JP2008041398A - Microwave generator and microwave processor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a microwave generator safely mountable on various kinds of apparatuses, and using a semiconductor element. <P>SOLUTION: A microwave amplification part 400 includes a heat radiation fin 401, a circuit board 402 and a cover member. Three amplifiers 403, 404 and 405 are formed on the circuit board 402. The circuit board 402 is arranged on the heat radiation fin 401 in the cover member. The output terminals of the amplifiers 404 and 405 are connected to one-side ends of coaxial cables CC2 and CC3 through lines L6 and L7. The other-side ends of the coaxial cables CC2 and CC3 are connected to antennas A1 and A2, respectively. The coaxial cables CC2 and CC3 and the lines L6 and L7 are connected to each other at insulating connection parts MC. External conductors of the coaxial cables CC2 and CC3 are electrically insulated from the heat radiation fin 401 and the cover member. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a microwave generation device that generates a microwave and a microwave processing device that processes an object using the microwave.

  In an apparatus for processing an object using a microwave, such as a microwave oven, a magnetron is used as a microwave generator (for example, Patent Document 1). Magnetrons can easily generate high-power microwaves and are generally used as microwave generators.

By the way, when a magnetron is used as the microwave generator, it is not easy to control the frequency of the generated microwave. Therefore, as a microwave generation apparatus that replaces the magnetron, an apparatus using a semiconductor element has been conventionally studied.
JP 05-049442 A

  In a microwave generation device using a semiconductor element, for example, a microwave generated by a microwave generation source including a transistor or the like is amplified by an amplifier including a transistor or the like. Thereby, the microwave generator can radiate the amplified high-power microwave.

  However, until recently, a high breakdown voltage semiconductor element has not been developed, and a sufficient voltage could not be applied to the amplifier. Therefore, a commercial power source cannot be used in a conventional microwave generator using a semiconductor element.

  Thus, the conventional microwave generator using a semiconductor element has poor versatility, and it has hardly been considered to be actually mounted on various devices. Accordingly, little consideration has been given to problems that occur when a microwave generator using a semiconductor element is mounted on a device using a commercial power supply.

  The objective of this invention is providing the microwave generator using the semiconductor element which can be safely mounted in various apparatuses.

  Another object of the present invention is to provide a microwave processing apparatus in which a microwave generator using a semiconductor element is safely mounted.

  (1) A microwave generator according to a first invention is a microwave generator that generates a microwave, an oscillator that generates a microwave, an amplifier that amplifies the microwave generated by the oscillator, and an amplifier The amplifier includes a semiconductor element made of a compound semiconductor having a band gap of 3 eV or more, and the amplifier is electrically insulated from the ground potential.

  In the microwave generator, the microwave generated by the oscillator is amplified by the amplifier and then radiated from the radiating unit. The amplifier includes a semiconductor element made of a compound semiconductor having a band gap of 3 eV or more.

  In this case, since a sufficiently high voltage can be applied to the amplifier, the microwave power generated by the oscillator can be sufficiently amplified in the amplifier.

  The amplifier is electrically isolated from the ground potential. Therefore, when the microwave generator is mounted on various devices, it is possible to prevent a high voltage applied to the amplifier from being applied to the housing of the device. Thereby, it is possible to prevent a high voltage from being applied to the user of the device. That is, the microwave generator can be safely mounted on various devices.

  (2) The microwave generator further includes a first housing that accommodates the amplifier therein, the amplifier and the first housing are electrically connected, and the first housing is electrically connected from the ground potential. May be insulated.

  In this case, the reference potential (one power supply potential) of the amplifier can be stabilized. Thereby, the output of the amplifier can be stabilized. In addition, since the first casing is electrically insulated from the ground potential, a high voltage applied to the amplifier is applied to the casing of the apparatus when the microwave generator is mounted on various apparatuses. Can be prevented.

  (3) The microwave generator further includes a coaxial line that transmits the microwave amplified by the amplifier to the radiating unit, and the coaxial line includes an internal conductor that transmits the microwave amplified by the amplifier, and leakage of the microwave. The first housing and the outer conductor may be electrically insulated from each other.

  In this case, it is possible to prevent the microwave from leaking outside the coaxial line between the first housing and the device housing by connecting the outer conductor to the device housing. As a result, malfunction of the device can be prevented.

  In addition, since the first housing and the external conductor are electrically insulated, a high voltage applied to the amplifier is applied to the device housing even when the external conductor is connected to the device housing. This can be prevented.

  (4) The first housing and the coaxial line may be connected via an insulating member, and the outer conductor and the insulating member may form a choke structure that shields leakage of microwaves transmitted by the inner conductor.

  In this case, the microwave can be prevented from leaking at the connection portion between the first housing and the coaxial line. Thereby, it is possible to reliably prevent malfunction of the device.

  (5) The coaxial line has a cylindrical insulating material provided so as to cover the inner conductor in the outer conductor, the first casing has a cylindrical guide portion, and the coaxial line has a cylindrical shape. This insulating material may be connected to the first housing by fitting it into a cylindrical guide portion.

  In this case, the coaxial line can be reliably fixed to the first housing. Thereby, it is possible to prevent the choke structure formed by the outer conductor and the insulating member from being deformed. As a result, it is possible to reliably prevent the microwave from leaking at the connection portion between the first housing and the coaxial line.

  (6) The microwave generator may further include a second casing that houses the oscillator therein, and the first casing may be electrically insulated from the second casing.

  In this case, when the microwave generator is mounted on the device housing, even if the second housing is electrically connected to the device housing, a high voltage applied to the amplifier is applied to the device housing. It can prevent being applied. Therefore, the microwave generator can be safely mounted on the device.

  (7) The microwave generation device may further include a capacitive element provided between the output terminal of the amplifier and the radiation unit. In this case, it is possible to prevent a high DC voltage applied to the amplifier from being applied to the radiating unit. As a result, safety is further improved.

  (8) The microwave generator may further include a capacitive element provided between the output terminal of the oscillator and the input terminal of the amplifier. Thereby, even when a high DC voltage is applied to the amplifier, it is possible to prevent a high DC voltage from being applied to the oscillator. As a result, failure of the oscillator can be prevented.

  (9) A microwave processing apparatus according to a second aspect of the present invention is a microwave processing apparatus that processes an object using microwaves, and includes a third casing in which the object is disposed, and a third casing. The microwave generator according to the first aspect of the invention radiates microwaves to an object placed in the body, and the amplifier of the microwave generator is electrically insulated from the third casing. .

  In the microwave processing apparatus, the microwave generated from the microwave generation apparatus according to the first aspect of the invention is radiated to the object arranged in the third casing.

  In this case, since the above microwave generator is mounted, a sufficiently high voltage can be applied to the amplifier of the microwave generator. Therefore, after the microwave power generated by the oscillator is sufficiently amplified by the amplifier, the microwave can be radiated from the microwave generator into the third housing.

  The amplifier is electrically insulated from the third housing. Therefore, it is possible to prevent a high voltage applied to the amplifier from being applied to the third casing. Thereby, it is possible to prevent a high voltage from being applied to the user of the microwave processing apparatus. That is, the microwave generator can be safely mounted on the microwave processing apparatus.

  According to the present invention, since a sufficiently high voltage can be applied to the amplifier of the microwave generator, the power of the microwave generated by the oscillator can be sufficiently amplified in the amplifier.

  The amplifier is electrically isolated from the ground potential. Therefore, when the microwave generator is mounted on various devices (microwave processing devices), it is possible to prevent a high voltage applied to the amplifier from being applied to the housing of the device (microwave processing device). . Thereby, it can prevent that a high voltage is applied to the user of an apparatus (microwave processing apparatus). That is, the microwave generation device can be safely mounted on various devices (microwave processing devices).

  Hereinafter, a microwave generator according to an embodiment of the present invention and a microwave processing apparatus equipped with the same will be described with reference to the drawings. Hereinafter, a microwave oven will be described as an example of a microwave processing apparatus.

(1) Outline of Configuration and Operation of Microwave Oven FIG. 1 is a block diagram showing a configuration of a microwave oven according to an embodiment of the present invention. As shown in FIG. 1, a microwave oven 1 according to the present embodiment includes a microwave generator 100 and a housing 501. In the housing 501, antennas A1 and A2 are provided. The housing 501 is grounded.

  The microwave generation apparatus 100 includes a voltage supply unit 200, a microwave generation unit 300, and a microwave amplification unit 400. The microwave generator 100 is connected to a commercial power source via the power plug 10.

  In the microwave generation apparatus 100, the voltage supply unit 200 converts an AC voltage supplied from a commercial power source into a variable voltage and a DC voltage, applies the variable voltage to the microwave generation unit 300, and supplies the DC voltage to the microwave amplification unit 400. To give.

  The microwave generator 300 generates a microwave based on the variable voltage supplied from the voltage supply unit 200. The microwave amplifying unit 400 operates with a DC voltage supplied from the voltage supply unit 200, amplifies the microwave generated by the microwave generating unit 300, and an antenna A <b> 1 provided in the housing 501. To A2. Accordingly, microwaves are radiated from the antennas A1 and A2 in the housing 501. Details of configurations and operations of the voltage supply unit 200, the microwave generation unit 300, and the microwave amplification unit 400 will be described later.

(2) Configuration of Microwave Generator FIG. 2 is a schematic side view of the microwave generator 100 constituting the microwave oven 1 of FIG. 1, and FIG. 3 shows a circuit configuration of the microwave generator 100 of FIG. It is the figure shown typically.

  2 includes a rectifier circuit 201 (FIG. 3) and a voltage control device 202 (FIG. 3). Voltage control device 202 includes a transformer 202a and a voltage control circuit 202b. The rectifier circuit 201 and the voltage control device 202 are sealed with an insulating material such as resin in the cover member IM1 (FIG. 2). The cover member IM1 is made of a resin material, and cover members IM2 and IM3 described later are made of a metal material such as aluminum (Al), for example.

  The microwave generation unit 300 in FIG. 2 includes heat radiation fins 301, a circuit board 302, and a cover member IM2. A microwave generator 303 shown in FIG. 3 is formed on the circuit board 302. The circuit board 302 is provided on the heat radiation fin 301 in the cover member IM2. The microwave generator 303 is configured by a circuit element such as a transistor, for example.

  2 includes a heat radiation fin 401, a circuit board 402, and a cover member IM3. On the circuit board 402, the three amplifiers 403, 404, and 405 of FIG. 3 are formed. The circuit board 402 is provided on the heat radiation fin 401 in the cover member IM3. Details of the amplifiers 403, 404, and 405 will be described later.

  As shown in FIG. 3, the output terminal of the microwave generator 303 is connected to the input terminal of the amplifier 403 via the line L1 formed on the circuit board 302, the coaxial cable CC1, and the line L2 formed on the circuit board 402. Has been. Note that the coaxial cable CC1 and the line L2 are connected at an insulation coupling portion MC. Details of the insulating connecting portion MC will be described later.

  An output terminal of the amplifier 403 is connected to an input terminal of the power distributor 410 via a line L3 formed on the circuit board 402. The power distributor 410 distributes the microwave input from the amplifier 403 via the line L3 and outputs it.

  Two output terminals of the power distributor 410 are connected to respective input terminals of the amplifiers 404 and 405 via lines L4 and L5 formed on the circuit board 402.

  An output terminal of the amplifier 404 is connected to one end of the coaxial cable CC <b> 2 via a line L <b> 6 formed on the circuit board 402. The other end of the coaxial cable CC2 is connected to the antenna A1. The antenna A1 is provided in the housing 501 of the microwave oven 500. Note that the coaxial cable CC2 and the line L6 are connected at the insulating connection portion MC.

  The output terminal of the amplifier 405 is connected to one end of the coaxial cable CC3 via a line L7 formed on the circuit board 402. The other end of the coaxial cable CC3 is connected to the antenna A2. The antenna A2 is provided in the housing 501 of the microwave oven 500. The coaxial cable CC3 and the line L7 are connected to each other at the insulating connection part MC.

The AC voltage _VCC is supplied from the commercial power source PS to the pair of input terminals of the rectifier circuit 201 and the primary winding of the transformer 202a. The AC voltage _VCC is, for example, 100 (V). A pair of output terminals of the rectifier circuit 201 is connected to a power line LV1 on the high potential side and a power line LV2 on the low potential side.

The rectifier circuit 201 rectifies the AC voltage VCC _supplied from the commercial power source PS, and applies the DC voltage V _DD between the power supply lines LV1 and LV2. The DC voltage V _DD is, for example, 140 (V). The power terminals of the amplifiers 403, 404, and 405 are connected to the power line LV1, and the ground terminals of the amplifiers 403, 404, and 405 are connected to the power line LV2.

The secondary winding of the transformer 202a is connected to a pair of input terminals of the voltage control circuit 202b. Trans 202a is down the AC voltage _{V CC.} The voltage control circuit 202b provides the microwave generator 303 with a variable voltage _VVA that can be arbitrarily adjusted from the AC voltage stepped down by the transformer 202a. The variable voltage _VVA is a voltage that can be adjusted between 0 and 10 (V), for example.

The microwave generator 303 generates a micro wave based on the variable voltage _{V VA} supplied from the voltage control circuit 202b. The microwave generated by the microwave generator 303 is given to the amplifier 403 via the line L1, the coaxial cable CC1, and the line L2.

  The amplifier 403 amplifies the microwave power supplied from the microwave generator 303. The microwave amplified by the amplifier 403 is given to the amplifiers 404 and 405 via the lines L3, L4, and L5.

  The amplifiers 404 and 405 amplify the microwave power supplied from the amplifier 403. The microwave amplified by the amplifier 404 is given to the antenna A1 via the line L6 and the coaxial cable CC2. The microwave amplified by the amplifier 405 is given to the antenna A2 via the line L7 and the coaxial cable CC3. Microwaves applied to the antennas A 1 and A 2 from the amplifiers 404 and 405 are radiated into the housing 501.

(3) Configuration of Amplifier and Insulation Connection Portion Next, the configuration of the amplifiers 403, 404, 405 and the insulation connection portion MC will be described.

  FIG. 4 is a diagram for explaining the amplifiers 403, 404, and 405 and the insulating connection part MC. FIG. 5 is a diagram for explaining the insulating connection part MC.

  4 is a schematic diagram showing a circuit configuration of the amplifier 404 and a cross-sectional structure of the insulating connecting portion MC as viewed from above, and FIG. 5 is a schematic diagram showing a cross-sectional structure of the insulating connecting portion MC as viewed from the side. It is. FIG. 5 shows a state where the line L6 and the coaxial cable CC2 are not connected. Although not shown, the amplifiers 403 and 405 and other insulating connection parts MC have the same configuration.

(3-1) Configuration of Amplifier First, the amplifier 404 will be briefly described.

  As shown in FIG. 4, the amplifier 404 includes chip capacitors C1 and C2, a field effect transistor (FET, hereinafter abbreviated as a transistor) Q, a line L11 constituting an input matching circuit of the transistor Q, and an output matching circuit of the transistor Q. And a line L13 for supplying driving power for the transistor Q. The line L13 is connected to the line L12. Further, the transistor Q is directly attached on the heat radiation fin 401 in an opening 406 formed in a predetermined region of the circuit board 402. Therefore, the heat generated in the transistor Q is efficiently dissipated by the heat radiation fin 401.

  The chip capacitor C1 is connected between the line L4 and the line L11. The transistor Q is connected between the line L11 and the line L12. One end of the line L13 is connected to the power supply line LV1 (see FIG. 3). The chip capacitor C2 is connected between the line L12 and the line L6.

The gate of the transistor Q is connected to the line L11, the drain is connected to the line L12, and the source is connected to the radiation fin 401. The heat radiation fin 401 is connected to the power supply line LV2 (see FIG. 3). Here, as described above, the line L13 is connected to the power supply line LV1. Therefore, a DC voltage V _DD is applied between the drain and source of the transistor Q. Further, a microwave is given to the gate of the transistor Q from the amplifier 403 (FIG. 3) via the line L3 (FIG. 3), the power distributor 410 (FIG. 3), the line L4, the capacitor C1, and the line L11.

  With the configuration as described above, the microwave given from the amplifier 403 to the amplifier 404 is amplified by the transistor Q and then given to the line L6 via the line L12 and the capacitor C2.

  As the material of the transistor Q, for example, a compound semiconductor having a high heat resistance and a high breakdown voltage such as SiC (silicon carbide) and GaN (gallium nitride) is used. The band gap of the compound semiconductor used for the transistor Q is preferably 3 (eV) or more.

(3-2) Configuration of Insulating Connection Portion Next, the insulating connection portion MC will be described.

  As shown in FIG. 5, the insulating connection part MC includes a cable side connection part 20 and an amplification part side connection part 30. The cable side connecting portion 20 is formed at one end of the coaxial cable CC2. The coaxial cable CC <b> 2 includes a first inner conductor 21, a cylindrical insulating member 22, and a cylindrical first outer conductor 23.

  The insulating member 22 is provided so as to cover the outer peripheral surface of the first inner conductor 21. One end of the first inner conductor 21 is exposed to the outside from one end of the insulating member 22, and the other end of the first inner conductor 21 is connected to the antenna A1 (FIG. 3). The other ends of the antenna A1 and the first inner conductor 21 are insulated from the housing 501.

  The first outer conductor 23 is provided so as to cover the outer peripheral surface of the insulating member 22. For example, copper, aluminum, or the like can be used as the first outer conductor 23. One end of the first outer conductor 23 has a large diameter so that a predetermined space is formed between the outer peripheral surface of the insulating member 22 and the inner peripheral surface of the first outer conductor 23 at one end of the coaxial cable CC2. ing. The other end of the first outer conductor 23 is connected to the housing 501 (FIG. 3).

  The amplification unit side coupling unit 30 is fixed to the microwave amplification unit 400 (FIG. 2). The amplifying unit side coupling unit 30 includes a cylindrical insulating member 31, a cylindrical second outer conductor 32, and a cylindrical support member 33. As the insulating member 31, for example, a dielectric insulating material such as PEEK (polyether ether ketone) which is a high heat-resistant resin and alumina which is a ceramic material is used. The support member 33 is also made of the same insulating material.

  A flange portion 31 a is formed at one end of the insulating member 31. One surface of the flange portion 31a is bonded to the cover member IM3 via the third outer conductor 35. On the inner peripheral surface of the other end of the insulating member 31, an annular protruding portion 31 b that protrudes toward the axis of the insulating member 31 is formed.

  The second outer conductor 32 has a choke guide portion 32a on one end side and a coupling guide portion 32b on the other end side. The choke guide portion 32a has a larger diameter than the connection guide portion 32b. The choke guide portion 32 a is bonded to the outer peripheral surface of the insulating member 31.

  The support member 33 is provided in the third outer conductor 35. A second inner conductor 34 is provided in the support member 33. One end of the second inner conductor 34 is connected to a line L 6 formed on the circuit board 402. A hole into which the first inner conductor 21 can be inserted is formed at the other end of the second inner conductor 34.

  Further, the inner peripheral surface of the third outer conductor 35, the inner peripheral surface of the protruding portion 31b, and the inner peripheral surface of the coupling guide portion 32b are substantially flush.

  In the above configuration, the cable side connecting portion 20 and the amplifying portion side connecting portion 30 are connected by inserting one end side of the insulating member 22 into the connecting guide portion 32b. At this time, as shown in FIG. 4, the first inner conductor 21 is inserted into the second inner conductor 34, and the first inner conductor 21 and the second inner conductor 34 are fitted and joined. Thereby, the line L6 and the first inner conductor 21 are electrically connected, and the microwave generated in the microwave generator 100 can be radiated into the housing 501 via the antenna A1.

  Note that when the microwave amplifying unit 400 is attached to the housing 501, a fixing member made of an insulating material is used.

(4) Microwave Leakage Prevention Structure Next, the microwave leakage prevention structure in the insulating connection part MC will be described.

  As shown in FIG. 4, the insulating connecting portion MC is formed so that the space portion 40 constituting the choke structure is surrounded by the first outer conductor 23, the insulating member 31, and the second outer conductor 32.

  In the present embodiment, the inner surface of the first outer conductor 23 facing the flange portion 31a across the space portion 40 (the boundary surface A between the space portion 40 and the first outer conductor 23 (in FIG. The distance between the one end of the second outer conductor 32 and the region B (the region indicated by the dotted ellipse in FIG. 4) between the one end of the second outer conductor 32 and the cover member IM3 (and the heat radiation fin 401 in FIG. 5) is It is set to an electrical length corresponding to a quarter of the wavelength of the microwave in the space 40.

  With this configuration, since the first outer conductor 23 is a metal conductor, the impedance of the boundary surface A becomes zero. Further, the impedance of the region B has a very large value (ideally infinite). This is because the impedance of the region B is inverted with respect to the impedance of the boundary surface A by the electrical action of the space portion 40.

  Further, in the present embodiment, similarly to the space portion 40, the space in which the insulating member 31 is arranged has a choke structure corresponding to a quarter of the microwave wavelength. That is, the distance between the region B and the region C facing the insulating member 22 of the protruding portion 31b is set to an electrical length corresponding to a quarter of the wavelength of the microwave in the insulating member 31. .

  As a result, the impedance of the region C is inverted with respect to the impedance of the region B, and the impedance of the region C becomes an extremely small value (ideally zero). As a result, the microwave propagating through the first inner conductor 21 is shielded (shielded) in the region C. That is, it is possible to prevent microwaves from leaking from the first inner conductor 21 to the outside via the insulating member 31. Thereby, malfunction of various apparatuses which comprise the microwave oven 1 (FIG. 1) can be prevented.

  The wavelength of the microwave varies depending on the dielectric constant of the dielectric. The dielectric constant of ceramic is larger than that of air. In the present embodiment, a dielectric material such as ceramic having a dielectric constant larger than that of air is used as the insulating member 31. Therefore, the distance between the region B and the region C is set shorter than the distance between the region B and the boundary surface A.

(5) Effect of this Embodiment As described above, in this embodiment, a compound semiconductor having a band gap of 3 (eV) or more is used as the material of the transistor Q of the amplifiers 403, 404, and 405. In this case, since a sufficiently high voltage can be applied to the transistor Q, the microwave power generated by the microwave generator 303 can be sufficiently amplified. That is, according to this embodiment, a microwave with sufficient power can be easily generated with a simple circuit configuration using a transistor.

  As shown in FIG. 4, one end of the first outer conductor 23 is in contact with the other surface of the flange portion 31 a of the insulating member 31. Further, an insulating member 31 is disposed between the second outer conductor 32 and the third outer conductor 35.

  Therefore, the first outer conductor 23 and the second outer conductor 32 are electrically insulated from the third outer conductor 35, the cover member IM3, and the heat radiation fin 401 (FIG. 5). Thereby, the housing 501 (FIG. 3) and the microwave amplifying unit 400 (FIG. 3) are electrically insulated.

  In this case, even if a high voltage is applied to the amplifiers 403, 404, and 405 (FIG. 3) of the microwave amplifying unit 400, a high voltage is not applied to the casing 501, so that the safety of the user is ensured. . In addition, since it is not necessary to provide a high-voltage transformer for insulation between the commercial power source PS and the voltage supply unit 200, the product cost of the microwave generator 100 can be reduced.

  Further, in order to electrically insulate the casing 501 (FIG. 3) and the microwave amplifying unit 400 (FIG. 3), no external conductor is provided on a part of the outer peripheral surface of the insulating member 22 (FIG. 4). By forming the region C (FIG. 4) and using the choke structure, the impedance of the region C viewed from the microwave transmitted through the first and second inner conductors 21 and 34 is extremely small (ideally, Zero). Thereby, it is possible to prevent the microwave from leaking to the outside while insulating the cover member IM3 and the radiation fin 401 from the first outer conductor 23 in the insulating connection part MC. As a result, it is possible to prevent malfunction of the components of the microwave oven 1 while ensuring the safety of the user.

  Further, in the present embodiment, the first inner conductor 21, the second inner conductor 34, the insulating member 22, and the coupling guide portion 32b are inserted while being fitted, so that the coupling guide portion 32b and the first inner conductor 21 are connected to each other. The cable-side connecting portion 20 and the amplifying portion-side connecting portion 30 are connected by fitting and joining the outer conductor 23. In this case, it is possible to prevent the cable side connecting portion 20 from rattling with respect to the amplifying portion side connecting portion 30. Thereby, since the shape of the space part 40 is prevented from changing, the impedance of the region C can be prevented from changing. As a result, it is possible to reliably prevent the microwave from leaking to the outside at the insulating connection part MC.

In the present embodiment, as described with reference to FIG. 4, the chip capacitor C <b> 2 is provided on the output terminal side of the amplifiers 404 and 405. Thereby, it is possible to prevent a high DC voltage V _DD from being applied to the user via the antennas A1 and A2. As a result, safety is further improved.

Further, a chip capacitor is provided on the input terminal side of the amplifier 403 in the same manner as the configuration of the amplifier 404 described above. Here, as described above, for example, a variable voltage _VVA of 0 to 10 (V) is applied to the microwave generator 303, and a DC voltage V _DD of 140 (V) is applied to the amplifier 403, for example. Applied. In this case, a large potential difference is generated between the microwave generator 303 and the amplifier 403. Therefore, in this embodiment, a chip capacitor is provided on the input terminal side of the amplifier 403. Thereby, failure of the microwave generator 303 due to the potential difference can be prevented.

  Further, in the present embodiment, an insulating connection part MC is provided at a connection part between the coaxial cable CC1 (FIG. 2) and the microwave amplifying part 400 (FIG. 2). Thereby, the coaxial cable CC1, the heat radiation fin 301 (FIG. 2), and the cover member IM2 (FIG. 2) can be electrically insulated from the microwave amplifying unit 400.

  Therefore, even when the radiation fin 301 or the cover member IM2 of the microwave generation unit 300 (FIG. 2) is attached to the housing 501 (FIG. 1), the microwave amplification unit 400 is electrically insulated from the housing 501. . As a result, even if a high voltage is applied to the amplifiers 403, 404, and 405 (FIG. 3) of the microwave amplifying unit 400, a high voltage is not applied to the housing 501, so that the safety of the user is reliably ensured. Is done.

(6) Other Embodiments In the above embodiment, the case where the microwave generation device 100 is mounted on the microwave oven 1 has been described. However, the microwave generation device 100 performs a plasma generation device, a drying device, and an enzyme reaction. You may mount in other apparatuses, such as a device to promote.

  In the above embodiment, the amplifiers 404 and 405 are arranged in parallel and the antennas are connected to the respective outputs. However, the outputs of the amplifiers 404 and 405 are combined with each other and connected to only one antenna. Also good.

  In the above embodiment, two parallel amplifiers are shown, but three or more amplifiers may be arranged in parallel. Three or more antennas may be provided.

  In the above embodiment, three amplifiers 403, 404, and 405 are provided. However, one, two, or four or more amplifiers may be provided.

  Further, a dielectric material such as ceramic may be provided in the space 40 of FIG. When a dielectric material such as ceramic having a dielectric constant larger than that of air is provided in the space 40, it is necessary to make the impedance of the region B viewed from the first outer conductor 23 infinite. The length along the axial direction of the space 40 can be set short. Thereby, the insulation connection part MC can be reduced in size.

(7) Correspondence between each constituent element of claims and each element of the embodiment Hereinafter, an example of correspondence between each constituent element of the claims and each element of the embodiment will be described. It is not limited to.

  In the above embodiment, the microwave generator 302 is an example of an oscillator, the antennas A1 and A2 are examples of a radiating portion, the cover member IM3 and the heat radiation fin 401 are examples of a first housing, and a coaxial cable CC2 and CC3 are examples of coaxial lines, the insulating member 31 is an example of an insulating member, the insulating member 22 is an example of a cylindrical insulating material, and the cover member IM2 and the radiation fins 301 are the second casing. For example, the chip capacitors C1 and C2 are examples of capacitive elements, and the casing 501 is an example of a third casing.

  INDUSTRIAL APPLICABILITY The present invention can be used for an apparatus that processes an object with microwaves such as a microwave oven, a plasma generation apparatus, a drying apparatus, and an apparatus that promotes an enzyme reaction.

The block diagram which shows the structure of the microwave oven which concerns on one embodiment of this invention The schematic side view of the microwave generator which comprises the microwave oven of FIG. The figure which showed typically the circuit structure of the microwave generator of FIG. The figure for demonstrating an amplifier and an insulation connection part A figure for explaining an insulation connection part

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Microwave oven 10 Power plug 100 Microwave generator 200 Voltage supply part 300 Microwave generation part 400 Microwave amplification part 401 Radiation fin 402 Circuit board 403,404,405 Amplifier 501 Housing A1, A2 Antenna CC1-CC3 Coaxial cable IM1 , IM2, IM3 Cover member MC Insulation connection

Claims (9)

A microwave generator for generating microwaves,
An oscillator that generates microwaves;
An amplifier for amplifying the microwave generated by the oscillator;
A radiating unit that radiates microwaves amplified by the amplifier;
The amplifier includes a semiconductor element made of a compound semiconductor having a band gap of 3 eV or more,
The microwave generator is characterized in that the amplifier is electrically insulated from a ground potential. A first housing for accommodating the amplifier therein;
The amplifier and the first housing are electrically connected,
The microwave generator according to claim 1, wherein the first casing is electrically insulated from a ground potential. A coaxial line for transmitting the microwave amplified by the amplifier to the radiating section;
The coaxial line includes an inner conductor for transmitting the microwave amplified by the amplifier, and an outer conductor for preventing leakage of the microwave,
The microwave generator according to claim 2, wherein the first casing and the outer conductor are electrically insulated. The first casing and the coaxial line are connected via an insulating member,
4. The microwave generator according to claim 3, wherein the outer conductor and the insulating member form a choke structure that shields leakage of microwaves transmitted by the inner conductor. The coaxial line has a cylindrical insulating material provided to cover the inner conductor in the outer conductor,
The first housing has a cylindrical guide portion,
The microwave generator according to claim 4, wherein the coaxial line is connected to the first housing by fitting the cylindrical insulating material into the cylindrical guide portion. 6. The apparatus according to claim 2, further comprising a second housing that houses the oscillator therein, wherein the first housing is electrically insulated from the second housing. The microwave generator described in 1. The microwave generator according to any one of claims 1 to 6, further comprising a capacitive element provided between an output terminal of the amplifier and the radiation unit. The microwave generator according to claim 1, further comprising a capacitive element provided between an output terminal of the oscillator and an input terminal of the amplifier. A microwave processing apparatus for processing an object using a microwave,
A third housing in which the object is disposed;
The microwave generator according to any one of claims 1 to 8, which radiates microwaves to an object arranged in the third casing,
The microwave processing apparatus, wherein an amplifier of the microwave generator is electrically insulated from the third casing.

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