A high-efficiency stepped metal corrugated microwave uniform heating device

Abstract

The present invention discloses a high-energy-efficiency stepped metal corrugated microwave uniform heating device, which comprises: a heating chamber, one side of the heating chamber is connected to a chamber door for opening and closing, a loading platform is provided at the inner bottom of the heating chamber, and food to be heated is placed on the loading platform; a metal cavity is formed between the bottom of the loading platform and the heating chamber; a magnetron, the magnetron is connected to a power supply to generate microwaves; a microwave transmission component, one end of the microwave transmission component is connected to the magnetron, and the other end of the microwave transmission component is connected to the metal cavity and transmits the microwaves generated by the magnetron into the metal cavity; a stepped metal corrugated structure, the stepped metal corrugated structure is provided with multiple groups, each group of the stepped metal corrugated structures includes multiple longitudinally arranged metal plates, the multiple metal plates are fixedly connected to the bottom surface of the metal cavity, and the heights of adjacent metal plates are different. The microwaves generated by the magnetron generate uniform upward microwave energy on the stepped metal corrugated structure, which passes through the loading platform to uniformly heat the food.

Description

Technical Field

[0001] The present invention relates to the field of application of electromagnetic wave near-field characteristics and microwave heating technology, and in particular to a high-energy-efficiency stepped metal corrugated microwave uniform heating device. Background Art

[0002] Cutting-edge technological innovation is the driving force behind the continuous improvement of our quality of life. Since its introduction, the household microwave oven has occupied an indispensable position in home cooking due to its fast heating speed and simple operation. With the continuous development of cutting-edge technology, microwave ovens have evolved from their original purpose of heating leftovers to a versatile kitchen appliance capable of steaming, frying, baking, and cooking.

[0003] However, microwave ovens have two problems: First, uneven heating. Because the electromagnetic field is unevenly distributed, and the physical properties of food affect the absorption of microwave energy, microwave ovens often experience uneven heating and unstable thermal shapes, failing to achieve the same heating results as traditional cooking methods. Second, low heating efficiency. When unloaded, traditional microwave ovens experience multiple reflections and refractions, causing more electromagnetic energy to be reflected back into the magnetron, resulting in low heating efficiency and even damage. While much research has been conducted on improving microwave heating performance, the stability and uniformity of microwave heating remain poor, resulting in low energy efficiency and inconvenience. Therefore, improving the heating uniformity and efficiency of microwave ovens is crucial.

[0004] Currently, many technologies have been applied to microwave ovens to improve heating performance and energy efficiency. Turntables were first used to improve heating uniformity. Turntable microwaves allow food to rotate periodically, allowing different positions on the food to experience different electric fields, thus improving heating uniformity. Rotating the food during the heating process ensures a relatively uniform final temperature. Another approach involves flat-panel microwave ovens, where a rotating antenna or stirring blade is installed at the bottom of the cavity. This antenna is connected to the motor shaft. The motor's rotation drives the antenna or stirring blade, increasing standing wave modes in the microwave resonant cavity, ensuring a sufficient number of electromagnetic field modes within the cavity and improving microwave energy distribution. Microwave ovens using antennas can also utilize the principles of probe coupling and coupling windows to transfer more energy generated by the magnetron into the cavity, improving heating efficiency.

[0005] Turntable microwave ovens evenly distribute temperature along the turntable's axis, but they don't eliminate uneven heating of food from top to bottom or from inside to outside. Therefore, the turntable's improvement in heating uniformity is limited. Furthermore, the turntable's use reduces the space available, resulting in inefficient use of the microwave's space. Furthermore, the rotation creates vibrations, making it difficult to clean stains after use. These are the drawbacks of turntable microwave ovens.

[0006] Adding antennas, mode stirrers, and other devices can alter the electric field distribution and improve microwave heating uniformity. However, the overall size and mass of a microwave oven cannot be excessively large. Therefore, the size of the resonant cavity is limited, and the electromagnetic field patterns that can be established within the cavity are theoretically finite. This does not effectively address the problem of uneven heating in microwave ovens. Furthermore, simply changing the relative position of the electric field and the food does not effectively address edge heating. Edge heating of the food remains severe. While the use of antennas in flat-panel microwave ovens can increase energy transmission to the cavity, it does not fundamentally address the reflection and refraction issues within the metal cavity, and heating efficiency issues remain.

[0007] Therefore, how to provide a new type of high-energy-efficiency stepped metal corrugated microwave uniform heating device is an urgent problem that needs to be solved by those skilled in the art. Summary of the Invention

[0008] In view of this, the present invention provides a high-energy-efficiency stepped metal corrugated microwave uniform heating device to solve the problem of uneven heating of food under the existing heating mode and the problem of insufficient microwave energy fed into the microwave oven cavity, thereby improving the space utilization of the microwave oven and enhancing the heating uniformity and energy efficiency of the microwave oven.

[0009] In order to achieve the above object, the present invention adopts the following technical solution: a high-efficiency stepped metal corrugated microwave uniform heating device, comprising:

[0010] A heating chamber, one side of which is connected to a chamber door, a loading platform is provided at the bottom of the inner side of the heating chamber, and food to be heated is placed on the loading platform; a metal cavity is provided below the loading platform;

[0011] a magnetron connected to a power source to generate microwaves;

[0012] a microwave transmission component, one end of which is connected to the magnetron, and the other end of which is in communication with the metal cavity and transmits the microwaves generated by the magnetron into the metal cavity;

[0013] A stepped metal corrugated structure is provided in multiple groups. Each group of the stepped metal corrugated structures includes multiple longitudinally arranged metal plates. The multiple metal plates are fixedly connected to the bottom surface of the metal cavity. The heights of adjacent metal plates are different. The microwaves generated by the magnetron generate uniform upward microwave energy on the stepped metal corrugated structure, which passes through the loading platform to evenly heat the food.

[0014] The beneficial effects of the present invention are as follows: the magnetron is connected to a power source to generate microwaves, which are efficiently transmitted into the metal cavity through the microwave transmission component. The stepped metal corrugated structure at the bottom of the metal cavity acts to convert the microwave energy into uniform microwave energy. The stepped metal corrugated structure can regulate the electromagnetic waves radiated into the metal cavity, and can generate uniformly radiated electromagnetic waves under the action of the metal corrugated structure, making the microwave energy distribution above the device more uniform, thereby improving the uniformity of food heating. The propagation speed of the electromagnetic waves through the metal corrugated structure is less than the wave speed in free space, so that the food absorbs the microwave energy more fully, further improving the heating efficiency. The residual electromagnetic energy in the cavity is relatively small, and accordingly, the electromagnetic waves reflected back to the magnetron are relatively small. The energy efficiency of the microwave oven is significantly improved, and the heating device is not easily damaged.

[0015] Preferably, the spacing between the multiple metal plates in each group of the stepped metal corrugated structures is different.

[0016] Preferably, the heights of the metal plates in two adjacent stepped metal corrugated structures are different, the thicknesses of the metal plates in two adjacent stepped metal corrugated structures are different, and the numbers of the metal plates in two adjacent stepped metal corrugated structures are different.

[0017] Preferably, there are three groups of stepped metal corrugated structures, which are distributed side by side on the bottom surface of the metal cavity.

[0018] Preferably, the operating wavelength of the magnetron is λ, and the width of each metal plate in the stepped metal corrugated structure is W, then λ / 4<W<λ / 2 is satisfied.

[0019] Preferably, the microwave transmission component is a waveguide or an antenna capable of radiating electromagnetic waves, and the waveguide or antenna radiates the microwave energy generated by the magnetron onto the stepped metal corrugated structure.

[0020] Preferably, a bending portion is provided at the top of the waveguide, a curved microwave transmission path is formed inside the waveguide, the magnetron is connected to the bending portion of the waveguide, the bending portion of the waveguide is located at the top of the heating chamber, and the length of the waveguide is consistent with the height of the heating chamber.

[0021] The present invention adopts a waveguide or antenna structure to transmit and radiate electromagnetic waves, which can form a good match with the magnetron. The use of waveguide to transmit microwave energy or antenna to directly radiate electromagnetic waves can reduce the energy leakage of microwave energy during transmission, shorten the heating time, and improve the energy efficiency of the heating device.

[0022] Alternatively, by directly transmitting microwave energy through a waveguide or directly radiating electromagnetic waves through an antenna, the antenna itself can be smaller or the waveguide can be bent. This allows the heating device to fit more comfortably within the microwave oven cavity, improving the space utilization of the microwave oven. Furthermore, the use of an antenna or a bent waveguide prevents electromagnetic waves from being reflected back to the magnetron, thus protecting the magnetron. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a schematic diagram of Example 1 of a high-efficiency stepped metal corrugated microwave uniform heating device of the present invention;

[0024] Figure 2 This is a schematic diagram of Example 2 of a high-energy-efficiency stepped metal corrugated microwave uniform heating device according to the present invention;

[0025] Figure 3 for Figure 1 and Figure 2 The main view;

[0026] Figure 4 for Figure 1 and Figure 2 Side view of the corresponding stepped metal corrugated structure;

[0027] Figure 5 This is a schematic diagram of Example 3 of a high-efficiency stepped metal corrugated microwave uniform heating device of the present invention;

[0028] Figure 6 This is a schematic diagram of Example 4 of a high-efficiency stepped metal corrugated microwave uniform heating device of the present invention;

[0029] Figure 7 for Figure 5 and Figure 6 Side view of the corresponding stepped metal corrugated structure;

[0030] Figure 8 A schematic diagram of a microwave oven application of a high-efficiency stepped metal corrugated microwave uniform heating device according to the present invention;

[0031] Figure 9 for Figure 8 Electric field distribution on the stage after application;

[0032] Figure 10 for Figure 8 Standing wave result after application.

[0033] 1. Magnetron, 2. Antenna, 3. Metal cavity, 4. Outer metal corrugated structure, 5. Inner metal corrugated structure, 6. Stage, 7. Waveguide, 8. Heating chamber. DETAILED DESCRIPTION

[0034] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0035] See the attached Figures 1 to 10 ;

[0036] Example 1: A high-efficiency stepped metal corrugated microwave uniform heating device according to the present invention comprises:

[0037] A heating chamber 8, one side of which is connected to a chamber door, is provided with a loading platform 6 at the bottom of the inner side of the heating chamber 8, on which food to be heated is placed; a metal cavity 3 is provided below the loading platform 6;

[0038] The magnetron 1 is connected to a power source to generate microwaves; the magnetron is a component for generating microwaves;

[0039] Antenna 2, the top end of antenna 2 is connected to magnetron 1, and the other end of antenna 2 is connected to metal cavity 3 and transmits microwaves generated by magnetron 1 into metal cavity 3;

[0040] The antenna uses a high-power directional antenna 2 to radiate and transmit electromagnetic waves. It should be noted that high-power directional antennas are not limited to the antenna types shown in the figure. Any antenna that meets the requirements can be used. The specific structural design needs to adapt to the heating requirements. First, the antenna 2 can achieve good matching with the magnetron 1. At the same time, the magnetron 1 can be directly used as the feeding structure of the antenna, so that more electromagnetic energy can be radiated from the antenna and excited to the metal corrugated structure. The metal corrugated structure cooperates with the bottom surface of the metal cavity to form a metal corrugated surface, thereby significantly improving the energy efficiency of the uniform heating device. Second, the antenna has strong directionality. The electromagnetic waves radiated from the antenna propagate along the Y-axis to the metal corrugated surface, and are excited to generate uniform electromagnetic energy on it. This avoids the traditional method in which part of the electromagnetic energy is fed into the cavity and then propagates directly upward or the omnidirectional antenna radiates to the surroundings, thereby improving the heating uniformity of the entire microwave heating device.

[0041] The stepped metal corrugated structure is provided with four groups, which are distributed side by side on the bottom surface of the metal cavity. Each group of stepped metal corrugated structures includes multiple longitudinally arranged metal plates (along the y-axis direction). The multiple metal plates are fixedly connected to the bottom surface of the metal cavity 3. The height dimensions of adjacent metal plates are different. The microwaves generated by the magnetron generate uniform upward microwave energy on the stepped metal corrugated structure, which passes through the stage to evenly heat the food.

[0042] Furthermore, the spacing between the multiple metal plates in the four groups of stepped metal corrugated structures is different, that is, the spacing between the multiple metal plates in the outer metal corrugated structure 4 is different, and the spacing between the multiple metal plates in the inner metal corrugated structure 5 is also different.

[0043] Example 2

[0044] Different from Example 1, a waveguide 7 is used to transmit the microwaves generated by the magnetron to the metal cavity 3. A bend is provided at the top of the waveguide 7, forming a curved microwave transmission path inside the waveguide 7. The magnetron 1 is connected to the bend of the waveguide. The bend of the waveguide 7 is located at the top of the heating chamber 8. The length of the waveguide 7 is consistent with the height of the heating chamber 8.

[0045] Example 3

[0046] Different from Example 1, the stepped metal corrugated structure has three groups, such as Figure 5 As shown;

[0047] Example 4

[0048] Different from the embodiment 2, the stepped metal corrugated structure is provided with three groups, such as Figure 6 As shown;

[0049] During specific use, the type of waveguide 7 is not limited to the waveguide structure shown in the figure, and any type of waveguide structure meets the requirements. First, in order to avoid the heating device having more microwave energy reflected back to the magnetron when in use, the temperature of the anode plate of the magnetron increases, causing damage to the magnetron and resulting in a reduction in the life of devices such as microwave ovens. The waveguide 7 is bent here, taking the application of a uniform heating device to a microwave oven as an example. The waveguide 7 is suspended on the side of the microwave oven cavity, and the length of the waveguide 7 is consistent with the actual microwave oven cavity height. The bending position of the waveguide is at the top of the microwave oven cavity, which fully guarantees the space utilization of the microwave oven and ensures that its overall size is not too large. Secondly, in order to enable the energy of the magnetron to be coupled into the waveguide and matched with the waveguide, if it is a rectangular waveguide, the size of the bent waveguide should meet the following requirements:

[0050]

[0051] where λ cis the cut-off wavelength, a is the wide side dimension, and b is the narrow side dimension. At the same time, in the present invention, in order to ensure the transmission of electromagnetic waves, the size of the bent waveguide is also related to the operating wavelength λ of the magnetron, and the wide side dimension satisfies a=0.6-0.8λ, and b=0.5a. If other types of waveguides are selected, such as circular waveguides, ridge waveguides, etc., their corresponding dimensions should be designed according to the operating wavelength and cut-off wavelength of the heating device. Finally, compared with embodiment 1, its advantage is that it can reduce the electromagnetic energy leakage problem during the transmission of electromagnetic waves, ensure the transmission of microwave energy and the safety of the heating device during use, and improve the safety, stability and energy efficiency of the heating device.

[0052] The electromagnetic waves radiated by the antenna or waveguide structure in Examples 1 and 2 excite the stepped metal corrugated structure, radiating uniform electromagnetic waves toward the loading platform through the corrugated metal surface. The metal plates within the metal cavity can generate different types of electromagnetic waves depending on their size, number, and placement. By designing the number, size, and placement of these metal corrugations, uniform electromagnetic waves can be generated that radiate upward from the loading platform, achieving uniform heating of the food.

[0053] In the present invention, a stepped metal corrugated structure is placed within a metal cavity. To ensure the uniform heating device can be directly applied to a microwave oven while simultaneously maintaining the overall dimensions of the microwave oven, the length and width of the metal cavity are identical to the actual dimensions of the microwave oven, with the height of the metal cavity slightly exceeding the height h of the highest metal plate. The metal cavity also prevents electromagnetic energy leakage during use, ensuring heating uniformity and energy efficiency.

[0054] In order to make the heating device have better heating uniformity, it is necessary to ensure that the electric field in the furnace cavity and on the stage is evenly distributed. The present invention abandons the traditional radiation method. The traditional radiation method forms a standing wave field in the furnace cavity. Obviously, the field distribution is uneven and it is impossible to achieve uniform heating of food. The present invention adopts a surface wave radiation method. The electromagnetic waves radiated by the antenna or waveguide excite the stepped metal corrugated surface to generate surface waves. The surface waves propagate along the metal corrugated surface, and in the direction perpendicular to the metal corrugated surface, the amplitude of the field decays exponentially. In order to further homogenize the field in the furnace cavity, that is, to still have a uniform distribution of electromagnetic energy at a higher position in the cavity / a position higher than the stage, the present invention adopts a stepped metal corrugated array. Specifically;

[0055] In such Figure 1-2 In the uniform heating device shown, the propagation constant k of the electromagnetic wave radiated by the antenna or waveguide can be decomposed into

[0056]

[0057] The wave propagates along the Y axis. In general, the propagation constant can be expressed as a complex number, which can be expressed as

[0058] k z =β z -jα z (3)

[0059] β z represents the phase constant, α z Represents the attenuation constant. When the surface wave propagates on the corrugated surface of the metal, β z = 0. Therefore, β z = 0. In the positive direction of the z-axis, the amplitude of the field decays exponentially, that is,

[0060]

[0061] Therefore, above the metal corrugated surface, that is, on the stage, the electromagnetic field distribution is uniform. However, in order to ensure that there is still a uniform distribution of electromagnetic energy at a higher position in the heating chamber / a higher position from the stage, a stepped metal corrugated array is required, the purpose of which is to reduce the amplitude of the electromagnetic field attenuation in the Z-axis direction. The metal plates in the stepped corrugated metal surface array are parallel to each other and placed perpendicular to the ground at the bottom of the cavity. In order to ensure that the metal corrugated surface can guide the propagation of electromagnetic waves and make the propagation speed of electromagnetic waves on the metal surface less than the wave speed of electromagnetic waves radiated from the antenna or waveguide. Assume that the height of the metal plate in the metal corrugated sheet array is h, the spacing between the metal plates is d, and the thickness of the metal plate is l, so each metal plate unit should theoretically satisfy:

[0062]

[0063] Where λ is the microwave oven's operating wavelength. Its function is to stimulate the generation of uniform surface waves while also slowing the propagation of electromagnetic waves, allowing them to be fully absorbed by the heated food. This reduces reflection of electromagnetic waves from the cavity walls, reducing the energy reflected to the antenna, waveguide, and magnetron. This enhances heating uniformity and improves the efficiency of the uniform heating device.

[0064] In a specific implementation, since the height h of the metal plates follows a step-like pattern, the variation in the height h of each metal plate along the Y-axis can conform to an exponential function, an arithmetic progression, a geometric progression, etc. Therefore, the height, thickness, and spacing between each metal plate unit in the array are theoretically different.

[0065] At the same time, to ensure uniform electromagnetic energy in the X-axis direction and not affect the radiation direction of the electromagnetic wave after exciting the metal corrugated surface (i.e., upward radiation), the widths W1 and W2 of each metal plate unit in the metal corrugated surface array satisfy λ / 4<W1<λ / 2; λ / 4<W2<λ / 2, that is, the upper surface of the metal corrugated surface along the X-axis direction is a short road surface, ensuring uniform electromagnetic wave.

[0066] In summary, by rationally designing the placement and size (length, width, height, thickness) of each unit in the metal corrugated array, we can obtain -α z Approaches 0. Finally, the electric field strength E above the stage is satisfied. z ≈A. That is, in the Z direction, the electromagnetic wave amplitude no longer decays exponentially, thus avoiding the problem of lower electric field strength at higher locations above the stage. Compared to traditional microwave heating methods, the wave amplitude does not reach zero (wave nodes).

[0067] The number of groups of the stepped metal corrugated array and the number of each group can be adjusted according to the actual size and performance requirements of the microwave oven. The number of groups and the number of metal plates are arbitrary. Figure 1-4 The schematic diagram given is a 4-group stepped metal corrugated array. For smaller microwave ovens, such as Figure 5-7 As shown, the heating device with dimensions of c2 and d2 has three sets of stepped metal corrugated arrays placed inside. In order to ensure good heating uniformity and energy efficiency when applied to equipment such as miniaturized microwave ovens, the height h of each metal plate placed along the Y axis should change according to the law of exponential function, arithmetic progression, geometric progression, etc. The spacing between the metal plates is d, the thickness of the metal plates is l, and each metal plate unit should theoretically meet the following requirements: The widths W3 and W4 of each metal plate unit in the metal corrugated surface array satisfy λ / 4<W3<λ / 2; λ / 4<W4<λ / 2.

[0068] Figure 8 This is a schematic diagram of the application of the high-efficiency stepped metal corrugated microwave uniform heating device structure of the first embodiment of the present invention to a microwave oven. As can be seen from the figure, the microwave uniform heating device in the present invention has a simple structure and can be conveniently and directly applied to heating equipment such as microwave ovens, facilitating its subsequent industrial design, processing and production.

[0069] Figure 9-10 yes Figure 8 The simulation results of the embodiment in which the high-efficiency stepped metal corrugated microwave uniform heating device is applied to a microwave oven are shown. Figure 9This diagram shows the electric field distribution on the microwave oven's loading platform. The electric field distribution on the loading platform shows that the electric field strength is relatively uniform. The electromagnetic waves radiated by the antenna or waveguide can stimulate the stepped metal corrugated surface to produce uniform electromagnetic waves that radiate upward. These electromagnetic waves propagate within the microwave oven cavity as surface waves. Therefore, a microwave oven using this heating device can evenly heat food. Figure 10 This is the standing wave ratio (SWR) result of the high-efficiency uniform heating device of the present invention. Standing wave ratio is a key indicator for microwave oven simulation verification and is closely related to the energy efficiency of actual microwave ovens. As can be seen from the figure, the SWR is less than 3 within the operating frequency band, and in actual testing, an energy efficiency exceeding 60% can be achieved, significantly improving the energy efficiency of this heating device. The high-efficiency stepped metal corrugated microwave uniform heating device of the present invention can also be applied to other open or closed microwave heating equipment, as well as other industrial equipment requiring high-power uniform heating.

[0070] As for the devices and methods of use disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple, and the relevant parts can be referred to the description of the methods.

[0071] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A high energy efficiency stepped metal corrugated microwave uniform heating device, characterized in that: include: A heating chamber, one side of which is connected to a chamber door, a loading platform is provided at the bottom of the inner side of the heating chamber, and food to be heated is placed on the loading platform; a metal cavity is provided below the loading platform; a magnetron connected to a power source to generate microwaves; a microwave transmission component, one end of which is connected to the magnetron, and the other end of which is in communication with the metal cavity and transmits the microwaves generated by the magnetron into the metal cavity; A stepped metal corrugated structure is provided with multiple groups. Each group of the stepped metal corrugated structures includes multiple longitudinally arranged metal plates. The multiple metal plates are fixedly connected to the bottom surface of the metal cavity. The heights of adjacent metal plates are different. The spacing between the multiple metal plates in each group of the stepped metal corrugated structures is different. The microwaves generated by the magnetron generate uniform upward microwave energy on the stepped metal corrugated structure, which passes through the loading platform to evenly heat the food.

2. A high energy efficiency stepped metal corrugated microwave uniform heating device according to claim 1, characterized in that: The metal plates in two adjacent stepped metal corrugated structures have different heights, the metal plates in two adjacent stepped metal corrugated structures have different thicknesses, and the number of metal plates in two adjacent stepped metal corrugated structures is different.

3. The high energy efficiency stepped metal corrugated microwave uniform heating device according to claim 2, characterized in that: There are three groups of stepped metal corrugated structures, which are distributed side by side on the bottom surface of the metal cavity.

4. The high energy efficiency stepped metal corrugated microwave uniform heating device according to claim 3, characterized in that: The operating wavelength of the magnetron is λ, and the width of each metal plate in the stepped metal corrugated structure is W, thus satisfying λ / 4<W<λ / 2.

5. A high energy efficiency stepped metal corrugated microwave uniform heating device according to any one of claims 1 to 4, characterized in that: The microwave transmission component is a waveguide or an antenna capable of radiating electromagnetic waves, and the waveguide or antenna radiates microwave energy generated by the magnetron onto the stepped metal corrugated structure.

6. The high energy efficiency stepped metal corrugated microwave uniform heating device according to claim 5, characterized in that: A bending portion is provided at the top of the waveguide, a curved microwave transmission path is formed inside the waveguide, the magnetron is connected to the bending portion of the waveguide, the bending portion of the waveguide is located at the top of the heating chamber, and the length of the waveguide is consistent with the height of the heating chamber.

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