Modified S-parameter measurement and usage in solid state RF oven electronics
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Solution Overview
Problem
Conventional microwave ovens lack control over energy penetration and application, leading to suboptimal cooking results due to indiscriminate energy distribution, and existing methods for calibrating RF energy in combination ovens are inadequate for accurate RF energy level measurement.
Innovation Solution
An oven using solid state electronic components for RF energy generation, with a measurement assembly that includes directional couplers to extract forward and reflected power parameters, enabling the calculation of modified S parameters for precise calibration of RF energy application.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional microwave ovens use magnetron for RF energy generation, then RF energy can be provided to cooking chamber, but control over energy penetration and application is lost leading to indiscriminate energy distribution
Solution Approach 1:
The patent replaces the conventional magnetron-based RF generation system with a solid-state electronic system comprising power amplifiers, antennas, and measurement assemblies. This substitution enables precise electronic control of RF energy levels while allowing accurate measurement through integrated directional couplers and network analyzers, thereby resolving the contradiction between control capability and measurement precision.
2Measurement precision
If S parameter measurement is performed using conventional two-port network analyzer in closed system, then forward and reflected power can be measured, but it is not possible to identify ports for oven cavity measurement
Solution Approach 1:
The patent segments the oven cavity measurement system into multiple identifiable ports, each equipped with directional couplers. This segmentation allows the network analyzer to measure forward and reflected power at discrete locations within the cooking chamber, transforming the impossible single-port measurement into multiple feasible measurement points that collectively provide comprehensive RF energy characterization.
Solution Approach 2:
The patent introduces directional couplers as intermediary devices between the power amplifiers/antennas and the network analyzer. These couplers serve as mediators that extract a portion of the forward and reflected RF signals without disrupting the main energy transfer, enabling accurate measurement while maintaining the integrity of the RF heating system.
3Adaptability or versatility
If combination oven uses multiple heating sources (convection, steam, microwave), then cooking capabilities are improved, but limitations of microwave penetration and control remain
Solution Approach 1:
The patent implements a universal measurement and control system that works across all heating modes (convection, steam, microwave). The solid-state RF system with integrated measurement capabilities provides consistent precision control regardless of the heating source being used, enabling the combination oven to leverage the versatility of multiple heating sources while eliminating the previous limitations of microwave control.
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 allows for accurate control and calibration of RF energy levels, improving cooking performance and uniformity by identifying proper ports for modified S parameter measurement, enhancing the cooking experience and efficiency.
Implementation Method 1
The first and second antennas may be operably coupled to respective ones of the first and second power amplifiers via a first coupling structure and a second coupling structure, respectively. A directional coupler may be provided at a port section defined at at least one of the first and second coupling structures.
Implementation Method 2
an RF heating system configured to provide RF energy into the cooking chamber using solid state electronic components. The solid state electronic components may include power amplifier electronics configured to provide a signal into the cooking chamber via an antenna assembly.
Implementation Method 3
The directional coupler may be configured to provide a forward power parameter and a reflected power parameter to a measurement assembly configured to calculate modified S parameters at the port section.
Data Source
AI summary
An oven includes a cooking chamber configured to receive a load and an RF heating system configured to provide RF energy into the cooking chamber using solid state electronic components. The solid state electronic components include power amplifier electronics configured to provide a signal into the cooking chamber via an antenna assembly. The power amplifier electronics include at least a first power amplifier and a second power amplifier operably coupled to the cooking chamber by respective ones of a first antenna and second antenna of the antenna assembly. The first and second antennas are operably coupled to respective ones of the first and second power amplifiers via a first coupling structure and a second coupling structure, respectively. A directional coupler provided at a port section defined for at least one of the first and second coupling structures. The directional coupler is configured to provide a forward wave parameter and a reflected wave parameter to a measurement assembly configured to calculate modified S parameters at the port section.