Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01P—WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE
  • H01P5/00—Coupling devices of the waveguide type
  • H01P5/08—Coupling devices of the waveguide type for linking dissimilar lines or devices
  • H01P5/10—Coupling devices of the waveguide type for linking dissimilar lines or devices for coupling balanced lines or devices with unbalanced lines or devices
  • H01P5/103—Hollow-waveguide/coaxial-line transitions

Definitions

• the present invention aims to improve the aforementioned prior art by ensuring that the coupling between the magnetron and the enclosure is not or practically not sensitive to the object or to the load placed in the enclosure.
• This object is achieved thanks to the fact that the two wave reflection walls are respectively spaced from the plane of the transmitter by a distance substantially equal to 0.2. ⁇ g + k. 2 and a distance substantially equal to 0.3. ⁇ g + p. XJ2, where k and p are whole numbers.
• the two wave reflection walls are respectively. spaced from the transmitter plane by a distance close to 0.2.
• the Rieke diagram which, as a function of the distance from the reference plane of the antenna which emits microwaves, indicates the power of the energy carried by the waves and the deviations frequency.
• This diagram shows that in regions distant from the plane of the antenna by a distance of the order of 0.2. ⁇ g and in regions distant from the antenna by a distance of the order of 0.3. ⁇ g , the energy loss is the lowest. These regions therefore constitute optimal zones from the point of view of limiting energy loss. Due to the repetitivity of the wave at intervals equal to ⁇ g 2 > the regions which are separated from the above optimal zones by a distance which is a multiple of ⁇ g / 2 also constitute optimal regions.
• planes distant from the plane of the antenna by a distance equal to ⁇ g / 4 modulo ⁇ g / 2 constitute planes of symmetry for the dissipation of energy.
• the imaginary impedances of the portions are substantially opposite. This is the case of two respectively spaced planes of the plane of the emitter with a distance substantially equal to 0.2 ⁇ g and a distance substantially equal to 0.3. ⁇ g . Due to the repetitivity of the wave at intervals of ⁇ g / 2, the two walls reflectors defined as indicated above are arranged in zones in which the impedances are conjugate.
• the impedance of the reflected waves measured in the plane of the magnetron transmitting antenna, is substantially purely real, that is to say that it is expressed by a complex number having a imaginary part substantially zero, which means that the resultant of these reflected waves does not disturb the emission of waves by the antenna which consequently emits at maximum power and this, whatever the load which is placed in the pregnant.
• substantially zero imaginary part it should be understood that the imaginary part contributes at most up to approximately 5% to the value of the modulus of the complex number.
• the device comprises an adjustment member disposed at a distance from the plane of the transmitter which is equal to n. ⁇ g / 2, n being an integer.
• the planes which are separated from the plane of the transmitter by a distance equal to a multiple of the half-wavelength in the waveguide ( ⁇ g / 2) constitute equivalent planes, in which the electromagnetic field behaves in the same way as in the transmitter plan.
• the adjustment member comprises a conductive rod capable of being more or less pressed into the waveguide.
• This field is in fact the result of the waves emitted by the transmitter and the waves reflected by the reflection walls.
• the impedance at a point of the waveguide therefore depends on its distance from the plane of the transmitter and from the reflection walls.
• the respective distances between each of the two reflection walls and the plane of the emitter are such that the imaginary parts of the impedances respectively measured on each of these two walls are substantially opposite.
• the adjustment of the adjustment member, associated with the choice of the distance between the reflection walls and the plane of the emitter is such that the impedances on each of these two walls are expressed respectively by complex conjugate numbers .
• the impedance of the resultant of the waves reflected on each of the two reflection walls, measured in the plane of the transmitter has a zero imaginary part.
• the adjustment means constituted for example by an adjustment screw make it possible to refine the coupling to take account of the deviations in dimensions due to manufacturing tolerances and disturbances in the electromagnetic field due, for example, to the thickness of the antenna .
• the waveguide has secondary outputs in addition to the aforementioned main outputs.
• These secondary outlets are formed by secondary slots located in a front wall of the wave guide cavity which opens into the enclosure to be excited by the microwaves, these slots being distributed so as to promote the homogeneity of the distribution. microwaves in the enclosure.
• FIG. 2 is a side view of the waveguide device
• FIG. 3 is an elevational view along arrow III of Figure 2.
• the means used to excite this enclosure include a magnetron 12 capable of generating microwaves, for example at a standard frequency close to 2450 MHz, and a launcher waveguide device, providing the interface between the magnetron and the enclosure.
• the electric field E of the electromagnetic field which prevails in the waveguide is perpendicular to the front and rear walls 20 and 22, while the magnetic field H is perpendicular to the side walls 24 and 26.
• the waveguide 16 is delimited by two reflection walls, respectively 28 and 30 which are perpendicular to the direction F.
• the guide wave has two main outputs, respectively 32 and 34, which are respectively located in the vicinity of the reflection walls 28 and 30. More specifically, the two main outputs are formed by main slots which extend parallel to the reflection walls 28 and 30 and which are respectively located at the junctions of these walls with the front wall 22.
• the slots 32 and 34 are formed in this front wall and extend over the entire width of this wall, their extreme edges being respectively delimited through walls 28 and 30.
• the reflection walls 28 and 30 are therefore located in regions in which, as a function of the Rieke diagram associated with magnetron 12, it is expected that the impedances of the wave will be conjugate. However, certain parameters slightly disturb the conformation of the electromagnetic field in the waveguide. In particular, the antenna of the transmitter 18 is not punctual, but it has a certain thickness.
• the device comprises a member 36.
• This adjustment member is constituted by a conductive or dielectric rod advantageously disposed in the rear wall 20 which can be more or less pressed into the waveguide 16.
• This rod is located at a distance D3 from the plane of the transmitter P 0 .
• This distance D3 is equal to a multiple of the half-wavelength of the electromagnetic wave maintained in the waveguide. It is thus located on an equivalent plane P L
• the phenomena which occur in such a plane are the same as those which occur in the plane of the emitter P 0 .
• the adjustment of the rod 36 modifies the value of the electric field in the plane Pi to optimize the power of the wave in this plane. This therefore makes it possible to optimize the power in the plane of the transmitter Po.
• the presence of this adjustment rod combined with the choice of the distances D1 and D2 for the reflection walls 28 and 30, makes it possible to optimize the power emitted by the antenna and to prevent the latter from having to suffer from disturbances due to the waves reflected on the walls 28 and 30, the imaginary parts of which cancel each other out substantially at the plane P 0 .
• the waveguide device has, in addition to the main outputs 32 and 34, secondary outputs.
• the secondary outlets are formed by secondary slots which are located in the front wall 22 and which are inclined relative to the reflection walls 28 and 30.
• These slots are symmetrical with respect to the median plane PM.
• the geometric centers of these slots, C38 and C40, are located in a median longitudinal plane P of the device.
• the secondary outlets further comprise a third secondary slot 42 which is substantially parallel to the direction F of propagation of the microwaves in the cavity 16 and which is substantially located at equal distance from each of the two reflection walls 28 and 30 This slot 42 is centered on the median plane P M and is located in the open part of the angle formed by the slots 38 and 40.

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• Agricultural Chemicals And Associated Chemicals (AREA)

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• 2001
  • 2001-02-13 FR FR0101916A patent/FR2820939B1/fr not_active Expired - Fee Related
• 2002
  • 2002-02-12 DE DE60227051T patent/DE60227051D1/de not_active Expired - Lifetime
  • 2002-02-12 DK DK02706842T patent/DK1360736T3/da active
  • 2002-02-12 AT AT02706842T patent/ATE398342T1/de active
  • 2002-02-12 PT PT02706842T patent/PT1360736E/pt unknown
  • 2002-02-12 EP EP02706842A patent/EP1360736B1/de not_active Expired - Lifetime
  • 2002-02-12 ES ES02706842T patent/ES2307728T3/es not_active Expired - Lifetime
  • 2002-02-12 WO PCT/FR2002/000517 patent/WO2002065575A1/fr active IP Right Grant

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