JP2018032471A - High frequency heating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high frequency heating device capable of burning brown a desired region of a heated object, by controlling microwave energy distribution during surface wave propagation.SOLUTION: A high frequency heating device includes a surface wave transmission unit for propagating a stub periodic structure, with microwaves space propagating from a microwave generation unit as surface wave, and a heating chamber constituted to be able to house the heated object placed closely to the stub periodic structure. A surface wave adjustment unit for changing the propagation direction of the surface wave is disposed between the stub periodic structure of the surface wave transmission unit and the heated object.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a high-frequency heating device using microwaves, and more particularly to a high-frequency heating device that performs heat treatment using surface waves.

  As a device for heat-treating an object to be heated using a microwave, there is a so-called microwave oven. The microwave oven has the great advantage that the heated object can be heated uniformly in a short time, but has the disadvantage that the heated object cannot be burnt. For this reason, for the object to be heated that needs to be burnt, for example, heating cooking is performed in which the object to be heated is directly heated using a heating power such as gas or a heater.

  As a heating device for scoring an object to be heated using a microwave, a configuration using surface wave heating has been proposed (for example, see Patent Documents 1 to 3). Surface wave heating utilizes surface wave mode propagation of microwaves, and is a heating method that burns an object to be heated by microwave energy concentrated in the vicinity of the surface wave transmission line. The microwave energy propagating in the surface wave transmission line in the surface wave transmission line is attenuated exponentially as the distance from the surface wave transmission line is increased. Therefore, the object to be heated needs to be disposed in the vicinity of the surface wave transmission line.

Japanese Patent Laid-Open No. 49-16944 JP-A-5-66019 JP-A-8-210653

  A high-frequency heating apparatus that performs surface wave heating has a configuration in which microwaves generated by microwave generation means are sent to a surface wave transmission line via a waveguide, and the microwave energy is concentrated in the vicinity of the surface wave transmission line. . For this reason, in the surface wave transmission line, it is desired to optimize the distribution of surface wave propagation and to give a desired burn to the object to be heated arranged in the vicinity of the surface wave transmission line.

  The present invention provides a configuration capable of controlling the microwave energy distribution during propagation of surface waves, which has not been considered in conventional high-frequency heating apparatuses that perform surface wave heating, and provides a desired structure for an object to be heated. An object of the present invention is to provide a high-frequency heating device capable of scoring.

One aspect of the high-frequency heating device according to the present invention is:
A microwave generation unit that generates a microwave, and a heating chamber that has a periodic structure for propagating the generated microwave as a surface wave and is configured to accommodate an object to be heated that is disposed in proximity to the periodic structure With
A surface wave adjusting unit is disposed in a region between the periodic structure and the object to be heated to change the propagation direction of the surface wave.

  ADVANTAGE OF THE INVENTION According to this invention, the high frequency heating apparatus which can control the microwave energy distribution in surface wave propagation and can give a desired burn to a to-be-heated object can be provided.

The figure which shows typically the whole structure of the high frequency heating apparatus of Embodiment 1 which concerns on this invention The perspective view which shows the state by which the surface wave adjustment part was arrange | positioned on the stub periodic structure comprised in the high frequency heating apparatus of Embodiment 1 by the surface wave conversion part and the surface wave transmission part. The schematic diagram explaining the electric current flow path and electric field distribution in the stub periodic structure which is a surface wave transmission line in the high frequency heating apparatus of Embodiment 1 The schematic diagram which shows the state by which the to-be-heated object was directly mounted in the protrusion end of the several stub arranged in parallel in the stub periodic structure as a comparative example The schematic diagram which shows the state by which the to-be-heated material is arrange | positioned only a predetermined distance away from the protrusion end of the several stub in a stub periodic structure as a comparative example In the high-frequency heating apparatus of Embodiment 1, the schematic diagram which shows the state by which the surface wave adjustment part was provided in the air layer between a stub periodic structure and a to-be-heated material. In the high-frequency heating apparatus of Embodiment 1, the schematic diagram which shows the state by which the surface wave adjustment part was provided in the air layer between a stub periodic structure and a to-be-heated material. The perspective view which shows the example which comprised the stub periodic structure with the some rod-shaped member in the high frequency heating apparatus of another structure which concerns on this invention.

The high-frequency heating device according to the first aspect of the present invention includes:
A microwave generation unit that generates a microwave, and a heating chamber that has a periodic structure for propagating the generated microwave as a surface wave and is configured to accommodate an object to be heated that is disposed in proximity to the periodic structure With
A surface wave adjusting unit is disposed in a region between the periodic structure and the object to be heated to change the propagation direction of the surface wave.
The high-frequency heating device according to the first aspect configured as described above can perform surface wave propagation with high efficiency and can burn a desired region with respect to an object to be heated with low power consumption.

  The high frequency heating apparatus according to a second aspect of the present invention is the high frequency heating apparatus according to the first aspect, wherein the surface wave adjustment unit covers at least a part of the periodic structure and is disposed immediately below the object to be heated. Good.

  The high-frequency heating device according to a third aspect of the present invention is the high-frequency heating device according to the first or second aspect, wherein the surface wave adjusting unit is formed of a dielectric having a non-linear boundary surface that concentrates or diffuses surface waves. May be.

  A high-frequency heating device according to a fourth aspect of the present invention is the high-frequency heating device according to the first or second aspect, wherein the surface wave adjusting unit is formed of a dielectric having a curved boundary surface that concentrates or diffuses surface waves. May be.

  A high-frequency heating device according to a fifth aspect of the present invention is the high-frequency heating device according to the first or second aspect, wherein the surface wave adjusting unit is formed of a dielectric having a bent boundary surface that concentrates or diffuses surface waves. May be.

  A high-frequency heating device according to a sixth aspect of the present invention is the high-frequency heating device according to the first or second aspect, wherein the surface wave adjusting unit has a surface inclined with respect to a surface on which the surface wave propagates in the periodic structure. You may comprise with the dielectric material which has.

  A high-frequency heating device according to a seventh aspect of the present invention is the object to be heated, in which the object to be heated is placed in the vicinity of the periodic structure in any one of the first to sixth aspects. The surface wave adjusting unit may be configured to be insertable into a gap between the periodic structure and the heated object placing unit.

  The high-frequency heating device according to an eighth aspect of the present invention is the high-frequency heating device according to the seventh aspect, wherein the surface wave adjustment unit includes a plurality of adjustment bodies having different shapes and / or dielectric constants, It may be configured such that at least one adjustment body selected from the plurality of adjustment bodies can be inserted into the gap between the object to be heated placement unit.

  A high-frequency heating device according to a ninth aspect of the present invention is the high-frequency heating device according to any one of the first to eighth aspects, wherein a plurality of stubs having substantially the same configuration are arranged in parallel at a predetermined interval. The periodic structure may be configured by a stub configured as described above.

  Hereinafter, an embodiment of one aspect according to the high-frequency heating device of the present invention will be described with reference to the drawings. In addition, the same code | symbol is attached | subjected to the same element and the description may be abbreviate | omitted when description overlaps. In addition, the drawings schematically show each component as a main component for easy understanding.

  Note that each of the embodiments described below shows an example of the high-frequency heating device of the present invention. For example, numerical values, shapes, configurations, steps, and order of steps shown in the embodiments are only examples. There is no limitation to the present invention. Among the constituent elements in the following embodiments, constituent elements that are not described in the independent claims indicating the highest concept are described as optional constituent elements. In all the embodiments, the configurations in the respective modified examples are the same, and the configurations described in the modified examples can be combined, and the effects of the respective configurations can be achieved.

[Embodiment 1]
FIG. 1 is a diagram schematically showing the overall configuration of the high-frequency heating device according to Embodiment 1 of the present invention. In FIG. 1, the inside of the heating chamber 1 is configured so that an object to be heated 7 can be placed, and a door (not shown) that can be opened and closed is provided at the front opening portion of the heating chamber 1. It is configured to be accommodated. In the configuration of the high-frequency heating device according to the first embodiment, the mounting plate 9 is a heated object mounting portion made of a material that transmits microwaves with low loss to the bottom surface of the heating chamber 1, for example, glass or resin. Can be accommodated. In the configuration shown in FIG. 1, a mounting tray 8 such as a pottery for holding the article 7 to be heated is placed on the mounting plate 9.

  As shown in FIG. 1, in the high frequency heating apparatus of the first embodiment, surface wave heating means is provided facing an opening provided on the bottom surface side of the heating chamber 1. The surface wave heating means includes a microwave generation unit 2 that generates a microwave having a desired frequency suitable for the heat treatment of the object 7 to be heated, and a microwave that spatially propagates from the microwave generation unit 2 to the inside of the waveguide 4. The surface wave conversion unit 5 that converts the surface wave with high efficiency so that the surface wave propagates directly under the heating chamber 1, and the stub periodic structure that propagates the surface wave converted in the surface wave conversion unit 5 directly under the heating chamber 1 And a surface wave transmission unit 6.

  Further, in the high frequency heating apparatus of the first embodiment, a dielectric material such as ceramic, mica, resin, or the like is provided between the mounting plate 9 serving as the bottom surface of the heating chamber 1 and the surface wave transmission unit 6 in the surface wave heating means. The surface wave adjusting unit 12 is provided. In the configuration of the high-frequency heating device according to the first embodiment, a surface wave transmission unit 6 having a stub periodic structure, which is a surface wave transmission line, is provided with a predetermined distance from a mounting plate 9 serving as a bottom surface of the heating chamber 1. An air layer is formed between the stub tip of the surface wave transmission unit 6 and the bottom surface of the mounting plate 9. That is, the surface wave adjustment unit 12 is provided in the air layer, and the surface wave adjustment unit 12 is disposed at a position immediately below the object to be heated 7 accommodated in the heating chamber 1. . Details of the surface wave adjusting unit 12 will be described later.

  The microwave generator 2 is a high-frequency oscillator that generates microwaves having a frequency suitable for the heat treatment for the object 7 to be heated. The microwave generator 2 may be constituted by a magnetron and an inverter power supply circuit, or may be constituted by a solid state oscillator and a power amplifier.

  The output end 3 (antenna) of the microwave generation unit 2 is formed so as to be led out into the waveguide 4, and the microwave radiated from the output end 3 of the microwave generation unit 2 is guided to the waveguide 4. Is transmitted to the surface wave converter 5. The waveguide 4 in the first embodiment is a metal hollow waveguide having a square cross section (for example, a horizontally long rectangle).

  The waveguide 4 supplies the microwave from the microwave generator 2 to the surface wave converter 5. In the surface wave converter 5, the surface wave is transmitted to the surface wave transmission unit 6, which is the next stage, and propagates in the surface wave mode in the periodic structure of the surface wave transmission unit 6.

  FIG. 2 is a perspective view showing a state in which the surface wave adjusting unit 12 is disposed on the stub periodic structure formed by the surface wave converting unit 5 and the surface wave transmitting unit 6 in the high frequency heating apparatus of the first embodiment. . In FIG. 2, the surface wave conversion unit 5 and the surface wave transmission unit 6 are made of a conductor, and a plurality of metal flat plates, which are plate-like members, are continuously arranged on the metal flat plate with a predetermined interval. The stub periodic structure. The surface wave adjustment unit 12 is disposed so as to cover at least a part of the surface wave transmission unit 6 in the stub periodic structure.

  The surface wave converter 5 is a stub periodic structure in which conversion stubs 10, which are a plurality of plate-like members having different protrusion heights in the vertical direction, are arranged side by side with a predetermined interval, and the protrusion height of the conversion stub 10 ( h), the configuration differs stepwise along the transmission direction of the microwave transmitted from the microwave generation unit 2 through the waveguide 4 (the direction from right to left in FIG. 2), that is, gradually. It is getting higher. The protrusion height (h) of the last conversion stub 10 in the surface wave converter 5, that is, the terminal conversion stub 10 z at the end in the microwave transmission direction, is the protrusion height of the transmission stub 11 in the surface wave transmitter 6 ( Same as H).

  The surface wave transmission unit 6 is provided so that a transmission stub 11 that is a plurality of metal flat plates protrudes in the direction of the heating chamber 1 (projects vertically upward) on the metal plate that is the bottom surface of the surface wave heating means. . The plurality of transmission stubs 11 constituting the surface wave transmission unit 6 have the same shape and configuration and the same protruding height (H). For this reason, the projecting end portions of the plurality of transmission stubs 11 are included in the same plane, and the projecting end portions of the plurality of transmission stubs 11 are constant with respect to the object-to-be-heated object mounting portion serving as the bottom surface of the heating chamber 1. They are arranged at intervals.

  In the high-frequency heating device according to the first embodiment, the conversion stub 10 (first stub) of the surface wave converter 5 and the transmission stub 11 (second stub) of the surface wave transmitter 6 transmit microwaves. The width (W), which is the length in the longitudinal direction orthogonal to the direction, that is, the propagation direction of the surface wave, is the same. In the present invention, the conversion stub 10 in the surface wave converter 5 is referred to as a first stub, and the transmission stub 11 in the surface wave transmitter 6 is referred to as a second stub. In the surface wave converter 5, a stub periodic structure configured by arranging a plurality of conversion stubs 10 (first stubs) in parallel is defined as a first stub periodic structure. In the surface wave transmission unit 6, a stub periodic structure formed by arranging a plurality of transmission stubs 11 (second stubs) side by side with a predetermined interval is referred to as a second stub periodic structure.

  As shown in FIG. 2, the surface wave adjustment unit 12 disposed so as to cover at least a part of the surface wave transmission unit 6 has a curved configuration and is lifted to the heating chamber side, that is, vertically upward. And has a quadric surface shape. The surface wave adjustment unit 12 according to the first embodiment is described as a shape having a quadratic curved surface of a developable surface that becomes a curve when cut in the propagation direction of the surface wave. However, the direction is perpendicular to the propagation direction of the surface wave. Even when cut by a step, the shape may be a three-dimensional curved surface that is not a developable surface that is a curve. The shape of the surface wave adjusting unit 12 includes a dielectric having a non-linear outer surface (boundary surface), a dielectric having a curved outer surface (boundary surface), a dielectric having a bent outer surface (boundary surface), and / or Various shapes such as a dielectric having a surface inclined with respect to the same plane including a plurality of stub tips in the stub periodic structure of the surface wave transmission unit 6 can be used. In addition, the shape of the surface wave adjusting unit 12 is appropriately selected in consideration of the shape and configuration of the object to be heated 7 to be heat-treated in the heating chamber 1 and the state of charred.

  In the high-frequency heating device according to the first embodiment, the surface wave adjustment unit 12 is a gap (air layer) between the stub periodic structure of the surface wave transmission unit 6 and the mounting plate 9 serving as the bottom surface of the heating chamber 1. It is configured to be mounted at a predetermined position. In the configuration of the first embodiment, the vertical distance between the stub tip of the surface wave transmission unit 6 and the bottom surface of the article 7 to be heated is preferably in the range of several mm. The gap (air layer) between the stub tip of the stub periodic structure on which the surface wave adjusting unit 12 is mounted and the lower surface of the heated object placing unit is about 1 mm. Further, the thickness of the sheet-like surface wave adjusting section 12 is preferably a mica plate of about 0.3 mm, and the curvature is about 0.3 mm.

  Next, the function of the surface wave adjustment unit 12 provided so as to cover at least a part of the stub periodic structure in which the surface wave is propagated in the surface wave heating means in the high frequency heating apparatus of the first embodiment will be described.

  FIG. 3 is a schematic diagram for explaining a current flow path and an electric field distribution generated in the stub periodic structure 13 which is a surface wave transmission line. As shown in FIG. 3, a current flow path is formed in the stub periodic structure 13, and the start end and the end of the current flow path are near the tip of the stub 14. In the vicinity of the stub tip, the potential is reversed, and an electric field is distributed between the stub tips having different potentials. The length of the current flow path formed in the stub periodic structure 13 is ½ of the wavelength (λ) of the microwave. For this reason, the height of the transmission stub 11 which is the second stub in the surface wave transmission unit 6 is λ / 4 or less.

  4 and 5 are diagrams schematically showing a comparative example. FIG. 4 shows a state where the protruding ends of the plurality of stubs 14 arranged in parallel in the stub periodic structure 13 and the object 7 to be heated are placed in direct contact. FIG. 5 shows a state in which the protruding ends of the plurality of stubs 14 arranged in parallel in the stub periodic structure 13 and the object 7 to be heated are placed with a gap therebetween. In the stub periodic structure, the surface wave propagates through the surface wave line of the stub periodic structure 13 by an electric field generated in the vicinity of the stub tip. The microwave energy of the surface wave propagating is distributed in the vicinity of the tip of the stub 14 and decreases exponentially with increasing distance. Therefore, the heated object 7 is heated more strongly as it approaches the tip of the stub 14.

  As shown in FIG. 4, in the state in which the object 7 to be heated is in direct contact with the tip which is the protruding end of the stub 14 and placed, the surface wave propagated through the stub periodic structure 13 and the object 7 to be heated The microwave energy is intensively absorbed by the article 7 to be heated at the contact portion. In this way, only the portion 7a where the surface wave propagation of the heated object 7 is concentrated is heated and burnt. In addition, since much microwave energy is absorbed by the concentrated portion 7a, the tip is hardly heated, and extreme heating unevenness occurs in the article 7 to be heated.

  FIG. 5 shows a state in which the object to be heated 7 is arranged through a space layer at a predetermined distance from the tips of the plurality of stubs 14 in the stub periodic structure 13. As shown in FIG. 5, when a gap (air layer) is formed between the stub periodic structure 13 of the surface wave transmission line and the object 7 to be heated, a path through which the surface wave propagates can be secured, The object to be heated 7 can be subjected to a scorching process with little unevenness in a wide range 7b.

  In the high-frequency heating device according to the first embodiment of the present invention, the surface wave adjusting unit 12 is provided in the gap (air layer) between the stub periodic structure 13 and the article 7 to be heated. FIG. 6 shows a curved surface that swells toward the heating chamber (vertically upward) in the gap (air layer) between the stub periodic structure 13 and the object 7 to be heated in the configuration of the high-frequency heating device of the first embodiment. The state in which the wave adjustment part 12 (12a) was provided is shown typically. FIG. 7 schematically shows a state in which a curved surface wave adjustment unit 12 (12b) that swells vertically downward is provided in the gap (air layer) between the stub periodic structure 13 and the object 7 to be heated. ing.

  In the configuration shown in FIGS. 6 and 7, when the surface wave adjustment unit 12 is not provided, the surface that propagates by optimally selecting the gap (air layer) between the stub periodic structure 13 and the object 7 to be heated. By the waves, the microwave energy is concentrated on the stub tip of the stub periodic structure 13 and is widely distributed in the propagation direction, and the scoring process for the object 7 to be heated can be performed in a wide range. However, when a dielectric having an outer surface (boundary surface) that is not parallel to the same plane including a plurality of stub tips is provided in an air layer (propagation path) through which surface waves propagate, surface waves are reflected and refracted. Due to the reflection and refraction of the surface wave generated at the boundary surface of the dielectric, the distribution of the surface wave propagation is biased.

  The surface wave adjusting unit 12 (12a, 12b) shown in FIGS. 6 and 7 changes the propagation direction by reflecting and refracting the surface wave propagating through the air layer between the stub periodic structure 13 and the object 7 to be heated. The distribution of the microwave energy that propagates the surface wave is changed. By providing the surface wave adjustment unit 12 (12a, 12b) in this way, the propagation direction of the surface wave is changed, the microwave energy distribution is changed, and the heating region of the object to be heated 7 is concentrated at the central portion, for example. It is possible to make a heating region that diffuses in the surrounding area or scorches a desired region.

  In the configuration of the high-frequency heating device according to the first embodiment, the shape of the surface wave adjusting unit 12 is used to concentrate and diffuse the surface wave propagating through the air layer between the stub periodic structure 13 and the article 7 to be heated. Including, for example, a dielectric having a non-linear interface, a dielectric having a curved interface, a dielectric having a bent interface, and / or a plurality of stub tips in a stub periodic structure of a surface wave transmission unit The stub periodic structure 13 is made of a dielectric having a plane inclined with respect to the same plane, and each surface wave adjusting unit 12 is formed according to the shape, material, heating content, cooking content, etc. of the object 7 to be heated. You may comprise so that it can selectively remove | desorb to the clearance gap (air layer) between the to-be-heated objects 7. FIG.

  Further, as an embodiment of another configuration according to the present invention, a plurality of adjusting bodies having different shapes are prepared in advance in the surface wave adjusting unit 12 and / or the dielectric constants in the surface wave adjusting unit 12 are different as described above. A plurality of adjustment bodies made of a dielectric are prepared in advance, and in consideration of the shape, material, heating contents, cooking contents, etc. of the object to be heated 7, from the above-mentioned plurality of adjustment bodies in the surface wave adjustment unit 12 A desired adjustment body may be selected, and the selected adjustment body may be configured to be mounted in a space (air layer) between the stub periodic structure 13 and the article 7 to be heated.

  In the configuration of the above-described embodiment, the gap between the stub periodic structure of the surface wave transmission unit 6 and the mounting plate 9 serving as the bottom surface of the heating chamber 1 has been described as an air layer. In addition, the structure of the present invention can be applied to a structure having a dielectric having a dielectric constant different from that of an adjacent region and having a boundary surface. Moreover, as a structure of a high frequency heating apparatus, the surface wave adjustment part 12 is good also as a structure which serves as the mounting board 9. FIG. Furthermore, as a periodic structure in the high-frequency heating apparatus, an interdigital periodic structure having a metal plate provided with a folding slit may be used.

  Moreover, in said embodiment, the conversion stub 10 (1st stub) of the surface wave converter 5 and the transmission stub 11 (2nd stub) of the surface wave transmission part 6 are made into several plate-shaped members (flat plate). The stub periodic structure configured as described above has been described, but the same effect can be achieved by a stub periodic structure configured by projecting a plurality of rod-shaped members (round columns or prisms) in parallel on a metal flat plate. FIG. 8 is a perspective view showing a stub periodic structure (10, 11) in which the conversion stub 10 of the surface wave conversion unit 5 and the transmission stub 11 of the surface wave transmission unit 6 are composed of rod-shaped members that are a plurality of prisms. In addition, when a stub periodic structure is comprised by the stub of a rod-shaped member in this way, the stub part comprised with one flat plate is arranged by arranging a plurality of rod-shaped members in a line at a predetermined interval. .

  In the high-frequency heating device according to the embodiment of the present invention configured as described above, the microwave energy distribution during surface wave propagation is controlled by the stub periodic structure of the surface wave transmission unit, and the object to be heated is controlled. Thus, it is possible to surely apply the desired distribution of charred.

  Although the present invention has been described in each embodiment with a certain degree of detail, the disclosure content of these embodiments should be changed in details of the configuration, and the combination and order of elements in each embodiment should be changed. Changes may be made without departing from the scope and spirit of the claimed invention.

  The high-frequency heating device of the present invention can control the microwave energy distribution during propagation of the surface wave, and can burn the desired distribution to the object to be heated. Become.

DESCRIPTION OF SYMBOLS 1 Heating chamber 2 Microwave generation part 3 Output part 4 Waveguide 5 Surface wave conversion part 6 Surface wave transmission part 7 Object to be heated 8 Placement plate 9 Placement plate 10 Conversion stub (1st stub)
11 Transmission stub (second stub)
12 Surface wave adjustment part 13 Stub periodic structure 14 Stub

Claims (9)

A microwave generation unit that generates a microwave, and a heating chamber that has a periodic structure for propagating the generated microwave as a surface wave and is configured to accommodate an object to be heated that is disposed in proximity to the periodic structure With
A high-frequency heating apparatus configured to dispose a surface wave adjusting unit in a region between the periodic structure and the object to be heated to change a propagation direction of the surface wave.   The high frequency heating apparatus according to claim 1, wherein the surface wave adjustment unit covers at least a part of the periodic structure and is disposed immediately below the object to be heated.   The high-frequency heating device according to claim 1, wherein the surface wave adjusting unit is configured by a dielectric having a non-linear boundary surface that concentrates or diffuses a surface wave.   The high-frequency heating device according to claim 1, wherein the surface wave adjustment unit is configured by a dielectric having a curved boundary surface that concentrates or diffuses surface waves.   The high-frequency heating device according to claim 1, wherein the surface wave adjusting unit is configured by a dielectric having a bent boundary surface that concentrates or diffuses a surface wave.   The high-frequency heating device according to claim 1, wherein the surface wave adjusting unit is configured by a dielectric having a surface inclined with respect to a surface on which the surface wave propagates in the periodic structure. In proximity to the periodic structure, a heated object placing part for placing the heated object is disposed,
The high-frequency heating device according to any one of claims 1 to 6, wherein the surface wave adjustment unit is configured to be insertable into a gap between the periodic structure and the heated object placement unit.   The surface wave adjustment unit includes a plurality of adjustment bodies having different shapes and / or dielectric constants, and is selected from the plurality of adjustment bodies with respect to a gap between the periodic structure and the heated object placement unit. The high-frequency heating device according to claim 7, wherein at least one adjusting body is insertable.   The high-frequency heating device according to any one of claims 1 to 8, wherein the periodic structure is configured by stubs configured by arranging a plurality of stubs having substantially the same configuration in parallel with a predetermined interval.

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