Waveguide-Structure Antenna Radial Heating Control

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Solution Overview

Problem

Conventional microwave heating apparatuses face challenges in achieving controlled local heating in the radial direction due to the limited directivity of waveguide-structure antennas, which results in uneven heating distribution, especially when heating objects are positioned closer or farther from the distal-end opening parts.

Innovation Solution

The microwave heating apparatus incorporates a waveguide-structure antenna with a microwave sucking-out opening in its wall surface, allowing for adjustable microwave radiation based on the presence or absence of a food item, enabling controllable radial direction heating by varying the dielectric constant and optimizing the size and position of the sucking-out opening for efficient microwave radiation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If microwaves are radiated only from the distal-end opening parts of the waveguide-structure antennas, then local heating performance is enhanced in the rotation direction, but heating uniformity deteriorates in the radial direction and objects distant from the distal-end opening parts cannot be heated

Engineering Contradiction:

Improvelocal heating performanceVSAvoidheating coverage

Core Design Contradiction:

Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

The waveguide structure is segmented into multiple radiation openings: the original distal-end opening and additional side openings formed in the waveguide walls. This segmentation allows microwaves to be radiated from multiple locations, providing both localized heating capability and broader coverage for objects at different radial positions.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different portions of the waveguide structure are given different functions: the distal-end opening provides directed heating for objects near the antenna, while the side openings provide supplementary heating for objects at greater radial distances. This local differentiation of function resolves the contradiction between focused heating performance and overall heating coverage.

Inventive Principle:

Principle #3Local quality

2Length of moving object

If the distance of the distal-end opening parts from the coupling shafts is designed short, then heating objects near the edge can be heated, but heating objects near the center cannot be heated

Engineering Contradiction:

Improvedistance of distal-end opening from coupling shaftVSAvoidheating distribution uniformity

Core Design Contradiction:

Length of moving objectVSManufacturing precision

Solution Approach 1:

The solution transitions from a one-dimensional radiation pattern (only from distal-end opening) to a two-dimensional radiation pattern by adding side openings in the waveguide walls. This dimensional expansion allows the antenna to effectively serve objects at multiple radial distances simultaneously, resolving the positioning dilemma.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Length of moving object

If the distance of the distal-end opening parts from the coupling shafts is designed long, then heating objects near the center can be heated, but heating objects near the edge cannot be heated

Engineering Contradiction:

Improvedistance of distal-end opening from coupling shaftVSAvoidheating coverage

Core Design Contradiction:

Length of moving objectVSAdaptability or versatility

Solution Approach 1:

The waveguide-structure antenna is designed to perform multiple functions simultaneously: it maintains its primary directed heating function through the distal-end opening while also providing omnidirectional supplementary heating through the side openings. This multi-functionality allows the single antenna structure to adapt to various object positions without requiring multiple antenna configurations.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 configuration provides enhanced controllability in local heating performance, ensuring that heating is tailored to the position of the food object, achieving more uniform and efficient microwave radiation by adjusting the radiation pattern according to the food's location.

Implementation Method 1

Methodology Applied

Scientific EffectMicrowave radiation: Microwave Radiation

Implementation Method 2

supplies a microwave radiated from a magnetron as a typical microwave generating unit, into a metal heating chamber to inductively heat a heating object in the heating chamber

Methodology Applied

Scientific EffectInductive heating: Induction Heating

Implementation Method 3

allowing for adjustable microwave radiation based on the presence or absence of a food item, enabling controllable radial direction heating by varying the dielectric constant

Methodology Applied

Scientific EffectDielectric constant variation: Dielectric Permittivity

Data Source

PatentUS10356855B2Microwave heating apparatus

Publication Date: 2019.07.16 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD

AI summary

A microwave heating apparatus includes: a heating chamber which houses a heating object; a microwave generating unit which generates a microwave; a transmitting unit which transmits the microwave generated by the microwave generating unit; a waveguide-structure antenna which radiates to the heating chamber the microwave transmitted from the transmitting unit; and a rotation driving unit which drives the waveguide-structure antenna to rotate, wherein the waveguide-structure antenna has a microwave sucking-out opening in a wall surface forming a waveguide structure of the waveguide-structure antenna.