JP2017224983A - Microwave processing apparatus and coaxial antenna - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a microwave processing apparatus and a coaxial antenna which allow for uniform microwave processing without using a stirrer, and without being limited by the state of a sample or the structure of a chamber.SOLUTION: By providing a reflector 6 formed to surround an antenna part of a coaxial cable 2, and opened in the shape of a half hemisphere, directivity for the opening direction of the reflector 6 can be imparted to the microwave propagation direction. A coaxial antenna conforming to a λ/4 vertical grounding antenna is obtained. A horizontal plane of directivity is in the opening direction of the reflector 6, and a vertical plane is in the shape of the half hemisphere of the reflector 6 and in the opening direction. Furthermore, when providing a rotary mechanism 7 for rotating the reflector 6 around a coaxial core, microwave heating can be performed uniformly without using a stirrer, without being limited by the state of a sample s or the structure of a heating furnace 3.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a microwave processing apparatus and a coaxial antenna that perform microwave processing, and more particularly to a technique for controlling the directivity of microwaves.

  Hereinafter, microwave heating will be described as an example of microwave processing. In general, in microwave heating, a microwave generated from an oscillator such as a magnetron is supplied to a heating furnace (chamber) in which a sample is installed by a waveguide, and the sample is heated by applying the microwave to the sample. .

  When uniformity of heating is required, as shown in FIG. 10, the microwave is diffused by using a stirrer made of metal blades, that is, a stirrer, and the propagation of the microwave applied to the sample is changed. To ensure the uniformity of heating. Note that the stirrer is configured to reflect and scatter microwaves by rotating a shaft to which metal blades are attached. In FIG. 10, symbol O is an oscillator, symbol wg is a waveguide, symbol C is a chamber, symbol S is a stirrer, symbol s Is a sample, the solid line is the microwave in the chamber C propagated from the waveguide wg, and the broken line is the microwave whose propagation is changed by the stirrer S.

  By the way, a normal waveguide is composed of a metal hollow waveguide having a circular or square cross section, and a microwave propagates through the hollow waveguide. In addition, the present applicant has proposed a technique in which a coaxial waveguide having a central conductor and an outer conductor surrounding it from the outside instead of the hollow waveguide is used in a microwave processing apparatus (for example, Patent Documents). 1).

JP2013-098626A

  However, in the case of a waveguide, since it is composed of a metal tube such as aluminum (Al), routing is not easy, and there is a limit to the place where the oscillator is installed. In addition, regardless of the type of waveguide, the state of the sample (shape and physical properties of heating (for example, dielectric constant and dielectric loss tangent)) changes the propagation of microwaves, which may be sufficient depending on the state of the sample (depending on the processing) It may be difficult to ensure uniformity. A chamber represented by a heating furnace or the like, or a larger stirrer size, is easier to ensure uniformity due to the characteristics of microwave processing. That is, when the size of the chamber or the stirrer is large, a combination of various microwaves reflected by the chamber or the stirrer (multi-mode) is obtained.

  Therefore, it is often difficult to ensure uniformity in a small chamber. In addition, in a small chamber, it may be difficult to install a stirrer or a turntable for rotating the sample in terms of space, making it more difficult to ensure uniformity.

  The present invention has been made in view of such circumstances, and is not limited to the state of the sample or the structure of the chamber, and a microwave processing apparatus capable of uniformly performing microwave processing without using a stirrer and An object is to provide a coaxial antenna.

In order to achieve such an object, the present invention has the following configuration.
That is, the microwave processing apparatus according to the present invention is a microwave processing apparatus for performing microwave processing, has a central conductor and an external conductor surrounding it from the outside, a coaxial cable for propagating microwaves, A ground plane electrically connected to the outer conductor, and a chamber for performing microwave processing using microwaves propagated from the coaxial cable in a state where the ground plane is grounded, and an antenna portion of the coaxial cable It is characterized by comprising a reflecting plate formed so as to surround and at least partially opened, and a rotating mechanism for rotating the reflecting plate around the coaxial core of the coaxial cable.

[Operation / Effect] According to the microwave processing apparatus of the present invention, a coaxial cable having a central conductor and an external conductor surrounding it from the outside is used in place of the waveguide, so that the oscillator can be routed by the coaxial cable. The degree of freedom of the installation location is increased. Without a reflector and a rotating mechanism to be described later, a λ / 4 vertical ground antenna consisting of a ground plane electrically connected to the outer conductor of the coaxial cable and a central conductor without the outer conductor of the coaxial cable. Since the outer conductor of the coaxial cable is grounded, the ground plane is brought into a grounded state by electrically connecting the ground plane to the outer conductor.

  The directivity of the λ / 4 vertical ground antenna is omnidirectional in the horizontal plane (plane perpendicular to the coaxial direction) (see Fig. 3) and in the vertical plane (plane parallel to the coaxial direction) in the hemispherical direction. (See FIG. 4). That is, when the λ / 4 vertical ground antenna is used for a microwave processing power supply mechanism, the propagation of the microwave spreads omnidirectionally in the space above the ground plane (the side opposite to the coaxial cable side). However, the sample may not be evenly irradiated with microwaves depending on the state of the sample, such as the shape and physical properties of the sample, and the structure of the chamber, and the uniformity of the sample (due to processing) is often not obtained.

  Therefore, in the present invention, by providing a reflecting plate that is formed so as to surround the antenna portion of the coaxial cable and that is at least partially opened, directivity in the direction of the opening of the reflecting plate is provided in the microwave propagation direction. . The coaxial antenna conforms to the λ / 4 vertical ground antenna. In the directivity, the horizontal plane is in the direction of the opening of the reflecting plate, and the vertical plane is in the direction of the opening in the shape of the opening of the reflecting plate. Furthermore, by providing a rotation mechanism that rotates the reflecting plate around the coaxial core of the coaxial cable, the microwave processing can be performed uniformly without using a stirrer without being limited to the sample state or the chamber structure.

  The microwave processing apparatus according to the present invention described above preferably includes a radome that protects the antenna portion of the coaxial cable. For the radome, for example, glass fiber or fluororesin is used as a dielectric having high radio wave transmittance such as microwaves. Of course, the radome need not necessarily be provided.

  When a radome is provided, there are the following modes. In this embodiment, the reflector is provided on the outer periphery of the radome (the former embodiment), and conversely, the reflector is provided on the inner periphery of the radome (the latter embodiment). In the case of the latter mode, since there is a radome on the outer periphery of the reflector, it is possible to prevent particles from entering the reflector from the outside of the radome. Further, as a mode combining the former mode and the latter mode, the radome is composed of an inner circumferential radome and an outer circumferential radome surrounding it from the outer circumference, and a reflector is disposed on the outer circumference of the inner circumferential radome and on the inner circumference of the outer circumferential radome. It is an aspect to provide.

  The above-described microwave processing apparatus according to the present invention includes control means for controlling the rotation speed of the reflecting plate by the rotation mechanism. The control means controls the reflector to rotate at a constant speed, and when performing microwave processing while rotating the reflector at a constant speed, or the controller means to rotate the reflector while variably controlling the rotation speed. Controlling and performing microwave processing while rotating the reflecting plate at a predetermined rotational speed at a predetermined portion, and (a) rotating the reflecting plate at a speed lower than the predetermined rotational speed except for the predetermined portion, or (B) Useful when performing microwave processing after being temporarily stopped.

  When microwave processing is performed while rotating the reflecting plate at a constant speed, a directivity characteristic equivalent to that of a λ / 4 vertical ground antenna is obtained as time integration, so that microwave processing can be performed uniformly on the sample. On the other hand, even if non-uniformity (due to processing) occurs with respect to the sample due to the state of the sample or the structure of the chamber, the reflector is rotated at a predetermined rotational speed at a predetermined portion so that the opening is directed to the non-uniform portion. In addition to performing the microwave processing while rotating in step (a), the microwave processing is performed by rotating the reflector at a speed lower than the predetermined rotation speed, or (b) temporarily stopping at a portion other than the predetermined portion. Do. As a result, a lot of microwaves can be propagated in the direction of the portion where the non-uniformity has occurred, and thus irradiated, and the microwave processing can be selectively performed on the portion where the non-uniformity has occurred. On the other hand, the microwave treatment can be performed uniformly.

  The coaxial antenna according to the present invention includes a central conductor and an outer conductor that surrounds the central conductor, and includes a coaxial cable for propagating microwaves and a ground plane that is electrically connected to the outer conductor. And a reflection plate formed so as to surround the antenna portion of the coaxial cable and having at least a part opened, and a rotation mechanism for rotating the reflection plate around the coaxial center of the coaxial cable. Is.

  [Operation / Effect] The coaxial antenna according to the present invention is the same as the above-described microwave processing apparatus according to the present invention, except that a chamber for performing microwave processing is not provided. That is, by providing a reflecting plate that is formed so as to surround the antenna portion of the coaxial cable and that is at least partially opened, directivity in the direction of the opening of the reflecting plate is given in the propagation direction of the microwave. The coaxial antenna conforms to the λ / 4 vertical ground antenna. In the directivity, the horizontal plane is in the direction of the opening of the reflecting plate, and the vertical plane is in the direction of the opening in the shape of the opening of the reflecting plate. Furthermore, by providing a rotation mechanism that rotates the reflecting plate around the coaxial core of the coaxial cable, the microwave processing can be performed uniformly without using a stirrer without being limited to the sample state or the chamber structure.

  According to the microwave processing device and the coaxial antenna according to the present invention, the reflection plate is formed in the microwave propagation direction by providing the reflection plate that is formed so as to surround the antenna portion of the coaxial cable and that is at least partially opened. Give directivity to the direction of the opening. The coaxial antenna conforms to the λ / 4 vertical ground antenna. In the directivity, the horizontal plane is in the direction of the opening of the reflecting plate, and the vertical plane is in the direction of the opening in the shape of the opening of the reflecting plate. Furthermore, by providing a rotation mechanism that rotates the reflecting plate around the coaxial core of the coaxial cable, the microwave processing can be performed uniformly without using a stirrer without being limited to the sample state or the chamber structure.

It is the schematic of the microwave heating apparatus which concerns on an Example. It is the schematic sectional drawing which expanded the peripheral part of the reflecting plate of FIG. It is the schematic which showed the directivity in the horizontal surface in the conventional (lambda) / 4 vertical ground antenna. It is the schematic which showed the directivity in the vertical surface in the conventional (lambda) / 4 vertical ground antenna. It is the schematic which showed the directivity in the horizontal surface in the directivity control coaxial antenna which concerns on an Example. It is the schematic which showed the directivity in the vertical surface in the directivity control coaxial antenna which concerns on an Example. FIG. 3 is a schematic diagram in which regions are shown in FIG. 2. (A) And (b) is a schematic perspective view of the reflecting plate which concerns on a modification. (A) And (b) is a schematic sectional drawing of the radome and reflector which concern on a modification. It is the schematic of the conventional microwave heating apparatus.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a schematic view of a microwave heating apparatus according to an embodiment, and FIG. 2 is an enlarged schematic cross-sectional view of a peripheral portion of the reflector in FIG. In this embodiment, microwave heating will be described as an example of microwave treatment, and a heating furnace will be described as an example of a chamber.

  In this embodiment, the microwave heating apparatus includes an oscillator 1, a coaxial cable 2, and a heating furnace 3 as shown in FIG. The oscillator 1 oscillates a microwave of 2.45 GHz, for example. As the oscillator 1, for example, a magnetron or a semiconductor oscillator is used. As shown in FIG. 2, the coaxial cable 2 has a center conductor 2A and an outer conductor 2B surrounding the center conductor 2A, and propagates microwaves from the oscillator 1 (see FIG. 1). The heating furnace 3 performs microwave heating using microwaves propagated from the coaxial cable 2 in a state where a later-described ground plane 4 is grounded. The coaxial cable 2 corresponds to the coaxial cable in the present invention, and the heating furnace 3 corresponds to the chamber in the present invention.

  In this embodiment, the coaxial cable 2 is installed at the bottom at the center of the heating furnace 3 as shown in FIG. The heating furnace 3 in FIG. 1 is a rectangular parallelepiped, and by installing the coaxial cable 2 in the center of the heating furnace 3, microwave heating can be uniformly performed regardless of at least the structure of the heating furnace 3.

  In addition, the microwave heating apparatus includes a ground plane 4 (see also FIG. 2), a radome 5 (see also FIG. 2), a reflector 6 (see also FIG. 2), a rotating mechanism 7 and a controller as shown in FIG. 8 and. The ground plane 4 corresponds to the ground plane in the present invention, the radome 5 corresponds to the radome in the present invention, the reflecting plate 6 corresponds to the reflecting plate in the present invention, and the rotating mechanism 7 corresponds to the rotating mechanism in the present invention. The controller 8 corresponds to the control means in the present invention.

  The ground plane 4 is formed of a metal such as stainless steel (SUS), for example, and is electrically connected to the external conductor 2B as shown in FIG. Since the external conductor 2B is grounded, the ground plane 4 is grounded by electrically connecting the ground plane 4 to the external conductor 2B.

  The radome 5 is formed in a hemispherical shape so as to surround the antenna portion of the coaxial cable 2, and thus the radome 5 protects the antenna portion of the coaxial cable 2. For the radome 5, for example, glass fiber or fluororesin is used as a dielectric having a high radio wave transmittance such as a microwave. The radome 5 may be filled or hollow.

  The reflection plate 6 is formed so as to surround the antenna portion of the coaxial cable 2 and at least a part thereof is opened. In the present embodiment, by providing the reflector 6 having a shape divided into half of the hemisphere (sphere is ¼), an opening portion where the portion without the reflector 6 is divided into half of the hemisphere (sphere is ¼) is provided. It becomes. In this embodiment, as shown in FIGS. 1 and 2, a reflector 6 is provided on the outer periphery of the radome 5. The reflector 6 is not particularly limited as long as it is a metal, but is preferably a metal that is easy to process and has heat resistance. For example, the reflection plate 6 may be formed of stainless steel (SUS), aluminum (Al), copper (Cu), or the like.

  The rotating mechanism 7 is configured to rotate the reflecting plate 6 around the coaxial core of the coaxial cable 2. In this embodiment, the rotation mechanism 7 includes a motor 71, a rotation shaft 72, a gear 73, an outer ring 74, a bearing 75, and an inner ring 76 as shown in FIG. The gear 73 is attached to the motor 71 via the rotating shaft 72, and the rack of the outer ring 74 is fitted to the gear 73. The inner ring 76 is fixedly disposed on the ground plane 4, and the outer ring 74 is supported by the inner ring 76 via a bearing 75. The reflecting plate 6 is attached to the outer ring 74, and the gear 73 rotates when the motor 71 is driven via the rotating shaft 72. When the gear 73 rotates, the entire outer ring 74 rotates around the coaxial center of the coaxial cable 2, so that the reflector 6 attached to the outer ring 73 also rotates around the coaxial center of the coaxial cable 2. The rotation mechanism is not limited to the mechanism shown in FIG. For example, a non-contact type rotating mechanism may be used in which the reflecting plate is made of a magnetic material and the magnetic poles are arranged opposite to each other so that the reflecting plate is rotated by magnetism.

  The controller 8 controls the rotation speed of the reflection plate 6 by the rotation mechanism 7. The controller 8 includes a central processing unit (CPU). In the present embodiment, control for rotating the reflecting plate 6 at a constant speed, or control for rotating the reflecting plate 6 while variably controlling the rotating speed as described below. When performing control to rotate the reflecting plate 6 while variably controlling the rotation speed, the microwave processing is performed while rotating the reflecting plate 6 at a predetermined rotation speed at a predetermined portion, and (a ) The microwave processing is performed while rotating the reflector 6 at a speed lower than the predetermined rotation speed or (b) temporarily stopping the reflection plate 6. These controls will be described later in detail with reference to FIG.

  Next, the directivity of each antenna will be described with reference to FIGS. 3 is a schematic diagram showing the directivity in the horizontal plane of the conventional λ / 4 vertical ground antenna, and FIG. 4 is a schematic diagram showing the directivity in the vertical plane of the conventional λ / 4 vertical ground antenna. FIG. 5 is a schematic view showing the directivity in the horizontal plane in the directivity control coaxial antenna according to the embodiment. The axis of FIGS. 3 to 6 is the relative electric field strength, and the symbol O is the center of the antenna.

  As described in the section “Means for Solving the Problems”, the directivity of the conventional λ / 4 vertical ground antenna is as shown in FIGS. As shown in FIG. 3, the horizontal plane (plane orthogonal to the coaxial direction) is omnidirectional, and the vertical plane (plane parallel to the coaxial direction) is directional in the hemispherical direction as shown in FIG.

  On the other hand, in the directivity control coaxial antenna of the present embodiment, the reflector 6 having a shape in which the sphere is divided into ¼ is used (see FIGS. 1 and 2), and therefore there is no reflector. Compared with, the electric power per unit area of the emitted microwave is approximately doubled. Since power is proportional to the square of the electric field strength, if the electric power is doubled, the electric field strength becomes √2 times, and the relative electric field strength is about 1.4 times that of the conventional λ / 4 vertical ground antenna (= (√2 times).

  The directivity of the directivity control coaxial antenna of the present embodiment is as shown in FIGS. As shown in FIG. 5, the horizontal plane (plane orthogonal to the coaxial direction) has directivity in the direction opposite to the reflecting plate 6 (see FIGS. 1 and 2), that is, in the opening direction, and as shown in FIG. The inside of the (plane parallel to the coaxial direction) is half the hemisphere and has directivity in the direction opposite to the reflecting plate 6 (opening direction).

  Next, the microwave heating method of the present embodiment will be described with reference to FIG. 7 together with FIG. FIG. 7 is a schematic diagram in which regions are shown in FIG.

When the sample s having a shape as shown in FIG. 1 is heated, a region surrounded by a thick broken line in FIG. Therefore, the microwave is irradiated in the direction indicated by the arrow in FIG. Therefore, as shown in FIG. 7, a region that is difficult to be heated (that is, a portion where heating non-uniformity occurs) is denoted as _RR, and a region in the reverse direction is denoted as _RL . The region that is difficult to be heated (the portion where the uneven heating has occurred) _RR is on the right side of FIG. 7, and the region _{RL in the} reverse direction is on the left side of FIG.

The heated hard region by setting the (heterogeneous occurs part of the heating) R _R a predetermined portion, the predetermined rotational speed a reflector 6 in a predetermined portion (in FIG. 7 right R _R) (for example, 1 rotation / sec) (A) While rotating the reflector 6 at a speed lower than the predetermined rotation speed except for the predetermined portion (R _L on the left side in FIG. 7), or (b) Temporarily stop and perform microwave heating. That is, when the reflecting plate 6 is positioned at the right _RR , microwave heating is performed while rotating the reflecting plate 6 at a predetermined rotation speed. When the reflector 6 is positioned at the left side _RL , microwave heating is performed while (a) the reflector 6 is rotated at a speed lower than the predetermined rotation speed or (b) is temporarily stopped. . In this way, microwave heating is performed so that the opening is directed to a region that is difficult to be heated.

  In addition, the coaxial cable 2 is provided in the center of a rectangular parallelepiped heating furnace 3 as shown in FIG. 1 when heating a sample having a uniform and symmetrical heating physical property instead of the sample s as shown in FIG. In the case of installation, microwave heating can be performed uniformly regardless of the state of the sample and the structure of the chamber such as the heating furnace 3. However, as described above, it is difficult to install a stirrer or a turntable in a small chamber as described above. Therefore, in order to reliably perform microwave heating without using a stirrer or a turntable, the reflector 6 is set at a constant speed ( For example, microwave heating is performed while rotating at 1 rotation / second).

  Here, although 1 rotation / second was mentioned as an example of a rotational speed, it is not limited to this value. The rotation speed is appropriately set to a predetermined value according to the processing conditions such as the frequency of the microwave, the type and shape of the sample to be subjected to the microwave processing, the structure of the chamber, and the target temperature. Further, the design dimensions of the ground plane 4 (see FIGS. 1 and 2), the radome 5 (see FIGS. 1 and 2), the reflector 6 and the antenna portion are also set appropriately according to the processing conditions described above. . In this embodiment, microwaves of 2.45 GHz are used. However, since the coaxial cable of this embodiment conforms to the λ / 4 vertical ground antenna, the length of the antenna portion is actually λ / 4. It should be noted that the length of the antenna portion is appropriately set according to the surrounding structure (for example, a reflector) and processing conditions.

  According to the microwave processing apparatus according to the present embodiment (microwave heating apparatus in the present embodiment), the coaxial cable 2 having the center conductor 2A and the outer conductor 2B surrounding it from the outside is used instead of the waveguide. Thus, the degree of freedom of the installation location of the oscillator 1 is increased by being routed by the coaxial cable 2. Without the reflector 6 and the rotating mechanism 7, a λ / 4 vertical ground antenna comprising a ground plane 4 electrically connected to the outer conductor 2B of the coaxial cable 2 and a center conductor 2A without the outer conductor 2B of the coaxial cable 2; Become. Since the outer conductor 2B of the coaxial cable 2 is grounded, the ground plane 4 is brought into a grounded state by electrically connecting the ground plane 4 to the outer conductor 2B.

  The directivity of the λ / 4 vertical ground antenna is omnidirectional in the horizontal plane (plane perpendicular to the coaxial direction) (see Fig. 3) and in the vertical plane (plane parallel to the coaxial direction) in the hemispherical direction. (See FIG. 4). That is, when the λ / 4 vertical ground antenna is used as a power supply mechanism for microwave processing, the propagation of the microwave spreads omnidirectionally in the space above the ground plane 4 (the side opposite to the coaxial cable side). However, the sample may not be evenly irradiated with microwaves depending on the state of the sample, such as the shape and physical properties of the sample, and the structure of the chamber (heating furnace 3 in this embodiment). Often not.

  Therefore, in this embodiment, a microwave is provided by providing a reflector 6 formed so as to surround the antenna portion of the coaxial cable 2 and having at least a part of an opening (in this embodiment, a half hemisphere). In the propagation direction, directivity with respect to the direction of the opening of the reflection plate 6 (half the opening of the hemisphere) is given. The coaxial antenna conforms to the λ / 4 vertical ground antenna. In the directivity, the horizontal plane is in the direction of the opening of the reflecting plate 6 (half hemisphere opening), and the vertical plane is in the shape of the opening of the reflecting plate 6 (half hemisphere shape) in the direction of the opening. Furthermore, by providing a rotating mechanism 7 that rotates the reflecting plate 6 around the coaxial core of the coaxial cable 2, it is not limited to the state of the sample or the structure of the chamber (heating furnace 3), and microwave processing is performed without using a stirrer. (Microwave heating) can be performed uniformly.

  As in this embodiment, it is preferable to include a radome 5 that protects the antenna portion of the coaxial cable 2. As described above, for the radome 5, for example, glass fiber or fluororesin is used as a dielectric having a high radio wave transmittance such as a microwave. In this embodiment, as shown in FIGS. 1 and 2, a reflector 6 is provided on the outer periphery of the radome 5.

In this embodiment, as a control means for controlling the rotation speed of the reflecting plate 6 by the rotation mechanism 7, the microwave processing device (microwave heating device) is provided with a controller 8 as shown in FIG. The controller 8 controls the reflector 6 to rotate at a constant speed, and performs microwave processing (microwave heating) while rotating the reflector 6 at a constant speed, or the controller 8 variably controls the rotational speed. The reflector 6 is controlled to rotate, and microwave processing (microwave heating) is performed while rotating the reflector 6 at a predetermined rotational speed at a predetermined portion (R _R on the right side in FIG. 7). Other than the above (R _L on the left side in FIG. 7), (a) microwave processing (microwave heating) while rotating the reflector 6 at a speed lower than the predetermined rotation speed or (b) temporarily stopping the reflection plate 6 Useful when doing.

When microwave processing (microwave heating) is performed while rotating the reflecting plate 6 at a constant speed, a directional characteristic equivalent to that of a λ / 4 vertical ground antenna is obtained as time integration. Heating) can be performed uniformly. On the other hand, even if non-uniformity (due to processing) occurs with respect to the sample due to the state of the sample or the structure of the chamber (heating furnace 3), the predetermined portion (FIG. 7) Then, microwave processing (microwave heating) is performed while rotating the reflecting plate 6 at a predetermined rotation speed with R _R on the right side, and (a) reflection is performed at a portion other than the predetermined portion (R _L on the left side in FIG. 7). While the plate 6 is rotated at a speed lower than the predetermined rotation speed, or (b) is temporarily stopped, the microwave treatment (microwave heating) is performed. Thereby, a lot of microwaves can be propagated in the direction of the part where the non-uniformity has occurred, and hence irradiated, and microwave processing (microwave heating) can be selectively performed on the part where the non-uniformity has occurred. As a result, microwave treatment (microwave heating) can be performed uniformly on the sample.

  Further, the coaxial antenna according to the present embodiment includes the above-described coaxial cable 2, ground plane 4, reflecting plate 6, and rotating mechanism 7. That is, according to the coaxial antenna according to the present embodiment, except that the chamber (heating furnace 3) for performing microwave treatment (microwave heating) and the oscillator 1 and the controller 8 are not provided in the present embodiment, This is the same as the above-described microwave processing apparatus (microwave heating apparatus) according to this example. In other words, the reflection plate 6 is formed so as to surround the antenna portion of the coaxial cable 2 and at least a part of the opening is opened (in this embodiment, the shape is a half of a hemisphere), thereby reflecting in the microwave propagation direction. Directivity is given to the direction of the opening of the plate 6 (the opening of half of the hemisphere). The coaxial antenna conforms to the λ / 4 vertical ground antenna. In the directivity, the horizontal plane is in the direction of the opening of the reflecting plate 6 (half hemisphere opening), and the vertical plane is in the shape of the opening of the reflecting plate 6 (half hemisphere shape) in the direction of the opening. Furthermore, by providing a rotating mechanism 7 that rotates the reflecting plate 6 around the coaxial core of the coaxial cable 2, it is not limited to the state of the sample or the structure of the chamber (heating furnace 3), and microwave processing is performed without using a stirrer. (Microwave heating) can be performed uniformly.

  The present invention is not limited to the above embodiment, and can be modified as follows.

  (1) In the above-described embodiment, the microwave heating is described as an example of the microwave treatment, but the microwave treatment is not limited to the microwave heating as long as it is performed locally. For example, the present invention may be applied to microwave plasma processing (plasma etching, plasma ashing, etc.).

  (2) In the embodiment described above, the coaxial cable 2 is installed at the center of the bottom of the chamber (heating furnace 3 in the embodiment), but the installation location of the coaxial cable is not particularly limited. For example, a coaxial cable may be installed on the ceiling or side of the chamber, or a coaxial cable may be installed on the end other than the center of the chamber. Further, the number of coaxial cables to be installed is not necessarily singular and may be plural. For example, coaxial cables may be installed at the four corners of the chamber.

  (3) In the embodiment described above, the reflecting plate has the shape shown in FIG. 1 and FIG. 2 and the opening portion has a half shape of the hemisphere shown in FIG. 1 and FIG. Is not particularly limited. For example, an opening 6A as shown in the perspective view of FIG. 8A may be provided, or a plurality of openings 6A (two in FIG. 8B) are provided as shown in the perspective view of FIG. 8B. May be. In addition, a cylindrical diaphragm may be provided in the opening so that the microwave is squeezed and irradiated in the direction of the opening.

  (4) Although the radome which protects the antenna part of a coaxial cable was provided in the Example mentioned above, it is not necessary to necessarily provide a radome. Moreover, you may provide the reflecting plate 6 in the inner periphery of the radome 5, as shown to sectional drawing of Fig.9 (a). In the case of FIG. 9A, since the radome 5 is provided on the outer periphery of the reflecting plate, it is possible to prevent particles from entering the reflecting plate from the outside of the radome. Furthermore, you may combine the structure of an Example and the structure of Fig.9 (a). That is, as shown in the cross-sectional view of FIG. 9 (b), the radome includes an inner peripheral radome 5a and an outer peripheral radome 5b surrounding the outer radome 5a from the outer periphery, and the outer periphery of the inner peripheral radome 5a and the inner periphery of the outer peripheral radome 5b. A reflector is provided. The radome 5 in the structure of FIG. 9 may be filled or hollow as described in the embodiment.

2 ... Coaxial cable 2A ... Center conductor 2B ... Outer conductor 3 ... Heating furnace 4 ... Ground plane 5 ... Radome 6 ... Reflector 7 ... Rotating mechanism 8 ... Controller

Claims (9)

A microwave processing apparatus for performing microwave processing,
A coaxial cable for propagating microwaves, having a center conductor and an outer conductor surrounding it from the outside;
A ground plane electrically connected to the outer conductor;
A chamber for performing microwave processing using microwaves propagated from the coaxial cable in a state where the ground plane is grounded,
A reflector formed so as to surround the antenna portion of the coaxial cable, and at least a part of which is opened;
A microwave processing apparatus comprising: a rotating mechanism that rotates the reflecting plate around a coaxial core of the coaxial cable. The microwave processing apparatus according to claim 1,
A microwave processing apparatus comprising a radome for protecting an antenna portion of the coaxial cable. The microwave processing apparatus according to claim 2, wherein
A microwave processing apparatus, wherein the reflector is provided on an outer periphery of the radome. The microwave processing apparatus according to claim 2, wherein
A microwave processing apparatus, wherein the reflecting plate is provided on an inner periphery of the radome. The microwave processing apparatus according to claim 2, wherein
The radome consists of an inner circumference radome and an outer circumference radome surrounding it from the outer circumference,
A microwave processing apparatus, wherein the reflector is provided on the outer periphery of the inner radome and on the inner periphery of the outer radome. In the microwave processing apparatus in any one of Claims 1-5,
A microwave processing apparatus comprising control means for controlling a rotation speed of the reflection plate by the rotation mechanism. The microwave processing apparatus according to claim 6, wherein
The microwave processing apparatus, wherein the control means controls the reflector to rotate at a constant speed, and performs the microwave processing while rotating the reflector at a constant speed. The microwave processing apparatus according to claim 6, wherein
The control means controls the rotation of the reflection plate while variably controlling the rotation speed, performs the microwave processing while rotating the reflection plate at a predetermined rotation speed at a predetermined portion, and at other than the predetermined portion. (A) The microwave processing apparatus performs the microwave processing while rotating the reflecting plate at a speed lower than the predetermined rotation speed, or (b) temporarily stopping the reflection plate. A coaxial cable for propagating microwaves, having a center conductor and an outer conductor surrounding it from the outside;
A ground plane electrically connected to the outer conductor, and
A reflector formed so as to surround the antenna portion of the coaxial cable, and at least a part of which is opened;
And a rotating mechanism for rotating the reflecting plate around the coaxial core of the coaxial cable.

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