US3851133A - Microwave oven with antenna chamber, antenna, and radiation slots - Google Patents

Microwave oven with antenna chamber, antenna, and radiation slots Download PDF

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Publication number
US3851133A
US3851133A US00444153A US44415374A US3851133A US 3851133 A US3851133 A US 3851133A US 00444153 A US00444153 A US 00444153A US 44415374 A US44415374 A US 44415374A US 3851133 A US3851133 A US 3851133A
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US
United States
Prior art keywords
antenna
oven
chamber
microwave
radiation
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
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US00444153A
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English (en)
Inventor
H Dygve
P Risman
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Husqvarna Vapenfabriks AB
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Husqvarna Vapenfabriks AB
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Publication of US3851133A publication Critical patent/US3851133A/en
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Expired - Lifetime legal-status Critical Current

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    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B6/00—Heating by electric, magnetic or electromagnetic fields
    • H05B6/64—Heating using microwaves
    • H05B6/72—Radiators or antennas
    • H05B6/725—Rotatable antennas
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B6/00—Heating by electric, magnetic or electromagnetic fields
    • H05B6/64—Heating using microwaves
    • H05B6/6426—Aspects relating to the exterior of the microwave heating apparatus, e.g. metal casing, power cord
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B6/00—Heating by electric, magnetic or electromagnetic fields
    • H05B6/64—Heating using microwaves
    • H05B6/72—Radiators or antennas

Definitions

  • the present invention relates to microwave ovens for processing foods and the like, and has a specially shaped ovenspace, which space, together with radiation elements provides exceptionally good energy transfer to the object being processed.
  • one pattern of standing waves is formed within'the cavity, lack of adaptation between the cavity and the waveguide/generator entails a reduction in the energy which, through a cooling unit, or the like, is given up to the atmosphere as lost heat. It must therefore be considered as an urgent requirement to provide an oven chamber, having improved efficiency and economy.
  • the processing chamber for such uniform objects as sausages and the like can suitably form a terminal enlargement of a waveguide with proportions adapted to the packaging, there is inducement to discover whether such a space is an advantageous form of treatment chamber for other forms of loads as well. Therefore the application of the cavity resonance principle was abandoned and instead, a socalled near field principle was utilized.
  • microwave ovens which are known, are those having a slotted bottom plate of metal, through which microwaves from a magnetron are led through a wave-guide system to the oven chamber.
  • This type of energy transfer to the oven chamber has two drawbacks, however.
  • the waveguides cannot feed the slotted plate/oven chamber symmetrically, since the microwaves can come from 1 normally one and at the most three, sides.
  • the field pattern in the wave-guides is affected to a relatively large extent by the geometry and the character of the load in the oven chamber.
  • the field pattern can in certain cases be such that there will be alternating cold and overheated parts of the load.
  • the pattern of energy absorbed in the load is thus determined to a certain extent by the load itself, and the tendency that internal resonances will occur in the load remains.
  • An antenna chamber is located under or over the oven chamber, between the waveguide and the oven chamber, having a small infeed opening, relative to the microwave wavelength, i.e., coaxial transition, and a side thereof nearest the oven chamber equipped with holes or slots. Furthermore, an antenna system is provided in the antenna chamber by means of which stable control of the microwave field in the chamber is obtained. The antenna and antenna chamber are made so that the electromagnetic energy stored in the system is large with respect to the energy transport through it.
  • FIG. 1 shows, in perspective, a microwave oven according to the invention.
  • FIG. 2 is a cross section of the microwave oven as shown in FIG. 1.
  • the roof height is about one wavelength, i.e., at the frequency of 2,400 megacycles, about 12 cm.
  • the sides 1, 2, 3 and the lid 4 of the furnace chamber serve first of all for the purpose of keeping the microwave radiation contained in a limited volume.
  • the energy enters the oven chamber according to FIG. 1 through slots 5 in the bottom 6 of the oven. Below the bottom there is an antenna chamber 7, and under this a waveguide 8 leading to this chamber from a magnetron 9.
  • the antenna chamber 7 Immediately below the oven chamber, in the embodiment shown, is the antenna chamber 7 whose height is less than half a wavelength of the microwave radiation.
  • the chamber 6 participates in the energy transfer from the magnetron to the oven chamber, and in addition this transfer includes an antenna system 11 with extensions into the antenna chamber, a coaxial inner conductor 12, which feeds the'antenna system, and waveguide 8 with door-knob transition 13 to the coaxial conductor.
  • the wave-guide is of the TE, type and is closed at both ends.
  • the magnetron 9 is preferably placed in a chamber to one side of, or behind the antenna chamber.
  • the socalled door knob transition is formed in principle of a cupolashaped indentation 14 in the lower wave-guide side, and the coaxial conductor which also forms the central conductor of the antenna system, is connected in the center of the indentation 14.
  • the wave-guide also has an antenna passage in the end facing the magnetron, in which the antenna of the magnetron projects into the wave-guide.
  • the antenna system in the embodiment shown, is composed of two metal rods 15, 16 placed crosswise to one another and fed from the center.
  • the system is supported from below by a central conductor 12 which passes through a hole 17 in the upper side 18 of waveguide 8, and the bottom 19 of the antenna chamber.
  • a bearing of the central conductor on the indentation 14, so that the system is rotatable. This is indicated in FIG. 2 with an appropriate arrow around an extended shaft 20.
  • Metal rods l5, 16 are suitably coated with a plastic or ceramic layer to re Jerusalem the risk of arcing to adjoining parts of the chamber.
  • the walls and roof of the antenna chamber can be provided with similar coatings.
  • a reactance stub 21 which extends from the floor to the roof of the chamber. This fulfills the purpose, on the one hand, of providing greater mechanical strength at the oven bottom and on the other hand to modify the field in the antenna chamber.
  • the bottom of the oven is also reinforced by a plate 22 of, for example, ceramic above the slotted bottom 6.
  • Each slot is arranged in a certain pattern and in the model shown are parallel and oblique at a given angle.
  • Each slot has a length of approximately half a wavelength of the microwave radiation, and can be straight or arced.
  • Each slot serves as a radiating element and is surrounded by a field pattern resembling that around a dipole.
  • An object to be heated is placed in the oven and is exposed to the near field from the radiating element which is spread out in a pattern over the entire bottom surface of the oven.
  • the energy field from slots with no load near them is evanescent and the energy is returned back into the antenna chamber. This means, that the energy output from slots with a load above and near them is increased, thus improving the microwave efficiency without causing unwanted effects, such as uneven distribution of the energy in the load.
  • Some part of the microwave energy may pass through the object but is reflected against the roof of the oven and then back to the object. The total efficiency of the energy transfer to the object therefore is particularly good.
  • a microwave oven for processing food with microwave radiation comprising:
  • an oven chamber the top and bottom walls of which are spaced apart by substantially no more than one wavelength of said microwave radiation, said oven chamber having a door for access thereto and at least one side thereof having a plurality of radiation openings for the introduction of said microwave energy thereto; antenna chamber means disposed adjacent to said at least one side of said oven chamber so that said radiation openings radiatively communicate said antenna chamber means with said oven chamber;
  • said antenna means having feeding means connnected thereto for receiving said microwave radiation located substantially in the center of said antenna chamber means and having structural distributing elements which lie in a plane substantially parallel to said radiation openings in said at least one side of said oven chamber.
  • said antenna chamber means is disposed adjacent to said bottom wall of said oven chamber and has a height of substantially no more than half of a wavelength of said microwave energy, which height is measured between the top side of said antenna chamber means adjacent said bottom wall of said oven chamber, and the bottom side of said antenna chamber means substantially parallel thereto.
  • An oven as claimed in claim 4 wherein said antenna means receives microwave radiation at said feeding means by means of wave-guide transition, and said feeding means comprising a feeder line connected to said antenna means through a wall of said antenna chamber means.
  • said structural distributing elements of said antenna means comprise at least two metal rods disposed crosswise to one another so as to define an interconnecting point thereof which interconnecting points is joined to said feeder line.
  • said feeding means comprises rotatable means whereby said antenna means connected thereto is rotatable in said antenna chamber means.

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  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Constitution Of High-Frequency Heating (AREA)
  • Electric Ovens (AREA)
US00444153A 1973-03-07 1974-02-20 Microwave oven with antenna chamber, antenna, and radiation slots Expired - Lifetime US3851133A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
SE7303174A SE369026B (de) 1973-03-07 1973-03-07

Publications (1)

Publication Number Publication Date
US3851133A true US3851133A (en) 1974-11-26

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Family Applications (1)

Application Number Title Priority Date Filing Date
US00444153A Expired - Lifetime US3851133A (en) 1973-03-07 1974-02-20 Microwave oven with antenna chamber, antenna, and radiation slots

Country Status (7)

Country Link
US (1) US3851133A (de)
JP (1) JPS5424134B2 (de)
CH (1) CH567696A5 (de)
FR (1) FR2220958B1 (de)
GB (1) GB1461194A (de)
NL (1) NL7402977A (de)
SE (1) SE369026B (de)

Cited By (23)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2295672A1 (fr) * 1974-12-18 1976-07-16 Husqvarna Ab Applicateur de micro-ondes, notamment pour fours de cuisson de produits alimentaires
DE2622173A1 (de) * 1975-05-19 1976-12-02 Matsushita Electric Ind Co Ltd Vorrichtung zur beheizung eines gegenstandes mittels hochfrequenter strahlung, insbesondere mikrowellen- ofen
JPS5276751A (en) * 1975-11-07 1977-06-28 Philips Nv Microwave furnace
DE2757710A1 (de) * 1976-12-23 1978-06-29 Raytheon Co Verfahren und anordnung zur erhitzung von substanzen mit mikrowellenenergie
WO1981003701A1 (en) * 1980-06-10 1981-12-24 Envirotech Corp Integrity check for ultrasonic fluid interface sensing system
US4314127A (en) * 1977-11-02 1982-02-02 Raytheon Company Microwave oven with rotating multiport radiator
US4316069A (en) * 1979-12-03 1982-02-16 General Electric Company Microwave oven excitation system
US4342896A (en) * 1976-12-23 1982-08-03 Raytheon Company Radiating mode stirrer heating system
US4343976A (en) * 1979-03-19 1982-08-10 U.S. Philips Corporation Energy feed system for a microwave oven
US4350859A (en) * 1980-05-05 1982-09-21 Raytheon Company Microwave oven feed system
US4354083A (en) * 1980-11-05 1982-10-12 General Electric Company Microwave oven with novel energy distribution arrangement
US4430538A (en) 1980-08-28 1984-02-07 Tokyo Shibaura Denki Kabushiki Kaisha High-frequency heating device
US4458126A (en) * 1982-03-30 1984-07-03 General Electric Company Microwave oven with dual feed excitation system
US4962298A (en) * 1988-07-18 1990-10-09 Barilla G.E.R. F.LII-Societa per Azoni Machine for thermally treating and sterilizing pre-packaged food articles by means of microwaves
US5990466A (en) * 1998-04-02 1999-11-23 Turbochef Technologies, Inc. Apparatus for supplying microwave energy to a cavity
US6008483A (en) * 1998-10-09 1999-12-28 Turbochef Technologies, Inc. Apparatus for supplying microwave energy to a cavity
US6617558B2 (en) * 1998-02-19 2003-09-09 Framatome Anp Gmbh Furnace for microwave sintering of nuclear fuel
US20050173422A1 (en) * 2004-01-15 2005-08-11 Hiroyuki Kato Cooking device
US7092988B1 (en) 1997-05-27 2006-08-15 Jeffrey Bogatin Rapid cooking oven with broadband communication capability to increase ease of use
US8224892B2 (en) 2000-04-28 2012-07-17 Turbochef Technologies, Inc. Rapid cooking oven with broadband communication capability to increase ease of use
RU2581689C2 (ru) * 2014-08-08 2016-04-20 Федеральное государственное бюджетное образовательное учреждение высшего образования "Саратовский государственный технический университет имени Гагарина Ю.А." (СГТУ имени Гагарина Ю.А.) Свч-печь
US20170171922A1 (en) * 2014-07-10 2017-06-15 Panasonic Intellectual Property Management Co., Ltd. Microwave heating device
FR3065612A1 (fr) * 2018-06-12 2018-10-26 Omar Houbloss Guide d'onde couple a une antenne pour la distribution thermique dans un four micro-onde ou un four multimode avec la fonction micro-onde

Families Citing this family (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5259343A (en) * 1975-11-10 1977-05-16 Matsushita Electric Ind Co Ltd High frequency heater
JPS5241939A (en) * 1975-09-29 1977-03-31 Matsushita Electric Ind Co Ltd High-frequency heating apparatus
JPS5258143A (en) * 1975-11-08 1977-05-13 Matsushita Electric Ind Co Ltd High frequency heating device
JPS5295348A (en) * 1976-02-05 1977-08-10 Matsushita Electric Ind Co Ltd High-frequency heater
JPS52125857A (en) * 1976-04-14 1977-10-22 Matsushita Electric Ind Co Ltd High-freq uency heater
JPS5369954A (en) * 1976-12-02 1978-06-21 Matsushita Electric Ind Co Ltd High frequency heating system
CA1118844A (en) * 1977-11-02 1982-02-23 Bernard J. Weiss Combination microwave oven with a multi-port radiator
CA1114453A (en) * 1977-11-25 1981-12-15 Bernard J. Weiss Combination microwave and resistively heated oven
JPS56133694U (de) * 1981-03-05 1981-10-09
JPS5750997U (de) * 1981-08-13 1982-03-24
JPS5750998U (de) * 1981-08-13 1982-03-24
DE3319170C2 (de) * 1982-05-31 1985-03-14 Tokyo Shibaura Denki K.K., Kawasaki, Kanagawa Drehtisch zur Anordnung in einem Mikrowellenherd

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3641301A (en) * 1969-09-10 1972-02-08 Mitsubishi Electric Corp Microwave oven
US3742177A (en) * 1972-01-10 1973-06-26 Philips Corp A microwave oven having synchronously rotatable reflectors

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3641301A (en) * 1969-09-10 1972-02-08 Mitsubishi Electric Corp Microwave oven
US3742177A (en) * 1972-01-10 1973-06-26 Philips Corp A microwave oven having synchronously rotatable reflectors

Cited By (28)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4027133A (en) * 1974-12-18 1977-05-31 Husqvarna Ab Microwave radiators
FR2295672A1 (fr) * 1974-12-18 1976-07-16 Husqvarna Ab Applicateur de micro-ondes, notamment pour fours de cuisson de produits alimentaires
US4476362A (en) * 1975-05-19 1984-10-09 Matsushita Electric Industrial Co., Ltd. High frequency heating apparatus
DE2622173A1 (de) * 1975-05-19 1976-12-02 Matsushita Electric Ind Co Ltd Vorrichtung zur beheizung eines gegenstandes mittels hochfrequenter strahlung, insbesondere mikrowellen- ofen
JPS5276751A (en) * 1975-11-07 1977-06-28 Philips Nv Microwave furnace
US4165454A (en) * 1975-11-07 1979-08-21 U.S. Philips Corporation Microwave oven
US4342896A (en) * 1976-12-23 1982-08-03 Raytheon Company Radiating mode stirrer heating system
DE2757710A1 (de) * 1976-12-23 1978-06-29 Raytheon Co Verfahren und anordnung zur erhitzung von substanzen mit mikrowellenenergie
US4314127A (en) * 1977-11-02 1982-02-02 Raytheon Company Microwave oven with rotating multiport radiator
US4343976A (en) * 1979-03-19 1982-08-10 U.S. Philips Corporation Energy feed system for a microwave oven
US4316069A (en) * 1979-12-03 1982-02-16 General Electric Company Microwave oven excitation system
US4350859A (en) * 1980-05-05 1982-09-21 Raytheon Company Microwave oven feed system
WO1981003701A1 (en) * 1980-06-10 1981-12-24 Envirotech Corp Integrity check for ultrasonic fluid interface sensing system
US4430538A (en) 1980-08-28 1984-02-07 Tokyo Shibaura Denki Kabushiki Kaisha High-frequency heating device
US4354083A (en) * 1980-11-05 1982-10-12 General Electric Company Microwave oven with novel energy distribution arrangement
US4458126A (en) * 1982-03-30 1984-07-03 General Electric Company Microwave oven with dual feed excitation system
US4962298A (en) * 1988-07-18 1990-10-09 Barilla G.E.R. F.LII-Societa per Azoni Machine for thermally treating and sterilizing pre-packaged food articles by means of microwaves
US7092988B1 (en) 1997-05-27 2006-08-15 Jeffrey Bogatin Rapid cooking oven with broadband communication capability to increase ease of use
US7493362B2 (en) 1997-05-27 2009-02-17 Turbochef Technologies, Inc. Rapid cooking oven with broadband communication capability to increase ease of use
US6617558B2 (en) * 1998-02-19 2003-09-09 Framatome Anp Gmbh Furnace for microwave sintering of nuclear fuel
US5990466A (en) * 1998-04-02 1999-11-23 Turbochef Technologies, Inc. Apparatus for supplying microwave energy to a cavity
US6008483A (en) * 1998-10-09 1999-12-28 Turbochef Technologies, Inc. Apparatus for supplying microwave energy to a cavity
US8224892B2 (en) 2000-04-28 2012-07-17 Turbochef Technologies, Inc. Rapid cooking oven with broadband communication capability to increase ease of use
US20050173422A1 (en) * 2004-01-15 2005-08-11 Hiroyuki Kato Cooking device
US20170171922A1 (en) * 2014-07-10 2017-06-15 Panasonic Intellectual Property Management Co., Ltd. Microwave heating device
US11153943B2 (en) * 2014-07-10 2021-10-19 Panasonic Intellectual Property Management Co., Ltd. Microwave heating device
RU2581689C2 (ru) * 2014-08-08 2016-04-20 Федеральное государственное бюджетное образовательное учреждение высшего образования "Саратовский государственный технический университет имени Гагарина Ю.А." (СГТУ имени Гагарина Ю.А.) Свч-печь
FR3065612A1 (fr) * 2018-06-12 2018-10-26 Omar Houbloss Guide d'onde couple a une antenne pour la distribution thermique dans un four micro-onde ou un four multimode avec la fonction micro-onde

Also Published As

Publication number Publication date
CH567696A5 (de) 1975-10-15
FR2220958A1 (de) 1974-10-04
GB1461194A (en) 1977-01-13
DE2410105A1 (de) 1974-09-19
DE2410105B2 (de) 1976-05-06
JPS49119249A (de) 1974-11-14
JPS5424134B2 (de) 1979-08-18
NL7402977A (de) 1974-09-10
FR2220958B1 (de) 1980-05-23
SE369026B (de) 1974-07-29

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