JP5674914B2 - High frequency heating device - Google Patents

Description

  The present invention relates to a high-frequency heating device, and more particularly to a high-frequency heating device configured to suppress heating unevenness of an object to be heated.

  As a conventional high-frequency heating device, “a heating chamber that houses an object to be heated, a high-frequency oscillator that oscillates a high frequency for heating the object to be heated in the heating chamber, and a high-frequency wave oscillated from the high-frequency oscillator And an antenna for diffusing the high frequency propagated from the waveguide into the heating chamber. The antenna has a flat plate that emits the high frequency, and one end disposed in the waveguide. An antenna shaft that connects the flat plate to the end and propagates the high frequency of the waveguide to the flat plate is connected to the flat plate and the antenna shaft through a conductive path that is bifurcated from the top of the antenna shaft. Have been proposed (see, for example, Patent Document 1).

JP 2009-170335 A (page 3, FIG. 3, FIG. 4)

  The high-frequency heating device described in Patent Document 1 includes a heating chamber provided in a substantially rectangular parallelepiped, a high-frequency oscillator that oscillates high frequency, a waveguide that propagates high frequency, and an antenna that propagates high-frequency in the waveguide into the heating chamber. And a high-frequency transmission plate that doubles as an antenna protection plate and an object to be heated is installed on the upper surface of the antenna.

  The antenna includes a flat plate portion that emits high frequency, and an antenna shaft that has one end disposed in the waveguide and has a flat plate connected to the other end to propagate the high frequency of the waveguide to the flat plate. Are connected through a conductive path branched in two from the upper part of the antenna shaft. With such an antenna configuration, a strong electric field can be emitted in a wide area on the antenna flat plate, so that it has a certain effect on heating an object to be heated relatively uniformly.

  However, on the other hand, since a large current tends to flow from the waveguide via the antenna shaft to the conductive path portion connected to the flat plate portion that emits high frequency, the microscopic path is stronger than the flat plate portion. May have wave radiation characteristics. For this reason, there is a concern that the heating immediately above the conductive path located in the center of the heating chamber becomes excessively strong, and that the deterioration of the metal is accelerated due to resistance heat generation in the conductive path portion.

  The present invention has been made to solve the above-described problems, and provides a high-frequency heating apparatus that can propagate a high-frequency wave oscillated from a high-frequency oscillator more evenly into a heating chamber.

A high-frequency heating device according to the present invention includes a heating chamber that houses an object to be heated, a high-frequency oscillator that oscillates a high frequency for heating the object to be heated, a waveguide that guides a high frequency oscillated from the high-frequency oscillator, An antenna shaft for propagating high frequency in the waveguide, a flat plate antenna connected to the antenna shaft and disposed substantially parallel to the bottom of the heating chamber, and diffusing high frequency into the heating chamber, and the antenna shaft Rotation driving means for rotating the antenna via the first antenna, the antenna having a first radiating portion as at least one opening formed in a conductor portion connected to the antenna shaft; A first radiation path and a second conduction path branched from the first antenna, and a flat plate portion connected to the first conduction path and the second conduction path are radiated second. And then, the antenna shaft, conductor portions of the first antenna, and comprising a second antenna is a plate antenna which is powered to emit circularly polarized wave through the first conductive path and said second conductive path Is.

According to the present invention, the first conductive path and the second conductive path are connected from the antenna shaft that is the power feeding unit via the first antenna having the first radiating unit. For this reason, the electric field concentration to a 1st conductive path and a 2nd conductive path can be suppressed, and deterioration of a conductive path can be suppressed.
In addition, a strong electric field is radiated in a relatively narrow range from the first radiating section, and an intermediate strength electric field is radiated in a relatively wide range from the second radiating section. Can be propagated more evenly in the heating chamber.

It is a cross-sectional schematic diagram of the principal part of the heating cooker which concerns on embodiment. It is a perspective view of the principal part of the cooking-by-heating machine concerning an embodiment. It is a principal part perspective view of the heating chamber bottom face of the heating cooker which concerns on embodiment. It is a top view of the antenna of the heating cooker which concerns on embodiment. It is a top view of the antenna of the heating cooker which concerns on embodiment. It is a schematic diagram of the high frequency propagation on the antenna of the heating cooker which concerns on embodiment. It is a transition diagram of the surface current on the antenna flat plate of the heating cooker which concerns on embodiment. It is a schematic diagram explaining the electric field distribution at the time of antenna rotation which concerns on embodiment. It is a top view explaining the other antenna which concerns on embodiment. It is an antenna top view of the conventional heating cooker.

Embodiment In this embodiment, a cooking device used at home or the like will be described as an example of a high-frequency heating device.
FIG. 1 is a schematic cross-sectional view of a main part of a heating cooker according to an embodiment. FIG. 2 is a perspective view of a main part of the heating cooker according to the embodiment. FIG. 3 is a perspective view of the main part of the bottom surface of the heating chamber of the cooking device according to the embodiment. The antenna shown in FIG. 3 is a characteristic configuration of the heating cooker according to the present embodiment.

As shown in FIG. 1, a heating chamber 2 is provided inside the main body 1 of the heating cooker, and a door 4 and an operation panel 3 are provided on the front surface of the main body 1.
The heating chamber 2 is composed of a casing formed in a substantially rectangular parallelepiped shape with the front surface opened. At the bottom of the heating chamber 2, a high-frequency transmission plate 6 having a function as a mounting table for the object 7 to be heated housed in the heating chamber 2 is detachably installed. The high frequency transmission plate 6 is made of, for example, ceramic that transmits high frequency. The operation panel 3 accepts various input operations from the user such as a heating start instruction, a heating time setting, and a target heating temperature setting. The door 4 is attached to the main body 1 so as to be freely opened and closed, and is provided with a door viewing window 5 configured by sandwiching a punching metal with glass. The cooking state of the object to be heated 7 accommodated in the heating chamber 2 can be confirmed by the door viewing window 5.

  As shown in FIG. 2, in the main body 1, there are a high-frequency oscillator 11 that oscillates a high frequency for heating the object 7 to be heated, and a waveguide 12 that guides the high-frequency oscillated from the high-frequency oscillator 11 to the heating chamber 2. Is provided. A high frequency oscillator 11 provided at the bottom of the heating chamber 2 of the main body 1 is a magnetron that oscillates a high frequency.

  Between the bottom plate 9 and the high-frequency transmission plate 6 of the heating chamber 2, an antenna chamber 10 that houses the antenna 20 is formed. The antenna 20 is for diffusing the microwave oscillated from the high frequency oscillator 11 into the heating chamber 2. An antenna motor 23 for rotating the antenna 20 is attached to the antenna 20.

  The temperature detection device 8 installed in the heating chamber 2 is, for example, an infrared sensor that measures the temperature of the heated object 7 based on infrared rays emitted from the heated object 7.

  The heating cooker includes a control unit (not shown) including a control circuit that drives and controls the high-frequency oscillator 11 and the antenna motor 23 based on an input from the operation panel 3. This control unit has a function of controlling the output of the high frequency oscillator 11 based on the temperature detected by the temperature detecting device 8 and rotating / stopping the antenna motor 23 at a predetermined timing. Thus, by rotating / stopping the antenna 20 by the antenna motor 23, it is possible to change the irradiation state of the microwave to the heated object 7 and to heat the heated object 7 uniformly and at high speed. .

Here, a method of high frequency propagation from the high frequency oscillator 11 to the object 7 to be heated via the antenna 20 will be described.
For example, in a home microwave oven, a high frequency of 2.45 GHz is oscillated from the magnetron which is the high frequency oscillator 11. For example, in a microwave oven for home use, a high frequency of about 1000 W to 200 W is oscillated.
The high frequency oscillated by the high frequency oscillator 11 propagates through the space in the waveguide 12 that is closed and configured by a conductor.
A shaft hole 12 a is provided in the waveguide 12, and a shaft hole 9 a is provided in a position corresponding to each other in the bottom plate 9 of the heating chamber 2, and the high frequency propagated through the space in the waveguide 12 is transmitted through the shaft hole 12 a. This is a mechanism for propagating into the heating chamber 2 via the shaft hole 9a.

  However, the high frequency does not efficiently flow into the heating chamber 2 simply by providing the shaft hole 12a and the shaft hole 9a. For this reason, a metallic and conductive antenna shaft 22 is coaxially coupled to the shaft of the antenna motor 23 and inserted into the shaft hole 12a and the shaft hole 9a, and a flat antenna 20 connected to one end of the antenna shaft 22 is provided. The heating chamber 2 is arranged in the antenna chamber. In such a configuration, a high frequency propagating in the waveguide 12 is converted into a surface current in the antenna shaft 22 of the antenna 20. The converted current flows on the surface of the antenna 20, and a magnetic field is excited by the current as the current changes with time, and an electric field is generated by the excited magnetic field. Electromagnetic waves are radiated when the time change of the magnetic field and electric field increases or decreases with the phase of the high frequency.

  That is, since a current flows on the surface of the antenna 20, the high-frequency behavior that propagates from the flat plate portion of the antenna 20 into the heating chamber 2 changes depending on how the surface current flows in a time change (phase change) of the high frequency. . Therefore, it can be said that the high frequency can be generated from a wide area on the flat plate by causing the current flowing on the antenna surface and the time change of the current in a wider area. Thus, the transmission efficiency is improved by propagating the high frequency into the heating chamber 2 through the antenna shaft 22 and the antenna 20.

  Here, a conventional antenna will be described. FIG. 10 is a top view of a conventional antenna. In the conventional example, a current path is bifurcated from a shaft connecting portion 66 that is a connecting portion with an antenna shaft (not shown) serving as a current source to the antenna 60. Each of the branched currents extends from the shaft connecting portion 66 in the horizontal direction on the paper surface and is bent once to be bent to the antenna flat plate 63. The branched current extends from the shaft connecting portion 66 in the horizontal direction on the paper surface and is bent twice to be bent to the antenna flat plate 63. Through the conductive path 65 to reach, it takes the form of merging on the antenna flat plate 63 shown in a disk shape in FIG. In the conventional example, a high-frequency current coming from the lower side of the drawing sheet via the conductive path 64 and a high-frequency current coming from the right side of the drawing sheet via the conductive path 65 are combined in vector, and various currents are generated on the antenna plate 63. It aims to produce an effect that makes it possible to diversify the distribution of generated electromagnetic waves.

However, in the conventional antenna, since current also flows through the conductive paths 64 and 65 leading to the antenna flat plate 63, it has been found from research leading to the present invention that electromagnetic waves having a level that cannot be ignored are generated.
In the conductive paths 64 and 65, which are narrow paths having a smaller surface area than the antenna flat plate 63, the current tends to be relatively large due to the small surface area, and as a result, the energy per unit area (power density) emitted as electromagnetic waves is large. End up.
That is, the portion directly above the conductive paths 64 and 65 in the vicinity of the shaft from the antenna shaft which is the power feeding portion is relatively easily heated, which may lead to uneven heating.

  The antenna 20 according to the present embodiment is configured in view of the conventional example as described above. FIG. 4 is a top view of the antenna of the heating cooker according to the embodiment, and is a diagram for structurally explaining the antenna 20.

First, the antenna 20 will be described from the structural side.
As shown in FIG. 4, the antenna 20 is composed of a flat conductor as a whole and is connected to the antenna shaft 22. The antenna 20 is accommodated in the antenna chamber 10 such that the flat plate surface is substantially parallel to the bottom surface of the heating chamber 2 .
The antenna 20 includes two slot antennas 31 and 32 (both are referred to as a first antenna), a disk-shaped antenna flat plate 41 (second antenna), and a conductive path 42 that connects the antenna flat plate 41 and the slot antenna 31. (First conductive path) and a conductive path 43 (second conductive path) for connecting the antenna flat plate 41 and the slot antenna 32 are provided. A shaft connecting portion 21 for vertically connecting the antenna shaft 22 is provided at the center of the antenna 20. The antenna 20 is rotated while maintaining a substantially horizontal position around the shaft connection portion 21, thereby leveling the high frequency applied to the article 7 to be heated, thereby achieving leveling of heating.

  Each of the slot antenna 31 and the slot antenna 32 includes a strip-shaped or arc-shaped slit hole 31b and a slit hole 32b (opening) formed in the conductor portions 31a and 32a. The slot antennas 31 and 32 use the slit holes 31b and 32b as high-frequency radiation portions. In particular, when the length of the slit holes 31b and 32b is approximately ½ of the wavelength used, the slit holes 31b and 32b can resonate and emit a strong high frequency. Each of the slot antennas 31 and 32 has a substantially sector shape, and conductive paths 42 and 43 are connected to sides 31c and 32c corresponding to the radius of the sector shape. In the present embodiment, the two slot antennas 31 and 32 are symmetrically arranged with the shaft connecting portion 21 that is the central portion of the antenna 20 as the center.

  The antenna flat plate 41 is a radiating portion capable of high frequency, as will be described later. In the present embodiment, the antenna flat plate 41 has a disk shape, and is disposed in a substantially fan-shaped region sandwiched between the slot antenna 31 and the slot antenna 32 on the same plane. The diameter of the antenna flat plate 41 is slightly shorter than the length of the side 31 c of the slot antenna 31. The antenna flat plate 41 is connected to the first antenna by a conductive path 42 and a conductive path 43 that are branched from the first antenna. In the present embodiment, the antenna flat plate 41 is connected to one slot antenna 31 by a conductive path 42 and is connected to the other slot antenna 32 by a conductive path 43.

  The conductive path 42 and the conductive path 43 are connected in the same plane as the antenna flat plate 41 at a position shifted by approximately 90 ° with respect to the central portion of the antenna flat plate 41. Further, the distance L2 from the connection point 43a between the conductive path 43 and the antenna flat plate 41 to the shaft connection portion 21 is larger than the distance L1 from the connection point 42a between the conductive path 42 and the antenna flat plate 41 to the shaft connection portion 21. It is configured to be long. In this embodiment, the connection point between the side 31c of the slot antenna 31 and the conductive path 42 is the connection point 42b, and the connection point between the side 32c of the slot antenna 32 and the conductive path 43 is the connection point 43b. Then, the distance from the connection point 42b to the shaft connection part 21 is made shorter than the distance from the connection point 43b to the shaft connection part 21.

  The antenna flat plate 41 is disposed in a fan-shaped region sandwiched between the substantially fan-shaped slot antenna 31 and the slot antenna 32, and the conductive paths 42 and 43 connecting the antenna flat plate 41 and the slot antennas 31 and 32 are provided as slots. The antennas 31 and 32 are connected to the sides 31c and 32c. With such an arrangement relationship, the conductive paths 42 and 43 can be formed in a straight line without bending, and the path lengths of the conductive paths 42 and 43 can be shortened.

Next, functional aspects of the antenna 20 will be described. FIG. 5 is a top view of the antenna according to the embodiment, and is a diagram for functionally explaining the antenna 20. FIG. 6 is a schematic diagram of high-frequency propagation on the antenna of the cooking device according to the embodiment, and FIG. 7 is a transition diagram of the surface current on the antenna plate of the cooking device according to the embodiment.
The functional side of the antenna 20 will be described with reference to FIGS.

  As shown in FIG. 6, high frequency waves are emitted from the slot antennas 31 and 32 with a linearly polarized wave 100 having a plane crossing the slit holes 31b and 32b as a plane. The slit holes 31 b and 32 b that radiate the high frequency are referred to as a first radiation portion 30. Then, the slot antennas 31 and 32 are referred to as a strong electric field region F having a strong electric field (see FIG. 5). In the present embodiment, it is possible to improve the radiation efficiency from the antenna 20 and improve the heating efficiency of the article 7 to be heated by providing two slot antennas 31 and 32 that can radiate strong high frequencies.

Next, the electric field radiation from the antenna flat plate 41 will be described.
When the conductive paths 42 and 43 are viewed as current sources with respect to the antenna flat plate 41, the geometric current source arrangement is shifted by 90 °, so that the surface current vector is on the antenna flat plate 41. It changes greatly and it becomes possible to radiate high frequency in various directions.
Further, the high frequency introduced onto the antenna flat plate 41 is installed such that the distances (L1, L2) from the antenna shaft 22 as the introduction positions are different from each other so that a current whose phase is shifted by 90 ° can be introduced. . Then, by synthesizing the introduced currents, it is possible to generate a circularly polarized wave 101 that can radiate a high electric field in an annular shape. This antenna flat plate 41 is referred to as a second radiating unit 40.

  Here, the principle of circularly polarized wave generation will be described with reference to FIG. FIG. 7 shows the current flowing on the antenna flat plate 41. The solid line represents the current flowing on the antenna flat plate 41, and the broken line represents the current flowing into and out of each conductive path. The length of the broken line indicates the magnitude of the current.

  The current excited by the high frequency has an amplitude so that the direction of flow is reversed every 90 ° phase. For example, the incident from the conductive path 43 flowing in from the lower side of the paper surface at the phase 0 ° flows greatly downward, but the current decreases as the phase changes to 22.5 ° and 45 °, and then the current is reduced. The flowing direction starts to reverse, and at phase 90 °, the current flows in the reverse direction with the same magnitude as phase 0 °.

As shown in the solid line on the antenna flat plate 41, the current flowing from the lower side of the paper and the right side is sequentially changed as the combined current in the flowing direction for each phase. As a result, the direction of the current flowing on the antenna flat plate 41 is rotated once while the phase changes by 180 °.
That is, the electromagnetic wave generated in the vertical direction on the paper surface accompanying the movement of the current moves in a strong electric field portion in an annular shape with a phase.

As shown in FIG. 6, the circularly polarized wave 101 emitted from the antenna flat plate 41 can emit a high frequency having a medium energy although it is slightly weaker than the energy emitted from the slot antenna 31. . The high frequency tends to be relatively strong particularly at the end portion of the antenna flat plate 41 where current easily flows. The outer peripheral end of the disk portion of the antenna flat plate 41 is referred to as a medium electric field region G having a moderate electric field strength (see FIG. 5).
When the phase of the current flowing on the antenna flat plate 41 is shifted by 90 °, measures such as changing the positions and lengths of the conductive path 42 and the conductive path 43 are taken by analyzing and confirming with, for example, electromagnetic field simulation software. It is possible.

FIG. 8 is a schematic diagram for explaining the electric field distribution during antenna rotation according to the embodiment. The electric field distribution when the antenna 20 is rotated will be described with reference to FIGS.
First, as shown in FIG. 5, the locus of the central portion of the strong electric field region F of the slot antennas 31 and 32 when the antenna 20 is rotated is indicated by a locus C. Further, the trajectories near the outer end and the inner end of the middle electric field region G of the antenna flat plate 41 when the antenna 20 is rotated are referred to as a trajectory D and a trajectory E, respectively.

  As shown in FIG. 8, when the antenna 20 rotates, the strong electric field region F strengthens the electric field in the region of the locus C, so that the electric field immediately above the slot antennas 31 and 32 tends to become concentrically strong. Therefore, the object 7 to be heated that is very close to the antenna 20 placed immediately above the slot antennas 31 and 32 is also heated in the same manner. In addition, since the middle electric field region G strengthens the electric field in the region between the trajectory D and the trajectory E due to the rotation of the antenna 20, the electric field directly above the antenna flat plate 41 also tends to become concentrically strong.

  In this way, when the antenna 20 rotates, a relatively narrow annular electric field region F1 is formed by the strong electric field region F, and a relatively wide annular electric field region G1 is formed by the middle electric field region G. The Since the strong electric field region F and the intermediate electric field region G are different from each other in range and position, the annular electric field region F1 formed by the strong electric field region F overlaps the annular electric field region G1 formed by the intermediate electric field region G. The region F1 and the electric field region G1 do not match. Since the electric field is emitted from the circular trajectory D and the trajectory E together with the trajectory C with respect to the rotation region immediately above the antenna 20, the electric field is emitted from a wide range of the rotation region of the antenna 20. Since the electric field is emitted from a wide range, an efficient and uniform temperature increase effect can be given to the object 7 to be heated. For example, when only the slot antennas 31 and 32 are provided, the heating is relatively weak because there is no heating element at a position shifted from the locus C. However, by providing the antenna flat plate 41 as the second radiating portion as in the present embodiment, leveled heating is possible as compared with the case where only the slot antennas 31 and 32 are configured.

As described above, according to the present embodiment, the slot antennas 31 and 32 having the first radiating portion 30 as the slit holes 31b and 32b formed in the conductor portions 31a and 32a connected to the antenna shaft 22, and the slot antenna. Conductive paths 42 and 43 branched into two from 31 and 32, and a second antenna having an antenna flat plate 41 connected to the conductive paths 42 and 43 as a second radiation portion.
In the present embodiment, since the conductive path 42 and the conductive path 43 are connected from the antenna shaft 22 which is a power feeding unit via the first antenna (slot antennas 31 and 32), the conductive paths 42 and 43 are Compared to the conductive paths 64 and 65 of the antenna shown in the conventional example, it can be configured shorter, and there is almost no electric field radiation from the same part, and it is possible to suppress the adverse effect of locally increasing heating. Therefore, electric field concentration on the conductive path 42 and the conductive path 43 can be suppressed, and deterioration of the conductive paths 42 and 43 can be suppressed.

  The slot antennas 31 and 32 connected to the antenna shaft 22 radiate a strong electric field in a relatively narrow range above the slit holes 31b and 32b, while the antenna plate 41 has a relatively wide range. A moderately strong electric field is emitted. As described above, by providing the radiation portions having different electric field strengths, the intensity of the electric field radiation on the antenna 20 can be diversified. For example, by changing the range of field radiation of the first radiation part 30 and the second radiation part 40, there is an effect of changing the intensity of field radiation on the antenna 20. Moreover, the intensity | strength of the electric field radiation on the antenna 20 can also be made more uniform by adjusting the range and arrangement | positioning of the 1st radiation | emission part 30 and the 2nd radiation | emission part 40. FIG.

  Further, since the two slot antennas 31 and 32 are provided, the center of gravity at the time of rotation is stable, the plane portion of the antenna 20 is less likely to be shaken at the time of rotation, and the operation is stabilized. Further, the slot antennas 31 and 32 are installed at positions that are symmetrical with respect to the shaft connecting portion 21 that is the center of the antenna 20. By doing so, the distance between the slot antenna 31 and the slot antenna 32 can be increased. Therefore, the interaction of the high frequency radiated from each of the slot antennas 31 and 32 can be suppressed, and the high frequency can be efficiently radiated from each of the slot antennas 31 and 32. As described above, the two slot antennas 31 and 32 enable stable center of gravity and efficient high-frequency emission.

  Moreover, in this Embodiment, the locus | trajectory of the 1st radiation | emission part 30 at the time of rotating the antenna 20 and the locus | trajectory of the 2nd radiation | emission part 40 were varied. That is, as shown in FIG. 8, the annular electric field region F <b> 1 due to the strong electric field region F of the first radiating unit 30 overlaps the annular electric field region G <b> 1 due to the middle electric field region G of the second radiating unit 40. The electric field regions are not matched. For this reason, since an electric field can be radiated in a wide range on the antenna 20, uneven heating can be suppressed.

  In the present embodiment, the second radiating unit 40 radiates circularly polarized waves whose electric field vectors change periodically. For this reason, the direction of the microwave which injects into the to-be-heated material 7 can be diversified, and there exists an effect which improves a heating nonuniformity suppression effect.

In the above-described embodiment, the case where the slit hole 31b and the slit hole 32b are on the same radius has been described as an example, but the slit hole 31b and the slit hole 32b may be arranged at positions shifted in the radial direction. In this case, it is necessary to equalize the length of the slit of the slit hole 31 b and the slit holes 32 b, although sector angle will be different from each other, is more suppressed effectively uneven heating.
In order to balance the weight at this time, the radial length of the slit hole with the larger sector angle may be shorter than the radial length of the other slit hole.

  Moreover, although the example which provides the two slot antennas 31 and 32 was shown in the said embodiment, it can also be set as the structure which provides one slot antenna (1st antenna). FIG. 9 is a top view illustrating another antenna according to the embodiment. When the antenna 20 shown in FIG. 9 is compared with that shown in FIG. 4, the antenna 20 shown in FIG. 9 is different in that it does not have the slit hole 31b. For example, when two slot antennas are provided and heating is too strong, as shown in FIG. 9, one slot antenna 32 is provided so that high frequency is radiated only from the slit holes 32b. There is a case where leveling can be performed more. Three or more slot antennas may be provided. Also, a plurality of radiating portions may be configured by providing a plurality of openings for one slot antenna (first antenna). Moreover, you may provide a some 2nd radiation | emission part.

  In addition, it is also possible to combine with the high frequency heating which is this invention, after providing the radiation heater which is a heating apparatus which is not shown in figure in the heating chamber top surface, providing a hot-air heater in the back surface, and providing the steam generation apparatus. Moreover, it is also possible to perform heating control including power stop according to the finished state of the object to be heated using a temperature detection device provided in the heating chamber.

  DESCRIPTION OF SYMBOLS 1 Main body, 2 Heating chamber, 3 Operation panel, 4 Door, 5 Door visual recognition window, 6 High frequency transmission plate, 7 Heated object, 8 Temperature detection device, 9 Bottom plate, 9a Shaft hole, 10 Antenna room, 11 High frequency oscillator, 12 Waveguide, 12a Shaft hole, 20 Antenna, 21 Shaft connection part, 22 Antenna shaft, 23 Antenna motor, 30 First radiation part, 31 Slot antenna, 31a Conductor part, 31b Slit hole, 31c side, 32 Slot antenna, 32a Conductor part, 32b slit hole, 32c side, 40 second radiating part, 41 antenna flat plate, 42 conductive path, 42a connection point, 42b connection point, 43 conductive path, 43a connection point, 43b connection point, 100 linear polarization, 101 Circular polarization.

Claims (8)

A heating chamber for storing an object to be heated;
A high frequency oscillator that oscillates a high frequency for heating an object to be heated;
A waveguide for guiding a high frequency oscillated from the high-frequency oscillator;
An antenna shaft for propagating high frequency in the waveguide;
A plate-like antenna connected to the antenna shaft and arranged substantially parallel to the bottom of the heating chamber to diffuse high frequency into the heating chamber;
Rotation driving means for rotating the antenna via the antenna shaft,
The antenna is
A first antenna having a first radiating portion as at least one opening formed in a conductor portion connected to the antenna shaft;
A first conductive path and a second conductive path branched from the first antenna;
The flat plate portion connected to the first conductive path and the second conductive path is defined as a second radiating portion, and the antenna shaft, the conductor portion of the first antenna, and the first conductive path and the second conductive path are interposed therebetween. And a second antenna that is a flat plate antenna that is fed with power and radiates circularly polarized waves . At least two of the first antennas are coupled to the antenna shaft;
2. The high frequency according to claim 1, wherein the first conductive path is connected to any one of the first antennas, and the second conductive path is connected to another one of the first antennas. Heating device. A heating chamber for storing an object to be heated;
A high frequency oscillator that oscillates a high frequency for heating an object to be heated;
A waveguide for guiding a high frequency oscillated from the high-frequency oscillator;
An antenna shaft for propagating high frequency in the waveguide;
A plate-like antenna connected to the antenna shaft and arranged substantially parallel to the bottom of the heating chamber to diffuse high frequency into the heating chamber;
Rotation driving means for rotating the antenna via the antenna shaft,
The antenna is
A first antenna having a first radiating portion as at least one opening formed in a conductor portion connected to the antenna shaft;
A first conductive path and a second conductive path branched from the first antenna;
A second antenna having a flat plate portion connected to the first conductive path and the second conductive path as a second radiating section;
A pair of the first antennas configured symmetrically with respect to the connecting portion with the antenna shaft is provided,
Together with the the one of the first antenna first conductive path is connected, the other high-frequency heating apparatus you characterized in that said second conductive path is connected to the first antenna. Locus of rotation defined by the first radiating part when rotating the antenna shaft, of claims 1 to 3, characterized in that different from the rotation locus defined by the second radiating portion The high frequency heating apparatus as described in any one of Claims . The high-frequency heating device according to any one of claims 1 to 4, wherein a plurality of one or both of the first radiating portion and the second radiating portion are provided. From the connecting portion with the antenna shaft to the connection point between the flat plate portion and the first conductive path, and from the connecting portion with the antenna shaft to the connection point between the flat plate portion and the second conductive path. The high-frequency heating device according to any one of claims 1 to 5, wherein the distance is different from each other. The first conductive path and the second conductive path are connected to positions geometrically shifted by 90 ° with respect to the center of the flat plate portion. The high-frequency heating device described in 1. The phase of the high frequency incident on the second radiating portion from the first conductive path and the phase of the high frequency incident on the second radiating portion from the second conductive path are shifted by approximately 90 °. The high-frequency heating device according to any one of claims 1 to 7.

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