) signal from an RF signal source. Each multi-level electrode is positioned adjacent to a wall of the cavity, and each multi-level electrode includes a base portion coupled to an elevated portion. A radiating surface of the elevated portion is at a height of at least 0.5 centimeters (cm) from a radiating surface of the base portion.