JP6212705B2 - Microwave heating device - Google Patents

Description

  The present invention relates to a microwave heating apparatus such as a microwave oven, and more particularly to a microwave heating apparatus characterized by the structure of a microwave radiation portion.

  A typical microwave heating apparatus that heats an object to be heated with a microwave is a microwave oven. In the microwave oven, the microwave generated in the microwave supply means is radiated into the metal heating chamber, and the object to be heated in the heating chamber is heated by the radiated microwave.

  A magnetron is used as a microwave supply means in a conventional microwave oven. Microwaves generated by the magnetron are radiated into the heating chamber through the waveguide. 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.

  As a means for uniformly heating the object to be heated, a structure for rotating the object to be heated by rotating a table on which the object to be heated is rotated, a structure for rotating an antenna for radiating microwaves while fixing the object to be heated, or A microwave heating apparatus having a structure in which the phase of the microwave generated from the microwave supply means is changed by a phase shifter has been common.

  For example, in a conventional microwave heating apparatus, a rotating antenna, an antenna shaft, and the like are arranged inside a waveguide. By driving a magnetron while rotating the rotating antenna by an antenna motor, the microwave distribution in the heating chamber is increased. Non-uniformity is reduced.

  Further, as described in Patent Document 1, a rotatable antenna is provided on the upper part of the magnetron, and the antenna is rotated by the wind of the blower fan by applying cooling air from the blower fan to the blades of the rotary antenna. There has been proposed a microwave heating apparatus that changes the microwave distribution in the heating chamber.

  On the other hand, as described in Patent Document 2 which reduces the uneven heating of the object to be heated by microwave heating and reduces the cost and saves the space of the power feeding unit, it simply radiates circularly polarized waves into the heating chamber. A microwave heating apparatus having a single microwave radiating portion has been proposed.

JP 62-064093 A U.S. Pat. No. 4,301,347

  However, in the microwave heating apparatus such as the microwave oven having the above-described conventional configuration, it is required to efficiently heat an object to be heated with a simple structure as much as possible, and has been proposed so far. There were various problems with the structure.

In addition, microwave heating devices, particularly microwave ovens, have been developed for high-power technology, and a rated high-frequency output of 1000 W has been commercialized in Japan. Microwave ovens are notable for heating food by heat conduction, but the convenience of directly heating food using dielectric heating is a major feature of the product. The problem of non-uniform heating will become more apparent.

  The following two points can be cited as structural problems of the conventional microwave heating apparatus.

  The first point requires a mechanism for rotating the table or antenna in order to reduce non-uniform heating. Therefore, it is necessary to secure a rotation space and an installation space such as a motor for rotating the table or antenna. That was hindering the miniaturization of the range.

  The second point is that in order to stably rotate the table or antenna, it is necessary to provide the rotating antenna above or below the heating chamber, and the structure is limited.

  Installing a table or a phaser rotation mechanism in the microwave irradiation chamber of the microwave heating apparatus lowers the reliability. Therefore, there is a demand for a microwave heating apparatus that does not require these mechanisms.

  Further, circularly polarized light is radiated into the heating chamber as described in Patent Document 2 which reduces the uneven heating of the object to be heated by microwave heating and reduces the cost and saves the space of the power feeding unit. The microwave heating apparatus having a single microwave radiating portion has an advantage that it does not have a rotating mechanism, but the problem is that sufficient uniform heating by microwave heating has not been realized.

  The present invention solves the above-described conventional problems, and an object of the present invention is to provide a microwave heating apparatus that can uniformly heat an object to be heated without using a rotating mechanism.

  In order to solve the above-described conventional problems, the microwave supplied from the microwave supply means and transmitted through the waveguide is guided to the waveguide structure antenna by the coupling axis, so that the microwave supply point is guided to the waveguide structure antenna. Is changed to a position where it can radiate microwaves with symmetry, and by radiating microwaves from multiple microwave radiation openings, symmetrical microwave radiation is performed and the object to be heated is made uniform. Can be heated.

  Further, by providing the traveling wave promoting opening provided in the microwave transmission direction, the microwave transmitted through the waveguide structure antenna can be a traveling wave. As a result, the traveling wave whose amplitude changes passes through the microwave radiation opening, and therefore, the microwave whose radiation amount changes is radiated from the openings dispersed in a plurality of locations, and the object to be heated is made uniform. Can be heated.

  In addition, the waveguide structure antenna is configured as a rectangular parallelepiped polyhedron, and includes a waveguide structure portion provided with a microwave radiation opening on the upper surface portion, and a flange portion in contact with the waveguide structure portion on the lower surface portion, The flange part is formed in parallel with the microwave transmission direction to prevent microwave leakage from other than the traveling wave promoting opening, and uniform heating with a simple configuration that does not allow the waveguide antenna to be fixed to the heating chamber. Can be realized.

  In addition, because the waveguide structure antenna is configured to have an axis of symmetry, microwaves can be transmitted symmetrically with respect to the axis of symmetry, and the uniformity of microwave radiation from the microwave radiation aperture Can be improved.

  In addition, by using a shape that radiates circularly polarized waves as the microwave radiation opening, microwaves that have spread from the microwave radiation part are radiated, and the microwave radiation to the object to be heated is uniform over a wider range. Can be

  Also, a plurality of microwave indirect radiation openings that radiate microwaves from the waveguide are provided, and the plurality of microwave indirect radiation openings are arranged at positions farther from the object to be heated than the arrangement surface of the microwave radiation openings. Thus, the microwave that contributes to the heating of the heated object side surface and the upper surface can be supplied to the heating chamber, and the uniform heating performance of the heated object can be further improved.

  According to the present invention, the microwave supplied from the microwave supply means and transmitted through the waveguide is guided to the waveguide structure antenna by the coupling axis, so that the microwave supply point is symmetrical from the waveguide structure antenna. By changing to a position where microwaves can be emitted and radiating microwaves from multiple microwave radiation openings, symmetrical microwave radiation is performed, and the object to be heated is moved without using a rotating mechanism. A microwave heating apparatus capable of heating uniformly can be provided.

Sectional drawing of the microwave heating apparatus in Embodiment 1 of this invention The perspective view of the microwave heating apparatus in Embodiment 1 of this invention FIG. 3 is a diagram illustrating the relationship between the microwave radiation opening of the microwave heating apparatus and the traveling wave in the first embodiment of the present invention The top view which shows the symmetry in the waveguide structure antenna in Embodiment 1 of this invention Schematic explaining the configuration of the waveguide structure antenna according to the second embodiment of the present invention. Sectional drawing of the microwave heating apparatus in Embodiment 3 of this invention Explanatory drawing of the relationship between the microwave radiation opening part and traveling wave of the microwave heating apparatus in Embodiment 3 of this invention Explanatory drawing which shows the example of the microwave radiation | emission opening part which radiates | emits the circularly polarized wave of the microwave heating apparatus in Embodiment 3 of this invention Sectional drawing of the microwave heating apparatus in Embodiment 4 of this invention Schematic perspective view explaining the configuration of the waveguide structure antenna according to the fourth embodiment of the present invention. The top view which shows the structure of the microwave heating apparatus in Embodiment 4 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 waveguide , a waveguide structure antenna having a substantially rectangular parallelepiped shape for radiating the microwave to the heating chamber, and the waveguide structure antenna from the waveguide The waveguide structure antenna is provided with traveling wave promoting openings on both left and right end faces, which are the transmission direction of the microwave, A plurality of microwave radiation openings for radiating microwaves to the heating chamber are provided symmetrically from a substantially center to the left-right direction in a plan view, and one end of the coupling axis is the waveguide structure Near the approximate center of the antenna With the microwave heating apparatus is continued, the microwave transmitting waveguide is supplied from the microwave supplying means, by leading to the waveguide structure antenna by coupling shaft, guides the microwave supply point By changing the position of the tube structure antenna to a position where it can radiate microwaves with symmetry, by radiating microwaves from multiple microwave radiation openings, symmetrical microwave radiation is performed, and the object to be heated It is possible to provide a microwave heating apparatus that uniformly heats the liquid. In addition, since traveling waves with varying amplitudes pass through the microwave radiation section, microwaves with varying radiation amounts are emitted from openings dispersed in multiple locations, heating the object to be heated uniformly. A microwave heating apparatus can be provided.

According to a second aspect of the invention, in particular, in the first aspect of the invention, the waveguide structure antenna is configured as a rectangular parallelepiped polyhedron, and has a waveguide structure portion provided with a microwave radiation opening in the upper surface portion, and A microwave heating device having a flange portion in contact with the waveguide structure portion, the flange portion being formed in parallel with the microwave transmission direction, prevents microwave leakage from other than the traveling wave promoting opening. It is possible to provide a microwave heating apparatus that realizes uniform heating with a simple configuration in which the waveguide structure antenna is not fixed to the heating chamber.

In a third aspect of the invention, in particular, in any one of the first and second aspects of the invention, the waveguide structure antenna is configured to be symmetrical in the left-right direction and the depth direction with respect to the substantially center in a plan view. By providing a microwave heating apparatus, a microwave heating apparatus that can transmit microwaves symmetrically with respect to the axis of symmetry and improves the uniformity of microwave radiation from the microwave radiation opening is provided. be able to.

In a fourth aspect of the present invention, in particular, in any one of the first to third aspects, the microwave radiation opening may be a microwave heating device having a shape that radiates circularly polarized waves. The microwave which spreads from the part is radiated, and the microwave heating apparatus which makes the radiation of the microwave to the object to be heated uniform in a wider range can be provided.

According to a fifth aspect of the invention, in particular, in any one of the first to fourth aspects of the invention, a plurality of microwave indirect radiation openings that radiate microwaves from the waveguide are provided, and the plurality of microwave indirect radiation openings are provided. By using the microwave heating device disposed at a position farther in the vertical direction from the object to be heated than the arrangement surface of the microwave radiation opening, microwaves contributing to the heating of the side surface and the upper surface of the object to be heated are heated. It is possible to provide a microwave heating apparatus that further improves the uniform heating performance of an object to be heated.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, a preferred embodiment of a microwave heating apparatus according to the invention will be described with reference to the accompanying 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, 101 is a housing, 102 is an object to be heated, 103 is a heating chamber in which the object to be heated 102 is placed, 104 is a placement portion on which the object to be heated 102 is placed, 105 is a microwave supplied to the heating chamber 103 , A waveguide for transmitting the microwave supplied from the microwave supply means 105 to the heating chamber 103, 107 a waveguide structure antenna, 108 a coupling axis, 109 a microwave A wave radiation opening 110 is a traveling wave promoting opening. The mounting portion 104 is a glass plate, the microwave supply means 105 is a magnetron, the waveguide 106 is a rectangular waveguide, the waveguide structure antenna 107 is a rectangular parallelepiped, and the coupling axis 108 is a waveguide. A coaxial structure for transmitting microwaves transmitted through the tube 106 to the waveguide structure antenna 107, a microwave radiation opening 109 is an opening provided in the waveguide structure antenna 107, and a traveling wave promoting opening 110 is a waveguide. This configuration can be easily realized by using an opening provided in the transmission direction of the microwave transmitted through the tube structure antenna 107.

  FIG. 2 is a perspective view of the microwave heating apparatus according to the first embodiment. In FIG. 2, reference numeral 201 denotes a door for taking the article to be heated 102 into and out of the heating chamber 103.

  3A is a schematic side view of the waveguide 106 and the waveguide structure antenna 107, and FIG. 3B is a schematic view of the microwave radiation opening 109 on the top surface of the waveguide structure antenna 107. In FIG. 3, the coupling shaft 108 is joined to the waveguide structure antenna 107, and a part of the coupling shaft 108 is inserted into the waveguide 106, so that the microwave transmitted through the waveguide 106 is transmitted to the waveguide structure antenna. The configuration is a microwave supply point to 107. Further, the waveguide structure antenna 107 has a traveling wave 301 from the coupling axis 108 serving as a microwave supply point toward the traveling wave promoting opening 110 by a traveling wave promoting opening 110 serving as an opening provided in the transmission direction. Is transmitted. The microwave radiation opening 109 is an opening provided on the waveguide structure antenna 107 and radiates microwaves to the heating chamber 103.

  Hereinafter, the operation of the microwave heating apparatus will be described. When the object to be heated 102 is placed on the mounting portion 104 in the heating chamber 103 and a heating start instruction is given by the user, the microwave heating device moves from the magnetron serving as the microwave supply means 105 into the waveguide 106. To supply microwaves. As shown in FIG. 3, the microwave transmitted through the waveguide 106 is transmitted to the waveguide structure antenna 107 through the coupling shaft 108 and transmitted as the traveling wave 301 toward the opening of the traveling wave promoting opening 110. . When the traveling wave 301 is transmitted through the waveguide structure antenna 107, the traveling wave 301 travels while changing the amplitude in the microwave radiation opening 109 as indicated by a dotted line in FIG. Therefore, the microwave that heats the object to be heated 102 is dispersed in the plurality of microwave radiation openings 109 and radiated to the heating chamber 103 while changing the amount of radiation in accordance with the amplitude change of the traveling wave 301 that is the radiation source. Thus, uniform heating can be realized.

  As described above, in the present embodiment, the microwave supplied from the microwave supply means 105 and transmitted through the waveguide 106 is guided to the waveguide structure antenna 107 by the coupling shaft 108, thereby supplying the microwave. The point is changed to a position where the microwave can be emitted from the waveguide structure antenna 107 with symmetry, and the microwave is emitted from the plurality of microwave radiation openings 109, so that the microwave radiation having symmetry is obtained. The object to be heated can be heated uniformly. According to this configuration, since the traveling wave 301 whose amplitude changes passes through the microwave radiation opening 109, the microwave whose radiation amount changes is radiated from the openings dispersed in a plurality of locations. A microwave heating apparatus that can uniformly heat the object to be heated 102 without using a rotation mechanism can be provided.

  Here, as shown in FIG. 4, the waveguide structure antenna 107 includes a left-right direction symmetry axis 401 and a depth-direction symmetry axis 402 in the left-right direction and the depth direction, respectively, so that the microwave is symmetrical with respect to the symmetry axis. It can be transmitted, and the uniformity of the microwave radiation from the microwave radiation opening can be improved.

  In the present embodiment, the opening shape of the microwave radiation opening 109 has been described with reference to the shape of FIG. 3, but the opening shape is not limited thereto.

  In the present embodiment, the case where there is one waveguide structure antenna 107 and one coupling axis 108 has been described. However, a microwave heating apparatus is configured using a plurality of waveguide structure antennas and coupling axes. Obviously it may be.

(Embodiment 2)
FIG. 5 is a schematic perspective view of the waveguide structure antenna 107 according to Embodiment 2 of the present invention. The operation and action will be described below. In the drawings, the same reference numerals are given to portions showing the same operations as those in the first embodiment. The basic operation in the second embodiment is the same as that in the first embodiment.

  In the present embodiment, as shown in FIG. 5, the waveguide structure antenna 107 is configured as a rectangular parallelepiped polyhedron, and the microwave radiating opening 109 is provided on the upper surface as in the first embodiment. However, the waveguide structure antenna 107 according to the second embodiment is structurally composed of a waveguide structure portion 501 having a flat portion and a vertical portion, and a flange portion 502. The flange portion 502 is formed of a microwave. The difference is that it is formed so as to be in contact with the lower surface portion of the waveguide structure portion 501 in parallel with the transmission direction 302. Here, the distance from the point in contact with the waveguide structure portion 501 to the outer edge of the flange portion 502 is appropriately set (for example, the quarter of the oscillation wavelength of the microwave supply means 105 generally used as a choke structure for preventing microwave leakage). 1), the microwave can be transmitted into the waveguide structure antenna 107 even with a simple configuration in which the waveguide structure antenna 107 is not fixed to the heating chamber 103 and the waveguide 106. . As a result, the microwave that heats the object to be heated 102 is dispersed in the plurality of microwave radiation openings 109 and radiated to the heating chamber 103 while changing the amount of radiation according to the change in the amplitude of the traveling wave that is the radiation source. Thus, uniform heating can be realized.

  As described above, in the present embodiment, the waveguide structure antenna 107 is configured as a rectangular parallelepiped polyhedron, and the waveguide structure portion 501 in which the microwave radiation opening 109 is provided on the upper surface portion, and the lower surface portion. Is provided with a flange portion 502 that is in contact with the waveguide structure portion 501, and the flange portion 502 is formed in parallel with the microwave transmission direction, thereby preventing microwave leakage from other than the traveling wave promoting opening 110 and introducing the flange portion 502. Even in a simple configuration in which the wave tube structure antenna 107 is not fixed to the heating chamber 103, uniform heating can be realized.

  In the case of such a configuration, it goes without saying that the direction of the waveguide structure antenna 107 can be freely set. In this case, it is possible to manually set the object 102 in an appropriate direction. In addition, if the rotating means is introduced, the standing wave in the heating chamber generated in the heating chamber 103 is changed, so that the uniformity can be further improved.

(Embodiment 3)
FIG. 6 is a cross-sectional view of the microwave heating apparatus according to the third embodiment of the present invention, and FIG. It is. The operation and action will be described below. In the drawings, the same reference numerals are given to portions showing the same operations as those in the first embodiment. The basic operation in the present embodiment is the same as that in the first embodiment.

In the present embodiment, the microwave radiation opening 109 is shaped to radiate circularly polarized waves as shown in FIGS. Circular polarization is a technique widely used in the field of mobile communication and satellite communication. Examples of familiar use include an ETC (Electronic Toll Collection System) “non-stop automatic toll collection system” and the like. Circular polarization is a microwave in which the polarization plane of the electric field rotates with respect to the traveling direction of the radio wave, and when the circular polarization is formed, the direction of the electric field continues to change with time. The radiation angle of the microwave radiated into the inside continues to change, and the electric field strength does not change with time. Thereby, compared with the microwave heating by the linearly polarized wave used in the conventional microwave heating apparatus, the microwave is dispersed and radiated over a wide range so that the object to be heated can be microwave heated uniformly. become. In particular,
There is a strong tendency for uniform heating in the circumferential direction of circular polarization. Note that circularly polarized waves are classified into two types, that is, right-handed polarization (CW: clockwise) and left-handed polarization (CCW: counterclockwise) from the direction of rotation, but there is no difference in heating performance.

  By utilizing the above features and emitting circularly polarized microwaves through the microwave radiation opening 109, the heating distribution in the heating chamber 103 can be made more uniform. In order to output circularly polarized wave from the microwave radiation opening 109 provided in the waveguide structure antenna 107, as shown in FIG. It is necessary to arrange the shape inclined 45 degrees with respect to the transmission direction at a position that does not pass through the tube axis 701 in the microwave transmission direction of the waveguide structure antenna 107.

  As described above, in the present embodiment, the microwave radiation opening 109 is shaped to radiate circularly polarized waves, so that microwaves having a spread from the microwave radiation part are radiated, and the object to be heated The microwave radiation to 102 can be made uniform over a wider range.

  In the present embodiment, the shape of the microwave radiation opening 109 that radiates circularly polarized waves has been described with reference to the shape shown in FIGS. 6 and 7. However, the shape is not limited to this shape and is shown in FIG. Any shape that radiates circularly polarized waves can be used.

(Embodiment 4)
FIG. 9 is a schematic cross-sectional view showing the configuration of the microwave heating apparatus according to the fourth embodiment of the present invention. FIG. 10 is a schematic perspective view of the waveguide structure antenna 107 used in FIG. In FIG. 9, a microwave indirect radiation opening 901 that is an opening is formed in the waveguide 106. The microwave indirect radiation opening 901 is arranged at a position farther from the object to be heated 102 than the arrangement surface of the microwave radiation opening 109 provided in the waveguide structure antenna 107. The operation and action will be described below. In the drawings, the same reference numerals are given to the portions showing the same operations as those in the first to third embodiments. The basic operation in the fourth embodiment is the same as that in the first embodiment.

  As shown in FIG. 9, the microwave indirect radiation opening arrangement surface 902 on which the microwave indirect radiation opening 901 is arranged is disposed so as to be farther from the object to be heated 102 than the microwave radiation opening arrangement surface 903. Has been. In this manner, by arranging the microwave radiation opening 109 and the microwave indirect radiation opening 901, the microwave radiation opening 109 is physically more relative to the object to be heated 102 than the microwave indirect radiation opening 901. Since it occupies a close position, the emitted microwave is easily absorbed directly into the lower portion of the object to be heated 102. In this case, an electric field in which microwaves are directly incident is generated in the vicinity of the microwave radiation opening 109 and the object to be heated 102, so that radiation from the microwave indirect radiation opening 901 is directly directed to the object to be heated 102. It becomes difficult to enter. Therefore, the microwave radiated from the microwave indirect radiation opening 901 passes through the placement portion 104 and is radiated into the heating chamber 103 to promote heating of the side surface and the upper portion of the object to be heated 102. By this action, microwaves can be supplied to the object to be heated 102 from the upper surface, the lower surface, and the side surfaces, and thus the uniform heating performance for the object to be heated can be further improved. In particular, the effect is that, in a small amount of the object to be heated 102 as a load of microwave heating (for example, food having a moisture content of 150 g or less), electric power concentrates on the lower part of the object to be heated 102 and overheating occurs. Works effectively when you want to prevent it.

  As described above, in the present embodiment, the microwave indirect radiation opening 901 is provided in the waveguide 106, and the microwave indirect radiation opening arrangement surface 902 is heated from the microwave radiation opening arrangement surface 903. By disposing at a position far from the microwave, the microwave that contributes to the heating of the side surface and the upper surface of the object to be heated 102 is supplied from the microwave indirect radiation opening 901 to the heating chamber, and the uniform heating performance of the object to be heated is further improved. Can do.

  In the present embodiment, the microwave indirect radiation opening 901 has been described with reference to an opening that radiates circularly polarized waves. However, the opening may not necessarily be a circularly polarized wave. Needless to say.

  In this embodiment, the microwave indirect radiation opening 901 and the microwave radiation opening 109 have been described with reference to the same axis. For example, as shown in FIG. It goes without saying that the direction of the structural antenna 107 may be set freely. When the direction of the waveguide structure antenna 107 is freely set, it is possible to manually set the antenna structure 107 in an appropriate direction. In addition, if the rotating means is introduced, the standing wave in the heating chamber generated in the heating chamber 103 is changed, so that the uniformity can be further improved.

  As described above, since the microwave heating apparatus of the present invention can uniformly irradiate an object to be heated, it can be effectively used for a microwave heating apparatus that performs heating processing or sterilization of food. In the present invention, the microwave device has been described as a microwave device that can uniformly heat an object to be heated without using a rotating mechanism. However, a heating chamber constant generated in the heating chamber by introducing the rotating mechanism is described. It is also possible to improve uniformity by making the standing wave more complex.

DESCRIPTION OF SYMBOLS 101 Case 102 To-be-heated object 103 Heating chamber 104 Mounting part 105 Microwave supply means 106 Waveguide 107 Waveguide structure antenna 108 Coupling axis 109 Microwave radiation opening 110 Traveling wave promotion opening 201 Door 301 Traveling wave 401 Left-right direction symmetry axis 402 Depth direction symmetry axis 501 Waveguide structure portion 502 Flange portion 701 Tube axis 901 Microwave indirect radiation opening portion 902 Microwave indirect radiation opening placement surface 903 Microwave radiation opening placement surface

Claims (5)

A heating chamber for storing the 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 microwaves supplied from the microwave supply means;
A waveguide structure antenna having a substantially rectangular parallelepiped shape for radiating microwaves to the heating chamber;
A coupling axis for transmitting microwaves from the waveguide to the waveguide structure antenna, the waveguide structure antenna,
Traveling wave promoting openings are provided on the left and right end faces that are the transmission direction of the microwave,
On the upper surface, a plurality of microwave radiation openings for radiating the microwaves to the heating chamber are provided symmetrically from the approximate center to the left-right direction in plan view,
One end of the coupling shaft is a microwave heating apparatus connected to the vicinity of the approximate center of the waveguide structure antenna . Said waveguide structure antenna is provided with a flange portion in contact with the waveguide structure on the lower surface portion, the flange portion according to claim 1, characterized in that it is formed parallel to the transmission direction of the microwave Microwave heating device. Said waveguide structure antenna, in plan view, relative to the generally central, according to any one of claims 1-2, characterized in being configured so as to be symmetrical in the lateral direction and the depth direction Microwave heating device. The microwave radiation opening, the microwave heating apparatus according to any one of claims 1 to 3, characterized in that has a shape that emits circularly polarized wave. A plurality of microwave indirect radiation openings that radiate microwaves from the waveguide are provided, and the plurality of microwave indirect radiation openings are vertically above the object to be heated relative to the arrangement surface of the microwave radiation openings. It arrange | positions in a distant position, The microwave heating apparatus of any one of Claims 1-4 characterized by the above-mentioned.