JP2008004331A - Microwave radiation apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a microwave radiation apparatus manufactured at low cost and providing high radiation output. <P>SOLUTION: The microwave radiation apparatus comprises a plurality of microwave generation sources, a plurality of microwave wave guides arranged so that their starting ends are coupled to the microwave generation sources and their terminal ends gather at one point, and a microwave radiation device arranged at the gathering point of the plurality of microwave guides and gathering and emitting the microwaves emitted from the terminal end of each of the microwave guides to an external space. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a relatively high-power microwave radiation device suitable for uses such as high-frequency dielectric heating.

Conventionally, a microwave radiation device having a relatively large output has been adopted for uses such as drying of wood by high-frequency dielectric heating, processing of food, sputtering and vapor deposition in a semiconductor process. As a microwave generation source used in such a microwave radiation device, a magnetron is usually used (see Patent Document 1).
JP 2001-250671 A

  This type of microwave source, when its rated output exceeds a certain value, its price increases rapidly, and the design of the peripheral control circuit tends to be complicated, and as a result, the entire microwave radiation device Cost increase.

  Under such a background, the present inventors can synthesize a plurality of outputs of relatively inexpensive low-power microwave generation sources rather than using one expensive microwave generation source. The idea was that the entire microwave radiation device could be manufactured at low cost.

  However, when trial production was repeated based on the above idea, microwaves generated from a plurality of microwave generation sources were merged into one common waveguide through respective dedicated waveguides. When a configuration is adopted in which the microwave is guided to the microwave radiator via the single common waveguide after the merging, and finally radiated from the microwave radiator to the external space, the reflection of the microwave at the merging point A problem was found that a sufficiently strong radiation output could not be obtained from the microwave radiator.

  The present invention has been made under such a technical background, and an object of the present invention is to provide a microwave radiation device that can be manufactured at a low cost and can obtain a high radiation output. There is to do.

  Still other objects and operational effects of the present invention will be easily understood by those skilled in the art by referring to the following description of the specification.

  In order to solve the above problems, the inventors of the present application propose a microwave radiation device having the following configuration.

  That is, the microwave radiation device includes a plurality of microwave generation sources, a plurality of microwave waveguides arranged such that the start ends are connected to the microwave generation sources and the end ends are gathered at one point, A microwave radiator at a set point of a plurality of microwave waveguides, which collects microwaves emitted from the end of each microwave waveguide and discharges them to the external space. .

  According to such a configuration, by arranging the microwave radiators at the collection point of the plurality of microwave waveguides, it is possible to reflect and reflect the microwaves between each microwave generation source and the common microwave radiator. Attenuation was reduced, and as a result, it was possible to obtain a sufficiently strong microwave radiation output from the microwave radiator.

  At this time, the microwave radiator may have a microwave mixing chamber having a front surface opened to an external space and a back surface and a peripheral side surface closed. On the peripheral side wall of the microwave mixing chamber, a microwave discharge port corresponding to the end of each microwave waveguide is formed so as to be positioned so as to avoid mutual opposition.

  According to such a configuration, while reducing the reflection at the end of each waveguide, the microwaves emitted from each end are directed in the same direction, thereby having a relatively uniform intensity distribution. Microwave radiation output can be obtained.

  In addition, there is a reflector at the center of the back wall of the microwave mixing chamber that bends the traveling direction of the microwaves emitted from the microwave outlets opened in the peripheral side wall toward the external space. May be. According to such a configuration, the directivity of the microwave output or the uniformity of the intensity distribution can be enhanced in combination with the action of the reflector.

  Further, the microwave mixing chamber may be circular in front view, the back wall surface may be flat, and the reflector may be a bowl. According to such a configuration, the microwave mixing chamber has a peripheral side wall along the circumference, so that the microwaves emitted from the end of each waveguide are on the peripheral side wall surface, the back wall surface, and the reflector. Both are affected under the same conditions, and the directivity of microwave output and the uniformity of intensity distribution can be further improved.

  In addition, when the three orthogonal axes constituting the three-dimensional space are the X axis, the Y axis, and the Z axis, all of the plurality of microwave waveguides and the microwave radiators are arranged on the same XY plane, The microwave emitted from the microwave radiator to the external space may be emitted in the Z-axis direction. According to such a configuration, it is possible to reduce the thickness of the entire apparatus, and it is easy to incorporate it into various apparatuses.

  According to the present invention, it is possible to provide a microwave radiation device that can be manufactured at a low cost and can obtain a high radiation output.

  Hereinafter, a preferred embodiment of a microwave radiation device according to the present invention will be described in detail with reference to the accompanying drawings.

  The basic configuration of the microwave radiation device of the present application is shown in FIG. In the figure, MG1, MG2, and MG3 are microwave generation sources (eg, magnetrons), WG1, WG2, and WG3 are waveguides, MH is a microwave radiator, and MW is a microwave.

  As is apparent from the figure, the microwave radiation device of the present invention includes a plurality of microwave generation sources MG1, MG2, and MG3, and a plurality of microwave waveguides WG1, WG2, connected to the microwave generation sources. WG3 and microwave radiator MH are included. Here, the microwave waveguides WG1, WG2, and WG3 are arranged so that the start ends are connected to the microwave generation sources MG1, MG2, and MG3, and the ends are gathered at one point. Further, the microwave radiator MH is located at an aggregation point of a plurality of microwave waveguides WG1, WG2, and WG3, collects microwaves emitted from the end of each microwave waveguide, and forms a microwave output MW as an external space. To be released.

  Next, a perspective view (No. 1) showing the microwave radiator and the peripheral structure is shown in FIG. In this example, the microwave radiator MH has a rectangular parallelepiped microwave mixing chamber 10 having a square shape in front view and a depth corresponding to the thickness of the waveguide.

  The back side of the microwave mixing chamber 10 is closed by a back wall 10a, and the left side and the bottom side are closed by a left side wall 10b and a bottom wall 10c. On the other hand, the upper surface side and the right side surface side are an upper surface opening 10d and a right surface opening 10e corresponding to the emission ports of the first waveguide WG1 and the second waveguide WG2.

  According to the above configuration, the microwaves MW1 and MW2 generated from the two microwave generation sources MG1 and MG2 are guided to the microwave mixing chamber 10 by the two microwave waveguides WG1 and WG2, respectively. It is guided. Here, the microwaves emitted from the microwave emission port of the first waveguide WG1 and the microwave emission port of the second waveguide WG2 into the microwave mixing chamber 10 face the back wall 10a. It is guided by the left side wall 10b or the lower wall 10c, changes its direction in the Z-axis direction in the figure, and is discharged into the external space. At this time, the reflected wave returning from each waveguide is reduced due to the structure of the microwave mixing chamber 10.

  FIG. 3 shows a graph (No. 1) showing the ratio of the backflow of the microwave reflected wave at this time for each waveguide. In the figure, the vertical axis is the ratio of the reflection component, the horizontal axis is the frequency of the introduced microwave, a is the reflection component that is radiated from the first waveguide WG1 and then returned to the first waveguide WG1, b Is a reflection component that enters the first waveguide WG1 after radiating from the second waveguide WG2, and c enters the second waveguide WG2 after radiating from the first waveguide WG1. The reflection component d is a reflection component that is radiated from the second waveguide WG2 and then returned to the second waveguide WG2. In the figure, although it seems that there are only two graphs, a and d, and b and c show exactly the same tendency, so the lines overlap.

  That is, as is apparent from the graph in the figure, when a microwave having a frequency of 2.45 GHz is introduced, the reflection component a radiated from the first waveguide WG1 and then returned to the first waveguide WG1 is approximately 0.18, the reflection component b entering the first waveguide WG1 after being radiated from the second waveguide WG2 is about 0.70, the second after being radiated from the first waveguide WG1 The reflection component c that enters the waveguide WG2 is approximately 0.70, and the reflection component d that is radiated from the second waveguide WG2 and returns to the second waveguide WG2 is approximately 0.18. Here, the square of the numerical value on the vertical axis means the reflectance (%) for the introduced microwave. As is clear from this, according to such a structure of the microwave radiator, microwaves can be efficiently radiated to the external space.

  Next, another example of the microwave radiator and the peripheral structure is shown in FIG. In this example, the microwave radiator MH includes a bowl-shaped microwave mixing chamber 10 having a circular shape in front view and a depth corresponding to the thickness of the waveguide.

  The back side of the microwave mixing chamber 10 is closed by a back wall 10a, and from the left side to the bottom side is closed by an annular peripheral wall 10f. On the other hand, the upper surface side and the right side surface side are an upper surface opening 10g and a right surface opening 10h corresponding to the emission ports of the first waveguide WG1 and the second waveguide WG2.

  According to the above configuration, the microwaves MW1 and MW2 generated from the two microwave generation sources MG1 and MG2 are guided to the microwave mixing chamber 10 by the two microwave waveguides WG1 and WG2, respectively. It is guided. Here, the microwaves emitted from the microwave outlet of the first waveguide WG1 and the microwave outlet of the second waveguide WG2 into the microwave mixing chamber 10 are the back wall 10a and the annular peripheral wall. It is guided to 10f, changes its direction in the Z-axis direction in the figure, and is discharged into the external space. At this time, the reflected wave returning from each waveguide is reduced due to the structure of the microwave mixing chamber 10.

  FIG. 5 shows a graph (part 2) showing the ratio of the backflow of the microwave reflected wave at this time for each waveguide. In the figure, the vertical axis is the ratio of the reflection component, the horizontal axis is the frequency of the introduced microwave, a is the reflection component that is radiated from the first waveguide WG1 and then returned to the first waveguide WG1, b Is a reflection component that enters the first waveguide WG1 after radiating from the second waveguide WG2, and c enters the second waveguide WG2 after radiating from the first waveguide WG1. The reflection component d is a reflection component that is radiated from the second waveguide WG2 and then returned to the second waveguide WG2. In the figure, although it seems that there are only two graphs, a and d, and b and c show exactly the same tendency, so the lines overlap.

  That is, as is apparent from the graph in the figure, when a microwave having a frequency of 2.45 GHz is introduced, the reflection component a radiated from the first waveguide WG1 and then returned to the first waveguide WG1 is approximately 0.18, the reflection component b entering the first waveguide WG1 after being radiated from the second waveguide WG2 is about 0.08, the second after being radiated from the first waveguide WG1 The reflection component c that enters the waveguide WG2 is about 0.08, and the reflection component d that is radiated from the second waveguide WG2 and returns to the second waveguide WG2 is about 0.18. Here, the square of the numerical value on the vertical axis means the reflectance (%) for the introduced microwave. As is clear from this, according to the structure of FIG. 4, there are fewer reflection components than in the example of FIG.

  Next, still another example of the microwave radiator and the peripheral structure is shown in FIG. In this example, the microwave radiator MH includes a bowl-shaped microwave mixing chamber 10 having a circular shape in front view and a depth corresponding to the thickness of the waveguide.

  The back side of the microwave mixing chamber 10 is closed by a back wall 10a, and a hemispherical bowl-shaped reflector 10i raised in the Z-axis direction is provided on the back wall 10a. Further, the rear wall 10a is closed by the annular peripheral wall 10f from the left side surface to the lower surface side. On the other hand, the upper surface side and the right side surface side are an upper surface opening 10g and a right surface opening 10h corresponding to the emission ports of the first waveguide WG1 and the second waveguide WG2.

  According to the above configuration, the microwaves MW1 and MW2 generated from the two microwave generation sources are guided to the microwave mixing chamber 10 by being guided by the two microwave waveguides WG1 and WG2, respectively. . Here, the microwaves emitted from the microwave emission port of the first waveguide WG1 and the microwave emission port of the second waveguide WG2 into the microwave mixing chamber 10 are the back wall 10a and the back wall. It is guided by the bowl-shaped reflector 10i provided in 10a and the annular peripheral wall 10f, changes its direction in the Z-axis direction in the figure, and is emitted to the external space. At this time, the reflected wave returning from each waveguide is reduced due to the structure of the microwave mixing chamber 10.

  FIG. 7 shows a graph (No. 3) showing the ratio of the backflow of the microwave reflected wave at this time for each waveguide. In the figure, the vertical axis is the ratio of the reflection component, the horizontal axis is the frequency of the introduced microwave, a is the reflection component that is radiated from the first waveguide WG1 and then returned to the first waveguide WG1, b Is a reflection component that enters the first waveguide WG1 after radiating from the second waveguide WG2, and c enters the second waveguide WG2 after radiating from the first waveguide WG1. The reflection component d is a reflection component that is radiated from the second waveguide WG2 and then returned to the second waveguide WG2. In the figure, it seems that there are only two graphs, but a and d and b and c show exactly the same tendency, so the lines overlap.

  That is, as is apparent from the graph in the figure, when a microwave having a frequency of 2.45 GHz is introduced, the reflection component a radiated from the first waveguide WG1 and then returned to the first waveguide WG1 is approximately 0.02, the reflection component b entering the first waveguide WG1 after being radiated from the second waveguide WG2 is about 0.05, and the second after being radiated from the first waveguide WG1 The reflection component c that enters the waveguide WG2 is approximately 0.05, and the reflection component d that is radiated from the second waveguide WG2 and returns to the second waveguide WG2 is approximately 0.02. Here, the square of the numerical value on the vertical axis means the reflectance (%) for the introduced microwave. As is clear from this, according to the structure of FIG. 6, there are fewer reflection components than in the examples of FIGS. 2 and 4, and microwaves can be radiated more efficiently to the external space.

  Next, still another example of the microwave radiator and the peripheral structure is shown in FIG. In this example, the microwave radiator MH includes a bowl-shaped microwave mixing chamber 10 having a circular shape in front view and a depth corresponding to the thickness of the waveguide.

  The back side of the microwave mixing chamber 10 is closed by a back wall 10a, and a hemispherical bowl-shaped reflector 10i raised in the Z-axis direction is provided on the back wall 10a. The rear wall 10a is closed by the annular peripheral wall 10f from the left side to the right side. On the other hand, for the left upper surface side, upper surface side, and right upper surface side, the upper left opening 10k corresponding to the emission port of the first waveguide WG1, the second waveguide WG2, and the third waveguide WG3, the upper opening 10j and upper right opening 10l.

  According to the above configuration, the microwaves MW1, MW2, and MW3 generated from the three microwave generation sources are guided by the three microwave waveguides WG1, WG2, and WG3, respectively, and are mixed in the microwave mixing chamber 10. Led to. Here, the microwave mixing chamber 10 through the microwave emission port 10k of the first waveguide WG1, the microwave emission port 10j of the second waveguide WG2, and the microwave emission port 10l of the third waveguide WG3. Microwaves emitted inwardly are guided by the back wall 10a, the saddle-shaped radiant pair 10i provided on the back wall 10a, and the annular peripheral wall 10f, and turn in the Z-axis direction in the figure to the external space. And released. At this time, the reflected wave returning from each waveguide is reduced due to the structure of the microwave mixing chamber 10.

  Next, still another example of the microwave radiator and the peripheral structure is shown in FIG. In this example, the microwave radiator MH includes a bowl-shaped microwave mixing chamber 10 having a circular shape in front view and a depth corresponding to the thickness of the waveguide.

  The back side of the microwave mixing chamber 10 is closed by a back wall 10a, and a hemispherical bowl-shaped reflector 10i raised in the Z-axis direction is provided on the back wall 10a. Further, side portions other than the openings described later are closed by an annular peripheral wall 10f provided along the edge of the back wall 10a. On the other hand, for the left upper surface side, upper surface side, right upper surface side, left lower surface side, and right lower surface side, the first waveguide WG1, the second waveguide WG2, the third waveguide WG3, The upper left opening 10k, the upper opening 10j, the upper right opening 10l, the lower left opening 10m, and the lower right opening 10n corresponding to the emission openings of the fourth waveguide WG4 and the fifth waveguide WG5.

  According to the above configuration, the microwaves MW1, MW2, MW3, MW4, and MW5 generated from the five microwave generation sources are respectively generated by the five microwave waveguides WG1, WG2, WG3, WG4, and WG5. Guided to the microwave mixing chamber 10. Here, the microwave emission port 10k of the first waveguide WG1, the microwave emission port 10j of the second waveguide WG2, the microwave emission port 101 of the third waveguide WG3, and the fourth waveguide. The microwaves emitted from the microwave outlet 10m of the tube WG4 and the microwave outlet 10n of the fifth waveguide WG5 into the microwave mixing chamber 10 are provided on the back wall 10a and the back wall 10a. Guided by the radial radiation pair 10i and the annular peripheral wall 10f, the direction is changed in the Z-axis direction in the figure, and the gas is discharged into the external space. At this time, the reflected wave returning from each waveguide is reduced due to the structure of the microwave mixing chamber 10.

  Next, a manufacturing example (rear view) of the microwave radiation device of the present application is shown in FIG. The example shown in FIG. 10 corresponds to the rear surface of the structure example of FIG. 6. In FIG. 10, MG1 and M2 are microwave generation sources, WG1 and WG2 are microwave waveguides, MH is a microwave radiator, and 10a is a rear wall. 10f is an annular peripheral wall, and 10i is a bowl-shaped reflector.

  The microwaves generated by the microwave generation sources MG1 and MG2 are guided to the microwave radiator MH through the microwave waveguides WG1 and WG2, respectively, and are emitted to the external space in the back direction of the drawing.

  According to the present invention, it is possible to provide a microwave radiation device that can be manufactured at a low cost and can obtain a high radiation output.

It is a figure which shows the basic composition of the microwave radiation apparatus of this application. It is a perspective view (the 1) which shows a microwave radiator and peripheral structure. It is the graph (the 1) which shows the ratio which the microwave reflected wave flows backward for every waveguide. It is a perspective view (the 2) which shows a microwave radiator and peripheral structure. It is the graph (the 2) which shows the ratio which the microwave reflected wave flows backward for every waveguide. It is a perspective view (the 3) which shows a microwave radiator and peripheral structure. It is the graph (the 3) which shows the ratio which the microwave reflected wave flows backward for every waveguide. It is a perspective view (the 4) which shows a microwave radiator and peripheral structure. It is a perspective view (the 5) which shows a microwave radiator and peripheral structure. It is a figure (rear view) which shows the manufacture example of this invention apparatus.

Explanation of symbols

MG1-5 Microwave generation source WG1-5 Waveguide MH Microwave radiator MW Microwave output MW1-5 Microwave input 10 Microwave mixing chamber 10a Back wall 10b Left side wall 10c Bottom wall 10f Annular peripheral wall 10i Spiral reflector 10d, 10e, 10g, 10h, 10k, 10j, 10l, 10m, 10n opening

Claims (5)

A plurality of microwave sources;
A plurality of microwave waveguides arranged such that a start end is connected to a microwave generation source and a termination is gathered at one point;
A microwave radiator at a set point of a plurality of microwave waveguides, which collects microwaves emitted from the end of each microwave waveguide and discharges them to the external space; A microwave radiation device. Microwave radiator
A microwave mixing chamber having a front surface opened to an external space and a back surface and a peripheral side surface closed,
A microwave discharge port corresponding to the end of each microwave waveguide is formed in the peripheral side wall of the microwave mixing chamber so as to be positioned so as to avoid mutual opposition, and is formed. The microwave radiation device according to claim 1.   In the center of the back wall of the microwave mixing chamber, there is a reflector that bends the traveling direction of the microwaves emitted from the microwave outlets opened in the peripheral side wall to the external space side. The microwave radiation device according to claim 2.   The microwave radiation device according to claim 3, wherein the microwave mixing chamber is circular in front view, the back wall surface is flat, and the reflector is a bowl-shaped body.   When the three orthogonal axes constituting the three-dimensional space are the X-axis, Y-axis, and Z-axis, all of the plurality of microwave waveguides and the microwave radiator are arranged on the same XY plane, and the microwave The microwave radiation device according to any one of claims 1 to 4, wherein the microwave emitted from the radiator to the external space is emitted in the Z-axis direction.

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