CN106545899B - Rectangular waveguide component and microwave oven with same - Google Patents

Abstract

The invention discloses a rectangular waveguide component and a microwave oven with the same. The rectangular waveguide assembly includes: a rectangular waveguide, the rectangular waveguide has a narrow side and a wide side, a microwave conduction cavity is arranged in the rectangular waveguide, and the microwave conduction cavity has a short-circuit surface; an antenna, the antenna is inserted in the direction of the broad side to extend into the microwave conduction cavity; at least one tuning component is provided on at least one side wall in the direction of the narrow side, and each tuning component includes a tuning block and a driving device, so The tuning block is arranged on the inner side wall of the rectangular waveguide so as to move up and down, the driving device is located outside the microwave conduction cavity and the driving device is suitable for driving the corresponding tuning block to move up and down to adjust the tuning The distance between the block and the top wall of the rectangular waveguide in the broadside direction. The rectangular waveguide component of the invention is beneficial to improving the heating efficiency and heating uniformity of the microwave oven.

Description

Rectangular waveguide component and microwave oven with same

technical field

The invention relates to the technical field of microwave ovens, in particular to a rectangular waveguide assembly and a microwave oven with the same.

Background technique

With the research on semiconductor microwave heating technology, in order to improve the heating efficiency and heating uniformity of microwave ovens, methods such as adjusting the output power, phase, frequency, and multi-feeding of semiconductor microwave sources are generally adopted. However, the heating efficiency of the microwave oven in the related art is still very low, and the heating uniformity is poor.

Contents of the invention

The present invention aims to solve one of the technical problems in the related art at least to a certain extent. To this end, the present invention proposes a rectangular waveguide assembly with an improved tuning assembly. When the rectangular waveguide assembly is used in a microwave oven, the heating efficiency and heating uniformity of the microwave oven can be improved.

The present invention also provides a microwave oven, including the above-mentioned rectangular waveguide assembly.

The rectangular waveguide assembly according to the embodiment of the present invention includes: a rectangular waveguide having a narrow side and a wide side, a microwave conduction cavity is arranged in the rectangular waveguide, and the microwave conduction cavity has a short-circuit surface; an antenna, the The antenna is inserted into the top wall in the direction of the broad side to extend into the microwave conduction cavity; at least one tuning component is provided on at least one side wall in the direction of the narrow side, and each tuning component includes a tuning block and a driving device, the tuning block can be moved up and down on the inner side wall of the rectangular waveguide, the driving device is located outside the microwave conduction cavity and the driving device is suitable for driving the corresponding tuning block Move up and down to adjust the distance between the tuning block and the top wall of the rectangular waveguide in the broadside direction.

According to the rectangular waveguide assembly of the embodiment of the present invention, by setting at least one tuning assembly, and adjusting the distance between the tuning block and the top wall of the rectangular waveguide in the broadside direction through the driving device, the distance between the tuning block and the antenna is adjusted , which in turn is beneficial to optimize the performance of microwave conduction in the microwave conduction cavity, and then when the rectangular waveguide assembly is used in a microwave oven, it is beneficial to improve the heating efficiency and heating uniformity of the microwave oven.

According to some embodiments of the present invention, the length of the tuning block is equal to the length of the rectangular waveguide.

According to some embodiments of the present invention, there are two tuning components, and the two tuning components are respectively arranged on two side walls of the rectangular waveguide in the direction of the narrow side.

According to some embodiments of the present invention, the side wall of the rectangular waveguide in the direction of the narrow side is provided with a positioning hole passing through the side wall, and the pivot shaft of the driving device passes through the positioning hole and corresponds to connected to the tuning block.

According to some embodiments of the present invention, the antenna is inserted into the microwave conduction cavity through an opening on the top wall in the broadside direction, and the distance between the center of the opening and the short-circuit surface is L, and L satisfies : L=λ/4, where λ=c/f, c is the speed of light, and f is the operating frequency.

Specifically, the center of the opening is located on the mid-perpendicular line of the broad side.

According to some embodiments of the present invention, the cross section of the tuning block is square.

According to some embodiments of the present invention, in the length direction of the tuning block, there is a rounded transition between two surfaces of the tuning block adjacent to the antenna.

According to some embodiments of the present invention, the side length of the square is D, and D satisfies D=10mm±5mm.

According to some embodiments of the present invention, the distance between the tuning block and the top wall located in the broadside direction is H, and H satisfies: 4mm≤H≤18mm.

According to some embodiments of the present invention, the length of the sidewall of the rectangular waveguide in the direction of the narrow side is M, the length of the sidewall of the rectangular waveguide in the direction of the broad side is N, and M and N satisfy : 30mm≤M≤50, 60mm≤N≤100mm.

A microwave oven according to an embodiment of the present invention includes a box body, wherein a cooking cavity and a placement cavity spaced apart from each other are arranged in the box; a microwave source is arranged in the placement cavity; the above-mentioned rectangular waveguide assembly, The rectangular waveguide assembly is connected between the microwave source and the cooking cavity.

According to the microwave oven of the embodiment of the present invention, the rectangular waveguide assembly is arranged, which is beneficial to improve the heating efficiency and heating uniformity of the microwave oven.

Description of drawings

Figure 1 is a perspective view of a rectangular waveguide assembly according to some embodiments of the present invention;

Figure 2 is a top view of a rectangular waveguide assembly according to some embodiments of the present invention;

Figure 3 is a front view of a rectangular waveguide assembly according to some embodiments of the present invention.

Reference signs:

Rectangular waveguide assembly 100;

Rectangular waveguide 1; narrow side 11; wide side 12; opening 121; microwave conduction cavity 13; short-circuit surface 131;

Antenna 2;

Tuning block 3.

Detailed ways

Embodiments of the invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below by referring to the figures are exemplary and are intended to explain the present invention and should not be construed as limiting the present invention.

In describing the present invention, it is to be understood that the terms "centre", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right" ", "vertical", "horizontal", "top", "bottom", "inner", "outer", "axial", "radial", "circumferential", etc. The orientation or positional relationship shown in the figure is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be construed as a reference to this invention. Invention Limitations.

In the present invention, unless otherwise clearly specified and limited, terms such as "installation", "connection", "connection" and "fixation" should be understood in a broad sense, for example, it can be a fixed connection or a detachable connection , or integrated; can be mechanically connected, can also be electrically connected or can communicate with each other; can be directly connected, can also be indirectly connected through an intermediary, can be the internal communication of two components or the interaction relationship between two components, unless expressly defined otherwise. Those of ordinary skill in the art can understand the specific meanings of the above terms in the present invention according to specific situations.

The following describes a rectangular waveguide assembly 100 according to an embodiment of the present invention with reference to the accompanying drawings, and the rectangular waveguide assembly 100 can be used in a microwave oven.

As shown in FIGS. 1-3 , a rectangular waveguide component 100 according to an embodiment of the present invention may include: a rectangular waveguide 1 , an antenna 2 and at least one tuning component. It can be understood here that "at least one" means one or more than one.

For ease of description, firstly, the rectangular waveguide assembly 100 is combined in a microwave oven for illustration.

A microwave oven according to an embodiment of the present invention may include a box body, a microwave source and a rectangular waveguide assembly 100 . Specifically, a cooking cavity and a placement cavity spaced apart from each other are provided in the box, wherein the cooking cavity is suitable for placing food, and the placement cavity is suitable for placing other structures of a microwave oven such as a microwave source and a rectangular waveguide assembly 100 .

Specifically, the rectangular waveguide assembly 100 is connected between the microwave source and the cooking cavity, and microwaves generated by the microwave source can be transmitted into the cooking cavity through the rectangular waveguide assembly 100, so as to heat food in the cooking cavity. Optionally, the microwave source may be a semiconductor microwave source. Certainly, in some other embodiments, the microwave source may also be a magnetron.

According to the microwave oven of the embodiment of the present invention, by providing the rectangular waveguide assembly 100, it is beneficial to improve the heating efficiency and heating uniformity of the microwave oven.

Specifically, the rectangular waveguide 1 has a narrow side 11 and a wide side 12. There is a microwave conduction cavity 13 inside the rectangular waveguide 1. When the rectangular waveguide assembly 100 is used in a microwave oven, microwaves emitted by a microwave source such as a semiconductor microwave source can pass through the microwave The conduction cavity 13 transports into the cooking cavity of the microwave oven.

The microwave conduction cavity 13 has a short-circuit surface 131 and an emission surface, and the short-circuit surface 131 of the microwave oven can prevent microwaves from passing through the short-circuit surface 131 so that more microwaves are transmitted to the cooking cavity of the microwave oven through the emission surface in the microwave conduction cavity 13, thereby facilitating microwave ovens heating of food in the cooking chamber.

As shown in FIG. 3 , the antenna 2 is inserted into the top wall in the direction of the broad side 12 to extend into the microwave conducting cavity 13 . Specifically, the antenna 2 can be electrically connected to the above-mentioned microwave source. When the microwave oven is in operation, the microwaves generated by the microwave source are transmitted to the antenna 2 and further radiated into the cooking cavity of the microwave oven through the antenna 2 .

A tuning assembly is provided on at least one side wall in the direction of the narrow side 11, that is to say, at least one tuning assembly can be provided on one of the side walls in the direction of the narrow side 11, or on both sides in the direction of the narrow side 11 At least one tuning component is respectively arranged on the walls. For example, two tuning components are respectively provided on two side walls in the direction of the narrow side 11 , or in other embodiments, one tuning component is provided on one of the side walls in the direction of the narrow side 11 . Alternatively, one tuning component is respectively provided on the two side walls in the direction of the narrow side 11 .

Specifically, each tuning assembly includes a tuning block 3 and a driving device, the tuning block 3 can be moved up and down on the inner side wall of the rectangular waveguide 1, the driving device is located outside the microwave conduction cavity 13 and the driving device is suitable for driving the corresponding tuning block 3 moves up and down to adjust the distance between the tuning block 3 and the top wall of the rectangular waveguide 1 in the direction of the broadside 12. The distance between the tuning block 3 and the top wall of the rectangular waveguide 1 in the direction of the broadside 12 is adjusted by the driving device, thereby adjusting the distance between the tuning block 3 and the antenna 2, which is conducive to optimizing the conduction microwave performance of the microwave conduction cavity 13 performance, and then when the rectangular waveguide assembly 100 is used in a microwave oven, it is beneficial to improve the heating efficiency and heating uniformity of the microwave oven. It should be noted here that the vertical direction refers to the direction perpendicular to the extending direction of the wide side 12 , that is, the extending direction of the narrow side 11 .

It can be understood that the tuning block 3 is conductive. Specifically, the tuning block 3 can be made of materials with high electrical conductivity, such as metal materials.

According to the rectangular waveguide assembly 100 of the embodiment of the present invention, by setting at least one tuning assembly, and adjusting the distance between the tuning block 3 and the top wall of the rectangular waveguide 1 in the direction of the broad side 12 through the driving device, the tuning block 3 and the The distance between the antennas 2 is conducive to optimizing the performance of microwave conduction of the microwave conduction cavity 13, and then when the rectangular waveguide assembly 100 is used in a microwave oven, it is beneficial to improve the heating efficiency and uniformity of the microwave oven.

Optionally, the length of the tuning block 3 is equal to the length of the rectangular waveguide 1 . Therefore, not only the structure is simple, but also it is beneficial to further optimize the microwave transmission performance of the microwave conduction cavity 13 .

In some embodiments of the present invention, as shown in Figure 1 and Figure 3, there are two tuning components, and the two tuning components are respectively arranged on the two side walls of the rectangular waveguide 1 in the direction of the narrow side 11, thus the structure Simple.

According to some embodiments of the present invention, the side wall of the rectangular waveguide 1 in the direction of the narrow side 11 is provided with a positioning hole penetrating the side wall, and the pivot shaft of the driving device is connected to the corresponding tuning block 3 through the positioning hole. Thus, the driving device can drive the pivot shaft to move up and down in the positioning hole, thereby further driving the tuning block 3 to move up and down, so as to adjust the tuning block 3 corresponding to the driving device and the top wall of the rectangular waveguide 1 in the direction of the wide side 12 The distance between them is simple and reliable in structure. Optionally, an insulator may be provided between the pivot shaft and the positioning hole.

In some embodiments of the present invention, as shown in FIG. 2 and FIG. 3 , the antenna 2 is inserted into the microwave conduction cavity 13 through the opening 121 on the top wall in the direction of the broadside 12 , and the center of the opening 121 and the short-circuit surface 131 The distance is L, and L satisfies: L=λ/4, where λ=c/f, c is the speed of light, and f is the operating frequency of the microwave oven. The speed of light mentioned here refers to the propagation speed of light in the air, that is, c=300000km/s. For example, when 2.4GHz≤f≤2.5GHz, optionally, L is 30mm. The size and structure of the antenna 2 assembly 100 are thereby optimized. Optionally, the opening 121 may be formed in a circular, square or elliptical shape and the like.

Preferably, the center of the opening 121 is located on the mid-perpendicular line of the wide side 12 . For example, when at least one tuning component is respectively arranged on the two side walls in the direction of the narrow side 11, by making the center of the opening 121 located on the mid-perpendicular line of the wide side 12, it is beneficial to optimize the distance between each tuning component and the antenna 2. distance, which in turn helps to optimize the performance of microwave conduction in the microwave conduction cavity 13, and then when the rectangular waveguide assembly 100 is used in a microwave oven, it is beneficial to improve the heating efficiency and heating uniformity of the microwave oven. Of course, the present invention is not limited thereto. In some other embodiments, the center of the opening 121 may deviate from the vertical line of the wide side 12, for example, when at least one tuning component is arranged on one of the side walls in the direction of the narrow side 11 , the center of the opening 121 can be arranged close to the one side wall.

Optionally, as shown in FIG. 3 , the cross section of the tuning block 3 is a square. For example, as shown in FIG. 3 , the side length of the square is D, and D satisfies D=10mm±5mm.

Of course, the present invention is not limited thereto, and in some other embodiments, the cross section of the tuning block 3 may also be formed in other shapes such as a rectangle.

Specifically, in the length direction of the tuning block 3, the two faces of the tuning block 3 adjacent to the antenna 2 have a rounded transition, thereby preventing the microwave radiated by the antenna 2 from being caught on the sharp edge between the two faces. The excitation makes the surrounding field strong and avoids sparks, thereby improving the reliability of the rectangular waveguide component 100 in use. Preferably, the radius of the rounded corner is greater than or equal to 1mm.

It can be understood that the minimum distance between the tuning block 3 and the top wall located in the direction of the wide side 12 can be 0 mm, and the maximum distance between the tuning block 3 and the top wall located in the direction of the wide side 12 can be the length of the narrow side 11 .

Optionally, the distance between the tuning block 3 and the top wall in the direction of the broad side 12 is H, and H satisfies: 4mm≤H≤18mm. That is to say, the minimum distance between each tuning block 3 and the top wall in the broadside 12 direction is 4mm, and the maximum distance between each tuning block 3 and the top wall in the broadside 12 direction is 18mm.

In some embodiments of the present invention, the length of the sidewall of the rectangular waveguide 1 located in the direction of the narrow side 11 is M, the length of the sidewall of the rectangular waveguide 1 located in the direction of the broad side 12 is N, and M and N satisfy: 30mm≤M≤50, 60mm≤N≤100mm. Therefore, the structure is simple.

The structure of a rectangular waveguide assembly 100 according to a specific embodiment of the present invention will be described in detail below with reference to FIGS. 1-3 .

As shown in FIGS. 1-3 , the rectangular waveguide component 100 of this embodiment includes: a rectangular waveguide 1 , an antenna 2 and two tuning components.

Specifically, the rectangular waveguide 1 has a narrow side 11 and a wide side 12. There is a microwave conduction cavity 13 inside the rectangular waveguide 1. When the rectangular waveguide assembly 100 is used in a microwave oven, microwaves emitted by a microwave source such as a semiconductor microwave source can pass through the microwave The conduction cavity 13 transports into the cooking cavity of the microwave oven. As shown in FIG. 1 and FIG. 3 , two tuning components are respectively arranged on two side walls of the rectangular waveguide 1 in the direction of the narrow side 11 .

The microwave conduction cavity 13 has a short-circuit surface 131 and an emission surface, and the short-circuit surface 131 of the microwave oven can prevent microwaves from passing through the short-circuit surface 131 so that more microwaves are transmitted to the cooking cavity of the microwave oven through the emission surface in the microwave conduction cavity 13, thereby facilitating microwave ovens heating of food in the cooking chamber.

As shown in Figures 2 and 3, the antenna 2 is inserted into the microwave conducting cavity 13 through a circular opening 121 located on the top wall in the direction of the broadside 12, and the distance between the center of the opening 121 and the short-circuit surface 131 is L, and L satisfies: L=λ/4, where λ=c/f, c is the speed of light, and f is the operating frequency of the microwave oven. Preferably, the center of the opening 121 is located on the mid-perpendicular line of the wide side 12 .

Specifically, each tuning assembly includes a tuning block 3 and a driving device. The tuning block 3 is arranged on the inner side wall of the rectangular waveguide 1 so as to move up and down. The positioning hole, the driving device is located outside the microwave conduction cavity 13 and the pivot shaft of the driving device is connected to the corresponding tuning block 3 through the positioning hole, and the driving device can move up and down in the positioning hole by driving the pivot shaft, thereby further driving the tuning block 3 Move up and down to adjust the distance between the tuning block 3 corresponding to the driving device and the top wall of the rectangular waveguide 1 in the direction of the wide side 12, and then adjust the distance between the tuning block 3 and the antenna 2, which is beneficial to optimize microwave transmission The microwave conduction performance of the cavity 13 is beneficial to improving the heating efficiency and heating uniformity of the microwave oven when the rectangular waveguide assembly 100 is used in a microwave oven.

Optionally, as shown in FIG. 3 , the cross section of the tuning block 3 is a square, the side length of the square is D, and D satisfies D=10mm±5mm.

Specifically, in the length direction of the tuning block 3, the two faces of the tuning block 3 adjacent to the antenna 2 have a rounded transition, thereby preventing the microwave radiated by the antenna 2 from being caught on the sharp edge between the two faces. The excitation makes the surrounding field strong and avoids sparks, thereby improving the reliability of the rectangular waveguide component 100 in use. Preferably, the radius of the rounded corner is greater than or equal to 1mm.

The length of the sidewall of the rectangular waveguide 1 in the direction of the narrow side 11 is M, the length of the sidewall of the rectangular waveguide 1 in the direction of the wide side 12 is N, and M and N satisfy: 30mm≤M≤50, 60mm≤N ≤100mm. The length of the tuning block 3 is equal to the length of the rectangular waveguide 1 . Therefore, not only the structure is simple, but also it is beneficial to further optimize the microwave transmission performance of the microwave conduction cavity 13 .

The inventors used a microwave oven without the above-mentioned tuning assembly and a microwave oven with the above-mentioned rectangular waveguide assembly 100 to conduct experiments in actual research.

In the test, 1L of water was put into the cooking cavity. When the tuning block 3 of the rectangular waveguide assembly 100 was taken out from the microwave oven, that is, when the tuning assembly was not used, and the operating frequency of the microwave oven was continuously changed between 2.4GHz and 2.5GHz, The standing wave values of the cooking cabinet are shown in the table below.

Frequency (GHz) 2.40 2.41 2.42 2.43 2.44 2.45 2.46 2.47 2.48 2.49 2.50 VSWR 5 2.2 1.2 1.75 4 4 1.6 2.8 4.3 1.5 3.9

Those skilled in the art understand that the smaller the standing wave value, the better. The ideal value is 1. When the standing wave value is equal to 2, the microwave transmission efficiency is 88.9%. When 1L of water is put in, it is usually necessary to optimize the standing wave value at 2 or less.

In the above table, there are still many standing wave values at frequencies that do not meet the design requirements. By assembling the tuning block 3 into the microwave oven, and adjusting the distance between the two tuning blocks 3 and the top wall of the rectangular waveguide 1 at the wide side 12 To optimize the standing wave value, as follows:

At 2.40 GHz, adjust the distance between one of the tuning blocks 3 and the top wall of the rectangular waveguide 1 at the broadside 12 to be 10mm, and the distance between the other tuning block 3 and the top wall of the rectangular waveguide 1 at the broadside 12 is 12mm, standing wave 1.3 is obtained;

At 2.41 GHz, adjust the distance between one tuning block 3 and the top wall of the rectangular waveguide 1 at the broadside 12 to be 12mm, and the distance between the other tuning block 3 and the top wall of the rectangular waveguide 1 at the broadside 12 is 18mm, get a standing wave of 1.45;

At 2.44GHz, adjust the distance between one of the tuning blocks 3 and the top wall of the rectangular waveguide 1 at the broadside 12 to be 4 mm, and the distance between the other tuning block 3 and the top wall of the rectangular waveguide 1 at the broadside 12 is 4mm, to get a standing wave of 1.5;

At 2.45 GHz, adjust the distance between one tuning block 3 and the top wall of the rectangular waveguide 1 at the broad side 12 to be 6mm, and the distance between the other tuning block 3 and the top wall of the rectangular waveguide 1 at the broad side 12 is 4mm, get a standing wave of 1.45;

At 2.47GHz, adjust the distance between one tuning block 3 and the top wall of the rectangular waveguide 1 at the broadside 12 to be 8mm, and the distance between the other tuning block 3 and the top wall of the rectangular waveguide 1 at the broadside 12 is 10mm, get standing wave 1.2;

At 2.48 GHz, adjust the distance between one tuning block 3 and the top wall of the rectangular waveguide 1 at the broadside 12 to be 8mm, and the distance between the other tuning block 3 and the top wall of the rectangular waveguide 1 at the broadside 12 is 14mm, to obtain a standing wave of 1.3;

At 2.50 GHz, adjust the distance between one tuning block 3 and the top wall of the rectangular waveguide 1 at the broad side 12 to be 6mm, and the distance between the other tuning block 3 and the top wall of the rectangular waveguide 1 at the broad side 12 is 6mm, the standing wave is 1.25;

Wherein, the tuning accuracy of the tuning block 3 is within 2 mm.

Thus, when the microwave oven is heated, by changing the operating frequency of the semiconductor microwave source, and on this basis, adjusting the distance between the two tuning blocks 3 and the top wall of the rectangular waveguide 1 at the wide side 12, it can be ensured that different The standing wave values under the phase are all less than 2, so that the heating efficiency is higher and the heating uniformity is better.

In the description of this specification, descriptions referring to the terms "one embodiment", "some embodiments", "example", "specific examples", or "some examples" mean that specific features described in connection with the embodiment or example , structure, material or characteristic is included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the described specific features, structures, materials or characteristics may be combined in any suitable manner in any one or more embodiments or examples. In addition, those skilled in the art can combine and combine different embodiments or examples and features of different embodiments or examples described in this specification without conflicting with each other.

Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and those skilled in the art can make the above-mentioned The embodiments are subject to changes, modifications, substitutions and variations.

Claims (12)

1. A rectangular waveguide assembly, characterized in that it comprises: A rectangular waveguide, the rectangular waveguide has a narrow side and a wide side, a microwave conduction cavity is arranged in the rectangular waveguide, and the microwave conduction cavity has a short-circuit surface; an antenna inserted into the top wall in the broadside direction to extend into the microwave conduction cavity; At least one tuning assembly is provided on at least one side wall in the direction of the narrow side, each of the tuning assemblies includes a tuning block and a driving device, and the tuning block can be moved up and down on the rectangular On the inner side wall of the waveguide, the driving device is located outside the microwave conduction cavity and the driving device is suitable for driving the corresponding tuning block to move up and down to adjust the tuning block and the rectangular waveguide on the wide side The distance between the top walls of the direction. 2. The rectangular waveguide assembly according to claim 1, wherein the length of the tuning block is equal to the length of the rectangular waveguide. 3. The rectangular waveguide component according to claim 1, wherein there are two tuning components, and the two tuning components are respectively arranged on the two side walls of the rectangular waveguide in the direction of the narrow side superior. 4. The rectangular waveguide assembly according to claim 1, wherein the sidewall of the rectangular waveguide in the direction of the narrow side is provided with a positioning hole penetrating through the sidewall, and the pivot of the driving device The rotating shaft passes through the positioning hole and is connected with the corresponding tuning block. 5. The rectangular waveguide assembly according to claim 1, wherein the antenna is inserted into the microwave conducting cavity through an opening on the top wall in the direction of the broadside, and the center of the opening is in contact with the short-circuit surface The distance between them is L, and L satisfies: L=λ/4, where λ=c/f, c is the speed of light, and f is the operating frequency of the microwave oven. 6 . The rectangular waveguide assembly according to claim 5 , wherein the center of the opening is located on the mid-perpendicular line of the broadside. 7. The rectangular waveguide assembly according to claim 1, wherein the cross-section of the tuning block is a square. 8 . The rectangular waveguide assembly according to claim 7 , wherein, in the length direction of the tuning block, there is a rounded transition between two surfaces of the tuning block adjacent to the antenna. 9. The rectangular waveguide assembly according to claim 7, wherein the side length of the square is D, and D satisfies D=10mm±5mm. 10 . The rectangular waveguide component according to claim 1 , wherein the distance between the tuning block and the top wall in the direction of the broadside is H, and H satisfies: 4mm≤H≤18mm. 11. The rectangular waveguide assembly according to claim 1, wherein the length of the sidewall of the rectangular waveguide in the direction of the narrow side is M, and the length of the sidewall of the rectangular waveguide in the direction of the broad side is M The length of N, M and N satisfy: 30mm≤M≤50, 60mm≤N≤100mm. 12. A microwave oven, characterized in that it comprises The box body is provided with a cooking cavity and a placement cavity spaced apart from each other in the box; a microwave source, the microwave source is arranged in the placement cavity; The rectangular waveguide assembly according to any one of claims 1-11, the rectangular waveguide assembly is connected between the microwave source and the cooking cavity.