阅读说明：本技术 修正s参数测量及在固态rf烤箱电子器件中的使用 (Modified S parameter measurements and use in solid state RF oven electronics ) 是由 马尔科·卡卡诺 米歇尔·斯克洛奇 达尼埃莱·克里科 于 2018-03-05 设计创作，主要内容包括：一种烤箱,该烤箱包括：烹饪室,该烹饪室被配置成接纳负载；以及,RF加热系统,该RF加热系统被配置成使用固态电子部件将RF能量提供到烹饪室中。固态电子部件包括功率放大器电子器件,该功率放大器电子器件被配置成经由天线组件将信号提供到烹饪室内。功率放大器电子器件包括至少第一功率放大器和第二功率放大器,第一功率放大器和第二功率放大器通过天线组件的第一天线和第二天线中的相应的天线可操作地耦接至烹饪室。第一天线和第二天线分别经由第一耦接结构和第二耦接结构可操作地耦接至第一功率放大器和第二功率放大器中的相应的功率放大器。定向耦接器被设置在端口部处,该端口部是为第一耦接结构和第二耦接结构中的至少一个耦接结构限定的。定向耦接器被配置成将前向波参数和反射波参数提供至测量组件,该测量组件被配置成计算端口部处的修正S参数。(An oven, comprising: 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 the antenna assembly. The power amplifier electronics include at least first and second power amplifiers operatively coupled to the cooking chamber by respective ones of the first and second antennas of the antenna assembly. The first and second antennas are operatively coupled to respective ones of the first and second power amplifiers via first and second coupling structures, respectively. The directional coupler is disposed at a port portion defined for at least one of the first and second coupling structures. The directional coupler is configured to provide the forward wave parameter and the reflected wave parameter to a measurement assembly configured to calculate a modified S-parameter at the port section.)

1. An oven, comprising:

A cooking chamber configured to receive a load; and

A Radio Frequency (RF) heating system configured to provide RF energy into the cooking chamber using solid state electronic components,

wherein the solid state electronic components comprise power amplifier electronics configured to provide a signal into the cooking chamber via an antenna assembly,

Wherein the power amplifier electronics include at least first and second power amplifiers operatively coupled to the cooking chamber by respective ones of first and second antennas of the antenna assembly, the first and second antennas being operatively coupled to respective ones of the first and second power amplifiers via first and second coupling structures, respectively,

Wherein a directional coupler is disposed at a port portion defined at least one of the first and second coupling structures; and

Wherein the directional coupler is configured to provide a forward parameter and a reflected parameter to a measurement component configured to calculate a modified S-parameter at the port portion.

2. The oven of claim 1, wherein the directional coupler is disposed downstream of the circulator relative to the power amplifier electronics.

3. the oven of claim 1, wherein the measurement assembly comprises a first measurement leg and a second measurement leg, the first measurement leg configured to measure a forward wave parameter and the second measurement leg configured to measure a reflected wave parameter, the first measurement leg and the second measurement leg operably coupled to respective opposite ends of the directional coupler.

4. The oven of claim 3, wherein the first measurement pin and the second measurement pin each comprise an adaptive attenuator, a corresponding connection structure, and a downconverter.

5. The oven of claim 4, wherein the down-converter of each of the first and second measurement pins is operatively coupled to a common analog-to-digital converter (ADC), and wherein an output of the ADC is the modified S parameter and is associated with a selected one of the forward wave parameter or the reflected wave parameter.

6. The oven of claim 3, wherein the first modified S parameter calculated for the first power amplifier comprises a ratio of a reflected wave parameter to a forward wave parameter generated by the first power amplifier and measured at a first directional coupler associated with the first power amplifier.

7. The oven of claim 6, wherein the second corrected S parameter calculated for the second power amplifier comprises a ratio of a reflected wave parameter attributable to the first power amplifier to a forward wave parameter generated by the first power amplifier and measured at a second directional coupler associated with the second power amplifier.

8. the oven of claim 1, wherein the measurement component is operably coupled to a calibration manager configured to receive the revised S parameter to perform a calibration of the power amplifier electronics.

9. The oven of claim 8, wherein the calibration of the power amplifier electronics comprises performing a single port calibration followed by a transmit calibration.

10. The oven of claim 9, wherein the transfer calibration is performed at least in part by: when a reference connection is provided between a first port associated with the first power amplifier and a second port associated with the second power amplifier, turning on the first power amplifier while the second power amplifier is off, and measuring a modified S-parameter at a directional coupler associated with each respective one of the first and second power amplifiers.

11. a measurement assembly for an oven, the oven including a cooking chamber and a Radio Frequency (RF) heating system, the cooking chamber configured to receive a load and the RF heating system configured to provide RF energy into the cooking chamber using solid state electronic components, the solid state electronic components including power amplifier electronics configured to provide a signal into the cooking chamber via an antenna assembly, the measurement assembly comprising:

A directional coupler disposed at a port portion defined at a first coupling structure that operatively couples a first power amplifier of the power amplifier electronics to a first antenna of the antenna assembly,

Wherein the directional coupler is configured to passively extract forward and reflected parameters from the port portion to a measurement component configured to calculate a modified S-parameter at the port portion.

12. The measurement assembly of claim 11 wherein the power amplifier electronics further comprise at least a second power amplifier operatively coupled to the cooking chamber through a second antenna of the antenna assembly, the second antenna operatively coupled to the second power amplifier via a second coupling structure.

13. The measurement assembly of claim 12 further comprising a first measurement leg and a second measurement leg, the first measurement leg extending from the directional coupler and configured to measure a forward wave parameter, and the second measurement leg extending from the directional coupler and configured to measure a reflected wave parameter.

14. The measurement assembly of claim 3 wherein the first measurement pin and the second measurement pin each comprise an adaptive attenuator, a corresponding connection structure, and a downconverter.

15. the measurement assembly of claim 14, wherein the down-converter of each of the first and second measurement pins is operatively coupled to a common analog-to-digital converter (ADC), and wherein an output of the ADC is the modified S-parameter and is associated with a selected one of the forward wave parameter or the reflected wave parameter.

16. The measurement assembly of claim 13 wherein the first modified S parameter calculated for the first power amplifier comprises a ratio of a reflected wave parameter to a forward wave parameter generated by the first power amplifier and measured at a first directional coupler associated with the first power amplifier.

17. The measurement assembly of claim 16 wherein the second corrected S parameter calculated for the second power amplifier comprises a ratio of a reflected wave parameter attributable to the first power amplifier to a forward wave parameter generated by the first power amplifier and measured at a second directional coupler associated with the second power amplifier.

18. The measurement assembly of claim 12 wherein the measurement assembly is operably coupled to a calibration manager configured to receive the revised S-parameters to perform calibration of the power amplifier electronics.

19. The measurement assembly of claim 18 wherein calibration of the power amplifier electronics comprises performing a single port calibration followed by a transmit calibration.

20. The measurement assembly of claim 19, wherein the transmission calibration is performed at least in part by: when a reference connection is provided between a first port associated with the first power amplifier and a second port associated with the second power amplifier, turning on the first power amplifier while the second power amplifier is off, and measuring a modified S-parameter at a directional coupler associated with each respective one of the first and second power amplifiers.

Technical Field

Exemplary embodiments relate generally to ovens, and more particularly to ovens that use Radio Frequency (RF) heating provided by solid state electronic components and calibration of equipment used in such ovens.

Background

combination ovens capable of cooking using more than one heat source (e.g., convection, steam, microwave, etc.) have been in use for decades. Each cooking source has its own unique set of characteristics. Thus, combination ovens may generally take advantage of each of the different cooking sources in an attempt to provide improved cooking processes in terms of time and/or quality.

However, even with the combination of microwave and airflow, the limitations of conventional microwave cooking with respect to food penetration may still make such a combination less desirable. In addition, typical microwaves are somewhat arbitrary or difficult to control in the manner in which they apply energy to the food product. Accordingly, it may be desirable to provide further improvements to the operator's ability to achieve superior cooking results. Accordingly, efforts have been expended to create ovens having improved capabilities with respect to cooking food products with controllable RF energy.

Controllable RF energy may be used alone or in combination with the application of convective energy to achieve superior results. However, if the level of applied RF energy is not accurately known, the advantages provided by allowing control over the application of RF energy may quickly be lost or reduced. As such, to truly achieve superior cooking results, it is necessary to be able to accurately know the RF energy level being applied within the cooking cavity of the oven. Accordingly, it may be desirable to provide methods and/or components for accurately calibrating components of an oven. S parameter calculations have been used previously for the same purpose. However, the S-parameters are typically calculated by a network analyzer having two ports for measuring the forward and reflected power of the device under test in a closed system. However, for oven cavities, it is generally not possible to identify ports that are effective to result in a closed system that can measure S-parameters in a conventional manner. Accordingly, a new method for determining a revised S parameter may be desired.

Disclosure of Invention

accordingly, some example embodiments may provide improved structures, methods, and/or systems for applying heat to food products within an oven. In addition, such improvements may require new configurations to support or operate these structures or systems. In particular, for ovens that use solid state components rather than magnetrons to generate RF energy, it may be desirable to define a method of calculating a revised S parameter that may be used to calibrate the oven components.

In an exemplary embodiment, an oven is provided. The oven may include: 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 may include power amplifier electronics configured to provide signals into the cooking chamber via the antenna assembly. The power amplifier electronics may include at least first and second power amplifiers operatively coupled to the cooking chamber by respective ones of the first and second antennas in the antenna assembly. The first and second antennas may be operatively coupled to respective ones of the first and second power amplifiers via first and second coupling structures, respectively. The directional coupler may be disposed at a port portion defined at least one of the first and second coupling structures. The directional coupler may be configured to provide the forward power parameter and the reflected power parameter to a measurement assembly configured to calculate a revised S-parameter at the port section.

In an exemplary embodiment, a measurement assembly for an oven is provided. The oven may include a cooking chamber configured to receive a load and a Radio Frequency (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 signals into the cooking chamber via the antenna assembly. The measurement assembly may include a directional coupler disposed at a port portion defined in a first coupling structure that operatively couples a first power amplifier of the power amplifier electronics to a first antenna of the antenna assembly. The directional coupler may be configured to passively extract forward and reflected power parameters from the port portion to a measurement component configured to calculate a modified S-parameter at the port portion.

Some example embodiments may improve cooking performance or operator experience when cooking by employing an oven of example embodiments.

drawings

Having thus described the invention in general terms, reference will now be made to the accompanying drawings, which are not necessarily drawn to scale, and wherein:

FIG. 1 illustrates a perspective view of an oven capable of employing at least two energy sources, according to an exemplary embodiment;

FIG. 2 illustrates a functional block diagram of the oven of FIG. 1 according to an exemplary embodiment;

FIG. 3 illustrates a cross-sectional view of an oven taken through a plane passing from the front of the oven to the back of the oven, according to an exemplary embodiment;

FIG. 4 is a top view of a top grid area of an oven according to an exemplary embodiment;

FIG. 5 illustrates a block diagram of portions of an antenna assembly and a cooking chamber of an oven, in accordance with an exemplary embodiment, to facilitate a description of port identification;

FIG. 6A illustrates a block diagram of a single port modified S parameter calculation technique in accordance with an exemplary embodiment;

FIG. 6B illustrates a block diagram of a dual port modified S-parameter calculation technique in accordance with an exemplary embodiment;

FIG. 7 illustrates a block diagram of a measurement component configured to determine a revised S parameter in accordance with an exemplary embodiment;

FIG. 8 illustrates a structure for a single port simplified calibration using modified S parameters in accordance with an exemplary embodiment;

FIG. 9 illustrates two system ports and connections that may be established to perform a transport calibration procedure in accordance with an exemplary embodiment;

FIG. 10 is a block diagram of control electronics for providing electronic circuitry for instantiating a calibration system according to an exemplary embodiment.

Detailed Description

Some example embodiments will now be described more fully hereinafter with reference to the accompanying drawings, in which some, but not all example embodiments are shown. Indeed, the examples described and illustrated herein should not be construed as limiting the scope, applicability, or configuration of the disclosure. Rather, these exemplary embodiments are provided so that this disclosure will satisfy applicable legal requirements. Like reference numerals refer to like elements throughout. Further, as used herein, the term "or" should be interpreted as a logical operator that results in true whenever one or more of its operands are true. As used herein, operably coupled should be understood to refer to a direct or indirect connection that, in either case, enables functional interconnection of components that are operably coupled to one another.

Some example embodiments may improve the cooking performance of the oven and/or may improve the operator experience of the individual employing the example embodiments. In this regard, the oven may cook food products relatively quickly and uniformly based on the application of RF energy under the instruction of control electronics configured to employ the calibration strategies and structures described herein.

The scattering or S-parameters are specific elements of a scattering or S-matrix that is used to describe the electrical network response to various stimuli provided by the electrical signals. S-parameters generally use matched loads to characterize an electrical network using quantities measured from wave voltages or coupling voltages (e.g., forward and reflected waves). An attempt to measure or understand scattering is an attempt to understand how RF energy and its operating voltage and current are affected when they encounter interruptions that are typically caused by going from the network to the transmission line. However, in the exemplary embodiment, this interruption is generally different because it is the interruption that is encountered when transitioning from the power amplifier, transmission line, and antenna to the cooking chamber. Accordingly, exemplary embodiments provide mechanisms by which to calculate revised S parameters that describe unique characteristics generated within the oven cavity and that may be used to calibrate oven components.

In particular, exemplary embodiments may allow for identifying a correct position within a chain of components feeding RF energy to a cooking chamber to identify it as a port at which to make a corrected S-parameter measurement. Once the port is identified, corresponding measurements can be made to allow calculation of the corrected S parameter. Thereafter, the revised S-parameters can be used for calibration purposes, enabling accurate control of the RF energy application (which is a characteristic feature of ovens). In the following, specific examples will be described in the context of a combination oven that uses both RF energy and another form of energy application for heating (e.g., convection heating). However, it should be understood that the exemplary embodiments may also be practiced in conjunction with any solid state RF energy cooking appliance, whether the RF energy is the sole energy of the employed cooking mechanism or only one energy of the employed cooking mechanism.

Fig. 1 illustrates a perspective view of an oven 1 according to an exemplary embodiment. As shown in fig. 1, oven 100 may include a cooking chamber 102, and a food item may be placed in cooking chamber 102 for application of heat by any one of at least two energy sources that oven 100 may employ. The cooking chamber 102 may include a door 104 and an interface panel 106, and the interface panel 106 may be located adjacent to the door 104 when the door 104 is closed. The door 104 may be operated by a handle 105, and the handle 105 may extend across the front of the oven 100 parallel to the ground. In some cases, in alternative embodiments, the interface panel 106 may be located substantially above the door 104 (as shown in fig. 1) or beside the door 104. In an exemplary embodiment, the interface panel 106 may include a touch screen display capable of providing visual indications to an operator and also capable of receiving touch inputs from the operator. The interface panel 106 may be a mechanism that provides instructions to the operator, or may be a mechanism that provides feedback to the operator regarding the status, options, and/or the like of the cooking process.

in some embodiments, oven 100 may include multiple shelves, or may include shelf (or pan) supports 108 or guide slots to facilitate insertion of one or more shelves 110 or pans containing food items to be cooked. In exemplary embodiments, the air delivery apertures 112 may be positioned adjacent to the rack supports 108 (e.g., directly below the level of the rack supports in one embodiment) to enable hot air to be forced into the cooking chamber 102 via a hot air circulation fan (not shown in fig. 1). The hot air circulation fan may draw air from the cooking chamber 102 via a chamber outlet port 120 provided at a back or rear wall of the cooking chamber 102 (i.e., the wall opposite the door 104). Air may be circulated from the chamber outlet port 120 back into the cooking chamber 102 via the air delivery apertures 112. After being removed from the cooking chamber 102 via the chamber outlet port 120, the air may be cleaned, heated, and pushed through the system by other components, and the cleaned, heated, and velocity controlled air is then returned to the cooking chamber 102. This air circulation system, including chamber outlet port 120, air delivery apertures 112, hot air circulation fan, cleaning components, and all ducts therebetween, may form a first air circulation system within oven 100.

In an exemplary embodiment, Radio Frequency (RF) energy may be used, at least in part, to heat food products placed on one of the pan or shelf 110 (or just on the bottom of the cooking chamber 102 in embodiments where the shelf 110 is not used). At the same time, the available air flow may be heated to achieve further heating or even browning to be accomplished. Note that a metal plate may be placed on one of the shelf supports 108 or the shelf 110 of some example embodiments. However, oven 100 may be configured to employ frequency and/or mitigation strategies to detect and/or prevent any electrical arcs that may otherwise be generated by using RF energy with metal components.

in an exemplary embodiment, the RF energy may be transmitted to the cooking chamber 102 via an antenna assembly 130 disposed near the cooking chamber 102. In some embodiments, multiple components may be provided in the antenna assembly 130, and these components may be placed on opposite sides of the cooking chamber 102. The antenna assembly 130 may include one or more instances of a power amplifier, transmitter, waveguide, strip transmission line, coaxial cable, and/or the like configured to couple RF energy into the cooking chamber 102.

Cooking chamber 102 may be configured to provide RF shielding on five sides thereof (e.g., top, bottom, back, and right and left sides), but door 104 may include choke 140 to provide RF shielding for the front side. Accordingly, the air dam 140 may be configured to mate with an opening defined at the front side of the cooking chamber 102 to prevent RF energy from leaking from the cooking chamber 102 when the door 104 is closed and RF energy is applied into the cooking chamber 102 via the antenna assembly 130.

In an exemplary embodiment, a gasket 142 may be provided to extend around the perimeter of air dam 140. In this regard, the gasket 142 may be formed of a material such as a mesh, rubber, silicon, or other such material that may have some degree of compressibility between the periphery of the door 104 and the opening into the cooking chamber 102. In some cases, gasket 142 may provide a substantially airtight seal. However, in other cases (e.g., where a wire mesh is employed), the gasket 142 may allow air to pass therethrough. Particularly where gasket 142 is substantially air tight, it may be desirable to provide an air purification system in association with the first air circulation system described above.

The antenna assembly 130 may be configured to generate controllable RF emissions into the cooking chamber 102 using solid state components. Accordingly, oven 100 may not employ any magnetrons, but instead use only solid state components to generate and control the RF energy applied into cooking chamber 102. The use of solid state components may provide unique advantages in that the use of solid state components may allow the characteristics of the RF energy (e.g., power/energy level, phase, and frequency) to be controlled to a greater extent than the use of magnetrons. However, since cooking food requires relatively high power, the solid part itself will also generate relatively high heat which must be removed efficiently in order to keep the solid part cool and avoid damage thereto. To cool the solid components, the oven 100 may include a second air circulation system.

The second air circulation system may operate within the oven body 150 of the oven 100 to circulate cooling air for preventing overheating of solid state components that power and control the application of RF energy to the cooking chamber 102. The second air circulation system may include an inlet array 152 formed at a bottom (or base) portion of the oven body 150. In particular, the base region of the oven body 150 may be a substantially hollow cavity within the oven body 150 disposed below the cooking chamber 102. The inlet array 152 may include a plurality of inlet ports disposed on each of opposite sides of the toaster body 150 (e.g., disposed on the right and left sides when viewing the toaster 100 from the front) near the base, and also disposed on the front of the toaster body 150 near the base. Portions of the inlet array 152 disposed on the sides of the toaster body 150 may be formed on each respective side at an angle with respect to the main portion of the toaster body 150. In this regard, portions of the inlet array 152 disposed on the sides of the toaster body 150 may be inclined inward toward each other at an angle of about 20 degrees (e.g., between 10 degrees and 30 degrees). Such inward angling may ensure that even when oven 100 is inserted into a space having a width dimension just sufficient to accommodate oven body 150 (e.g., due to walls or other equipment adjacent the sides of oven body 150), a space is created near the base to allow air to enter inlet array 152. When door 104 is closed, at a location where the front of oven body 150 is proximate to the base, a corresponding portion of inlet array 152 may lie in the same plane as the front of oven 100 (or at least in a plane parallel to the front of oven 100). Such inward angling is not required to provide access for air to the inlet array 152 at the front of the oven body 150, as that area must remain clear to allow the door 104 to open.

From the base, the duct may provide a path for air entering the base through the inlet array 152 to move upward (under the influence of cold air circulating fans) through the oven body 150 all the way to the top compartment portion within which the control electronics (e.g., solid state components) are located. The top bay portion may include various structures for ensuring that air flowing from the base to the top bay and ultimately exiting the oven body 150 via the outlet louvers 154 passes in proximity to the control electronics to remove heat from the control electronics. The hot air (i.e., air that has had heat removed from the control electronics) is then exhausted from the outlet louvers 154. In some embodiments, the outlet louvers 154 may be disposed at the right and left sides of the toaster body 150 near the top compartment and at the rear of the toaster body 150 near the top compartment. Arranging the inlet array 152 at the base and the outlet louvers 154 at the ceiling grid ensures that the normal tendency for the warmer air to rise will prevent the exhaust air (from the outlet louvers 154) from being recirculated through the system by being drawn into the inlet array 152. Furthermore, since at the oven sides (which include both inlet array 152 and outlet louvers 154), the shape of the base is such that the inward slope of inlet array 152 is provided on a wall that is also slightly adducted to form overhang 158 that blocks any air path between the inlet and outlet, inlet array 152 is at least partially isolated from any through path from outlet louvers 154. As such, the air drawn into the inlet array 152 can be reliably expected to be ambient room temperature air, rather than recirculated, exhausted cooling air.

Fig. 2 illustrates a functional block diagram of an oven 100 according to an exemplary embodiment. As shown in fig. 2, the oven 100 may include at least a first energy source 200 and a second energy source 210. The first energy source 200 and the second energy source 210 may each correspond to a respective different cooking method. In some embodiments, the first energy source 200 and the second energy source 210 may be an RF heating source and a convection heating source, respectively. However, it should be understood that additional or alternative energy sources may also be provided in some embodiments. Further, some example embodiments may be practiced in the context of an oven that includes only a single energy source (e.g., second energy source 210). As such, the exemplary embodiments may be practiced on other conventional ovens that apply heat for heating using, for example, gas or electricity.

As described above, the first energy source 200 may be an RF energy source (or RF heating source) configured to generate a relatively broad spectrum of RF energy (e.g., electromagnetic energy), or may be a specific narrow band phase-controlled energy source to cook food items placed in the cooking chamber 102 of the oven 100. Thus, for example, the first energy source 200 may include the antenna assembly 130 and the RF generator 204. The RF generator 204 of an example embodiment may be configured to generate RF energy at a selected level and at a selected frequency and phase. In some cases, the frequency may be selected in the range of about 6MHz to 246 GHz. However, other RF energy bands may be employed in some cases. In some examples, frequencies may be selected from the ISM band to be applied by the RF generator 204.

In some cases, the antenna assembly 130 may be configured to transmit RF energy into the cooking chamber 102 and receive feedback indicative of the absorption levels of the various frequencies in the food product. The absorption level can then be used to control the generation of RF energy to provide balanced cooking of the food product. However, feedback indicating the level of absorption need not be employed in all embodiments. For example, some embodiments may employ some algorithms for selecting frequencies and phases based on predetermined strategies identified for particular combinations of selected cooking times, power levels, food types, recipes, and/or the like. In some embodiments, the antenna assembly 130 may include a plurality of antennas, waveguides, transmitters, strip transmission lines, coaxial cables, and RF transparent covers that provide an interface between the antenna assembly 130 and the cooking chamber 102. Thus, for example, four waveguides may be provided, and in some cases, each waveguide may receive RF energy generated by its own respective power module or power amplifier of the RF generator 204 operating under the control of the control electronics 220. In alternative embodiments, a single multiplex generator may be employed to deliver different energies into each waveguide or pairs of waveguides to provide energy into the cooking chamber 102.

In an exemplary embodiment, the second energy source 210 may be an energy source capable of inducing browning and/or convective heating of the food product. Thus, for example, the second energy source 210 may be a convective heating system comprising an airflow generator 212 and an air heater 214. Airflow generator 212 may be embodied as or include a hot air circulation fan or another device capable of driving an airflow (e.g., via air delivery apertures 112) through cooking chamber 102. The air heater 214 may be an electric heating element or other type of heater that heats air to be driven by the airflow generator 212 toward the food product. Both the temperature of the air and the airflow rate will affect the cooking time achieved using the second energy source 210, and more specifically using the combination of the first energy source 200 and the second energy source 210.

In an exemplary embodiment, the first energy source 200 and the second energy source 210 may be controlled directly or indirectly by the control electronics 220. The control electronics 220 may be configured to receive input describing the selected recipe, food product, and/or cooking condition in order to provide instructions or control to the first energy source 200 and the second energy source 210 to control the cooking process. In some embodiments, the control electronics 220 may be configured to receive static and/or dynamic inputs regarding the food product and/or cooking conditions. The dynamic inputs may include feedback data regarding the phase and frequency of the RF energy applied to the cooking chamber 102. In some cases, the dynamic input may include adjustments made by an operator during the cooking process. The static input may include parameters input by an operator as initial conditions. For example, the static inputs may include a description of the type of food product, an initial state or temperature, a final desired state or temperature, a number and/or size of portions to be cooked, a location of items to be cooked (e.g., when multiple trays or levels are employed), a selection of recipes (e.g., defining a series of cooking steps), and/or the like.

In some embodiments, the control electronics 220 may be configured to also provide instructions or controls to the airflow generator 212 and/or the air heater 214 to control the airflow through the cooking chamber 102. However, rather than simply relying on control of the airflow generator 212 to affect the characteristics of the airflow in the cooking chamber 102, some exemplary embodiments may also employ the first energy source 200 to otherwise apply energy for cooking the food product, thereby managing the balance or management of the amount of energy applied by each source through the control electronics 220.

In an exemplary embodiment, the control electronics 220 may be configured to access algorithms and/or data tables defining RF cooking parameters for driving the RF generator 204 to generate RF energy at corresponding levels, phases, and/or frequencies for corresponding times determined by the algorithms or data tables based on initial condition information describing the food product and/or based on recipes defining a series of cooking steps. As such, the control electronics 220 may be configured to employ RF cooking as the primary energy source for cooking food products, while the convection heating application is an auxiliary energy source for browning and faster cooking. However, other energy sources (e.g., a third or other energy source) may also be employed during the cooking process.

In some cases, a cooking signature, program, or recipe may be provided to define cooking parameters to be employed for each of a plurality of potential cooking stages or steps that may be defined for the food product, and the control electronics 220 may be configured to access and/or execute the cooking signature, program, or recipe (all of which may be collectively referred to herein as a recipe). In some embodiments, the control electronics 220 may be configured to determine which recipe to execute based on input provided by the user in addition to providing dynamic input (i.e., changing cooking parameters when the program has been executed). In an exemplary embodiment, the input to the control electronics 220 may also include browning instructions. In this regard, for example, the browning instructions may include instructions regarding air speed, air temperature, and/or application time of set air speed and temperature combinations (e.g., start and stop times for certain speed and heating combinations). The browning instructions may be provided via a user interface accessible by an operator, or may be part of a cooking signature, program, or recipe.

As described above, the first air circulation system may be configured to drive hot air through the cooking chamber 102 to maintain a stable cooking temperature within the cooking chamber 102. At the same time, the second air circulation system may cool the control electronics 220. The first air circulation system and the second air circulation system may be isolated from each other. However, each respective system typically uses a pressure differential (e.g., generated by a fan) formed within the respective compartment in the respective system to drive the respective air flow required by each system. When the airflow of the first air circulation system is intended to heat the food product in the cooking chamber 102, the airflow of the second air circulation system is intended to cool the control electronics 220. As such, the cooling fan 290 provides cooling air 295 to the control electronics 220, as shown in fig. 2.

The structure forming the air cooling path via which the cooling fan 290 cools the control electronics 220 may be designed to provide efficient transport of the cooling air 295 to the control electronics 220, but also to minimize dirt problems or dust/debris accumulation in sensitive areas or areas of the oven 100 that are difficult to access and/or clean. At the same time, the structure forming the air cooling path may also be designed to maximize the ability to access and clean areas that are more prone to dust/debris accumulation. Furthermore, the structure forming the air cooling path via which the cooling fan 290 cools the control electronics 220 may be designed to strategically utilize various natural phenomena to further facilitate efficient and effective operation of the second air circulation system. In this regard, for example, the tendency for hot air to rise and the management of the high and low pressure zones that must result from fan operation within the system may each be strategically employed through the design and arrangement of various structures to maintain certain areas that are difficult to access relatively clean and other areas that are otherwise relatively easy to access are more likely to be areas that need to be cleaned.

Various configurations of typical airflow paths and secondary air circulation systems can be seen in fig. 3. In this regard, fig. 3 illustrates a cross-sectional view of the oven 100 taken through a plane passing from the front to the rear of the oven 100. The base (or base area 300) of oven 100 is defined below cooking chamber 102 and includes an entrance cavity 310. During operation, air is drawn into the inlet cavity 310 through the inlet array 152 and further into the cooling fan 290, and then forced radially outward (as indicated by arrows 315) out of the cooling fan 290 into a riser duct 330 (e.g., chimney) that extends from the base region 300 to the roof (or roof region 340) to turn the air upward (as indicated by arrows 315). Air is forced up through riser 330 into a ceiling area 340, where the ceiling area 340 is where components of the control electronics 220 are located. Subsequently, the air cools the components of the control electronics 220 and then exits the body 150 of the oven 100 via the outlet louvers 154. The components of the control electronics 220 may include power supply electronics 222, power amplifier electronics 224, and display electronics 226.

When the air reaches the ceiling area 340, the air is initially directed from the riser duct 330 to the power amplifier enclosure 350. The power amplifier housing 350 may house the power amplifier electronics 224. In particular, the power amplifier electronics 224 may be located on an electronic board to which all of these components are mounted. Thus, the power amplifier electronics 224 may include one or more power amplifiers mounted to the electronic board to power the antenna assembly 130. Thus, the power amplifier electronics 224 may generate a relatively large thermal load. To facilitate dissipation of this relatively large thermal load, the power amplifier electronics 224 may be mounted to one or more heat sinks 352. In other words, the electronic board may be mounted to one or more heat sinks 352. The heat sink 352 may include large metal fins that extend away from the circuit board on which the power amplifier electronics 224 are mounted. Thus, the fins may extend downward (toward the cooking chamber 102). The fins may also extend in a lateral direction away from the centerline of the oven 100 (front to back) to direct air provided into the power amplifier housing 350 and past the fins of the heat sink 352.

fig. 4 illustrates a top view of the top lattice region 340 and shows various components of the power amplifier housing 350 and antenna assembly 130, including the waveguide of the transmitter assembly 400 and waveguide assembly 410. Power is provided to each transmitter of the transmitter assembly 400 from the power amplifier electronics 224. The transmitter assembly 400 is operable to couple a signal generated by the power amplifier of the power amplifier electronics 224 into a corresponding one of the waveguides of the waveguide assembly 410 for transmission of the corresponding signal into the cooking chamber 102 via the antenna assembly 130 as described above.

The power amplifier electronics 224 are defined by a plurality of electronic circuit components (including operational amplifiers, transistors, and/or the like) that are configured to generate waveforms at respective power levels, frequencies, and phases as desired for a particular situation or cooking program. In some cases, the cooking program may select an algorithm for controlling the power amplifier electronics 224 to direct RF emissions into the cooking chamber 102 at a selected power level, frequency, and phase. One or more learning processes may be initiated to select one or more corresponding algorithms to direct power application. The learning process may include detecting feedback regarding the effectiveness of applying power into the cooking chamber 102 at a particular frequency (and/or phase). To determine this effectiveness, in some cases, a learning process may measure the efficiency and compare the efficiency to one or more thresholds. Efficiency can be calculated as forward power (P)_fwd) And reflected power (P)_refl) The difference between them divided by the forward power (P)_fwd). As such, for example, the power introduced into the cooking chamber 102 (i.e., the forward power) may be measured along with the reflected power to determine the amount of power absorbed in the food product (or workload) introduced into the cooking chamber 102. Efficiency ofIt can be calculated as: efficiency (eff) ═ P_fwd–P_refl)/P_fwd。

As can be appreciated from the foregoing description, measurement of the efficiency of the transmission of RF energy to the food product may be useful in determining how effective a particular (e.g., current) selection of combinations (or pairs) of frequency and phase parameters of the RF energy applied into the cooking chamber 102 when delivering thermal energy to the food product is. Therefore, a measure of efficiency may be beneficial in selecting the best combination or algorithm for energy application. It is therefore also desirable that the measurement of efficiency should be as accurate as possible to ensure that meaningful control is exerted by monitoring efficiency. However, if the measurement of a particular parameter involved in measuring efficiency is inaccurate, the value of the efficiency measurement may be compromised. Therefore, it is desirable to use accurate measurements. As previously mentioned, the revised S parameter may be included in the parameters measured and used to improve the operation of the oven 100. However, in order to accurately measure the modified S-parameters, a unique and specialized measurement paradigm must be designed and implemented.

fig. 5 illustrates a block diagram of various portions of the antenna assembly 130 and the cooking chamber 102 of the oven 100, in accordance with an exemplary embodiment, to facilitate description of port identification. As mentioned previously, the theory of S-parameter measurement is well known. However, an open cooking cavity such as cooking chamber 102 of oven 100 is not a typical component with respect to conventional methods for determining an S parameter. In this regard, the natural port location used to calculate the S-parameter will be at the antenna where the antenna radiates into the cooking chamber 102. However, this is far from an ideal port location and would make any calibration effort attempted by measuring the S-parameter at that location extremely difficult. Thus, the revised S parameters of the exemplary embodiments may be determined using specific port locations and equipment located elsewhere.

As shown in fig. 5, a cooking chamber 102 (or cavity) is located within oven 100. The load 500 may be placed within the cooking chamber 102 and RF energy 510 may be provided into the cooking chamber 102 to be applied to the load 500. During normal operation, the load 500 may be food. However, during calibration and/or testing, the load 500 may be a dummy load or a standard test load (e.g., a particular amount of water). As described above, the RF energy 510 may be provided to the cooking chamber 102 via the antenna assembly 130 and its various components, such as the transmitter assembly 400, the waveguide assembly 410, the power amplifier electronics 224 (see, e.g., fig. 3 and 4). The power amplifier electronics 224 may include a plurality of power amplifiers that may each be operatively coupled to a respective RF chain that includes respective instances of a transmitter and a corresponding antenna. In some cases, each RF chain may also include a respective instance of a strip transmission line, coaxial cable, waveguide, and/or the like to feed RF energy to the transmitter or directly into the cooking chamber 102.

In the example of fig. 5, portions of the power amplifier electronics 224 (see fig. 3) are represented by a first power amplifier 520 and a second power amplifier 522. However, it should be understood that more power amplifiers (e.g., four) may be used in some examples. The first power amplifier 520 and the second power amplifier 522 may each be operatively coupled to a respective first antenna 530 and second antenna 532 via a first coupling structure 540 and a second coupling structure 542, respectively. As previously mentioned, the first coupling structure 540 and the second coupling structure 542 may each be an example of one or more of a strip transmission line, a coaxial cable, a waveguide, and/or the like. The system port location may be defined at a port portion 550, the port portion 550 being disposed between the outputs of the first and second power amplifiers 520, 522 and the first and second antennas 530, 532.

The revised S parameter definition will now be described with reference to fig. 6A and 6B. FIG. 6A illustrates a block diagram of a single port modified S parameter calculation technique, according to an example embodiment. FIG. 6B illustrates a block diagram of a dual-port modified S-parameter calculation technique in accordance with an exemplary embodiment. As shown in fig. 6A, a first port (i.e., port i) may be defined with respect to the first power amplifier 520(PA _ i). The forward power (or incident power) of port i is denoted as Ai. Meanwhile, the reflected power of port i is denoted as Bi. In this example, there are n sources, and n is not equal to i. As shown in fig. 6A, the modified S parameter (Sii) for port i that can be determined from this arrangement is the ratio of Bi to Ai. Thus, the corrected S-parameter at each port can be calculated as the ratio of reflected power to forward power relative to the power attributable to that port. However, when there are multiple ports, reflected power contributions are also experienced at the other ports. Thus, fig. 6B shows that the modified S-parameter can also be calculated taking into account the reflected power at the other port.

as shown in fig. 6B, the forward power of port i is Ai and the reflected power of port i is Bi, while the reflected power of port j (measured at the second power amplifier 522(PA _ j)) is Bj. The modified S parameter (Sji) for port j that can be determined from this arrangement is the ratio of Bj to Ai.

After the system port location at port portion 550 has been defined as previously described, a mechanism must be established whereby the measurement is performed. One example of such a mechanism will be described with reference to fig. 7, which fig. 7 illustrates a conceptual block diagram of a measurement component 600 for determining a revised S parameter according to an exemplary embodiment. It is noted that measurement assembly 600 is shown in fig. 7 in connection with only one system source (i.e., first power amplifier 520). It should be understood, however, that in exemplary embodiments, an equal number of instances of measurement component 600 may be provided to that number of system sources.

The measurement assembly 600 may be operatively coupled to the port portion 550 via a directional coupler 610. Directional coupler 610 may be used to extract measurement data from port portion 550 without affecting any signals passing through port portion 550. As such, directional coupler 610 may be configured based on the forward wave (a) at port 550_i) And a reflected wave (b)_i) Forward wave parameters (e.g., b-fwd) are extracted in a first measurement leg 612 and reflected wave parameters (b-rfl) are extracted in a second measurement leg 614. After extraction by directional coupler 610, the extracted wave parameters may be passed through adaptive attenuator 620 (of the respective measurement pin) and corresponding connection structure 630 and to down-converter 640 (of the respective measurement pin). The downconverter 640 of each of the first measurement pin 612 and the second measurement pin 614 is operatively coupled to an analog-to-digital converter (ADC) 650. The output of the ADC 650 may be a scaling vector (b _ mis) that is proportional to the extracted actual wave parameter (b-fwd or b-rfl), depending on which measurement leg is selectedOutput to ADC 650.

As shown in fig. 7, measurement assembly 600 can be positioned such that directional coupler 610 extracts data from isolated portions of coupling structures (e.g., first coupling structure 540 and second coupling structure 542). Isolation may be provided, for example, by a circulator 660, which circulator 660 may be disposed between a power amplifier (e.g., first power amplifier 520) and port 550. The circulator 660 may ensure that any reflected waves do not affect or reach the corresponding power amplifier circuit.

using the port definitions described above, the modified S parameter may be calculated. Thereafter, calibration of oven 100 may be performed based on the calibration of the revised S parameter. Fig. 8 and 9 present block diagrams illustrating system components and their use for calibration according to an exemplary embodiment. As previously described, the modified S-parameter is calculated by: extracts data from the port portion 550 as defined above and determines the ratio of the incident (or forward) wave parameter to the reflected wave parameter (e.g., when a_kwhen 0, Sij ═ b_i/a_jwhere k ≠ i).

Calibration may be based on extracting actual wave parameters (e.g., a) at any system port_iAnd b_i) Is performed with the measured parameter b _ mis determined. The calibration term may compensate for any calibration and measurement error compensation of the vector, such as the directivity of the directional coupler 610. Many types of modified S-parameter calibrations can be performed after the modified S-parameters have been determined. However, for the oven 100 described herein, the calibration procedure may be performed according to a series of steps including: 1) single port calibration is performed, followed by 2) transmission calibration. Single port calibration may be applicable to any single port. Single port calibration can be used to calibrate the reflection parameter measurements and enable accurate measurements of the reflection coefficient at any port. This calibration may be performed using a set of standard calibration loads. The transmission calibration may be used to calibrate transmissions between any coupled system ports and may compensate for transmission loss and transfer phase.

Fig. 8 shows an exemplary structure of a single port simplified calibration using a modified S-parameter (e.g., Sii parameter evaluation). Short/open/load (SOL) techniques may be employed during this calibration step to make it availableA of (a)_mand b_mCalculating the ratio b on the basis of the measured values₁/a₁. In the example of fig. 8, port mismatch and any coupler directivity errors can be compensated for to make these measurements more accurate and reliable than simple scalar parameter evaluation. Error parameter matrix can measure the reflection coefficientLinked to the actual reflection coefficient at the port portionOnce the measurement of the standard termination (SOL) is over, the error matrix parameters can be calculated and the b parameter can be passed through_mAnd a_mTo calculateValue (when ADC 650 is connected to the reflective branch of the directional coupler, b_mCorresponding to b _ mis, and a when the ADC 650 is connected to the forward (or direct) leg or leg of the directional coupler 610_mCorresponding to a _ mis). By using vector measurements and calculations at any step of the algorithm, parameters in terms of amplitude and phase can be measured.

As can be appreciated from the above description, the definition of the port section can be made at strategic locations relative to the amplifier output and any waveguide and/or antenna section. The format of the calibration standard may change as the position of the port moves from the microstrip line portion to the waveguide portion or the antenna portion. Points (1, 2, 3, and 4) on fig. 8 have respective different parameter values (e.g., a-0, a-1, b-0, b-1, b-3, and b-4) associated therewith, which points may represent different parameters appearing at each respective point to be considered when performing a calibration procedure based on the nature of coupling structure 540. In this respect, or on a microstrip line portion, a short circuit may be formed by shorting a selected location on the output microstrip line to ground, and an open circuit may be formed by interrupting a microstrip line in the same microstrip line portion. It may be necessary to remove the interruptions, thereby giving a reliable continuity to the output of the microstrip line. For the waveguide portion, the short-circuit portion and the open-circuit portion may be formed using a metal plane and a ferrite plane to be arranged at the port position. For the antenna section, the definition of short/open/load becomes difficult to define, even though in theory this is the ideal section to define the cavity excitation port. In practice, the microstrip line segments may be selected to reduce system complexity and cost, with improved reliability and stability, while also having high directivity and good matching. The calibration port section may be defined after the directional coupler and just prior to transitioning to the antenna structure that drives the cooking chamber 102. Calibration references (open/short/load) for any port may be applied during a calibration session that is formed during electronic component testing. Over the lifetime of the electronics of the oven, calibration and error parameters may be calculated and stored within the electronic controller.

Fig. 9 illustrates two system ports and connections that may be established to perform a transport calibration procedure in accordance with an example embodiment. As shown in fig. 9, a reference connection 700 may be provided between port i and port j. The reference connection 700 may be embodied as a coaxial cable whose loss and transition phase properties have been previously characterized, or as a reference waveguide connection (also previously characterized).

After a single port calibration at any one of the N ports of the system (per fig. 8), the transmission S parameters Sii may be calibrated using the correction parameters calculated for any port and the reference connection 700. Thus, the transmission S parameter Sii may be calculated based on available measurements of a _ m-i, b _ m-i, a _ m-j, and b _ m-j. These measurements may be performed by a directional coupler that alternately connects a down-converter to the i-port and the j-port. Both the vector format of the transmission parameters and the vector format of the reflection parameters are available. Once oven 100 has been calibrated as described above, this set of Sii and Sij vector-type S parameters is available for use by oven 100.

Fig. 10 is a block diagram of control electronics 220 for providing electronic circuitry for instantiating a calibration system according to an exemplary embodiment. In some embodiments, the control electronics 220 may include or be in communication with processing circuitry 800, the processing circuitry 800 may be configured to perform actions in accordance with the exemplary embodiments described herein. As such, functions attributable to, for example, processing electronics 220 may be performed by processing circuitry 800.

Processing circuitry 800 may be configured to perform data processing, control function execution, and/or other processing and management services according to embodiments of the present invention. In some embodiments, the processing circuit 800 may be embodied as a chip or chip set. In other words, the processing circuit 800 may include one or more physical packages (e.g., chips) that include materials, components, and/or wires on a structural assembly (e.g., a baseboard). The structural assembly may provide physical strength, conservation of size, and/or limitation of electrical interference with component circuitry contained thereon. Thus, in some cases, the processing circuit 800 may be configured to implement embodiments of the present invention on a single chip, or as a single "system on a chip. As such, in some cases, a chip or chip set may constitute a means for performing one or more operations for providing the functionality described herein.

In an example embodiment, the processing circuit 800 may include one or more instances of each of the processor 810 and the memory 820, which processor 810 and memory 820 may communicate with or otherwise control the device interface 830 and the user interface 840. As such, the processing circuit 800 may be embodied as a circuit chip (e.g., an integrated circuit chip) configured (e.g., by hardware, software, or a combination of hardware and software) to perform the operations described herein. However, in some embodiments, the processing circuit 800 may be embodied as part of an on-board computer.

The user interface 840 (which may be embodied as, included with, or as part of the interface panel 106) may be in communication with the processing circuit 800 to receive indications of user inputs at the user interface 840 and/or to provide audible, visual, mechanical, or other outputs to a user (or operator). As such, the user interface 840 may include, for example, a display (e.g., a touch screen such as the interface panel 106), one or more hardware or software buttons or keys, and/or other input/output mechanisms.

The device interface 830 may include one or more interface mechanisms for enabling communication with a connected device 850, such as other components of the oven 100, sensors in a sensor network of the oven 100, removable memory devices, wireless or wired network communication devices, and/or the like, the connected device 850. In some cases, the device interface 830 may be any means, such as a device or circuitry embodied in hardware, or a combination of hardware and software, configured to receive and/or transmit data from/to a sensor that measures any of a number of device parameters, such as frequency, phase, temperature (e.g., temperature in the cooking chamber 102 or in an air channel associated with the second energy source 210), air velocity, and/or the like. As such, in one example, device interface 830 may receive input from at least measurement component 600 described above, or input including any other parameters described above, to communicate these parameters to calibration manager 860. Alternatively or additionally, the device interface 830 may provide an interface mechanism for any device capable of wired or wireless communication with the processing circuit 800. In still other alternatives, the device interface 830 may provide connections and/or interface mechanisms to enable the processing circuit 800 to control various components of the oven 100.

In an exemplary embodiment, the memory 820 may include one or more non-transitory memory devices, such as volatile and/or non-volatile memory that may be fixed or removable. The memory 820 may be configured to store information, data, cooking signatures, programs, recipes, applications, instructions or the like to enable the control electronics 220 to perform various functions in accordance with exemplary embodiments of the present invention. For example, the memory 820 may be configured to buffer input data for processing by the processor 810. Additionally or alternatively, memory 820 may be configured to store instructions for execution by processor 810. As yet another alternative, the memory 820 may include one or more databases that may store various data sets in response to input from a sensor network or in response to programming of any of various cooking programs. Within the contents of memory 820, applications can be stored for execution by processor 810 in order to implement the functionality associated with each respective application. In some cases, these applications may include a control application that utilizes the parametric data to control the application of heat by the first and second energy sources 200, 210 described herein. In this regard, for example, the applications may include a work guide that defines expected cooking speeds for given initial parameters (e.g., food type, size, initial state, location, and/or the like) using a corresponding table of frequencies, phases, RF energy levels, temperatures, and air speeds. Accordingly, some applications executable by processor 810 and stored in memory 820 may include tables defining combinations of RF energy parameters and air velocities and temperatures to determine cooking times for achieving certain degrees of doneness and/or for performing specific cooking recipes. Thus, different cooking programs may be performed to create different RF and/or convection environments to achieve desired cooking results. In still other examples, a data table may be stored to define calibration values and/or diagnostic values, as previously described. Alternatively or additionally, the memory 820 may store an application program for defining a response to a stimulus, including generating a protective action and/or notification function. In still other examples, memory 820 may store algorithms for determining the parameters described above and for performing calibration according to the description presented herein.

The processor 810 may be embodied in a number of different ways. For example, the processor 810 may be embodied as various processing means, such as one or more of the following: a microprocessor or other processing element, a coprocessor, a controller or various other computing or processing devices including integrated circuits such as, for example, an ASIC (application specific integrated circuit), an FPGA (field programmable gate array), and/or the like. In an exemplary embodiment, the processor 810 may be configured to execute instructions stored in the memory 820 or otherwise accessible to the processor 810. As such, whether configured by hardware or by a combination of hardware and software, the processor 810 may represent an entity (e.g., physically embodied in circuitry — such as an entity in the form of processing circuit 800) capable of performing operations according to exemplary embodiments of the present invention when configured accordingly. Thus, for example, when any instance of the processor 810 is embodied as an ASIC, FPGA or the like, the processor 810 may be specially configured hardware for performing the operations described herein. Alternatively, as another example, when the processor 810 is embodied as one or more executors of software instructions, the instructions may specifically configure the processor 810 to perform the operations described herein.

In an exemplary embodiment, the processor 810 (or processing circuit 800) may be embodied as, include or otherwise control the control electronics 220 and/or the calibration manager 860. As such, in some embodiments, the processor 810 (or processing circuit 800) may be considered to cause each of the operations described in connection with the control electronics 220 and/or the calibration manager 860 to be performed by: the control electronics 220 and/or calibration manager 860 are directed to assume corresponding functions, respectively, in response to execution of instructions or algorithms according to which the processor 810 (or processing circuit 800) is configured. As an example, the control electronics 220 (or more specifically, the calibration manager 860) may be configured to control responses to various stimuli associated with detecting the parameters and/or values discussed above with reference to fig. 5-9. Further, the control electronics 220 may be configured to determine parameters and perform calibration techniques using the parameters determined by the control electronics 220 (or the calibration manager 860) or parameters received at the control electronics 220 (or the calibration manager 860). In some cases, different instances of the processor(s) and memory may be associated with different portions of the control electronics 220 (e.g., including separate processors for controlling the power amplifier electronics 224 and the calibration manager 860, although other scenarios are possible).

In an exemplary embodiment, the control electronics 220 may also access and/or execute instructions for controlling the RF generator 204 and/or the antenna assembly 130 to control the application of RF energy to the cooking chamber 102. Thus, for example, the operator may provide static inputs for defining the type, quality, quantity, or other descriptive parameters (e.g., recipes) associated with the food items disposed within the cooking chamber 102. The control electronics 220 can then utilize the static input to locate an algorithm or other program to be executed that defines the application of RF energy and/or convective energy to be applied within the cooking chamber 102. The control electronics 220 may also monitor dynamic inputs for modifying the amount, frequency, phase, or other characteristics of RF energy to be applied within the cooking chamber 102 during the cooking process, and may also perform protection functions as described herein. Finally, the control electronics 220 may execute instructions for calibration and/or fault analysis. Thus, for example, the control electronics 220 (or more specifically, the calibration manager 860) may be configured to act locally to facilitate calibration of the power amplifier electronics 224.

In an exemplary embodiment, an oven may be provided. The oven may include: 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 the antenna assembly. The power amplifier electronics include at least first and second power amplifiers operatively coupled to the cooking chamber by respective ones of the first and second antennas of the antenna assembly. The first and second antennas are operatively coupled to respective ones of the first and second power amplifiers via first and second coupling structures, respectively. The directional coupler is disposed at a port portion defined at least one of the first and second coupling structures. The directional coupler is configured to provide a forward parameter (e.g., a forward power or wave parameter) and a reflected parameter (e.g., a reflected power or wave parameter) to a measurement component configured to calculate a corrected S-parameter at the port portion.

In some embodiments, additional optional features may be included or the above features may be modified or supplemented. Each of the additional features, modifications or additions may be practiced in combination with the above-described features and/or in combination with each other. Accordingly, some, all, or none of the additional features, modifications, or additions may be utilized in some embodiments. For example, in some cases, the directional coupler may be disposed downstream of the circulator relative to the power amplifier electronics. In some examples, the measurement component may include a first measurement leg configured to measure a forward wave parameter and a second measurement leg configured to measure a reflected wave parameter. The first and second measurement feet may be operatively coupled to respective opposite ends of the directional coupler. It will also be appreciated, however, that there may be two separate couplers, one dedicated to forward waves and a second dedicated to reflected waves. As such, the two legs may be physically separated, each leg being associated with a dedicated directional coupler, such that the first coupler couples forward waves and the second coupler couples reflected waves. In an exemplary embodiment, the first measurement leg and the second measurement leg may each include an adaptive attenuator, a corresponding connection structure, and a downconverter. In this example, the downconverters of each of the first and second measurement pins may be operably coupled to a common ADC. The output of the ADC may be a modified S parameter and may be associated with a selected one of a forward wave parameter or a reflected wave parameter. In some cases, the first modified S-parameter calculated for the first power amplifier may comprise a ratio of a reflected wave parameter to a forward wave parameter generated by the first power amplifier and measured at a first directional coupler associated with the first power amplifier. In an exemplary embodiment, the second modified S-parameter calculated for the second power amplifier may comprise a ratio of a reflected wave parameter attributable to the first power amplifier to a forward wave parameter generated by the first power amplifier and measured at a second directional coupler associated with the second power amplifier. In some embodiments, the measurement component may be operably coupled to a calibration manager. The calibration manager may be configured to receive the revised S-parameters to perform calibration of the power amplifier electronics. In some cases, calibration of the power amplifier electronics may include performing a single port calibration followed by a transmit calibration. In an exemplary embodiment, the transmission calibration may be performed, at least in part, by: when a reference connection is provided between a first port associated with the first power amplifier and a second port associated with the second power amplifier, the first power amplifier is turned on when the second power amplifier is turned off. The transmit calibration may include measuring a modified S-parameter at a directional coupler associated with each respective one of the first and second power amplifiers.

Many modifications and other embodiments of the inventions set forth herein will come to mind to one skilled in the art to which these inventions pertain having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the inventions are not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. Moreover, although the foregoing description and the associated drawings describe exemplary embodiments in the context of certain exemplary combinations of elements and/or functions, it should be appreciated that different combinations of elements and/or functions may be provided by alternative embodiments without departing from the scope of the appended claims. In this regard, for example, combinations of elements and/or functions other than those explicitly described above are also contemplated as may be set forth in some of the appended claims. Where advantages, benefits, or solutions to problems are described herein, it should be appreciated that such advantages, benefits, and/or solutions may apply to some example embodiments, but not necessarily all example embodiments. Thus, any advantages, benefits or solutions described herein should not be considered critical, required, or essential to all embodiments or embodiments claimed herein. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.