JP2013218904A - Microwave heating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a microwave heating device capable of equally heating an object to be heated.SOLUTION: The microwave heating device includes a heating chamber 1 for inputting an object to be heated, a mounting part 2 for mounting the object to be heated 7, microwave supplying means 3 for supplying a microwave to the heating chamber 1, a waveguide 4 for transmitting the microwave supplied from the microwave supplying means 3 to the heating chamber 1, and a microwave radiation part 5 for radiating the microwave passing in the waveguide 4 to the heating chamber 1, and is provided with an inclined plate 6 arranged from the vicinity of the microwave radiation part 5 toward an end part of the mounting part 2 between the microwave radiation part 5 and the mounting part 2. A microwave emitted from the microwave radiation part 5 is radiated widely into the heating chamber 1 without using a rotation mechanism, such as a turntable and a rotary antenna, and the object to be heated 7 existing on the mounting part 2 can be equally heated.

Description

  The present invention relates to a microwave heating apparatus such as a microwave oven used in general homes, restaurants, offices, and the like, and more particularly to a microwave heating apparatus characterized by the structure of a microwave radiation portion.

  A microwave heating apparatus that heats an object to be heated by microwaves radiates microwaves generated in the microwave supply means into a metal heating chamber and radiates the objects to be heated inside the heating chamber. Heated.

  The microwave generated by the microwave supply means propagates through the waveguide and is radiated from the supply port into the heating chamber. If the electromagnetic field distribution of the microwave in the heating chamber is not uniform, the object to be heated cannot be heated by microwaves uniformly.

  Conventionally, this type of microwave heating apparatus has a structure in which a heated object is rotated by rotating a turntable on which the heated object is rotated or a heated object is fixed as a means for uniformly heating the heated object. In general, a microwave heating apparatus has a structure in which an antenna that radiates microwaves is rotated, or a phase of a microwave generated from a microwave supply unit is changed by a phase shifter.

  In addition, as an example of this type of microwave heating apparatus, Patent Document 1 discloses that one or more of the side walls forming a polyhedron of hexahedrons constituting a heating chamber are predetermined on the front side around the rear corner. A method is disclosed in which the microwaves in the heating chamber are made uniform by constituting the heating chamber provided by being shifted inward by the center angle.

JP 2002-61847 A

  However, the microwave heating apparatus having the conventional configuration requires a mechanism for rotating the table or the antenna in order to reduce non-uniform heating. For this reason, the rotation space and the installation space for the motor for rotating the table or the antenna are required. It had to be secured, and the miniaturization of the microwave oven was hindered. Further, when a rotating mechanism such as a motor that rotates a turntable, an antenna, or the like is used, there is a problem that reliability such as the life of the motor must be ensured.

  On the other hand, if the side wall of the heating chamber is changed by a predetermined angle, the heating chamber is not a rectangular parallelepiped, but an asymmetrically distorted shape. There was a problem that it was difficult. Moreover, since it is necessary to incline a side wall, a large space is needed between the housing | casing of a microwave heating apparatus and a heating chamber, and an external dimension becomes large. Further, there is a problem that the manufacturing becomes difficult due to the structure in which the side wall is inclined.

  This invention solves the said subject, and it aims at providing the microwave heating apparatus which can make a to-be-heated object microwave heat uniformly, without using a rotation mechanism.

  In order to solve the above-described conventional problems, a microwave heating apparatus according to the present invention includes a heating chamber that houses an object to be heated, a placement unit that places the object to be heated, and a microwave that is supplied to the heating chamber. A microwave supply means for transmitting, a waveguide for transmitting the microwave supplied from the microwave supply means to the heating chamber, and for radiating a microwave passing through the waveguide to the heating chamber The microwave radiating unit is provided, and the microwave radiating unit is placed between the microwave radiating unit and the mounting part from the first position on the same plane as the microwave radiating part. An inclined plate is provided which is arranged toward the end of the portion or the second position inside the end.

  With this configuration, when the microwave radiated from the opening is radiated into the heating chamber through the mounting portion, the microwave is widely dispersed in the heating chamber by the inclined plate and radiates, and the object to be heated is more radiated. It can be heated uniformly.

  The microwave heating apparatus of the present invention can uniformly heat an object to be heated without providing a rotation mechanism, and the heating chamber is not a distorted shape but a rectangular parallelepiped. An easy-to-use microwave heating apparatus can be provided.

Sectional drawing of the microwave heating apparatus in Embodiment 1 of this invention Sectional drawing of the microwave heating apparatus in Embodiment 1 of this invention 1 is a top view of a waveguide and a microwave radiating portion in Embodiment 1 of the present invention. Sectional drawing of the microwave radiation | emission part, mounting part, and inclination board in Embodiment 1 of this invention Sectional drawing of the microwave heating apparatus in Embodiment 1 of this invention, and the schematic diagram which shows the radiation | emission of a microwave Sectional drawing of the microwave radiation | emission part, mounting part, and inclination board in Embodiment 1 of this invention The top view and sectional drawing of a microwave radiation | emission part and an inclination board in Embodiment 1 of this invention The top view and sectional view of the microwave radiation part in Embodiment 1 of the present invention Sectional drawing and schematic diagram of standing wave of microwave heating apparatus in Embodiment 1 of the present invention The top view of the microwave radiation | emission part and inclination board in Embodiment 1 of this invention

  1st invention is the heating chamber which puts a to-be-heated material, the mounting part which mounts the said to-be-heated material, the microwave supply means for supplying a microwave to the said heating chamber, The said microwave supply means A waveguide for transmitting the microwave supplied from the heating chamber to the heating chamber, and a microwave radiating portion for radiating the microwave passing through the waveguide to the heating chamber, the microwave radiating portion, The second part which is located on the same plane as the previous placement part from the first position on the same plane as the microwave radiation part or on the inner side of the placement part between the previous placement part and the end part. By using a microwave heating device provided with an inclined plate arranged toward the position, microwaves emitted from the radiating section can be widely radiated into the heating chamber without using a rotating mechanism such as a turntable or a rotating antenna. And the cover on the mounting part It can be heated uniformly heat thereof.

  According to a second aspect of the present invention, the microwave radiating section is a microwave heating device according to the first aspect of the present invention that is shaped so that microwaves are radiated in a circularly polarized shape. Even in the case of microwaves on the wave, the microwaves are widely distributed in the heating chamber, and the object to be heated can be heated uniformly.

A third aspect of the invention is the microwave heating apparatus according to the first aspect or the second aspect of the invention, wherein a plurality of the microwave radiating portions are provided, and the inclined plate is provided around the microwave radiating portion. By doing so, it becomes possible to put the microwaves coming out of the waveguide into the heating chamber more uniformly, and further uniforming can be achieved by providing an inclined plate around the plurality of radiation parts. .

  According to a fourth aspect of the present invention, the first position of the inclined plate is a position separated from the center of the microwave radiating unit by a quarter or more of the wavelength of the microwave supplied from the microwave radiating unit. By using the microwave heating apparatus according to any one of the inventions of the invention to the third invention, the microwave that the inclined plate exits from the radiating portion does not hinder the formation of circularly polarized waves, The microwave is circularly polarized, and the microwave exists uniformly in the heating chamber, so that the effect of heating the object to be heated uniformly can be obtained.

  According to a fifth aspect of the present invention, there is provided a microwave heating apparatus according to the third aspect in which the plurality of microwave radiating portions are arranged substantially evenly with respect to the center of the heating chamber, so that the heating chamber is evenly microscopically provided. Waves can be introduced, and the object to be heated can be heated uniformly.

  Hereinafter, preferred embodiments of a microwave heating apparatus according to the present invention will be described with reference to the drawings. In the microwave heating apparatus of the following embodiment, a microwave oven will be described. However, the microwave oven is an example, and the microwave heating apparatus of the present invention is not limited to the microwave oven, and uses dielectric heating. And a microwave heating device such as a garbage processing machine or a semiconductor manufacturing device. Further, the present invention is not limited to the specific configurations of the following embodiments, and configurations based on similar technical ideas are included in the present invention.

(Embodiment 1)
FIG. 1 is a cross-sectional view of the microwave heating apparatus according to Embodiment 1 of the present invention. In FIG. 1, a heating chamber 1 for storing an object 7 to be heated by microwaves, a placement unit 2 for placing the object 7 to be heated, a microwave supply means 3 for generating microwaves, and a microwave supply A waveguide 4 for propagating microwaves emitted from the means 3, a microwave radiating section 5 for emitting microwaves from the waveguide 4 to the heating chamber 1, and an inclined plate 6 are provided.

  The microwave supply means 3 usually uses a magnetron in many cases, but may be a semiconductor type or the like. The microwave supply unit 3 generates microwaves by supplying power from a control unit (not shown). The frequency of the generated microwave is normally 2450 MHz, but is not limited thereto.

  The heating chamber 1 is made of metal such as aluminum or Steel Use Stainless (SUS), the object to be heated 7 is mounted on the mounting portion 2 in the heating chamber 1, and the microwave generated by the microwave supply means 3 is received. The article 7 to be heated is heated by being introduced into the heating chamber 1.

  Ideally, when microwaves are introduced into the heating chamber 1, only the article 7 to be heated is heated by the microwaves. For this reason, when the heating chamber 1 is made of glass or the like, for example, the glass generates heat by microwaves, resulting in a heating loss.

  Therefore, in order to reduce the heating loss, it is desirable to use a metal that does not generate heat by the microwave and reflects the microwave. However, since it is necessary to introduce the microwave generated from the microwave supply means 3 into the heating chamber 1, the part for introducing the microwave is usually changed to another material, and in this embodiment, The mounting part 2 plays the role. A glass plate is often used as the material for the mounting portion 2.

  As shown in FIG. 2, the placement unit 2 is usually smaller than the bottom surface of the heating chamber 1. This is because the heating loss increases when the area other than the metal constituting the heating chamber 1 is increased by increasing the mounting portion 2. Moreover, since the mounting part 2 is comprised with a glass plate etc. more expensive than a metal, if the area of the mounting part 2 increases, a microwave heating apparatus will become high. Therefore, it is desirable to reduce the area of the mounting portion 2 within a range that does not deteriorate usability.

  In the present embodiment, the waveguide 4 is a rectangular waveguide, and the microwave radiating unit 5 uses an opening provided in a part of the waveguide 4 to convert the microwave existing in the waveguide 4 into a heating chamber. 1 is radiated to 1.

  First, the general operation of the microwave heating apparatus will be described. When a heated object 7 is placed on the mounting portion 2 in the heating chamber 1 and a heating start instruction is given by the user, the microwave heating device is moved from the magnetron, which is the microwave supply means 3, into the waveguide 4. To supply microwaves. The microwave heating apparatus heats the object to be heated 7 by radiating microwaves into the heating chamber 1 by the microwave radiating unit 5 provided in the waveguide 4.

  Next, the microwave radiation | emission part 5 is demonstrated. The microwave radiating unit 5 is for radiating the microwave passing through the waveguide 4 to the heating chamber 1. Specifically, the microwave radiating unit 5 is obtained by cutting out a part of the wall surface constituting the waveguide 4. Then, it is as shown in FIG.

  FIG. 3 is a top view of the waveguide 4 and the microwave radiating unit 5. In FIG. 3, the microwave supply means 3 is attached to the A side of the waveguide 4 and radiates microwaves into the waveguide 4. The B side of the waveguide 4 is a terminal part, and reflects the microwaves propagated from the A side. By doing so, a standing wave is formed in the waveguide 4, and the radiation of the microwave radiated into the heating chamber 1 is controlled by providing the microwave radiating unit 5 according to the position of the standing wave. can do. Actually, a standing wave may be easily formed by providing a convex portion in the waveguide 4.

  As the shape of the microwave radiating unit 5, even a simple quadrangle or the like is radiated from the waveguide 4 to the heating chamber 1. In the present invention, the microwave radiating portion 5 is shaped such that microwaves are radiated in a circular polarization. By doing so, it was necessary in order to radiate the microwave which radiates | emits from the turntable and antenna which mounts the to-be-heated material 7 used with the conventional microwave oven uniformly to the heating chamber 1. Even without a motor for rotating the antenna, the electric field and magnetic field of the microwave itself rotate over time, so compared to microwave heating by linear polarization used in conventional microwave heating devices, Microwaves are dispersed and radiated over a wide range, and the effect that the object to be heated 7 can be heated uniformly is obtained. Therefore, since the rotation mechanism is not required, the reliability is improved, and the microwave heating device can be provided at a low cost.

  Since circularly polarized waves are synthesized by shifting the phase of linearly polarized waves by π / 2 (90 °), they do not necessarily have to be X-shaped as shown in FIG. Moreover, the microwave radiation | emission part 5 may be one or more. However, when there is only one microwave radiating part 5, heating tends to concentrate on a part of the object 7 to be heated, so a plurality of microwave radiating parts 5 are provided and arranged symmetrically from the center of the heating chamber. Then, the distribution of microwaves is improved, and the effect of heating the object 7 to be heated uniformly is easily obtained.

However, even if a plurality of microwave radiating units 5 are arranged symmetrically from the center of the heating chamber, if the distance between the microwave radiating unit 5 and the mounting unit 2 is short, the microwave radiated from the microwave radiating unit 5 spreads. Since the object to be heated 7 is irradiated without being heated, a part of the object to be heated 7 is locally heated. For this reason, it is desirable that a distance be provided between the microwave radiating unit 5 and the mounting unit 2. As the distance increases, the microwave radiated from the microwave radiating section 5 spreads and is supplied to the heating chamber 1, but there is a problem that the microwave heating apparatus itself is increased in size.

  Therefore, in the present invention, between the microwave radiating unit 5 and the mounting unit 2, the mounting unit 2 is located on the same plane as the microwave radiating unit 5 from the first position in the vicinity of the microwave radiating unit 5. By providing the inclined plate 6 disposed toward the end portion of the mounting portion 2 or the second position inside the end portion on the same plane, the outer size of the microwave heating device is not increased. The microwave radiated from the microwave radiating unit 5 is uniformly distributed in the heating chamber 1, and the microwave heating apparatus is configured to heat the article 7 to be heated more uniformly.

  The first position and the second position will be described with reference to FIG.

  As described above, the placement unit 2 has an area smaller than the heating chamber 1 for reasons such as efficiency. That is, when expressed using the reference numerals in FIG. 4, (AF length)> (BE length). And in order to introduce into the heating chamber 1 the microwave emitted from the microwave radiation | emission part 5 more uniformly, the microwave radiation | emission part 5 is comprised so that it may be located between BE. Otherwise, that is, when the microwave radiating unit 5 is arranged between A and B or between E and F, the microwave radiated from the microwave radiating unit 5 is placed on the upper portion instead of the mounting unit 2. Since it becomes the metal part which comprises the heating chamber 1, a microwave reflects. Then, a part of the reflected microwave returns to the inside of the waveguide 4 or concentrates on a part of the heating chamber 1, so that a reduction in heating efficiency or a part of the object 7 to be heated is concentrated. This is because problems such as being heated by the heat occur.

  Since the first position is on the same plane as the microwave radiating unit 5 in the vertical direction, the first position is a position α in FIG. This α is at the same position as the waveguide 4. In the horizontal direction, the positions of C and D in the vicinity of the microwave radiating unit 5 are obtained, and (CD length) <(BE length). This is because, as described, the microwave radiating unit 5 is located between B to E, and therefore the distance between the first positions C and D in the vicinity thereof is naturally (length of CD) <(length of BE). Is).

  Here, the first positions of C and D in the vicinity of the microwave radiating portion 5 are outside the microwave radiating portion 5 formed in the waveguide 4.

  The second position is a position β that is on the same plane as the placement unit 2 in the vertical direction. In the horizontal direction, it is configured to be positioned between B, E, or B to E, which are the end portions of the placing portion 2.

  Since the inclined plate 6 is arranged so as to connect the first position and the second position, FIG. 4A shows the inclined plate 6 when the second position is the end portion of the mounting portion 2. FIG. 4B shows the inclined plate 6 when the second position is arranged on the inner side of the end portion of the placement portion 2. By configuring the inclined plate 6 in this way, the microwave radiated from the microwave radiating unit 5 is reflected upward by the inclined plate 6 and repeatedly reflected in the heating chamber 1 to be heated by the object 7 to be heated. Microwaves circulate from above, and the microwaves are widely radiated into the heating chamber 1 so that uniform heating is removed. FIG. 5 schematically shows the state.

  FIG. 6 is a cross-sectional view when the second position is on the same plane as the placement unit 2 and outside the end of the placement unit 2, that is, between A and B and between E and F. Shown in 6A shows the second position between A and B and between E and F when the second position is arranged at the positions of A and F which are side end portions of the heating chamber 1. FIG. FIG.

  In the case of the configuration as shown in FIG. 6A, since the placing portion 2 is shorter than the heating chamber 1, the portions A to B and E to F at the position of β in the vertical direction are made of metal, and therefore microwave radiation The microwave radiated from the unit 5 is reflected. At that time, a part of the microwave is concentrated, a part of the reflected microwave returns into the waveguide 4 or a part of the heating chamber 1 is concentrated, and thus the heating efficiency is reduced or the coverage is reduced. Problems such as a part of the heated object 7 being heated intensively occur.

  Moreover, as shown in FIG. 6B, when the wall surface is configured in the vertical direction from the end of the mounting portion 2 toward the inclined plate 6 (between β and γ), the end of the vertical wall surface (waterside direction) B, the position in the vertical direction β) serves as an antenna, and microwaves may be strongly emitted in a specific direction. At that time, microwaves concentrate on a part of the object 7 to be heated and the object 7 to be heated is burnt.

  Therefore, the inclined plate 6 is directed from the first position on the same plane as the microwave radiating unit 5 to the second position on the end of the mounting unit 2 or on the inner side of the mounting unit 2 on the same plane as the mounting unit 2. It is good to arrange.

  In FIG. 7, the top view and sectional drawing of a microwave radiation | emission part and an inclination board are shown. FIG. 7A is a top view, and FIG. 7B shows a cross section of (X)-(X) in the top view. FIG. 7 shows an example in which the microwave radiating portion 5 is configured by four radiating portions, and the inclined plate 6 is disposed so as to surround the four radiating portions. The outer periphery of the inclined plate 6 (A to B to C to D in FIG. 7A) coincides with the four corners of the placement unit 2. In this embodiment, since the mounting portion 2 is a quadrangle, the inclined plate 6 as shown in FIG. 7 is used. However, when the mounting portion 2 is circular or the like, the inclined plate 6 also coincides with the end of the mounting portion 2. What is necessary is just to comprise so.

  FIG. 8 shows a microwave radiating portion, a top view, and a cross-sectional view when there is no inclined plate 6. FIG. 8A is a top view, and FIG. 8B shows a cross section (X)-(X) in the top view. When there is no inclined plate 6, a rectangular parallelepiped space is formed between the placing portion 2 and the waveguide 4 as shown in FIG. In that case, the microwave radiated from the microwave radiating part 5 forms a standing wave in a rectangular parallelepiped space formed between the mounting part 2 and the waveguide 4, and the upper part of the node position of the standing wave. The portion located at is not heated, and the article 7 to be heated is not made uniform. This is shown in FIG.

  In FIG. 9, there are cuboid spaces (ab, c, c, d, a in FIG. 9) between the placing portion 2 and the waveguide 4. The wall surfaces, ab and cd, are perpendicular to the waveguide 4. When a microwave is radiated from the microwave radiating unit 5 in such a space, a standing wave 8 is formed there. In FIG. 9, a standing wave having three antinodes is illustrated, but this is determined by the wavelength of the microwave and the size of the rectangular parallelepiped space formed between the mounting portion 2 and the waveguide 4. It is not limited to three.

  At this time, since the wall surfaces ab and cd have a potential of 0, their positions are always nodes. For this reason, microwaves do not easily hit the positions A and D of the article 7 to be heated, and the heating becomes weaker than other parts, resulting in increased heating unevenness. In the case of the present embodiment, since there are four nodes, the heating of the positions B and C of the article 7 to be heated located at the other two upper parts is also weakened.

  In order to avoid such a state, as shown in FIG. 7, the gap between the microwave radiating unit 5 and the mounting unit 2 is directed from the vicinity of the microwave radiating unit 5 toward the end of the mounting unit 2. By providing the inclined plates 6 arranged in such a manner, it is possible to avoid the standing wave by making it difficult to exist.

In the case of a conventional microwave heating apparatus, even if a standing wave is generated in the microwave emitted from the waveguide 4, the heated object 7 placed on the turntable is heated by the turntable rotating. Since the portion to be changed changes from moment to moment, a portion where a specific portion is heated intensively or not heated is less likely to occur. Therefore, the heating unevenness of the article 7 to be heated does not change greatly depending on whether or not the inclined plate 6 is provided. In other words, the inclined plate 6 is not necessary. Similarly, in the case of the microwave heating apparatus configured to supply the microwave from the waveguide 4 to the heating chamber 1 via the antenna, the inclined plate is difficult to generate a standing wave that is fixed by rotating the antenna. 6 need not be provided.

  As the inclined plate 6, the smaller the angle formed between the waveguide 4 and the inclined plate 6, the harder the standing wave 8 exists, and the more the heating unevenness of the article 7 to be heated is reduced. However, in actuality, microwaves emitted from the microwave radiating unit 5 are energy used for directly heating the object 7 to be heated, and standing waves generated in the heating chamber 1 by being reflected by the heating chamber 1. Since there is both energy for heating the object 7 to be heated, and the heating unevenness of the object 7 to be heated is thereby determined, depending on the shape and arrangement of the microwave radiating unit 5, the shape of the heating chamber 1 and the object 7 to be heated, etc. Therefore, the angle of the inclined plate 6 may be determined according to the purpose.

  In this embodiment, the inclined plate 6 is provided on all four sides of the microwave radiating portion 5 as shown in FIG. 7, but only one side (for example, FIG. 7 (A) A-B-b-a-A).

  Furthermore, it is desirable that the inclined plate 6 is disposed at a position away from the center of the microwave radiating unit 5 by ¼ or more of the wavelength of the microwave supplied from the microwave radiating unit 5. In the microwave heating apparatus of the present invention, the shape of the microwave radiating unit 5 is configured such that the microwave is radiated in a circularly polarized shape. Specifically, the microwave transmitted through the waveguide 4 is partially blocked by the microwave radiating unit 5 formed in a part of the waveguide 4 so that the microwave is transmitted outside the waveguide 4. Radiated. At that time, for example, as shown in FIG. 10, the microwave radiating portion 5 has two slits having widths at the center and has a shape inclined by 45 degrees with respect to the microwave transmission direction of the waveguide 4. When the waveguide 4 is disposed at a position shifted from the tube axis center in the microwave transmission direction, the linearly polarized waves in the two directions are combined with the phase shifted by π / 2 (90 °) to be circularly polarized. .

  At this time, if the inclined plate 6 exists at a distance within a quarter of the wavelength of the microwave supplied from the microwave radiating unit 5 from the center of the microwave radiating unit 5, two linearly polarized waves that form circularly polarized waves are formed. When the combined wave vector becomes the direction of the inclined plate 6, the vector is displaced due to interference with the inclined plate 6. This hinders the formation of circularly polarized waves, and changes the characteristics, such as changing the axial ratio of circularly polarized waves. For this reason, the feature of uniform heating, which is a feature of circular polarization, is weakened, that is, the heating unevenness of the article 7 to be heated increases.

  Therefore, the inclined plate 6 should not be arranged within a quarter of the wavelength of the microwave supplied from the microwave radiating unit 5 from the center of the microwave radiating unit 5 that greatly contributes to the formation of circularly polarized waves. Since the formation of the circularly polarized wave is not hindered, it is possible to prevent a standing wave from being formed in the space formed between the mounting portion 2 and the waveguide 4, and as a result, It becomes possible to heat the heated object 7 more uniformly.

  As described above, the microwave heating apparatus of the present invention is provided with the inclined plate disposed between the microwave radiating unit and the mounting unit from the vicinity of the microwave radiating unit toward the end of the mounting unit. As a result, the microwave radiated from the waveguide to the heating chamber can be made more uniform, so that the effect of heating the object to be heated more uniformly can be obtained, and the microwave that performs heating processing and sterilization of foods can be obtained. It can be effectively used for a wave heating device or the like.

DESCRIPTION OF SYMBOLS 1 Heating chamber 2 Mounting part 3 Microwave supply means 4 Waveguide 5 Microwave radiation | emission part 6 Inclined plate 7 To-be-heated object 8 Standing wave

Claims (5)

A heating chamber for storing an object to be heated;
A placement section for placing the object to be heated;
Microwave supply means for supplying microwaves to the heating chamber;
A waveguide for transmitting the microwave supplied from the microwave supply means to the heating chamber;
A microwave radiating portion for radiating microwaves passing through the waveguide to the heating chamber; and a second portion on the same plane as the microwave radiating portion between the microwave radiating portion and the mounting portion. The microwave heating apparatus provided with the inclination board arrange | positioned from the position of 1 toward the 2nd position which exists on the same plane as the above-mentioned mounting part at the edge part of the above-mentioned mounting part, or an inner side. The microwave heating apparatus according to claim 1, wherein the microwave radiating unit has a shape in which microwaves are radiated in a circularly polarized shape. The microwave heating device according to claim 1, wherein a plurality of the microwave radiating units are provided, and the inclined plate is provided around the microwave radiating unit. The first position of the inclined plate is a position separated from the center of the microwave radiating unit by a quarter or more of the wavelength of the microwave supplied from the microwave radiating unit. 2. The microwave heating apparatus according to item 1. The microwave heating device according to claim 3, wherein the plurality of microwave radiating portions are arranged substantially evenly with respect to the center of the heating chamber.