Waveguide Opening Layout for Accurate Reflected Microwave Detection
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Solution Overview
Problem
Conventional microwave heating devices face challenges in accurately detecting incident and reflected waves propagating through a waveguide, limiting their separation and detection precision.
Innovation Solution
A microwave heating device design that includes a waveguide with a cross-shaped opening and a reflected-wave detection unit positioned within a specific distance range relative to the opening, allowing for the accurate detection of reflected waves by leveraging the difference in circularly polarized microwave rotation directions between incident and reflected waves.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional directional coupler with an opening and coupling line is used to detect microwave power levels, then the device can separate incident and reflected waves, but the detection accuracy is insufficient
Solution Approach 1:
The invention extracts only the necessary detection function from the conventional directional coupler structure. By placing the detection unit directly at the opening without requiring external coupling lines, the design simplifies the structure while maintaining the ability to detect both incident and reflected waves through the opening in the waveguide wall.
Solution Approach 2:
The opening in the waveguide wall serves as an intermediary element that allows microwave energy to couple from the waveguide interior to the detection unit. This intermediary structure enables the detection unit to measure power levels without direct contact with the high-power microwave environment, improving safety and measurement accuracy.
2Measurement precision
If the reflected-wave detection unit is positioned too far from the opening, then the structure is simpler, but the detection accuracy decreases
Solution Approach 1:
The detection unit is pre-positioned within the optimal distance range (0.05λ to 0.15λ) from the opening before operation begins. This preliminary positioning ensures that the unit is already in the optimal detection zone when microwaves are introduced, maximizing detection accuracy without requiring complex adjustment mechanisms during operation.
3Measurement precision
If the detection unit is placed closer to the opening, then detection accuracy improves, but the device becomes more complex and harder to install
Solution Approach 1:
The detection system is segmented into a modular detection unit that can be independently manufactured and then installed at the optimal position near the opening. This segmentation allows the detection unit to be precisely positioned for maximum accuracy while simplifying the overall manufacturing process, as the unit can be produced separately and attached during assembly rather than requiring complex integrated construction.
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 enables higher accuracy in separating and detecting incident and reflected waves, improving the overall performance of microwave heating devices by optimizing the placement and design of the waveguide and detection units.
Implementation Method 1
The wall surface has an opening for extracting a part of a microwave from the waveguide
Implementation Method 2
The reflected-wave detection unit detects a part of a reflected wave being a microwave propagating from the heating chamber toward the microwave generating unit
Implementation Method 3
the rotation direction of a circularly polarized microwave emitted from the opening fed by an incident wave, is opposite to that of a circularly polarized microwave emitted from the opening fed by a reflected wave
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
A microwave heating device according to the present disclosure includes: a heating chamber to accommodate a heating target object, a microwave generating unit, a waveguide, an opening, and a reflected-wave detection unit. The microwave generating unit generates a microwave. The waveguide transmits, to the heating chamber, the microwave generated by the microwave generating unit. The opening is disposed in a wall surface of the waveguide, and extracts a part of a microwave from the waveguide. The reflected-wave detection unit detects a part of a reflected wave being a microwave propagating from the heating chamber toward the microwave generating unit, with the part of the reflected wave having been extracted through the opening. The reflected-wave detection unit is disposed within a range from the opening to a distance equal to 1/2 of the maximum opening length of the opening.