Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01P—WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE
  • H01P1/00—Auxiliary devices
  • H01P1/32—Non-reciprocal transmission devices
  • H01P1/38—Circulators
  • H01P1/383—Junction circulators, e.g. Y-circulators
  • H01P1/39—Hollow waveguide circulators

Definitions

• the invention relates to an electromagnetic wave waveguide coupling and transmission device, in particular microwaves, comprising a coupling cavity provided with an antenna inlet opening, a circulator, a load receiving device, an output port, a first transmission channel between the coupling cavity and the circulator, a second transmission channel between the circulator and the exit port, and a third transmission channel between the circulator and the load receiving device.
• High frequency generators are used in a variety of applications.
• Common radio frequency (RF) generators for the frequency range above a few hundred MHz are magnetrons. These usually provide HF power at an antenna which, when mounted, dips into a waveguide and intercepts the alternating electromagnetic field generated by the antenna there. pelt.
• the waveguide coupling unit is also referred to as a "launcher.” Such waveguide coupling units optimally adapt the internal resistance of the magnetron to the characteristic impedance of the waveguide used.
• High-frequency systems generally have a compromise on cost, efficiency, space and signal quality.
• a prerequisite for optimum operation of a high-frequency source is a correct adaptation of the internal resistance of the high-frequency generator to the respective consumer.
• Such performance-matched systems achieve high system efficiencies and lifetimes.
• the consumer characteristics vary, so that rarely sets the optimal operating condition.
• the internal resistance of the high frequency generator is usually not sufficiently changed to bring about the adaptation to the respective consumer.
• an additional directional conductor is in the direction of the consumer interposed, which absorbs the reflection power.
• a directional ladder In a directional ladder is usually also a waveguide component, which is usually connected by means of a flange form-fitting with a launcher. Since the properties of conventional directional conductors are determined by a comparatively weak static internal magnetic field, stray magnetic fields emanating from an HF generator must be adequately attenuated so as not to attenuate the directional conductor. men. Therefore launcher and director are usually relatively far away and the corresponding components are large, so that moods caused by stray fields are negligible.
• An example of a directional is a circulator.
• the usually approximately cylindrical circulator has three ports and at least one microwave ferrite disc which is magnetized by an external magnetic field.
• the ports are arranged at angular intervals of 120 ° from each other on the circumference of the circulator.
• the magnetic field of the circulator is adjusted so that a power fed in at a first port is slightly attenuated to a second port while the third port is largely decoupled from the first port.
• a reflection power fed in at the second port is forwarded to the third port.
• a load resistor that receives reflected power is connected to this port. This power is then no longer returned to the first port and thus to the coupling antenna of the RF generator.
• the object underlying the invention is to provide a
• Waveguide coupling and transmission device to provide that allows a lossless transmission of electromagnetic waves and effective isolation of the generator of reflected power in a compact and simple design, the respective power states with little
• an electromagnetic wave waveguide coupling and transmitting device in particular microwaves, comprising a coupling cavity provided with an antenna inlet opening, a circulator, a load receiving device, an output port, a first transmission channel between the coupling cavity and the circulator, a second transmission channel between the circulator and the outlet opening and a third transmission channel between the circulator and the load receiving device, achieved in that the load receiving device has at least two load receiving devices.
• circulator in the context of the invention, other non-reciprocal components, such as optical elements, such as semipermeable mirrors understood. These can be used at very high frequencies instead of waveguide circulators.
• a basic idea of the invention is that a load receiving device with at least two spatially decoupled or spatially separated loads can absorb a power reflected by the load in a more effective manner than a single load. This also leads to a good decoupling of the high-frequency generator from reflected power by means of the circulator. This is achieved the better, the more accurately the transmission channels leading to the load receiving device are dimensioned in their geometry so that their input impedances at the circulator correspond to the complex conjugate of the output resistance of the circulator.
• the goal of good decoupling is limited and achieved over a low frequency bandwidth.
• a flexible and independent adjustment of the real and imaginary parts of the input impedance acting at the output of the circulator can be set since the waveguide section leading to it can be individually dimensioned for each load.
• any suitable phase shift between the two waveguides can be selected.
• the at least two loads have the same capacity for power consumption. For this they are the same size and / or of the same type.
• the at least two load receiving devices are connected by a waveguide, a selection of the phase shift between the load receiving devices is easy to make.
• a particularly effective absorption of back-reflected power is advantageously possible if the geometric dimensions of the waveguide and the arrangement of the load-receiving devices, a phase shift of substantially 90 ° relative to the
• Wavelength of the waveguide between the load receiving devices result.
• a phase shift of 90 ° results in a simple manner when the waveguide has a length of ⁇ / 4.
• the wavelength ⁇ of the waveguide is calculated on the one hand from the critical or cut-off wavelength ⁇ c, which results from the internal dimensions of the waveguide, for example the wider side of a rectangular waveguide, and on the other hand from the wavelength AL of the coupled electromagnetic radiation in free space (free space wavelength) according to the formula
• the waveguide preferably has a length of ⁇ / 4.
• a waveguide with a length of ⁇ / 4 a waveguide with a length of an odd integer multiple of ⁇ / 4, ie 3 ⁇ / 4, 5 ⁇ / 4, 7 ⁇ / 4, etc., meant that In any case, a phase shift of effectively 90 ° sets.
• the imaginary impedance components of the loads compensate each other while the real parts are averaged.
• the bandwidth for which this condition is approximately met is greater with the use of at least two loads than with only one load.
• the waveguide coupling and transmission devices are designed for a certain wavelength range, so that the information about the phase shifts relate to this wavelength range.
• the specific dimensioning of waveguides for specific or predetermined wavelengths is familiar to the expert.
• the waveguide leading to the load-receiving devices is crossed a second time in each case. This doubles the distance traveled by the power reflected by the loads. Choosing the length of the waveguide as ⁇ / 4 (and odd-numbered multiples thereof) results in a difference of ⁇ / 2 or in the case of considerable 180 ° between the waves reflected by the respective loads. This phase shift produces a destructive interference between the two components at a summing point of the waves. The remaining power reflected by the loads thus cancel each other out. In this way, only extremely little power is returned by the circulator to the generator. This increases the life of the generator.
• a power dividing device is provided between the at least two load receiving devices. This then results in that the reflection power, which is forwarded by the circulator from the second to the third port, is guided through the third transmission channel to a power divider.
• the power divider for example, has the shape of a protruding into the waveguide diaphragm, of which in two directions two
• Disconnect waveguide For example, the waveguides have the same geometric inner dimensions, but a length that is different by ⁇ / 4.
• the respective powers fed into the two waveguides are obtained according to the areas of the waveguide cross-section divided by the diaphragm. If, for example, the diaphragm is arranged centrally in the waveguide, in each case 50% of the power is coupled to both subsequent waveguides.
• This solution has the further advantage that the power is conducted completely to the loads arranged therein.
• a broadband impedance matching is achieved via the shape and depth of the diaphragm.
• a predetermined distance of the at least two load receiving devices or a predetermined distance between at least one load receiving device and the power splitting device in particular by means of a phase actuator, adjustable.
• This variability causes the relative position of the two loads in the phase space of the characteristic impedance to each other can be changed in order to adjust a phase angle of 90 ° as accurately as possible.
• the phase actuator can also cause the phase shift of about 90 ° itself.
• phase actuator is in the simplest form a ⁇ / 4 or similar long waveguide element.
• post and / or diaphragms which are driven into the waveguide are provided as phase actuators which, depending on their position and length in the waveguide and their material, cause a phase shift of, for example, ⁇ / 4 or ⁇ / 8.
• At least one of the load-receiving devices is a water load or a load based on another electromagnetic-field-absorbing liquid, which is guided in particular through a tube made of an electrically insulating material, preferably quartz glass.
• a tube made of an electrically insulating material, preferably quartz glass.
• the tube consists of microwave-absorbing material and a cooling and / or microwave-absorbing liquid can be passed through inside the tube.
• a particularly compact construction of the device or of the launcher is advantageously possible if, in the circulator, when the electromagnetic field is fed into the device, there is a stationary magnetic field which is aligned essentially perpendicular to the direction of the E field component of the electromagnetic field in the transmission channels.
• This orientation of the magnetic fields allows the curvature directions of the To arrange transmission channels and the expansion of the circulator in a plane, whereby a particularly flat design is possible.
• the direction of the magnetic field in the circulator is perpendicular to the magnetic field, which usually radiates from an RF generator, such as a magnetron, in the coupling cavity. This interference magnetic field from the magnetron is thus decoupled from the magnetic field in the circulator. Since the circulator is hardly detuned as a directional conductor, the distance between the circulator and Einkoppelhohlraum can be significantly reduced, creating an even more compact design is achieved.
• a waveguide coupling and transmission device for electromagnetic waves comprising a coupling cavity provided with an antenna inlet opening, a circulator, a load receiving device, an outlet opening, a first transmission channel between the Einkopplungshohlraum and the circulator, a second transmission channel between the circulator and the réelleöff- and a third transmission channel between the circulator and the load receiving device, which is formed by the fact that the coupling cavity, the first transmission channel, the circulator and the second transmission channel in one, preferably common, housing are arranged.
• the device according to the invention is particularly easy to produce if the housing advantageously comprises two housing moldings.
• Each housing molding for example in the form of a half shell, is machined in a conventional manner and has corresponding recesses which form the waveguides and chambers in the assembled state of the housing.
• the electric fields in the coupling-in section and in the loads lie in the same plane. Since no cross-currents flow through the boundary surfaces, it is possible to construct the complete unit in a two-shell design and at the same time allow very small constructional distances. The individual rooms remain decoupled. The high frequency density to the outside is guaranteed.
• the housing moldings are substantially mirror-symmetrical and thus complementary in terms of shape and function.
• the interface between the housings in the middle of the waveguide preferably it passes through the wide sides of the waveguide.
• Essentially mirror-symmetrical means that openings are provided for power monitors, for example in a housing mold body, but not in the other. However, this does not change the fundamentally similar dimensioning of the waveguide halves.
• a wide side of the hollow conductor is cut. It then finds no power transmission
• a further solution of the object underlying the invention consists in a device mentioned in the fact that in or at least one of the transmission channels at least one power measuring device is arranged or attachable, which comprises a coaxial conductor and a housing opening to the transmission channel, wherein the soul of the coaxial with the inner circumference of the housing opening is conductively connected.
• This type of power monitor or power meter provides an easily manufactured, accurate and reproducible measuring device for the power conducted in a transmission channel.
• the opening is designed in particular as a slot or as an oval, to which the soul of a conventional high-frequency coaxial cable is connected.
• This design replaces a conventional probe for a performance monitor in which a wire loop is inserted into the waveguide. With such probes, which are complicated and expensive to manufacture, the orientation and the position of the wire loop in the waveguide are not exactly reproducible.
• a part of the housing is used as a loop or antenna, so that consistent measurement results are guaranteed.
• this measure in addition to an increase in the measuring accuracy, there is also a saving in the complexity and complexity in the construction of the device according to the invention.
• Fig. 1 shows a device according to the invention in a schematic
• FIG. 2 is a perspective schematic representation of a housing molding of the device according to the invention
• FIG. 3 is a perspective schematic representation of the device in the assembled state with RF generator
• Fig. 4 is a schematic representation of a known power sensor with a coupling loop
• Fig. 5 is a schematic representation of a power sensor according to the invention.
• FIG. 1 shows a waveguide coupling-in and transmission device 1 according to the invention for electromagnetic waves or microwaves in a schematic sectional view.
• the waveguide coupling and transmission device 1 comprises a single housing 2 and a microwave coupling cavity 3 with an opening 4 for an antenna of a magnetron 28 (see Fig. 3).
• the first and second transmission channels 5, 10 each preferably have a length of about ⁇ / 4, so that a purely real impedance transformation is set by the waveguides 5, 10. This leads to an optimum adaptation of the impedances of the waveguide 10 to the characteristic impedance of the load or of the waveguide 5 to the characteristic impedance of the coupling-in cavity 3.
• a third transmission channel 13 leads to a centrally arranged power splitter 14 in the form of a diaphragm 14a, which projects centrally into the cross-sectional area of the transmission channel 13.
• the applied therein electromagnetic field is split by an arranged in the power splitter 14 aperture 14a in two equal proportions and guided over two laterally arranged transmission channels 15, 16 to two water loads 17, 18.
• the circulator 6 has flat cylindrical microwave ferrite 7.
• the magnetic field of the ferrites 7 and the circulator 6 point into the image plane. Because of this construction or arrangement, the narrow sides of the transmission channels 5, 10, 13 and the circulator 6 lie in a common plane.
• Electromagnetic waves coming from a magnetron 28 in the Einkoppelhohlraum 3 are irradiated, pass through the S-shaped transmission channel 5, which has a resistance transformer for impedance matching a length of ⁇ / 4, to the first port 8 of the circiutor 6.
• the impedance matching is not optimal, some of the power is reflected back to the circulator 6. This power is deflected 60 ° from the rectilinear propagation direction to the third port 12, where they are conducted via the transmission channel 13 to the power divider 14 and the transmission channels 15, 16 to the water loads 17, 18.
• the lengths and the further dimensions of the transmission channels 15 and 16 are selected or determined such that a phase shift of 90 ° or a length shift of ⁇ / 4 (or an odd integer multiple thereof) occurs between the two water loads 17, 18 to optimally dissipate the reflection power. Possibly waves reflected by the water loads 17, 18 in turn pass through the transmission channels 15, 16. At the summing point, the power divider 14, the reflected waves have a phase shift of a total of 180 °, so that they cancel each other out.
• first, second, third transmission channels 5, 10 and 13, elongated holes 19, 20, 21 of power monitors 22, 23, 24 are respectively embedded in the side wall of a housing shaped body.
• the magnetic field is arranged perpendicular to the plane of the drawing.
• the direction of the magnetic field radiating from a magnetron 28 (see Fig. 3) into the coupling cavity 3 is vertical in the plane of the drawing.
• These two magnetic fields are thus largely decoupled. Since even stronger stray fields of a magnetron 28 thus hardly cause a detuning of the circulator 6, a short distance between the coupling-in cavity 3 and the circulator 6 is sufficient.
• power losses are minimized by arranging all components of the device 6 in a common housing 2 and without any contact surfaces between the components which could cause loss of power.
• FIG. 2 shows a perspective schematic illustration of a housing shaped body 2 a of the device 1 according to the invention in a view obliquely from below.
• the housing-shaped body 2a can be assembled to the device 2 with a mirror-inverted housing molding 2b as shown in FIG.
• the depth of the transmission channels 5, 10, 13 is less than the depth of the coupling cavity 3.
• the depth in the region of the circulator 6 is reduced compared to the transmission channels 5, 10, 13.
• Openings in the form of oblong holes 19, 20, 21 for power monitors are in each case in the walls of the transmission channels 5, 10, 13
• elongated holes 19, 20, 21 are contacts 25, 26, 27 for sensor Terminals 25a, 26a, 27a mounted conductively, to each of which a line of a coaxial cable is connected.
• the elongated holes 19, 20, 21 are arranged with their longer extension respectively in the propagation direction of the electromagnetic waves. In this orientation of the elongated holes 19, 20, 21, the maximum coupling coefficient is achieved for given geometric dimensions of the transmission channels 5, 10, 13.
• Fig. 3 shows a schematic view of the device 1 according to the invention in the assembled state of the housing moldings
• a magnetron 28 is intended connected to the opening 4 of the coupling cavity 3.
• a flange is arranged, to which a consumer can be connected.
• FIG. 4 shows a schematic representation of a known power sensor with a coupling loop.
• a circular opening 19 is inserted for a performance monitor.
• the conductive shield 32 of a coaxial cable 29 is connected externally.
• the inner line 30 of the coaxial cable 29 protrudes into the interior of the transmission channel 5 and bends back to the housing 2.
• the tip of the inner lead 30 of the coaxial cable 29 is in conductive contact with the inner wall of the housing at the edge of the opening 19. In this way creates an induction loop.
• the bending back inner cable 30 of the coaxial cable encloses a surface which of the temporally rapidly changing magnetic field in the transmission channel 5 is penetrated.
• the change in the magnetic field over time induces a current flow in the coaxial cable 29.
• the magnitude of the induction current depends on the size of the enclosed area, the rate of change with time, the strength of the alternating electromagnetic field and the relative orientation of the enclosed area and the alternating electromagnetic field. Therefore, by rotating the coaxial cable 29 or its inner tube 30, the orientation of the enclosed surface is usually adapted to the local orientation of the field. The smallest attenuation is achieved if the field vectors of the alternating field are perpendicular to the enclosed area at the point of the loop. The attenuation factor is sensitive to the orientation of the inner conduit 30.
• the inventive arrangement of the induction loop shown in Figure 5 in a schematic representation is that instead of a round opening, a slot 19 is used and the inner line 30 of the coaxial cable 29 does not protrude into the interior of the transmission channel 5, but with the inner wall of the Opening 19 is conductively connected.
• an insulating layer 31 of the coaxial cable 29, which is delimited by the conductive shield 32, is shown through the opening 19.
• the shield 32 is in turn conductively connected to the outer wall of the housing 2.
• inner line 30 and shield 32 of the coaxial cable 29 for example, as an adapter or connector fixed to the opening 19, so that in each case reproducible
• the input resistance which is effective for a magnetron antenna is kept approximately constant for all occurring fitting ratios without additional components.
• the integrated circulator achieves a structurally compact launcher. Current-transmitting mechanical joints are completely eliminated, resulting in an excellent high-frequency tightness without soldering or welding joints, even without one piece of the
• the device according to the invention is suitable for frequencies above a few hundred MHz to a few GHz.
• the maximum power range depends on the operating frequency up to 100 kW in continuous wave mode.
• the maximum permissible pulse power can be many times higher.

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• 2005
  • 2005-12-12 DE DE502005011202T patent/DE502005011202D1/de active Active
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  • 2005-12-12 WO PCT/EP2005/013308 patent/WO2007068261A1/fr active Application Filing
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