Microwave Heating Uniformity via Frequency Hopping Control
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Solution Overview
Problem
Existing microwave processing apparatuses face challenges in achieving uniform heating without adding mechanical parts or increasing chamber capacity, leading to increased costs and reduced miniaturization potential due to the need for rotating mechanisms and uneven cavity wall surfaces.
Innovation Solution
A microwave processing apparatus that uses a semiconductor-based oscillator, power amplifier, power feeder, and controller to perform frequency hopping heating by determining minimum point frequencies and adjusting heating times based on detected reflected power, ensuring uniform heating distribution without mechanical parts or chamber expansion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If rotating mechanism parts are added to stir the microwave incident into the heating chamber, then uniform heating is achieved, but the capacity of the heating chamber is reduced and cost increases
Solution Approach 1:
The patent replaces mechanical stirring mechanisms (rotating fans, tables, or antennas) with an electronic control system that adjusts the oscillation frequency of the microwave generator. By varying the frequency within a predetermined range and performing frequency hopping heating, the system achieves uniform heating distribution without any moving parts in the heating chamber, thus preserving chamber capacity and reducing cost.
Solution Approach 2:
The patent changes the operating parameter (oscillation frequency) of the microwave generator dynamically. The controller adjusts the oscillation frequency within a predetermined range and selects multiple heating frequencies through frequency hopping, which modifies the microwave heating distribution in the chamber over time, achieving uniform heating without mechanical movement.
2Manufacturing precision
If multiple power feeding portions are added to concentrate and diffuse the microwave, then uniform heating is achieved, but the capacity of the heating chamber is reduced and cost increases
Solution Approach 1:
The patent replaces complex structural modifications (multiple power feeding portions, uneven cavity wall surfaces) with a simple frequency control system. By adjusting the oscillation frequency of the existing single power feeder, the system achieves the same effect of concentrating and diffusing microwave energy throughout the chamber, thereby avoiding additional structural complexity.
Solution Approach 2:
The patent makes the single power feeder system perform multiple functions by varying its operating frequency. The same power feeder structure can concentrate or diffuse microwave energy depending on the frequency used, eliminating the need for multiple specialized power feeding portions or complex cavity structures.
3Volume of stationary object
If the oscillation frequency is changed to change heating distribution, then uniform heating is achieved without mechanical parts, but control complexity increases
Solution Approach 1:
The patent implements periodic frequency hopping heating where the controller sequentially switches between multiple predetermined heating frequencies within a predetermined unit time. This periodic variation in frequency creates temporal diffusion of heating distribution, achieving uniform heating while using a simple digital control algorithm rather than complex continuous control systems.
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 enables efficient and uniform heating of objects within the microwave processing apparatus by controlling the oscillation frequency and power distribution, preventing local heating and achieving high-quality uniformity without the need for additional mechanical components or chamber expansion.
Implementation Method 1
an oscillator that outputs a source signal of a heating frequency... a power amplifier that power-amplifies an output of the oscillator... a power feeder that feeds an output of the power amplifier to the heating chamber
Implementation Method 2
a power detector that detects incident power fed from the power amplifier to the power feeder and reflected power reflected from the power feeder to the power amplifier
Implementation Method 3
the controller determines a plurality of points of heating frequencies... and performs frequency hopping heating within a predetermined unit time for the plurality of heating frequencies. This enables temporal diffusion of the heating distribution
Data Source
AI summary
A microwave processing apparatus is provided with an oscillator, a power amplifier, a heating chamber that accommodates an object to be heated, a power feeder which is disposed on a wall surface of the heating chamber, which receives an output transmitted from a microwave generator and which radiatively feeds the microwave into the heating chamber, and a power detector that detects the power reflected from the power feeder to the power amplifier. The microwave processing apparatus determines a plurality of points of heating frequencies by using top several points of minimum point frequencies of the reflected power, and performs frequency hopping heating within a predetermined unit time.