Adjustable Waveguide Impedance Matching for Microwave Ovens
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Solution Overview
Problem
Existing microwave ovens face energy loss and magnetron overheating due to impedance mismatch between the microwave oven cavity, waveguide, and load, leading to inefficient power transfer and potential damage to the magnetron.
Innovation Solution
A structurally adjustable waveguide with a movable wall that dynamically changes the volume of the middle chamber, allowing for adjustable impedance matching between the microwave cavity and load, achieved through a movement control mechanism with a rotatable main shaft and support shafts, ensuring maximum power transfer to the load while minimizing reflections back to the magnetron.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a fixed waveguide structure is used, then the device complexity is low, but impedance matching between the microwave cavity and load cannot be adjusted, causing energy loss and magnetron overheating
Solution Approach 1:
The waveguide structure is made dynamically adjustable through a movable partition wall that can change the volume of the middle chamber. This allows the waveguide to adapt its structural properties to match impedance with different loads, resolving the contradiction between maintaining simple structure and achieving energy efficiency through adjustability.
Solution Approach 2:
The volume parameter of the middle chamber is changed by moving the partition wall, which directly affects the equivalent impedance of the waveguide. This parameter adjustment enables impedance matching with various loads while minimizing energy loss and magnetron overheating.
2Reliability
If impedance matching is not adjusted, then the waveguide structure remains simple, but power is reflected back to the magnetron causing overheating and potential damage
Solution Approach 1:
The movable partition wall creates a dynamic waveguide structure that can be adjusted to match impedance with different loads. This dynamic adjustment prevents microwave reflection back to the magnetron, protecting it from overheating and damage while maintaining structural simplicity through a single movable component.
3Productivity
If the waveguide structure is made adjustable, then maximum power transfer to the load is achieved, but the device complexity increases
Solution Approach 1:
A single movable partition wall is used to dynamically adjust the middle chamber volume, enabling impedance matching for maximum power transfer to the load. This minimal dynamic adjustment mechanism achieves high productivity without excessive structural complexity.
Solution Approach 2:
The volume parameter of the middle chamber is varied to match the equivalent impedance of the waveguide with different load conditions. This parameter change optimizes power transfer efficiency while maintaining a relatively simple waveguide structure with only one movable component.
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 solution enables maximum power transfer to the load while reducing energy loss and overheating of the magnetron, providing a cost-effective and efficient solution by dynamically modifying the waveguide's structure to match impedances, thus improving cooking efficiency and extending the magnetron's lifespan.
Implementation Method 1
A movable wall dynamically changes the volume of the middle chamber in response to different load situations such that equivalent impedance presented to microwave generating device is adjustable
Implementation Method 2
a microwave transmission means (3), which transmits electric field and/or magnetic field, made of an electrically conductive metallic material allowing for the transmission of microwaves
Implementation Method 3
A typical household microwave oven available in the market generates an electromagnetic field of microwaves at a frequency of 2,450 MHz
Implementation Method 4
Microwaves are generated in a magnetron having metallic walls to be acting as a Faraday cage
Implementation Method 5
Waveguides usually being in the form of metal tubes of rectangular cross section, accordingly carry the microwaves from the magnetron to the oven cavity while the waves reflect off metal walls
Data Source
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AI summary
The present invention relates to a nnicrowave oven having a microwave transmission means (3), which transmits electric field and/or magnetic field, whose structural properties are adjustable in order for matching the impedances of the microwave oven cavity (4) together with various loads to a microwave generating device (2). The microwave oven (1) of the invention comprises a microwave transmission means (3) of an electrically conductive material allowing for the transmission of microwaves and which confines and carries the microwaves produced by the microwave generating device (2) to be transmitted into the oven cavity (4) adapted to contain food articles to be cooked.