JP3577433B2 - High frequency heating equipment - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an improvement of a high-frequency heating device using an industrial frequency band electromagnetic wave as a heating source.
[0002]
[Prior art]
The high-frequency heating device is a heating device that utilizes the dielectric heating characteristic of industrial frequency band electromagnetic waves (commonly called microwaves), which is widely used in the private sector under the name of a microwave oven.
[0003]
Conventionally, a magnetron is usually used for the high frequency generator of the high frequency heating device. This magnetron is a fixed-frequency two-pole oscillation tube whose oscillation frequency is determined when its structure is determined. The frequency stability is low, but the structure is simple and the conversion efficiency of input power to microwave is 70%. %, It is widely used for applications requiring large power.
[0004]
For consumer use, microwaves in the industrial frequency band of 2.45 GHz are generated by this magnetron, and are used as microwave ovens having a heating capacity of about 500 W. The size of the magnetron that generates the microwave of 2.45 GHz is physically substantially fixed, and occupies a space of about 7 cm to 10 cm 3. It can be understood that the space occupied by the magnetron is very large in view of the fact that the average size of a commercially available microwave oven is about 30 cm × 25 cm × 20 cm.
[0005]
In order to eliminate such dimensional restrictions, oscillation elements have been sought in place of magnetrons, and as an example, solid magnetrons using vacuum micro devices have been developed.
[0006]
The external dimensions of the vacuum microdevice are expected to be about 20 mm × 60 mm × 40 mm, and show extremely good volumetric efficiency as compared with the magnetron. However, at present, a device that can withstand practical use has not been developed, and at present, it has not been used as a high-frequency heating device.
[0007]
On the other hand, electrostatic induction type transistors (hereinafter abbreviated as SITs) have also met the background as magnetron replacements, and have attracted attention in the past. It is down. However, in recent years, an SIT having a recess gate structure in which the disadvantage has been improved has been developed (Japanese Utility Model Publication No. 2517175), and expectations for application to a microwave oven are increasing again. The SIT having the recessed gate structure is an active element in which a gate layer buried between a drain layer and a source layer is constituted by a plurality of grid-like gate portions including vertical stripe gates and horizontal stripe gates. is there.
[0008]
[Problems to be solved by the invention]
However, the specifications of the recess gate structure at the present stage in the SIT are an operating pressure of 60 V to 70 V, an output of 46 W, and a conversion efficiency of 40%, which are inferior to magnetrons.
[0009]
However, its outer dimensions are 20 mm × 10 mm × 4 mm, which is more compact than a vacuum microdevice. Therefore, it can be used as an auxiliary heating means of a conventional microwave oven or a combined heating means using a plurality of elements.
[0010]
Therefore, an object of the present invention is to provide a high-frequency heating device using a SIT having a recess gate structure as a microwave oscillation module.
[0011]
[Means for Solving the Problems]
To achieve the above object, the first invention is a high frequency heating apparatus utilizing industrial frequency band electromagnetic waves and oscillating source SIT recess gate structure, and a high frequency output module having a plurality of upper Symbol oscillation source, A Butler matrix that outputs a high frequency of a predetermined number of phases from the predetermined number of output terminals with an output of the high frequency output module as an input, and is connected to the predetermined number of output terminals of the Butler matrix and is connected to the predetermined number of directions. It is characterized by having a multiple antenna for outputting a beam .
[0012]
According to the above configuration, the output power of SI T recess gate structure in which a plurality chromatic synthesis. Thus, high output can be obtained based on the plurality of recess gate structures SIT. Further, the multiple antennas radiate multiple high-frequency beams in the predetermined number of directions based on high-frequency waves having a predetermined number of phases from the Butler matrix.
[0013]
Further, in the high-frequency heating device according to the first aspect of the present invention, it is preferable that the excitation unit of the high-frequency output module is configured by an external oscillation element outside the high-frequency output module.
[0014]
According to the configuration, the excitation unit of the high-frequency output module is configured by the external oscillation element outside the high-frequency output module. Therefore, by performing the phase conversion, it becomes possible to actively change the radiation characteristic of the above-mentioned industrial frequency band electromagnetic wave or to synthesize electric power.
[0015]
Also, with the first high-frequency heating apparatus of the invention, the Butler matrix has an input terminal of the same predetermined number of the number of phases of the high frequency output is connected to an output terminal of the high-frequency output module, It is desirable to have switching means for exclusively supplying an output from an output terminal of the high-frequency output module to any one of the predetermined number of input terminals of the Butler matrix .
[0016]
According to the above configuration, the output of the high frequency output module or colleagues, is supplied to one of input terminals of the exclusive the Butler matrix by the switching means. Accordingly, the radial RF beam emitted from the Tarenso antenna, Rukoto of varying puff in the direction of the predetermined number can be ing.
[0017]
Also, high-frequency heating apparatus of the second invention is a high frequency heating apparatus utilizing industrial frequency band electromagnetic waves and oscillating source SIT recess gate structure, a predetermined number of high-frequency output module having a plurality of upper Symbol oscillation source When, along with constituting the excitation portion of the high-frequency output module, the oscillator located outside the RF output module and connected to the preamplifier to an output terminal of the oscillator, the predetermined number on the basis of the output of the preamplifier And a Butler matrix that generates an excitation signal having a phase of the predetermined number and outputs the same to the predetermined number of high-frequency output modules, and the predetermined number of non-linear circuits connected in parallel to any one of the predetermined number of high-frequency output modules. It is characterized by having a directional antenna.
[0018]
According to the above configuration, each of the excitation signals having a predetermined number of phases output from the Butler matrix is input to the high-frequency output module having a plurality of SITs having the recess gate structure, and the high frequency having the predetermined number of phases is obtained. Then, the high frequency of each phase is input to any one of the predetermined number of omnidirectional antennas. Thus, the output of the plurality of recess gate structure SIT is power combining, besides, the multi-beam radiation characteristic be synthesized in the direction of the predetermined number are output.
[0019]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments. As of June 1999, it has been reported that the SIT having the recess gate structure has an operating voltage of 60 V to 70 V, an output of 46 W, and an efficiency of 40%. In the near future, an operating voltage of 50 V to 140 V, an output of 130 W, an efficiency of 70%, There is a prospect that the power gain can be improved up to about 10 dB. Nevertheless, magnetrons, which are microwave ovens of microwave ovens currently on the market, have an operating voltage of 4 kV, an output of 500 W to 1 kW, and an efficiency of 70%. Absent.
[0020]
<First embodiment>
Unlike the magnetron, the SIT can actively set the frequency and phase at the time of design, so that a plurality of SITs can be prepared and their output power can be combined. Therefore, by controlling the phase at that time and connecting it to an appropriate antenna, high-frequency radiation in multiple directions can be achieved without using a stirrer fan or turntable, which was indispensable for heating with a magnetron in the past. It has the possibility of realizing appropriate heating.
[0021]
FIG. 1 is a diagram illustrating a configuration example of a microwave oscillation module mounted on the high-frequency heating device according to the present embodiment. This microwave oscillation module has a 130 W output SIT output module 2 composed of a plurality of SITs 2 a and 2 b using a single external oscillation element 1 as an excitation unit. Then, the output of the SIT output module 2 is input to each of the switches (1) to (4) of the SPST (single-pole, single-throw) high-frequency switch 3, and the output of the SPST high-frequency switch 3 is supplied to the four power supply terminals a of the Butler matrix 4. To d) to exclusively input to any one of the power supply terminals. In the figure, "HB" is a 3 dB coupler.
[0022]
One of the switches constituting the SPST high-frequency switch 3 is a high-frequency on / off switch using a pin diode. As shown in FIG. It has the same function as a switch. In FIG. 2, ON and OFF of the diodes D1 and D2 correspond to forward and reverse directions, respectively. Note that “A” and “B” in the figure represent states of the SPST high-frequency switch 3.
[0023]
In FIG. 1, when the switch (1) of the SPST high-frequency switch 3 is turned on and the output of the SIT output module 2 is input to the feeder terminal a) of the Butler matrix 4, each of the four 1/4 .lambda. The phases of the high frequencies supplied to the / 4λ microstrip antennas A, B, C and D are respectively
(A, B, C, D) = (-45 °, -90 °, -135 °, -180 °)
Is converted to As a result, the direction of the high frequency output from the quadruple quarter-λ microstrip antenna 5 is directed in the direction of arrow 1.
[0024]
When the switch (2) of the SPST high-frequency switch 3 is turned on and the output of the SIT output module 2 is input to the feeder terminal b) of the Butler matrix 4, each quarter λ of the quadruple quarter λ microstrip antenna 5 The phases of the high frequencies supplied to the microstrip antennas A, B, C and D are respectively
(A, B, C, D) = (-135 °, 0 °, -225 °, -90 °)
Is converted to As a result, the direction of the high frequency from the quadruple quarter-λ microstrip antenna 5 is directed in the direction of arrow 2.
[0025]
Hereinafter, similarly, when the output of the SIT output module 2 is input to the feed terminal c) of the Butler matrix 4, the high frequency from the quadruple quarter-λ microstrip antenna 5 is supplied in the direction of arrow 3 and the feed terminal d). Is emitted in the direction of arrow 4.
[0026]
As described above, according to the present microwave oscillation module, the radiation direction of high frequency can be changed without using a mechanically moving antenna, and it is possible to have a function equivalent to that of a conventional stirrer fan. .
[0027]
As described above, in the present embodiment, the microwave oscillating module includes the external oscillating element 1, the SIT output module 2, the SPST high-frequency switch 3, the butler matrix 4, and the quadruple quarter λ microstrip antenna 5. It consists of.
[0028]
The single external oscillating element 1 is used as an excitation unit, and the output of the 130 W output SIT output module 2 composed of a plurality of SITs 2 a and 2 b is supplied to the respective feed terminals a of the butler matrix 4 via the SPST high frequency switch 3. ) To d) are input exclusively. Then, high frequencies from the four output terminals of the Butler matrix 4 are supplied to the respective quarter-λ microstrip antennas A, B, C and D of the quadruple quarter-λ microstrip antenna 5.
[0029]
Thus, a plurality of SIT2a constituting the SIT output module 2, since the power supply output of 2b by Butler matrix 4 to 4 twin 1 / 4.lamda microstrip antenna 5, to obtain a large heating capacity by using a plurality of SIT You can do it. Further, by sequentially turning on each of the switches (1) to (4) of the SPST high-frequency switch 3, the radiation direction of the high frequency from the quadruple quarter-λ microstrip antenna 5 is changed by arrows 1 to 4 in FIG. The direction can be changed sequentially. Therefore, uniform heating can be performed spatially, and when used for a heating source such as a microwave oven, a stirrer fan and a turntable conventionally required in a magnetron can be omitted.
[0030]
In the present embodiment, the excitation section of the SIT output module 2 is constituted by an external oscillating element 1 outside the SIT output module 2. However, the present invention is not limited to this, and the oscillation element may be built in the SIT output module.
[0031]
<Second embodiment>
By the way, as described above, at the present stage, the high output of the SIT is at most about 40 W, and even if it is improved to about 130 W in the near future, it is still far from the current magnetron of 500 W. Therefore, in the present embodiment, , A plurality of SITs are modularized, and outputs of the plurality of SIT output modules are combined to obtain a desired high output of 500 W.
[0032]
FIG. 3 is a diagram showing another configuration example of the microwave oscillation module. In this microwave oscillation module, two SIT output modules 12 and 13 of 130 W output using a single external oscillation element 11 as an oscillation source are combined by a Wilkinson coupler 14. Similarly, two SIT output modules 15 and 16 of 130 W output using the external oscillation element 11 as an oscillation source are combined by a Wilkinson coupler 17. Further, the output of the Wilkinson coupler 14 and the output of the Wilkinson coupler 17 are combined by the Wilkinson coupler 18 to obtain an output of 130 W × 4.
[0033]
The output of the Wilkinson coupler 18 is connected to a λλ short-circuited microstrip antenna 19 to improve the characteristics. Incidentally, the feeder terminals a) to d) of the Butler matrix in the first embodiment may be connected to the output of the Wilkinson coupler 18 to achieve multi-beam.
[0034]
As described above, in the present embodiment, four SIT output modules each having two SITs and exhibiting an output of 130 W are power-combined two by two with a Wilkinson coupler. Further, the outputs of the two Wilkinson couplers are combined by another Wilkinson coupler. Therefore, using a SIT exhibiting an output of (130/2) W, it is possible to obtain a heating capacity of 520 W comparable to the current magnetron.
[0035]
Incidentally, as in the present embodiment, it is also possible to increase the number of SIT output modules 2 in the first embodiment to further increase the output.
[0036]
<Third embodiment>
FIG. 4 is a diagram showing another configuration example of the microwave oscillation module. In this microwave oscillation module, the output of a single external oscillation element 21 is amplified by four preamplifiers 22, and the respective outputs are input to four feed terminals of a Butler matrix 23. Further, the four outputs from the Butler matrix 23 are input to four SIT output modules 24 to 27 exhibiting a 130 W output, and the output from each SIT output module 24 to 27 is output to each of the quadruple quarter-λ microstrip antennas 28. The signals are supplied to quarter-λ microstrip antennas A, B, C, and D.
[0037]
By adopting such a configuration, the quadruple quarter- [lambda] microstrip antenna 28 emits high frequencies in all directions of arrows 1 to 4 shown in FIG. Therefore, even though the radiation characteristics of the four quarter-λ microstrip antennas A, B, C, and D are omnidirectional, they can function as multi-beam antennas in four directions.
[0038]
The number of the preamplifiers 22 is not limited to four. In short, what is necessary is just to have a configuration in which the output of the preamplifier is input to the four power supply terminals of the Butler matrix 23.
[0039]
Here, the oscillating circuits in the SIT output modules 2, 12, 13, 15, 16, 24 to 27 may be LC oscillation circuits like ordinary transistors, and the output employs an emitter follower. FIG. It is. Incidentally, 31 is SIT.
[0040]
<Fourth embodiment>
In this embodiment, an example of mounting the multi-beam oscillation type microwave oscillation module in each of the above embodiments on a high-frequency heating device will be described.
[0041]
FIG. 6A shows a state in which the microwave oscillation module 42 of the multi-beam oscillation type is installed in a housing 41 of a microwave oven as a high-frequency heating device. FIG. 6B is a partially enlarged view of a place where the microwave oscillation module 42 in FIG. 6A is installed. FIG. 6A shows the inside of the housing 41, and the front side and right side walls of the housing 41 and the top plate are omitted.
[0042]
In the present embodiment, unlike a conventional magnetron system, a waveguide is not required, and the microwave oscillation module 42 can be directly installed in the housing 41, thereby saving the volume. The antenna section 43 has a configuration of a quadruple quarter-λ microstrip antenna.
[0043]
The quadruple quarter-λ microstrip antenna 43 has a simple structure in which four inverted-F-shaped quarter-λ microstrip antennas 46 are attached to a conductive base 45 as shown in FIG. I have. The central pin 47 serves as a power supply terminal, and power is supplied by the coaxial line 48.
[0044]
The antenna 43 may be constituted by a quadruple quarter-λ microrod antenna 50 as shown in FIG. The quadruple quarter-λ microrod antenna 50 is composed of four inverted F-shaped quarter-λ microrod antennas 51. A box 53 is provided on the back side of the conductive board 52 to which the 1 / 4λ microrod antenna 51 is attached, and the entire circuit is housed therein. Here, the internal base provided in the box 53 includes the external oscillating device 1, the SIT output module 2, the SPST high-frequency switch 3, and the Butler matrix 4 in the first embodiment, and the external oscillating device 11, in the second embodiment. The SIT output modules 12, 13, 15, 16, the Wilkinson couplers 14, 17, 18, and the circuits such as the external oscillating element 21, the preamplifier 22, the Butler matrix 23, and the SIT output modules 24-27 in the third embodiment. It is necessary to arrange them while considering interference.
[0045]
As described above, the microwave oscillating module 42 in which the quarter λ microstrip antenna 46 is integrally mounted in four units may be installed in the housing 41 of the microwave oven, but since the oscillating unit is modularized, It is also possible to separate the 4λ microstrip antenna 46 from the modularized oscillating section individually and to disperse and dispose it in each section of the housing 41.
[0046]
In that case, matching can be easily achieved by increasing the area of the 上 記 λ microstrip antenna 46. Therefore, a typical 1 / 4λ short-circuited microstrip antenna 61 as shown in FIG. 9 is used as the 1 / 4λ microstrip antenna 46, and is disposed in each part of the housing 41 to supply power through a transmission line such as a stripline. It is desirable to do.
[0047]
【The invention's effect】
As apparent from the above, the high frequency heating apparatus of the first invention comprises a high-frequency output module having a plurality of SIT of re Sesugeto structure, the Butler matrix which receives the output of the high-frequency output module, given from the Butler matrix Since the multiple antennas connected to the number of output terminals are provided, it is possible to combine the outputs of the plurality of recess gate structures SIT with power and obtain a high heating capability. Further, based on the high frequency of a predetermined number of phases by the Butler matrix, multiple high frequency beams can be emitted in the predetermined number of directions.
[0048]
That is, according to the present invention, spatially uniform heating can be performed, and a stirrer fan and a turntable, which have been indispensable in a conventional magnetron, can be omitted to achieve compactness. Therefore, it is possible to achieve both the compactness and the high output of the high-frequency heating device using the microwave.
[0049]
In the high-frequency heating device according to the first aspect of the present invention, if the excitation unit of the high-frequency output module is configured by an external oscillating element provided outside the high-frequency output module, phase conversion can be easily performed. This makes it possible to change the radiation characteristics of the microwave and to combine the power.
[0050]
Further, the first high-frequency heating apparatus of the invention relates to a form so as to have an input terminal of the same predetermined number of the number of phases of the high frequency of the Butler matrix, and outputs, connected to the output terminal of the high-frequency output module If switching means for exclusively supplying the output from the output terminal of the high-frequency output module to any one of the input terminals of the Butler matrix is provided, the radiation of the high-frequency beam radiated from the multiple antenna is provided. direction, Rukoto of varying puff in the direction of the predetermined number can be ing.
[0051]
Also, high-frequency heating apparatus of the second invention, an oscillation element constituting a predetermined number of high-frequency output module to a plurality have a SIT recess gate structure is outside the above high-frequency output module an excitation portion of the radio frequency output module A preamplifier connected to the oscillation element, a Butler matrix that generates an excitation signal having the predetermined number of phases and outputs the excitation signal to the high frequency output module, and is connected to any one of the predetermined number of high frequency output modules. Since the predetermined number of omnidirectional antennas are provided, the excitation signal of the predetermined number of phases from the Butler matrix can be input to a high-frequency output module to obtain the high frequency of the predetermined number of phases. Therefore, by inputting the high frequency of each phase to any one of the predetermined number of omnidirectional antennas, the power from the plurality of recess gate structures SIT is synthesized, and the radiation characteristics are also synthesized. Multiple beams can be emitted in a predetermined number of directions.
[0052]
That is, according to the present invention, the outputs of the plurality of recess gate structures SIT can be power-combined to obtain a high heating capability. Furthermore, it is possible to perform spatially uniform heating, and it is possible to omit a stirrer fan and a turntable that have been essential in a conventional magnetron.
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration example of a microwave oscillation module mounted on a high-frequency heating device of the present invention.
FIG. 2 is a diagram showing a configuration of a pin diode.
FIG. 3 is a diagram illustrating a configuration example different from FIG. 1;
FIG. 4 is a diagram illustrating an example of a configuration different from FIGS. 1 and 3;
FIG. 5 is a circuit diagram of an oscillation circuit using SIT.
FIG. 6 is a diagram illustrating a state in which the microwave oscillation module is installed in a housing of a microwave oven.
FIG. 7 is a schematic view of a quadruple quarter-λ microstrip antenna.
FIG. 8 is a schematic view of a quadruple quarter-λ microrod antenna.
FIG. 9 is a schematic view of a 1 / 4λ short-circuit type microstrip antenna.
[Explanation of symbols]
1, 11, 21 ... external oscillating element,
2,12,13,15,16,24-27 ... SIT output module,
3, SPST high-frequency switch, 4,23 Butler matrix,
5, 28, 43 ... quadruple quarter-λ microstrip antenna,
14, 17, 18 ... Wilkinson coupler,
19,61 ... 1 / 4λ short-circuit type microstrip antenna,
22 ... Preamplifier, 31 ... SIT,
41 ... housing, 42 ... microwave oscillation module,
45, 52 ... conductive base,
46 ... 1 / 4λ microstrip antenna,
47 ... pin, 48 ... coaxial line,
50 ... quadruple 1 / 4λ micro rod antenna,
51 1 / 4λ micro rod antenna,
53 ... Box.

Claims (4)

A high-frequency heating device using an industrial frequency band electromagnetic wave having an electrostatic induction transistor having a recess gate structure as an oscillation source,
And a high frequency output module having a plurality of upper Symbol oscillation source,
A Butler matrix that receives an output of the high-frequency output module as input, and outputs a high-frequency having a predetermined number of phases from the predetermined number of output terminals,
A high-frequency heating device, comprising: a multiple antenna connected to the predetermined number of output terminals of the Butler matrix to output beams in the predetermined number of directions . The high-frequency heating device according to claim 1,
A high-frequency heating device, wherein the excitation unit of the high-frequency output module is constituted by an external oscillation element outside the high-frequency output module. The high-frequency heating device according to claim 1,
The Butler matrix has a predetermined number of input terminals equal to the number of high-frequency phases to be output,
Is connected to the output terminal of the high frequency output module, comprising a switching means for supplying one of exclusively the Butler the predetermined number of input terminals of the matrix output from the output terminal of the high-frequency output module A high-frequency heating device. A high-frequency heating device using an industrial frequency band electromagnetic wave having an electrostatic induction transistor having a recess gate structure as an oscillation source,
A predetermined number of high-frequency output modules having a plurality of the oscillation sources,
An oscillation element that constitutes an excitation unit of the high-frequency output module, and is provided outside the high-frequency output module,
A preamplifier connected to the output terminal of the oscillation element,
A Butler matrix that generates an excitation signal having the predetermined number of phases based on the output of the preamplifier and outputs the excitation signal to the predetermined number of high-frequency output modules,
A high-frequency heating apparatus comprising: the predetermined number of omnidirectional antennas arranged in parallel and connected to any one of the predetermined number of high-frequency output modules .

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