JP2000277249A - Impedance varying unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an impedance varying unit of a new configuration to allow setting off a large width of impedance variation, with a simple configuration. SOLUTION: A wave guide tube 10 is provided in the inside of a microwave propagating space 11 at the metal boundary made of a metallic material, wherein the termination 12 of the propagation space 11 is closed as the metal boundary, while the other end 13 is left as open end 14. A dielectric substance plate 14 in a flat shape is arranged in the space 11, and support parts 15 and 16 in cylindrical shape are inserted in holes provided in an E-surface of the wave guide tube 10 at the two ends and assembled and the rotation is supported by these holes. The impedance of the open end can be easily varied over a wide range, by changing the rotation supporting angle of the dielectric substance plate 14.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variable impedance unit incorporated in a microwave transmission line or a microwave cavity resonator.

[0002]

2. Description of the Related Art When a microwave transmission path is a waveguide, a conventional unit of this type adopts a configuration in which a cylindrical metal is inserted from the H-plane of the waveguide, for example. In some cases, the insertion depth is varied to vary the capacitive component in the waveguide to vary the impedance.

Further, it is difficult to eliminate a gap at a connection portion when assembling connection flanges of the respective waveguides when connecting the waveguides. Therefore, a technique of providing a choke groove in a connection region has been proposed. is there. This choke groove has a depth which is の of the wavelength dimension of the frequency used with respect to the frequency to be used, and ideally makes the impedance of the opening of the choke groove desired in the waveguide wall zero. It is. When this technique is applied, the impedance of the opening of the choke groove can be varied by varying the depth of the choke groove.

[0004]

However, in the conventional variable impedance configuration, it is necessary to mechanically move the structure vertically or horizontally to move the variable member, and the configuration of the variable impedance drive system is complicated. Also, there are various problems such as measures against abrasion caused by sliding between the variable member and the waveguide main body or elimination of spark generation.

An object of the present invention is to provide an impedance variable unit having a novel configuration that has a simple impedance variable configuration and a large impedance variable width.

[0006]

In order to solve the above problems, the variable impedance unit according to the present invention comprises a waveguide terminated at one end, and a dielectric plate provided in the waveguide and driven to rotate. The impedance at the open end at the other end of the waveguide is varied by rotating the dielectric plate.

According to the above invention, when the dielectric plate is perpendicular to the termination surface, the effective length (hereinafter referred to as the electrical length) of the waveguide for microwaves propagating through the waveguide is maximized to make the waveguide parallel to the termination surface. In this case, the electrical length can be minimized. Thus, the impedance at the open end can be easily varied by rotating the dielectric plate.

[0008]

A variable impedance unit according to a first aspect of the present invention includes a waveguide having one end terminated, and a dielectric plate provided in the waveguide and driven to rotate. By rotating, the impedance of the open end at the other end of the waveguide is varied. In this way, the configuration in which the dielectric plate is rotationally driven can maximize the electrical length of the waveguide when the dielectric plate is perpendicular to the termination surface and minimize the electrical length when the dielectric plate is parallel to the termination surface. Thus, the impedance at the open end can be easily varied by rotating the dielectric plate.

According to a second aspect of the present invention, in the variable impedance unit, the waveguide is driven by rotating at least one of a waveguide terminated at one end and a plurality of dielectric plates provided in the waveguide. The impedance of the open end at the other end of the tube is varied. In such a configuration in which a plurality of dielectric plates are provided, the impedance at the open end can be varied over a wide range by combining the rotational positions of the dielectric plates.

In the variable impedance unit according to a third aspect of the present invention, the transmission mode of the waveguide is a TEn0 mode (n is a positive integer). By setting the transmission mode in the waveguide to TEn0 in this way, the electromagnetic field distribution in the waveguide can be specified, and the rotation support angle of the dielectric plate and the impedance value at the open end correspond one-to-one. it can. Also, n
Is increased, the area of the open end can be enlarged, and the region where the variable impedance acts can be increased.

According to a fourth aspect of the present invention, in the variable impedance unit, the reflection coefficient at the open end of the waveguide includes a phase value of a reflection coefficient having a phase value of at least ± 180 °. By setting the phase value of the reflection coefficient of the open end to ± 180 ° in this manner, the open end can function in the same way as a metal wall surface, and the characteristics can be easily compared with the case where the variable impedance unit is not used. be able to.

The impedance variable unit according to claim 5 of the present invention is characterized in that the reflection coefficient at the open end of the waveguide includes a phase value at which the phase value of the reflection coefficient is at least 0 °. Thus, the phase value of the reflection coefficient at the open end is set to 0.
By setting the angle to °, the action of variable impedance can be maximized.

The variable impedance unit according to claim 6 of the present invention is characterized in that the reflection coefficient at the open end of the waveguide includes the phase values of the reflection coefficient of 0 ° and ± 180 °. By maximizing the variable width of the phase of the reflection coefficient at the open end as described above, it is possible to easily measure the entire operation accompanying the variable impedance.

According to a seventh aspect of the present invention, in the variable impedance unit, the phase value of the reflection coefficient at the open end of the waveguide is substantially ± 180 when the wide surface of the dielectric plate is substantially parallel to the end of the waveguide. °. By rotating the dielectric plate in such a configuration, the phase range of the reflection coefficient at the open end is limited to the range from -180 ° to 0 °, and impedance of only the capacitive component can be formed at the open end. In addition, when the open end acts in the same manner as a metal surface, the support angle of the dielectric plate can be easily confirmed, and convenience can be improved.

According to the impedance variable unit of the present invention, the reflection coefficient at the open end of the waveguide is set when the wide surface of the dielectric plate is at approximately 45 ° or approximately 135 ° with respect to the end of the waveguide. Is approximately ± 180 °. By rotating the dielectric plate in such a configuration, the impedance between the inductive component and the capacitive component can be formed at the open end.

In the variable impedance unit according to a ninth aspect of the present invention, the plane at the end of the waveguide and the plane at the open end are approximately 90 °.
Make up the relationship. By configuring the end surface and the open end surface in this way, the variable impedance unit can be incorporated as a flat shape even when the length of the waveguide is long.

[0017]

Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) FIG. 1 is a configuration diagram of an impedance variable unit showing Embodiment 1 of the present invention, and FIG. 2 is a cross-sectional configuration diagram of a main part of FIG.

In FIGS. 1 and 2, the waveguide 10 of the variable impedance unit has a metal boundary portion made of a metal material and has a microwave propagation space 11 formed therein. The end 12 of the propagation space 11 is closed as a metal boundary. The other end 13 of the waveguide is an open end. In the propagation space 11, a flat dielectric plate 14 is arranged. At both ends of the dielectric plate 14, cylindrical support portions 15 and 16 are formed. The support portions 15 and 16 are inserted and assembled into holes provided on the E surface of the waveguide 10, and are rotated and supported by the holes. ing. Reference numeral 17 denotes a stepping motor which is a driving unit for driving the dielectric plate 14 to rotate;
Denotes a support 15 of the dielectric plate 14 and a stepping motor 17
This is a case in which a connecting portion for connecting to the drive shaft is incorporated. The dielectric plate 14 is arranged such that the gap between the open end 13 and the end 12 of the waveguide 10 is Li and Lb, respectively. Reference numeral 19 denotes a connection flange (not shown, but may be provided with a mounting hole) used when incorporating the variable impedance unit.

Next, the dielectric plate 14 which forms the basis of the variable impedance unit of the present invention will be described. For the dielectric plate 14, it is necessary to optimally select the relative permittivity and the plate thickness of the material. To understand this, an extreme example will be described below.

First, when the relative dielectric constant is set to 1, the waveguide 10
Is uniquely determined by (Li + Lb). In this case, even if the dielectric plate 14 is rotated, the electrical length of the waveguide does not change. Therefore, the impedance cannot be changed.

On the other hand, when the relative permittivity is set to a very large value, the microwave incident from the open end 13 is almost completely reflected by the dielectric plate 14 when the dielectric plate 14 is in the state shown in FIG. It cannot pass through the body plate 14. The electrical length in this case is (Li-t / 2). Here, t is the thickness of the dielectric plate. When the dielectric plate 14 is in the state shown in FIG. 2B, the propagation wavelength of the microwave propagating in the propagation space 11 in the waveguide 10 is slightly reduced by the presence of the dielectric plate 14, so that the substantial conduction is achieved. The electrical length of the waveguide 10 is (Li + Lb +
α). Therefore, the impedance of the open end 13 varies by an amount corresponding to (Lb−t / 2 + α) as the electrical length.
The magnitude of α at this time depends on the value of the relative dielectric constant and the thickness of the dielectric plate 14. When the thickness of the dielectric plate 14 is increased, α increases, but when the thickness is too large, the dielectric plate 14 increases.
The microwaves are reflected by this, so the plate thickness has an upper limit. Theoretically, α can be considerably increased, but as an example, the relative dielectric constant is set to 10000, and the plate thickness t is set to 1 which is the height H of the waveguide 10.
In the case of / 3, since the air and the dielectric plate 14 are connected in series, the effective relative permittivity of the propagation space 11 in which the dielectric plate 14 exists is about 1.5. Therefore, the electrical length that contributes to the variable impedance of the open end 13 is substantially Lb, and L
If b is the size of the propagation wavelength of the microwave in the waveguide 10, the variable width of the impedance can be maximized. But,
For example, when the microwave frequency is 2450 MHz, the propagation mode of the waveguide is the TE10 mode, and the width is 80 mm, Lb is about 190 mm, and the waveguide 10 has a problem of having a large configuration.

The above description has described that the selection of the relative permittivity of the dielectric plate 14 of the variable impedance unit of the present invention is important. The range of the relative permittivity used for the dielectric plate 14 of the variable impedance unit of the present invention is approximately 5 to 30 in consideration of practicality,
Desirably, it is 7 or more and 15 or less. This is because in a dielectric plate having such a relative dielectric constant, the energy of the microwave transmitted through the dielectric plate and the energy of the microwave reflected on the surface of the dielectric plate are distributed to a degree that cannot be ignored.
The material of the dielectric plate 14 that can be used can be selected from glass, ceramic, or resin according to the application.

When the dielectric plate is perpendicular to the termination surface, the electrical length of the waveguide is maximized, and when the dielectric plate is parallel to the termination surface, the electrical length is minimized. This makes it possible to easily and widely vary the impedance of the open end with a simple configuration for rotating the dielectric plate.

A specific characteristic example of the variable impedance unit having the above-described configuration and an application example thereof will be described below. The rotation support angle of the dielectric plate 14 used in the following description is represented by an angle shown in FIG.

FIG. 3 shows that the relative permittivity of the dielectric plate 14 is 12.
3. When the plate thickness is 6.2 mm, the width and height dimensions of the open end of the waveguide 10 are 80 mm and 30 mm, and Lb is 20 mm, the reflection coefficient S11 of the open end 12 with respect to the change in Li size. 3 shows the characteristics of the phase value. When θ = 0 deg, the dielectric plate 14 is in the state shown in FIG.
This is the state shown in FIG.

In FIG. 3, an arrow 20 (ie, Li = 2)
It is recognized that the phase of the reflection coefficient S11 of the open end 12 of the waveguide 10 can be varied in a range of approximately ± 180 ° to approximately 0 ° by adopting the configuration of 0 mm. Arrow 2
1 or Li = 35 mm, θ = 45 de
At the time of g, the phase of the reflection coefficient S11 of the open end 13 is set to approximately 0 °, and the dielectric plate 14 is rotated so that the open end 13 has an inductive component (phase range: from + 180 ° to approximately + 150 °) and a capacitive component. (Phase range: -180 ° to about -115 °)
It is recognized that values can be present.

By configuring the variable impedance unit having the characteristic indicated by the arrow 20, the phase of the reflection coefficient at the open end is set to ± 180 °, so that the open end has the same function as the metal wall surface. It is possible to easily check the characteristic comparison with the case where the variable impedance unit is not used. In addition, the unit configuration that allows the open end reflection coefficient to include 0 ° and ± 180 ° as the phase value of the reflection coefficient at the open end maximizes the variable width of the phase of the reflection coefficient at the open end, thereby facilitating the entire operation associated with the variable impedance. It can be confirmed and can have an effective and wide-ranging effect.

On the other hand, by configuring the variable impedance unit having the characteristic indicated by the arrow 21, the impedance of the inductive component and the capacitive component can be formed at the open end by rotating the dielectric plate.

Next, an application example of the above configuration will be described with reference to FIGS.

FIG. 4 shows a case where the variable impedance unit 22 having the configuration shown by the arrow 20 in FIG. 3 is mounted on a high-frequency heating device. In the figure, reference numeral 23 denotes a microwave space which is a microwave cavity resonator in which an object to be heated is stored;
Right wall 24, Left wall 25, Back wall 26, Upper wall 2
7. A substantially rectangular parallelepiped shape is formed by a bottom wall surface 28 and a front opening / closing wall surface (not shown) which is an opening / closing wall surface through which the object to be heated is put in and out of the microwave space 23, and the supplied microwave is substantially contained therein. It is formed so as to be confined. Reference numeral 29 denotes an opening formed in the left side wall surface 25 and corresponds to an open end of the variable impedance unit 22. The variable impedance unit 22 has its terminal surface 2
The opening 2a and the opening 29 corresponding to the open end face are formed in a relationship of about 90 °. This eliminates an increase in the size of the high-frequency heating device provided with the variable impedance unit 22, and provides convenience when using the high-frequency heating device.

Reference numeral 30 denotes a magnetron that generates a microwave to be fed into the microwave space 23, 31 denotes a waveguide having the magnetron 30 mounted on one end side, and a waveguide that transmits the microwave generated by the magnetron 30, and 32 denotes a waveguide. The power supply unit radiates the microwave transmitted through the microwave 31 into the microwave space 23, and is disposed on the right wall surface 24 of the microwave space 23. Reference numeral 33 denotes a mounting plate on which an object to be heated is mounted.

Next, FIG. 5 shows a heating distribution characteristic when the variable impedance unit 22 is operated in the high-frequency heating apparatus of FIG. FIG. 5 shows a heating distribution using 200 g of Adhair Glue (registered trademark) manufactured by Sekisui Jushi Corporation with respect to the rotation angle of the dielectric plate. The microwave space 23 is
The bottom area of a container having a width of 310 mm, a depth of 310 mm and a height of 215 mm and containing Adhair Glue (registered trademark) is 100 mm 2.

Adhair Synthetic Glue (registered trademark) is a polyvinyl alcohol aqueous solution, which is transparent at ordinary temperature but has a property of becoming cloudy at 45 ° C. or higher.

The microwave output was 500 W, and the heating distribution after heating for 40 seconds was shown. The white area is the heated area. The variable impedance unit used in this application example changes the phase of the reflection coefficient S11 of the open end, that is, the opening portion 29 as a capacitive component from approximately −180 ° to approximately 0 °, and is incident on the opening portion 29. Microwave and aperture 2
9, the phase difference from the microwave reflected back into the microwave space 23 can be changed by approximately 180 ° at the maximum.
Thereby, the standing wave distribution generated in the microwave space 23 can be moved according to the phase of the reflection coefficient S11 of the aperture 29. By varying the support angle of the dielectric plate, it is possible to move a region in the microwave space where the electric field is large, that is, a region where the temperature rise is large (that is, a white region) in heating the object to be heated.

Therefore, by mounting the variable impedance unit of the present invention on the high-frequency heating device, it is possible to heat a region to be heated by the user, such as the central portion or the peripheral portion of the object to be heated, and to adapt to the object to be heated. It is possible to provide a device capable of performing optimal or user-desired heating.

FIG. 6 provides a means for enlarging the area of the open end of the variable impedance unit. That is, FIG. 6A shows the impedance variable unit described above. The shape of the microwave propagation space 11 and the open bile 13 in the waveguide 10 changes the TE10 mode with respect to the frequency of the microwave to be propagated. It is shaped to be transmitted. On the other hand, FIG. 6B shows an embodiment in which the waveguide 34 is formed in the microwave propagation space 35 in the waveguide 34 so as to propagate the microwave in the TE20 mode. That is, the shape of the open end 36 of the waveguide 34 is
The width W2 of the open end 13 corresponding to the TE10 mode is twice as large as the width W1. In addition, the electric field distribution corresponding to each propagation mode is shown on the open end face in FIG.

By increasing the shape of the open end in this way, the area in which the variable impedance unit of the present invention can operate can be enlarged. The heating distribution can be varied over a wider range of shapes and quantities.

The TEn0 mode (n is a positive integer) is the most effective practically as a mode for propagating in the propagation space. In other words, if this mode is used, the thickness of the dielectric plate can be the same in any mode, and the impedance of the open end can be varied to a predetermined value with good controllability based on the rotation support angle of the dielectric plate. Can be done.

Next, FIG. 7 shows an application example in which the variable impedance unit 40 having the configuration shown by the arrow 21 in FIG. 3 is mounted on a high-frequency heating device. 7, members having the same or equivalent functions as those in FIG. 4 are denoted by the same reference numerals.

The variable impedance unit 40 shown in FIG.
Indicates that the support angle of the dielectric plate 41 is substantially four
The reflection coefficient S11 at the aperture 29 provided on the upper wall surface 27 of the microwave space 23 at 5 ° (similarly at 135 °)
Is approximately ± 180 °. The practical utility of the impedance variable unit 40 having such an operation and configuration will be described with reference to FIG.

FIG. 8 shows load characteristics when the microwave space 23 side is viewed from the magnetron 30 shown in FIG. 7. For example, a point A indicates that one mug containing 200 cc of milk is placed in the center of the microwave space 23. The point B shows the load characteristics when two mugs are placed side by side and placed in the microwave space 23. A region C is a region where the microwave supplied from the magnetron 30 is efficiently absorbed by the object to be heated, which is a load. In addition,
The above-mentioned load characteristics are characteristics in the case where there is no opening 29.

When the variable impedance unit 40 of the present invention is mounted on the high-frequency heating device having such load characteristics, the following effects can be obtained. That is, with respect to the load characteristic at the point A, the load characteristic point A can be moved to the point A ′ by setting the support angle of the dielectric plate of the variable impedance unit 40 to 0 °. Wave absorption can be promoted, the heating time can be shortened, and energy can be saved. On the other hand, with respect to the load characteristic point B, the point B of the load characteristic can be moved to the point B ′ by controlling the support angle of the dielectric plate to the 90 ° side. As a result, it is possible to shorten the heating time and save energy as described above.

(Embodiment 2) Next, Embodiment 2 of the present invention will be described with reference to FIG.
This will be described with reference to FIG. Embodiment 2 is different from Embodiment 1 in that a plurality of dielectric plates are provided.

FIG. 9 shows an example of the second embodiment having such a configuration. In FIG. 9, reference numeral 42 denotes a general-purpose waveguide for transmitting microwaves, and an opening 43 having a predetermined shape is provided on the H surface of the waveguide 42. The variable impedance unit 44 of the present invention having the opening 43 as an open end is provided. In the variable impedance unit 44, dielectric plates 45 and 46 having the same shape are arranged at predetermined intervals. The rotation of these dielectric plates can be controlled independently. Note that the support angles θ1 and θ2 of the dielectric plate used in the following description are angle expressions in the direction shown in FIG.

Referring to FIG. 10, the specific dimensions of the second embodiment having two dielectric plates are as follows. The distance Li between the dielectric plate 46 and the opening 43 is 20 mm, and each dielectric plate 45 , 46 are 40 mm, the distance between the dielectric plate 45 and the termination surface 47 is 20 mm, the opening is 80 mm and 30 mm in width and height, respectively, and the shape and specifications of each dielectric plate are implemented. The same one as in Example 1 is used.

FIG. 10 shows an example of the rotation angle control of two dielectric plates. FIG. 10A shows that the dielectric plate 46 is fixed at a support angle θ2 = 0 ° and the dielectric plate 45 is fixed. FIG. 10B shows that the rotation of the dielectric plate 4 is controlled.
6 indicates that the rotation of the dielectric plate 45 is controlled with the support angle 6 being fixed at θ2 = 90 °.

FIG. 11 shows the magnitude Mag of the reflection coefficient S11 of the opening 43, which is the open end, for the control shown in FIG. 10A, using the support angle θ1 of the dielectric plate 45 as a parameter.

From the characteristics shown in FIG. 11, the support angle θ1 of the dielectric plate 45 is set to a specific angle, that is, 45 ° or 135 °.
Thus, it is recognized that the impedance variable unit 44 including the two dielectric plates can be set to a resonance state. That is, according to the control method shown in FIG. 10A, the variable impedance unit can be used as a resonance element or a matching element.

Also, the magnitude Mag of the reflection coefficient S11 of the opening 43, which is the open end, when the support angle θ1 of the dielectric plate 45 is used as a parameter for the control shown in FIG. The phase of the transmission characteristic S21 of the waveguide 42 is shown in FIGS. 12 and 13, respectively.

According to the characteristics shown in FIG. 13, the impedance variable unit sets the support angle θ1 of the dielectric plate 45 to a specific angle, that is, 45 ° or 135 °, thereby setting the waveguide 42
It can be recognized that the transmission amount of the microwave transmitting the signal can be variably controlled. On the other hand, from the characteristic shown in FIG. 12, the reflection characteristic S1 of the support angle θ1 of the dielectric plate 45, which can greatly reduce the amount of transmission.
The magnitude Mag of 1 is 0.7 or more, and since the accumulation of microwaves in the variable impedance unit is small, the power of the microwaves transmitted through the waveguide 42 is 10
The present invention can be applied to a large power transmission system of 0 W or more, and the transmission amount can be variably controlled.

[0052]

As described above, the present invention has the following effects.

(1) According to the impedance variable unit of the first aspect, the variable impedance unit includes the waveguide terminated at one end, and the dielectric plate provided in the waveguide and driven to rotate, and the dielectric plate is rotated. By varying the impedance at the open end at the other end of the waveguide, the electrical length of the waveguide is maximized when the dielectric plate is parallel to the termination surface, and the electrical length when the dielectric plate is perpendicular to the termination surface. Can be minimized. Thus, the impedance at the open end can be easily varied by rotating the dielectric plate.

(2) According to the variable impedance unit of the second aspect, the waveguide is driven by rotating at least one of the waveguide terminated at one end and a plurality of dielectric plates provided in the waveguide. By varying the impedance at the open end at the other end of the waveguide, the impedance at the open end can be varied over a wide range by combining the rotational positions of the dielectric plates.

(3) According to the variable impedance unit of the third aspect, since the transmission mode of the waveguide is the TEn0 mode (n is a positive integer), the electromagnetic field distribution in the waveguide can be specified. The rotation support angle of the plate and the impedance value at the open end can be made to correspond one-to-one. Also, by increasing the value of n, the area of the open end can be enlarged, and the area where the variable impedance acts can be increased.

(4) According to the impedance variable unit of the fourth aspect, the reflection coefficient at the open end of the waveguide has a phase value of ± 180 ° because the phase value of the reflection coefficient includes at least ± 180 °. At 180 °, the open end can be made to act in the same way as a metal wall surface, and it is possible to easily check the characteristic comparison with the case where the variable impedance unit is not used.

(5) According to the variable impedance unit of the fifth aspect, the reflection coefficient at the open end of the waveguide has a phase value of 0 ° because the phase value of the reflection coefficient includes at least a phase value of 0 °. By doing so, the effect of varying the impedance can be maximized.

(6) According to the variable impedance unit of the sixth aspect, the reflection coefficient at the open end of the waveguide is such that the phase value of the reflection coefficient includes 0 ° and ± 180 °, so that the reflection at the open end is possible. By maximizing the variable width of the phase of the coefficient, it is possible to easily measure the entire operation associated with the variable impedance and to obtain a large operation width.

(7) According to the variable impedance unit of the seventh aspect, the phase value of the reflection coefficient at the open end of the waveguide is substantially reduced when the wide surface of the dielectric plate is substantially parallel to the end of the waveguide. By rotating the dielectric plate by ± 180 °, the phase range of the reflection coefficient at the open end is −18.
The impedance of only the capacitive component can be formed at the open end within the range of 0 ° to 0 °. In addition, when the open end acts in the same manner as a metal surface, the support angle of the dielectric plate can be easily confirmed, and convenience can be improved.

(8) According to the impedance variable unit of the eighth aspect, the phase value of the reflection coefficient at the open end of the waveguide when the wide surface of the dielectric plate is approximately 45 ° with respect to the end of the waveguide. Is set to about ± 180 °, the impedance of the inductive component and the capacitive component can be formed at the open end by rotating the dielectric plate, and can be used as a matching element.

(9) According to the variable impedance unit of the ninth aspect, the end face and the open end face of the waveguide are substantially 90 °.
With this configuration, even when the length of the waveguide is long, the assembled state can be made flat, and the mountability of this unit can be ensured high.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a variable impedance unit according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional configuration diagram showing a rotation control content of the variable impedance unit of FIG. 1;

FIG. 3 is a phase characteristic diagram of a reflection coefficient at an open end with respect to a configuration size of the impedance variable unit.

FIG. 4 is an application example 1 of mounting the variable impedance unit.
Diagram of high-frequency heating device showing

FIG. 5 is a heating distribution characteristic diagram showing the utility of the variable impedance unit in the high-frequency heating device of FIG. 4;

6A is a configuration diagram of a variable impedance unit showing a development example of the first embodiment of the present invention. FIG. 6B is a diagram showing an electric field distribution of the variable impedance unit of FIG. FIG. 6 is a configuration diagram of an impedance variable unit showing another development example of the first embodiment of the present invention. (D) A diagram showing the electric field distribution of the impedance variable unit in FIG.

FIG. 7 is a configuration diagram of a high-frequency heating apparatus showing a second application example of the variable impedance unit according to the first embodiment of the present invention.

FIG. 8 is a load characteristic diagram showing the utility of the variable impedance unit in the high-frequency heating device of FIG. 7;

FIG. 9 is a configuration diagram of a waveguide showing an application example of a variable impedance unit according to a second embodiment of the present invention.

10A is a cross-sectional configuration diagram illustrating rotation control of the variable impedance unit of FIG. 9; FIG. 10B is a cross-sectional configuration diagram illustrating rotation control of the variable impedance unit of FIG. 9;

FIG. 11 is a characteristic diagram of a reflection coefficient at an open end of the variable impedance unit shown in FIG.

FIG. 12 is a characteristic diagram of a reflection coefficient at an open end of the variable impedance unit shown in FIG.

FIG. 13 is a transmission characteristic diagram of the waveguide of FIG. 9 using the variable impedance unit shown in FIG.

[Explanation of symbols]

 10, 34 Waveguide 12, 47 End of waveguide 13, 36 Open end of waveguide 14, 41, 45, 46 Dielectric plate 22, 40, 44 Impedance variable unit 22a, 40a End of variable impedance unit 29 , 43 Opening (open end) 37 TE10 mode 38, 39 TE20 mode

Continued on the front page (72) Inventor Akemi Fukumoto 1006 Kazuma Kadoma, Kadoma-shi, Osaka Matsushita Electric Industrial Co., Ltd. F-term (reference) 3K090 AA02 AA03 AB02 BA01 BB01 BB17 CA02 CA21 DA15 EB03 5J012 GA02 GA04

Claims (9)

[Claims] 1. A waveguide having one end terminated, and a dielectric plate provided in the waveguide and driven to rotate, wherein the other end of the waveguide is opened by rotating the dielectric plate. Variable impedance unit with variable impedance. 2. The impedance of the open end at the other end of the waveguide by rotating and driving at least one of a waveguide terminated at one end and a plurality of dielectric plates provided in the waveguide. Variable impedance unit. 3. The transmission mode of a waveguide is a TEn0 mode (n
The variable impedance unit according to claim 1 or 2, wherein (a) is a positive integer. 4. The variable impedance unit according to claim 1, wherein the reflection coefficient at the open end of the waveguide includes a phase value of the reflection coefficient having a phase value of at least ± 180 °. 5. The variable impedance unit according to claim 1, wherein the reflection coefficient at the open end of the waveguide includes a phase value at which the phase value of the reflection coefficient is at least 0 °. 6. The variable impedance unit according to claim 1, wherein the reflection coefficient at the open end of the waveguide includes a phase value of the reflection coefficient of 0 ° and ± 180 °. 7. The method according to claim 1, wherein the phase value of the reflection coefficient at the open end of the waveguide is approximately ± 180 ° when the wide surface of the dielectric plate is substantially parallel to the end of the waveguide. Variable impedance unit. 8. The phase value of the reflection coefficient at the open end of the waveguide is approximately ± 180 ° when the wide surface of the dielectric plate is at approximately 45 ° or approximately 135 ° with respect to the end of the waveguide. The impedance variable unit according to claim 1. 9. The end face and open end face of the waveguide are approximately 90
The impedance variable unit according to claim 1 or 2, wherein the variable impedance unit has a relationship of °.