EP0205316B1 - Magnétron pour un four à micro-ondes - Google Patents

Magnétron pour un four à micro-ondes Download PDF

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Publication number
EP0205316B1
EP0205316B1 EP86304299A EP86304299A EP0205316B1 EP 0205316 B1 EP0205316 B1 EP 0205316B1 EP 86304299 A EP86304299 A EP 86304299A EP 86304299 A EP86304299 A EP 86304299A EP 0205316 B1 EP0205316 B1 EP 0205316B1
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EP
European Patent Office
Prior art keywords
choke
harmonic
annular groove
metal container
cylindrical
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP86304299A
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German (de)
English (en)
Other versions
EP0205316A1 (fr
Inventor
Hisao C/O Patent Division Saito
Norio C/O Patent Division Tashiro
Munetaka C/O Patent Division Mino
Heihachi C/O Patent Division Miura
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Toshiba Corp
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Toshiba Corp
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Filing date
Publication date
Priority claimed from JP1985100486U external-priority patent/JPS6210350U/ja
Application filed by Toshiba Corp filed Critical Toshiba Corp
Publication of EP0205316A1 publication Critical patent/EP0205316A1/fr
Application granted granted Critical
Publication of EP0205316B1 publication Critical patent/EP0205316B1/fr
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Expired - Lifetime legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J23/00—Details of transit-time tubes of the types covered by group H01J25/00
    • H01J23/14—Leading-in arrangements; Seals therefor
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J23/00—Details of transit-time tubes of the types covered by group H01J25/00
    • H01J23/36—Coupling devices having distributed capacitance and inductance, structurally associated with the tube, for introducing or removing wave energy
    • H01J23/54—Filtering devices preventing unwanted frequencies or modes to be coupled to, or out of, the interaction circuit; Prevention of high frequency leakage in the environment

Definitions

  • This invention relates to magnetrons for microwave ovens and more particularly to a construction such as to suppress radiation of higher harmonics.
  • a magnetron for a microwave oven generates microwaves in the 2450 MHz band in a cavity resonator of the anode. Apart from the power generated at the fundamental frequency in this 2450 MHz band, some power is also generated at so-called "higher harmonics". These higher harmonic components are frequencies which are integral multiples of the fundamental frequency. They are propagated into the heating cavity of the microwave oven. However, shielding of microwave radiation increases in difficulty as the wavelength becomes shorter. Proper electromagnetic shielding of the microwave oven therefore becomes difficult and such higher harmonic components tend to leak to the outside. Even slight microwave leakage causes radio interference and the permitted amount of such leakage is legally prescribed.
  • the output part of the magnetron itself is formed with a 1/4 wavelength choke to suppress higher harmonic generation, and it is already known to suppress radiation of arbitrarily specified higher harmonic components. Examples are disclosed in the specifications of Laid-open Japanese Utility Model No. Sho. 49-80648, Japanese Patent Publication No. Sho. 56-21215, Japanese Patent Publication No. Sho. 54-6862, or Japanese Utility Model Publication No. Sho. 54-18123.
  • a magnetron body 30 is equipped with an anode cylinder 31, a plurality of anode vanes 32, a pole piece 33, a cathode 34, and an output antenna 35.
  • Output antenna 35 is equipped with an antenna lead 36 that is electrically coupled to an anode vane 32, a tubular metal container 37, an inner metal cylinder 38, a ceramic insulating cylinder 39, a metal exhaust pipe 40, and an output cap 41.
  • a plurality of radiator fins 42 are fixed around the periphery of anode cylinder 31. Ferrite magnets 43 and 44 surrounded by a magnetic yoke 45 are disposed at both ends of body 30. Output antenna 35 extends through magnets 43 and yoke 45.
  • a cathode input terminal 47 is provided in a shielding box 46.
  • the end of antenna 36 is electrically coupled to metal exhaust pipe 40.
  • An arrangement providing a choking effect on the second and third harmonics is achieved by making the depth L1 of the inside space A of the metal exhaust pipe, that short-circuits the end of the antenna lead, of a dimension corresponding to about 1/4 of the wavelength of for example the second harmonic and by making the depth L2 of the annular groove B formed with the metal container 37 and inner metal cylinder 38 of a dimension corresponding to about 1/4 of the wavelength of for example the third harmonic.
  • the dimensions of such chokes can be set to correspond electrically to 1/4 of the wavelength of any arbitrarily specified higher harmonic.
  • magnetrons were manufactured incorporating chokes that suppressed the second or third harmonic, since there were the harmonics at which in general relatively most power was generated.
  • the magnetrons that are widely used in domestic microwave ovens have a fundamental frequency of about 2450 MHz, with microwave output power generally of the order 500-800 W.
  • the dimensions of the insulating cylinder of the output part and of its vicinity have to be made such as to avoid the possibility of discharge at microwave frequencies due to the microwave electric field when the magnetron is operated under no load conditions.
  • the internal diameter of the insulating cylinder should be at least 12 mm, and its axial length at least 10 mm.
  • the object of this invention is to provide a magnetron for a microwave oven having a choke construction that is very effective in suppressing radiation of harmonic frequencies of the fourth harmonic or higher.
  • a magnetron for a microwave oven generating a fundamental frequency in the 2450 Mhz band, and comprising:
  • Fig. 1 and Fig. 2 The embodiment shown in Fig. 1 and Fig. 2 is constructed as follows.
  • 30 is a magnetron body;
  • 34 is a cathode;
  • 34a and 34b are a pair of end hats;
  • 31 is an anode cylinder;
  • 32 is a plurality of radial anode vanes;
  • 32a and 32b are strap rings;
  • 33 is a funnel shaped pole piece;
  • 33a is a through hole provided in part of the pole piece for passage of the antenna lead;
  • 37 is a cylindrical metal container of the output part, sealed to the end face of the anode at which pole piece 33 is located, to form an evacuated envelope in combination with the anode;
  • 37a is a flange coupled hermetically to the anode cylinder;
  • 37b is an opening provided at its tip, through which antenna lead 36 passes;
  • 39 is a ceramic insulating cylinder of the output part;
  • 40 is a metal exhaust pipe
  • annular space A1 is formed between metal exhaust pipe 40 electrically connected to the tip of antenna lead 36 and the part of antenna lead 36 that lies inside this metal exhaust pipe.
  • annular space A2 is formed between this metal exhaust pipe and metal cylinder 48 for the external choke.
  • annular groove B of a choke B1 of prescribed depth showing a choke effect on the fifth harmonic is formed on the inside of tip opening 37b of metal container 37, whose flange- shaped peripheral edge is gas-tightly coupled to the open end of the anode cylinder.
  • an intermediate tubular conductor 51 is electrically coupled with the inside of tip opening 37b of metal container 37, a gasket-retaining metal ring is electrically coupled thereto, and in addition an expanded flange 53a of an inner tubular conductor 53 is in turn gas-tightly coupled thereto.
  • This expanded flange 53a is gas-tightly coupled by brazed joint 39a to the bottom end of insulating cylinder 39.
  • Inner tubular conductor 53 and intermediate tubular conductor 51 are arranged coaxially adjacent around antenna 36, which is formed as a cylindrical rod.
  • Annular choke groove B forthe fifth harmonic is formed by disposing two annular conductors 53 and 51 adjacent each other with a separation.
  • the depth Lb of this annular choke groove B is electrically about 1/4 of the wavelength of the fifth harmonic: that is, it has a choking effect showing high impedance for the fifth harmonic.
  • the microwave oven magnetron of this example has a fundamental frequency in the 2450 MHz band, with output of the order about 800 W.
  • Insulating cylinder 39 cylindrical pipe of internal diameter 13 mm, axial length 10 mm;
  • Antenna lead 36 cylindrical copper rod of diameter DO 2.5 mm;
  • Metal container 37 internal diameter 19.0 mm, axial height 12 mm;
  • Inner tubular conductor 53 thickness 0.5 mm, internal diameter D1 9.5 mm, axial length 6.5 mm;
  • Depth Lb of annular groove B formed by the two tubular conductors 5.8 mm, opening width Gb 0.8 mm.
  • the beneficial effect which is obtained by this invention is due to the fact that, thanks to the inner tubular conductor provided around the antenna lead for about 1/2 less of the higher harmonic wavelength, radiation of which is to be suppressed, the space between this inner tubular conductor and the antenna lead has a diametric dimension which is less than 1/2 of this higher harmonic wavelength and a choke is constituted consisting of the annular groove that is formed there.
  • a choke is constituted consisting of the annular groove that is formed there.
  • the choke for the fifth harmonic is constituted by this region.
  • the inventors measured the fifth harmonic radiation level for various different internal diameters D1 of this internal tubular conductor 53, keeping the diameter DO of the antenna lead constant at 2.5 mm.
  • the depth Lb of annular groove B was also kept constant at 5.8 mm. The results are shown in Fig. 4. From these results, it can be seen that sufficient choking effect is obtained provided the internal diameter D1 is not more than 14 mm. This confirms that the internal diameter D1 should be not more than about 1/2 of the wavelength of the fifth harmonic.
  • width Gb of the opening of the annular choke groove not more than 1/10 of the higher harmonic wavelength. That is, if, as shown in Fig. 5, the opening width Gb is made about 1/10, preferably about 1/20 or less (but not including zero width) wavelength of the fifth harmonic corresponding to the choke, an excellent choking effect is obtained.
  • the wavelength of the fifth harmonic is believed to be its interaction with the annular groove C that is provided at its periphery, or its electrical interactions, such as the fringing effect, at the openings of the two tubular conductors.
  • the depth of the annular groove need not necessarily be strictly identical with 1/4 of the spatial wavelength of the higher harmonic wavelength that is to be suppressed, but is to be set thereabouts to the value at which the greatest radiation suppression effect is obtained.
  • the inner tubular conductor projects inwards further than the gas-tight brazed joint at the bottom end of the insulating cylinder, so this brazed joint is screened from the high-frequency electric field between the antenna lead and these conductors, with the result that there is little risk of unwanted microwave discharge and resultant cracking of the brazed joint.
  • the inventors also recognized that the level of radiation of the fourth harmonic can be considerably reduced by further increasing the depth of the annular groove to in the neighbourhood of 7.1 mm. Any desired higher order harmonics such as the forth and higher harmonics can therefore be selectively and reliably suppressed in this way.
  • a combined choke construction can be achieved by setting annular groove C formed at the periphery of the choke groove for the fifth harmonic to about 1/4 of the wavelength of a specified harmonic.
  • This annular groove C is the annular groove formed by metal container 37 and intermediate tubular conductor 51.
  • FIG. 6 A further embodiment is shown in Fig. 6.
  • This embodiment consists of a magnetron wherein inner tubular conductor 53 that provides the higher order harmonic choke comprising annular groove B is directly gas-tightly soldered to the bottom end face of insulating cylinder 39.
  • the top end of tubular metal container 37 is bent inwards in the form a half cross-section U so that it is integrally formed with intermediate tubular conductor 51. At the top end of the bent portion it is electrically short-circuited by a gas-tight brazed joint with gasket-retaining ring 52 and the end face of inner tubular conductor 53.
  • the inner diameter D1 of inner tubular conductor 53 is of a dimension about 1/2 of, or less than the wavelength of the fifth harmonic. For example, dimension D1 is 13.6 mm, D2 is 15.8 mm, and Gb is 0.6 mm.
  • FIG. 7 A further embodiment is shown in Fig. 7.
  • the top end of metal container 37 is bent inwards to serve as intermediate tubular conductor 51, thereby forming an annular groove C of depth Lc corresponding to about 1/4 of the wavelength of the fourth harmonic.
  • the inner diameter D2 of intermediate tubular conductor 51 that forms this annular groove C is about 1/2 of, or less than the wavelength of the fourth harmonic.
  • Inner tubular conductor 53 is coaxially arranged so as to lie adjacent the inner periphery of intermediate tubular conductor 51, thus forming in cooperation with this intermediate tubular conductor 51 an annular groove choke B for the fifth harmonic.
  • the width Gc of annular groove C is less than about 1/10 of the wavelength of the fourth harmonic, and as stated previously opening width Gb of annular groove B is about 1/10 of the wavelength of the fifth harmonic.
  • Fig. 8 shows yet a further embodiment of this invention.
  • a small diameter portion 37c is formed by bending part of metal container 37, that is coupled hermetically to the anode, inwards, and inner tubular conductor 53 is electrically connected on the inside of this small diameter portion.
  • the internal diameter of this inner tubular conductor 53 is of a dimension about 1/2 of, or less than the wavelength of the fifth harmonic.
  • this region provides an annular groove B serving as a choke for the fifth harmonic.
  • the dimensions of this groove B are the same as in the preceding embodiment.
  • the opening of the choke for the fifth harmonic constituted by the annular groove, is constructed so as to face the anode direction.
  • opening Bg of annular groove B formed by two tubular conductors 51 and 53 can provide a choke for higher harmonics in the region inside metal container 37 and facing insulating cylinder 39.
  • the annular groove forming the choke for the higher order harmonics can be bent in L-shaped cross-section as shown in Fig. 9.
  • the groove depth that gives the choking effect is an electrical length determined by the spatial dimensions of the L shape.
  • the whole of the output part is constructed of a diametric dimension corresponding to about 1/2 of the higher harmonic wavelength corresponding to the higher harmonic choke provided in the internal region of the metal container, so reliable suppression of higher harmonic radiation can be achieved, and cylindrical permanent magnet 43 that is arranged at the periphery of the metal container part can be made of comparatively small dimensions. This increases the utilization of the magnetic field of the magnet and makes it possible to make the overall magnetron construction more compact.
  • choke annular groove C for the fourth harmonic and choke annular groove B for the fifth harmonic and a choke annular groove E for the sixth harmonic are mutually coaxially formed at the same location in the region inside metal container 37.
  • an approximately U-shaped choke member 61 is fixed to the inside of metal container 37 so as to form two annular grooves C and B arranged with their openings facing mutually opposite directions.
  • a further approximately U-shaped member 62 is fixed to the inside of this choke member 61 so as to form annular groove E.
  • the depth dimensions of these respective annular grooves correspond to about 1/4 of the wavelength of the higher order harmonic that they are intended to stop.
  • the internal diametric dimension D1 of inner cylindrical part of innermost choke member is about 1/2 of or less than the wavelength of the sixth harmonic, but is of such a dimension as not to give rise to microwave discharge between itself and antenna 36.
  • FIG. 12 A further embodiment of this invention is shown in Fig. 12.
  • four conductor cylinders 63, 64, 65 and 66 constituting a choke member are fixed mutually coaxially in the inside region of metal container 37.
  • Choke annular grooves C, B, E and F are thereby formed.
  • Choke annular groove C is of a depth dimension corresponding to about 1/4 of the wavelength of the fourth harmonic.
  • Choke annular groove B is of a depth dimension corresponding to about 1/4 of the wavelength of the fifth harmonic.
  • Choke annular groove E is of a depth dimension corresponding to about 1/4 of the wavelength of the sixth harmonic.
  • Choke annular groove F is of a depth dimension corresponding to about 1/4 of the wavelength of the seventh harmonic.
  • the internal diameter D1 of the innermost conductor cylinder 66 is 9 mm, corresponding to about 1/2 of the wavelength of the seventh harmonic.
  • outermost L-shaped annular groove C constitutes a choke groove of about 1/4 the wavelength of the fourth harmonic
  • groove B which lies inside it constitutes a choke groove of about 1/4 the wavelength of the fifth harmonic
  • groove E constitutes a choke groove of about 1/4 the wavelength of the sixth harmonic
  • groove F constitutes a choke groove of about 1/4 the wavelength of the seventh harmonic.
  • These choke members are formed by assembling U-shaped conductors 67 and 68, 69.
  • FIG. 14 A further embodiment of this invention is shown in Fig. 14.
  • choke annular grooves C, Band E for the fourth, fifth and sixth order harmonics are arranged in the inner region of metal container 37 so that their openings respectively face in the direction of insulating cylinder 39.
  • the inside diameter D1 of innermost conductor cylinder 66 is about 1/2 of the wavelength of the sixth harmonic.
  • integrally formed choke members 70 are provided in the inside region of metal container 37.
  • These choke members 70 consist of a double-skinned thin metal cylinder made for example of copper. This is a single component constructed of an inner cylindrical part 53 and outer cylindrical part 51 formed unitarily by deep drawing using a press. Their opening Bg is directed towards the anode vanes. As shown in Fig. 17, they fit from the bottom onto a step 37d near the upper end of the metal container, being brazed in place around the entire circumference.
  • Extreme end opening 37b of metal container 37 extends further inwards than the brazed joint 39a of insulating cylinder 39, so that it forms an essentially continuous conductive cylinder of the sam6,internal diameter with inner cylinder 53 of choke member 70.
  • the depth dimension Lb of choke member 70, and the internal diametric dimension D1 and opening width Bg of inner cylinder 53 respectively have the same dimensional relationships with the wavelength of the fifth harmonic that is to be suppressed as in the previous embodiments.
  • the choke cylinder consisting of inner and outer cylinders is integrally formed as a single component, the depth Lb of annular groove B can be precisely formed to the prescribed dimension before this component is fitted in the magnetron. This avoids statistical scatter, i.e. manufacturing variations, of the groove depth and therefore permits assembly with the dimension that gives the best possible supppression of any specified higher order harmonic. This enables products with a uniformly good higher order harmonic suppression characteristic to be mass-produced. Handling is also facilitated by the fact that the choke cylinder is a unitary component.
  • annular choke groove B for the fifth harmonic.
  • an electromagnetic wave absorber 71 such as carbon or silicon carbide (SiC) is disposed in annular choke groove B for the fifth harmonic.
  • choke member 70 is integrally coated with inner cylindrical part 53 and outer cylindrical part 51, which are formed by a continuous layer of copper plating on the inside and outside faces and one end face of a ceramic dielectric cylinder 72.
  • An end face 53g of the inner cylindrical part is formed as a curved face to prevent microwave discharge.
  • the end face of a thin part of a fixing metal ring 73 is brazed to one end face.
  • Ceramic dielectric 72 essentially constitutes annular choke groove B while its other end part 72a forms the opening of this choke member.
  • Choke member 70 is thus formed from a single integrally constructed component and is mounted in the inside region of metal container 37.
  • the electrical length of the choke cylinder is thereby increased by the dielectric constant of the ceramic dielectric, so the actual length in the axial direction can be decreased in proportion. Also, since the shape and dimensions of the "annular groove" choke formed by the ceramic dielectric and the conductive layer with which its circumference is coated are fixed, they can be preset accurately, so that the dimensions giving the optimum radiation suppressing effect are easily obtained.
  • More than one choke member can be connected to the inside of the metal container. These choke members can be used in combination or singly to>_construct chokes for suppression of higher order harmonics.

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  • Microwave Tubes (AREA)

Claims (13)

1. Magnétron pour fours à micro-ondes opérant à une fréquence fondamentale située dans la bande de 2450 MHz et qui comprend:
une cathode (34);
une anode cylindrique (31) entourée d'une cavité résonnante;
un boîtier cylindrique en métal (37) dont l'une des extrémités est scellée hermétiquement soit directement, soit à travers une pièce polaire (33), à ladite anode cylindrique afin de former une enveloppe évacuée, et présentant une ouverture à l'autre extrémité, et définissant un espace entre les deux extrémités dudit boîtier métallique cylindrique dans ladite enveloppe évacuée;
un cylindre isolant de sortie (39) couplé hermétiquement à ladite ouverture dudit boîtier métallique cylindrique;
un conducteur d'antenne de sortie (36) dont l'une des extrémités est couplée électriquement à ladite cavité résonnante de ladite anode et qui s'étend le long de l'espace intérieur dudit cylindre isolant de sortie, en passant à travers ladite ouverture dudit boîtier métallique cylindrique; et
un moyen d'arrêt entourant ledit conducteur d'antenne au moyen d'un conducteur cylindrique incluant une rainure annulaire formant un moyen d'arrêt quart d'onde d'un harmonique supérieur spécifié caractérisé en ce qu'il comprend:
un moyen pour supprimer le rayonnement desdits harmoniques supérieurs et, au moins, du cinquième harmonique, présente une rainure annulaire (B) (C) (E) (F) formant une ouverture et située dans ledit espace dudit boîtier métallique cylindrique; et
des moyens pour régler le diamètre intérieur (D1) dudit conducteur métallique cylindrique à une dimension égale à environ la moitié ou moins de ladite longueur d'onde dudit harmonique supérieur spécifié.
2. Magnétron selon la revendication 1, caractérisé en ce que la largeur radiale (Gb) dudit moyen de suppression à ou près de ladite ouverture de ladite rainure annulaire (B) est formée de façon à ne pas dépasser un dixième de la longueur d'onde dudit harmonique supérieur.
3. Magnétron selon la revendication 1, caractérisé en ce que ledit moyen de suppression est formé d'au moins un conducteur métallique (51, 53, 61, 63, 64, 65, 66) situé dans ledit boîtier métallique.
4. Magnétron selon la revendication 1, caractérisé en ce que ledit moyen de suppression présente plusieurs rainures annulaires.
5. Magnétron selon la revendication 1, caractérisé en ce que ledit boîtier métallique cylindrique fait partie dudit moyen de suppression.
6. Magnétron selon la revendication 1, caractérisé en ce que la paroi de l'ouverture dudit boîtier cylindrique en métal est définie par un cylindre faisant partie dudit moyen de suppression.
7. Magnétron selon la revendication 1, caractérisé en ce que ledit boîtier cylindrique en métal s'étend dans la direction dudit conducteur d'antenne et est entouré, au pourtour du boîtier cylindrique en métal par un aimant permanent cylindrique.
8. Magnétron selon la revendication 1, caractérisé en ce que ledit moyen de suppression comporte plusieurs rainures annulaires disposées coaxialement (B) (C), la rainure annulaire intérieure (B) formant un moyen de suppression pour des harmoniques d'ordre plus élevé que la rainure annulaire extérieure (C).
9. Magnétron selon la revendication 1, caractérisé en ce qu'une ouverture de ladite rainure annulaire (Bg) débouche en direction dudit cylindre isolant (39).
10. Magnétron selon la revendication 1, caractérisé en ce qu'un élément (71) absorbant les ondes électromagnétiques est disposé dans ladite rainure annulaire.
11. Magnétron selon la revendication 1, caractérisé en ce qu'une matière diélectrique est disposée dans ladite rainure annulaire.
12. Magnétron selon la revendication 1, caractérisé en ce qu'un conducteur cylindrique formant un moyen de suppression (A1) pour le second harmonique est arrangé à l'extrémité dudit cylindre isolant (39) et est connecté à l'extrémité dudit conducteur d'antenne.
13. Magnétron selon la revendication 12, caractérisé en ce qu'une rainure annulaire (A2) pour supprimer le second et le troisième harmoniques est aussi disposée coaxialement à ladite seconde rainure annulaire (A1) destinée audit second harmonique.
EP86304299A 1985-06-07 1986-06-05 Magnétron pour un four à micro-ondes Expired - Lifetime EP0205316B1 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
JP12260685 1985-06-07
JP122606/85 1985-06-07
JP1985100486U JPS6210350U (fr) 1985-07-03 1985-07-03
JP100486/85U 1985-07-03

Publications (2)

Publication Number Publication Date
EP0205316A1 EP0205316A1 (fr) 1986-12-17
EP0205316B1 true EP0205316B1 (fr) 1990-05-23

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Application Number Title Priority Date Filing Date
EP86304299A Expired - Lifetime EP0205316B1 (fr) 1985-06-07 1986-06-05 Magnétron pour un four à micro-ondes

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EP (1) EP0205316B1 (fr)
KR (1) KR890004840B1 (fr)
DE (1) DE3671568D1 (fr)

Families Citing this family (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4833367A (en) * 1986-11-21 1989-05-23 Hitachi, Ltd. Magnetron with resonant choke structure for supressing unwanted harmonics
EP0339374B1 (fr) * 1988-04-25 1994-03-02 Matsushita Electronics Corporation Magnétron
EP0426130B1 (fr) * 1989-10-31 1995-12-20 Kabushiki Kaisha Toshiba Magnétron pour four à micro-ondes ayant une structure de filtrage
US5180946A (en) * 1990-02-15 1993-01-19 Sanyo Electric Co., Ltd. Magnetron having coaxial choke means extending into the output side insulating tube space
KR100209690B1 (ko) * 1997-05-31 1999-07-15 구자홍 전자레인지용 마그네트론
KR19990001481A (ko) * 1997-06-16 1999-01-15 구자홍 마그네트론
JP3622742B2 (ja) * 2002-07-31 2005-02-23 松下電器産業株式会社 マグネトロン
JP6723043B2 (ja) * 2016-03-25 2020-07-15 東芝ホクト電子株式会社 マグネトロン
KR102082506B1 (ko) 2018-02-09 2020-02-27 엘지전자 주식회사 고조파 차폐 성능이 개선된 마그네트론

Family Cites Families (8)

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Publication number Priority date Publication date Assignee Title
CH466454A (de) * 1967-11-23 1968-12-15 Patelhold Patentverwertung Breitband-Filter am Ausgang eines Hochfrequenz-Generators für dielektrische Erwärmung
US3849737A (en) * 1972-12-18 1974-11-19 Hitachi Ltd Magnetron with choke structure for reducing harmonics in output
US3872412A (en) * 1974-04-26 1975-03-18 Bell Telephone Labor Inc Dielectric-loaded chokes
US4006382A (en) * 1975-09-24 1977-02-01 Raytheon Company Magnetron filter
NL7700417A (nl) * 1977-01-17 1978-07-19 Philips Nv Trilholtemagnetron voorzien van een antenne- -uitkoppelsysteem.
JPS5824371Y2 (ja) * 1977-09-27 1983-05-25 株式会社東芝 マグネトロン
NL7907593A (nl) * 1979-10-15 1981-04-21 Philips Nv Magnetron.
JPS6217973Y2 (fr) * 1980-04-30 1987-05-08

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Publication number Publication date
KR870000739A (ko) 1987-02-20
EP0205316A1 (fr) 1986-12-17
DE3671568D1 (de) 1990-06-28
KR890004840B1 (ko) 1989-11-29

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