JP2006286588A - Microwave or electromagnetic wave irradiator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem wherein a conventional microwave or electromagnetic wave irradiator has not uniformly irradiated an irradiated object with microwaves or electromagnetic waves or with a specified power distribution. <P>SOLUTION: A part of the microwaves or electromagnetic waves emitted from a linear antenna is reflected by a reflector to reach the irradiated object and the rest of it directly reaches the irradiated object. By using the interference of waves of the reflection components and the direct components, microwaves or electromagnetic waves can be made to have a uniform or specific power distribution in the irradiated object. The irradiated object is positioned with a cover that is brought into contact with the irradiated object, and it can be always irradiate with a similar power distribution. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a microwave or electromagnetic wave irradiation apparatus used for plasma generation, chemical reaction, or heating of a substance.

  As a conventional microwave or electromagnetic wave irradiation apparatus, for example, a method using a microwave oven for cooking shown in FIG.

  However, according to the above technique, the radiated microwave or electromagnetic wave does not reach the irradiated object evenly or with a specific power distribution desired by the user. For example, in the case of the microwave oven shown in FIG. 2, as a result of microwaves or electromagnetic waves being irregularly reflected in the apparatus and reaching the object to be irradiated, unevenness in the irradiation effect may be undesirably generated.

Therefore, an object of the present invention is to provide a microwave or electromagnetic wave irradiation apparatus that can irradiate an object to be irradiated with a microwave or electromagnetic wave with a flat or specific power distribution.

  In order to solve the above problems, the present invention provides a reflector having a parabolic cross-sectional shape, a microwave or electromagnetic radiation antenna fixed at a position including the focal point of the parabola, and an object to be irradiated with respect to the reflector. It is characterized in that it is provided with a mechanism for closely contacting or passing through.

  According to the present invention, a part of the microwave or electromagnetic wave radiated from the antenna is reflected by the reflector and reaches the irradiated object, and the other part reaches the irradiated object directly. By utilizing wave interference between these reflection components and direct components, the power of microwaves or electromagnetic waves in the irradiated object can be made flat or have a specific distribution. In addition, since microwaves or electromagnetic waves reach the irradiated object with at most one reflection, unexpected irregular reflection can be avoided.

FIG. 4 shows the path of the reflected component of the microwave or electromagnetic wave. The amplitude of the electromagnetic field attenuates in inverse proportion to the square of the distance from the antenna to the reflection point, and reaches from the reflection point to the irradiated object as a plane wave without being attenuated. As a result, power distribution is large near the center of the object to be irradiated and power is small in the peripheral portion. The phase of the electromagnetic field of the reflection component is equal on the surface on which the object is irradiated.

FIG. 5 shows the path of the direct component of microwaves or electromagnetic waves. The amplitude of the electromagnetic field attenuates in inverse proportion to the square of the distance from the antenna to the irradiated object, and varies depending on the position on the irradiated object. The phase of the electromagnetic field of the direct component is proportional to the distance from the antenna to the irradiated object, and takes a different value depending on the position on the irradiated object.

As shown in FIG. 6, at the position of the irradiated object, the wave of the reflection component and the direct component are superimposed and interference occurs. The distribution of interference is determined by the wavelength of the microwave or electromagnetic wave, the distance from the top of the parabola to the focal point, and the distance and angle from the reflector to the irradiated object. The shape of the parabola is uniquely determined from the distance between the apex of the parabola and the focal point.

For example, FIG. 7 shows the result of calculating the power distribution of the microwave irradiated to the non-irradiated object, assuming that the wavelength of the microwave is 120 mm, the distance between the parabola apex and the antenna is 46 mm, and the distance between the antenna and the irradiated object is 290 mm. It is. The combined power has a flat distribution and a large power value as compared with the case where only the reflection component or the direct component can be used.

FIG. 8 shows another example, which is a theoretical value of the power distribution when the wavelength of the microwave is 120 mm, the distance between the parabola apex and the antenna is 61 mm, and the distance between the antenna and the irradiated object is 290 mm. The combined power has a distribution having maximum points at two locations on the irradiated object.

The positional relationship between the reflector and the irradiated object is maintained by the mechanism for bringing the irradiated object into close contact with or passing through a specific position of the reflector opening, and there is an effect that the interference distribution is always kept constant.

  One embodiment of the present invention is shown in FIG. The reflector main body 1 is made of metal and includes a parabolic columnar reflecting surface 7, a planar upper lid 2 and a bottom lid 3, and the inside is hollow.

A hole 6 is formed in the upper lid 2 at a position corresponding to the focal point of the parabola, and a linear antenna 4 having a wavelength of about ¼ wavelength is attached to the position including the focal point. The distance between the apex of the parabola and the antenna is 46 mm, and the distance between the antenna and the irradiated object is 290 mm. The connector 5 is attached to the outside of the upper lid 2, passes through the upper lid 2, and is coupled to the linear antenna.

A glass cover 8 is attached to the opening surface of the cavity of the main body. The cover 8 has a thickness of about 3 mm, and is sufficiently thin with respect to the wavelength 120 mm of the microwave to be irradiated.

"Effect of the embodiment"
According to this embodiment, a microwave having a wavelength of 120 mm fed from the connector 5 is radiated from the linear antenna 4 into the cavity of the main body 1, and a part of the microwave passes through the cover 8 after reflection by the parabolic column wall 7. The other part of the light passes through the cover 8 and directly reaches the irradiated object 9, causing microwave interference at the position of the irradiated object and generating a power distribution.

As shown in FIG. 6, this power distribution has a flat distribution and a large power value as compared with the case where only the reflection component or the direct component can be used. The cover 8 is sufficiently thin and has little influence on the power distribution.

By bringing the cover 8 into close contact with the irradiated object, the irradiated object is positioned, and irradiation can always be performed with the same power distribution. Microwaves can be irradiated to an object to be irradiated having a large area while being translated along the cover 8 in close contact. The cover 8 also has an effect of preventing the irradiated object from entering the main body and damaging the antenna and the reflecting surface.

"Other embodiments"
In the embodiment bear of FIG. 1, the dimensions of the main body and the antenna position are determined so that the power distribution is flat, but in other embodiments, the dimensions are changed, for example, two or more in the irradiation power distribution. You may make it have the number of local maximum points. In the embodiment of FIG. 1, the glass cover 8 is used as a mechanism for closely contacting or rubbing the irradiated object to a specific position of the reflector opening. However, in other embodiments, resin or other insulation is used. It may be a body or other dielectric material. Further, the shape of the cover 8 may be a lattice shape, a net shape, or a shape of only the outer frame, depending on the properties of the irradiated object.

It is a figure which shows one Embodiment of this invention. It is a figure which shows a part of microwave oven as a figure which shows a prior art. It is a figure which shows the reflective path | route to the non-irradiated object of a microwave or electromagnetic waves. It is a figure which shows the direct path | route to the non-irradiation thing of a microwave or electromagnetic waves. It is a figure which shows the interference in the non-irradiated object position of a microwave or electromagnetic waves. It is a figure which shows the example which planarized the electric power distribution in a to-be-irradiated object. It is a figure which shows the example made into the electric power distribution which has two local maximum in a to-be-irradiated object.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Reflector main body 2 Top cover 3 Bottom cover 4 Linear antenna fixed to the position containing the focus of a parabolic column 5 High frequency coaxial connector 6 Hole for connecting a linear antenna and a high frequency coaxial connector 7 Parabolic column-shaped reflecting surface 8 Cover 9 Object to be irradiated 10 Metal housing 11 Waveguide or antenna 12 Object to be irradiated 13 Schematic diagram of microwaves or electromagnetic waves diffusely reflected in the case 14 Schematic diagram of microwaves or electromagnetic waves from the antenna toward the reflection point 15 Reflection points 16 Schematic diagram of microwaves or electromagnetic waves traveling from the reflection point to the irradiated object 17 Schematic diagram of microwaves or electromagnetic waves traveling directly from the antenna to the irradiated object 18 Point 19 where the microwaves or electromagnetic waves arriving through different paths are superimposed Power distribution 20 of the component that reaches the irradiated object via the power of the component that reaches the irradiated object directly from the antenna Distribution 21 Power distribution flattened by superposition 22 Power distribution 23 of the component that reaches the irradiated object via the reflector 23 Power distribution 24 of the component that reaches the irradiated object directly from the antenna Power distribution that has come to have

Claims (1)

A reflector having a parabolic cross-sectional shape, a microwave or electromagnetic wave radiation antenna fixed at a position including the focal point of the parabola, and a mechanism for closely contacting or passing the irradiated object at a specific position with respect to the reflector. A microwave or electromagnetic wave irradiation device.

Images