DE1008789B - Ultra high frequency oscillator using a spoked wheel type magnetic field tube - Google Patents

Description

The invention relates to magnetron oscillators. The main object of the present invention consists in reducing the influence of changes in load on the working frequency of such Oscillators.

It is characteristic of the previously known magnetron oscillators that the frequency of the oscillations depends to a considerable extent on the load, so that load changes are the tendency have to shift the frequency of oscillation, an effect known as "dragging". Such a one Frequency shifting is generally undesirable, especially if it is a reduced one The result is efficiency because the magnetron oscillator is at a certain fixed frequency most beneficial works. Various arrangements have heretofore been proposed to facilitate the pulling to avoid, but these generally require the interposition of a buffer element, e.g. B. a buffer amplifier to remove the load from the resonant cavities in which the vibrations are generated will be to separate. It would obviously be more beneficial to pull in an immediate manner to avoid.

For this purpose a magnetron oscillator is used, which is operated with a waveform where the useful electron interaction only takes place with an anode potential wave, which revolves in a particular direction relative to the direction of the electron orbits, while in the No interaction occurs in the opposite direction. It is advisable to use waveforms, at which the fields of neighboring resonance cavities oscillate neither according to the π mode nor in phase, referred to as non-degenerate waveforms.

It can be shown that operation of this type excludes the two modes in which adjacent resonators are in phase and π out of phase. Vibrational energy is then extracted from the resonant cavities with the aid of directional coupling in order to pass it on to a transmission path to the load at one end of the path, the other end of which is closed by an anechoic seal. A characteristic of this arrangement is the fact that the energy reflected from the load, which arises from mismatches caused by changes in the load, returns on the transmission path and is either destroyed at the reflection-free termination at the closed end of the transmission path or is fed back into the resonance cavities in order to be there to revolve in a direction that is the direction of the vibrations in the resonant ultra-high frequency oscillator

using a magnetron

the spoked wheel design

Applicant:

Western Electric Company, Incorporated, New York, N.Y. (V. St. A.)

Representative: Dr. Dr. R. Herbst, lawyer,
Fürth (Bay.), Bredtscheidstr. 7th

Claimed priority:
V. St. v. America October 2, 1952

Cassius Chapin Cutler, Gillette, NJ (V. St. A.),
has been named as the inventor

cavities belonging potential wave is opposite and therefore to the interaction with the electrons is unsuitable. As a result of the separation between the load and the Resonant cavities become the operating frequency of the magnetron oscillator due to changes in load little affected. In preferred embodiments, it is generally advantageous to have means of avoidance of other waveforms than the desired one for the interaction with the electrons to be provided.

A magnetron oscillator within the meaning of the invention thus differs from the previously known magnetron oscillators from how they z. B. in the USA. Patent 2 611 110 are explained and in which an external, A resonance cavity lying between the utility device and the anode resonance cavity is provided which is connected to the cavity of the magnetron by means of a plurality of coupling connections is omnidirectional coupled.

The invention is illustrated by the following, more detailed explanation with the drawings become more understandable.

Fig. 1 shows a vertical section (along the line 1-1 in Fig. 2) through a magnetron according to the invention, which is intended to operate with a phase difference of π / 2 between adjacent resonance cavities;

709 510/30?

in which the electrons in the interaction space with a standing wave are directly (i.e. without the help of wave reflections) interact and sustain them 5 are called "degenerate forms".

According to the invention, the magnetron is operated in a non-degenerate form in which the electrons advantageously only with one in a particular direction, preferably in the direction of

Fig. 2 shows a cross section through the magnetron shown in Fig. 1, (along the line 2-2 in Fig. 1);

FIG. 3 shows a view similar to FIG. 2 of a magnetron according to the invention, which is intended to be operated with a phase difference of 2π / 3 between adjacent resonance cavities.

That shown as an example in Figs
Magnetron consists of an evacuated tube housing 11, 12, 13 (piston), of non-magnetic, io electrons, advancing wave in reciprocal

conductive material, e.g. B. made of copper, which make a ring.

has shaped cylindrical part 11. The housing In connection with an ultra-high frequency oscilloscope forms a resonance cavity and is hermetically sealed by means of an isolator of the specified design with the use of soldered end parts 12 and 13. a magnetron of the spoked wheel type, with a plurality of radially arranged segments 14 15 of the anode segments in the form of radially extend from the inner surface of the cylindrical continuous sheet-like structure on an outer part 11. They are there at regular intervals cylinders are attached in such a way that cavity arranged and form a multi-segment aode. De-resonators arise and in which the outer cylinder along the center line of the cylindrical part 11 has coupling possibilities at several points to the axially stretching a long cylindrical cathode 16, 20 exit which in the cavity circles generated preferably an indirect heated oxide glow oscillations in a cathode is attached to the anode cylinder. The cathode 16 consists of an outer circle bordering the heating, the special filament 17 and a conductive element surrounding the filament of the invention consists in that the tube is in a sleeve 18, which is operated with a thermally emitting oscillator circuit, in which the oxide coating is covered. A pair of conductors 19 and 20 25 magnetic field and the bias voltage between the zen leads the heating voltage to the filament 17. The tral cathode and the anode cylinder so conductor 19 is also electrically selected with the conductive sleeve that adjacent cavity resonators 18 (emission surface) are connected while the conductor neither work in phase nor in antiphase and that 20 is insulated from the sleeve. The conductor 19 is the outer circle in the form of a rectangular wave at a high negative potential with respect to the conductor 30 which holds the anode only on a conductive housing 11, whereby a large part of its circumference surrounds, and that the coupling is radial electrical direct field between the cathode
16 and the multi-segment anode 11, 14 arises. The cathode 16 is supported by a pair of lead-in conductors 21
and 22 which is led to the conductors 19 and 20 35 which are welded to the end of the waveguide. These introductory leaders are lies,
by glass seals 23 and 24 in the upper and
lower end of the cylindrical part 11 of the housing
passed through.

In operation, the tube will have between suitable 40 radially disposed from the outer surface magnetic poles 25 which extend a magnetic field inwardly and provide a plurality of cavities which form resonators parallel to the axis of the cathode; every second resonator is at 16 and perpendicular to the radial electrical equilibrium a continuous outer auxiliary cavity anfeld, which is coupled between the cathode and the whose frequency can be changed by means of flexible parts formed by the segments 14 multi-segment anode 45 in the outer wall. 11:14 arises. When the tube is now in operation, it is common practice to take the vibrations out so that electrons circulate in the interaction space between the cathode 16 and the multi-segment anode 11, 14, vibrations arise in the area between each pair of neighboring 50, that is with regard to the phase position of the segments, which form a sequence of resonance cavities oscillations a phase difference of π between. Up to this point a magnetron was used in the
Technique known type described. With such a
Magnetrons can have different waveforms

occur, which depends on the strength of the magnetron is z. B. for operation with the π / 2 form

table field, determines the strength of the applied electrical, at which the phase difference between

Equal field and the number and geometry of the adjacent anode segments π / 2 . This in

different resonance cavities are. Such a Fig. 3 illustrated magnetron is on the other hand for

System of resonators can be determined in different operation with the 2π / 3-form. It works

Wave forms vibrate. With each of these ^6o the magnetron in any case with a non-degenerate

Shapes indicate the vibrations in neighboring rier form.

There are various means of suppressing gaps between the anode segments known to cause undesired waveforms and established phase relationships. The anode segment can of course contain a special shape by voltage sequence in each case η complete ⁵ 5 suitable choice of the strength of the radial electrical period in a revolution around the cylindrical anode. Field and the axial magnetic field as well as In general, these anode potential waves of the number and geometry of the anode segments can be waves or waves that are preferred in each Rieh-. Advance the general construction around the anode. The oscillation 7 ° corresponding to the principles are on pages 214 to 232 of an article entitled Anode Potential Waves entitled “The Magnetron as a Generator of

is designed as a directional coupling between the anode compartment and the waveguide (outer circle), in such a way that that the generated energy is supplied to a consumer

The previously known ultra-high frequency oscillators also include those in which the anode segments the shape of radially arranged flat members

Restrict to a particular shape for reasons of stability. Very often it becomes the so-called π-form applied, in which the anode potential wave exists so at adjacent anode segments. However is such a shape is a degenerate shape and undesirable in the present case. The one shown in FIG

Centimeter Waves "by J. B. Fisk, H. D. Hagstrum and P. L. Hartmann, who in Bell System Technical Journal, April 1946.

In the tube shown in Figs. 1 and 2, two means are used to adjust the operation to the desired one to constrain the -τ / 2 form. First be to separate the shapes and ease the oscillation only in the π / 2-shape connecting lines used between certain segments. For this purpose, all fourth anode segments are together tied together. In the magnetron shown here, which has twelve anode segments four connection lines 26, 27, 28 and 29 are used, each with three anode segments connected is. In the above-mentioned article in the Bell System Technical Journal, p. 222 through 227 describe the general considerations to be applied to the trunk lines.

In addition to the connecting lines, according to a feature of the invention, the suppression of undesired shapes by means of "absorption" is used. For this purpose a rectangular hollow waveguide piece 30, which is closed at both ends, is bent around part of the housing, the broad side of the waveguide preferably being in contact with the outer wall of the housing. A pointed dielectric block 31 is attached to each end of the waveguide 30 and is coated with waste material to absorb incident wave energy. In order to suppress the undesired waveforms, the absorption waveguide is firmly coupled to the tube with respect to the undesired waveforms, while it is only loosely coupled with respect to the desired shape. To this end, multiple coupling connections are provided between the absorption waveguide and the resonance cavities. This stress waveguide has a tendency to prevent excitation of all modes except the desired one. In the present embodiment, in which all shapes except the π / 2 shape are to be suppressed, three coupling connections 32, 33 and 34 are provided between three successive cavities and the absorption waveguide 30. Each coupling link includes a cavity coupling loop and a waveguide coupling loop, the two loops being connected by a conductor. The coupling connection 32 consists, for. B. from the cavity loop 32 ^, the conductor 5 = 32 ^fl and the waveguide loop 32 ^C. One end of each cavity coupling loop is electrically connected to the inner wall of the housing 11, 12, 13 and the other end of the coupling loop in question is connected to a conductor which passes through one of the bores in the walls of the housing 11, 12, 13 and of the waveguide 30 . This conductor is in turn connected to one end of the waveguide coupling loop inside the waveguide, the other end of which is electrically connected to the wall of the waveguide 30. The two cavity ^{loops 32 Λ} and 34 ^A are arranged in the same sense as their corresponding conductor loops 32 ^C and 34 ^C , while the cavity ^{loop 33 Λ is arranged} in the opposite sense as its corresponding conductor loop 33 ^C , whereby a phase inversion occurs as a result of the direction reversal. Furthermore, the middle connection 33 is set up so that a coupling that is twice as large as that of each of the connections 32 and 34 is produced. For this purpose, the associated loops 33 * ⁴ and 33 ^{C have} a larger diameter than the loops associated with the connections 32 and 34. In addition, the waveguide 30 is e.g. B. loaded by ribs or sheets 35, which extend from the waveguide wall opposite the waveguide wall in contact with the housing 11, 12, 13 in the radial direction in order to reduce the speed of wave propagation in the waveguide 30 so far that the conductor coupling loop 32 ° , 33 ^C and 34 ^C are a quarter of a conductor wavelength next to the desired waveform. An examination of the effect of the waveguide 30 shows that the coupling with this waveguide is a minimum for the desired π / 2 waveform. As a result, the wave energy of the desired waveform delivered to the conductor 30 by the three coupling connections has a tendency to cancel each other out, so that in fact no energy of that shape is delivered to the waveguide 30. With the other possible forms of oscillation, however, this cancellation does not take place. There is thus the possibility of only supplying certain wave energy to the waveguide, so that the formation of vibrations of the undesired shapes is prevented. In this way, a selective suppression of certain waveforms is achieved.

Furthermore, according to the invention, the vibration energy of the desired frequency is used for transmission taken from a consumer circuit or a load 38 with the aid of a directional coupler. In In simple terms, a directional coupler is a coupling arrangement through which a a primary path propagating wave in a secondary path a wave excited only in propagates in one direction.

The general principle of directional coupling is outlined in an essay entitled "Directive Couplers described in Wave Guides «by M. Surdin, the in the "Journal of the Institution of Electrical Engineers", Vol. 93, Part III A, pp. 725 to 736, published is.

To this end, the desired vibrational energy is set in the tube with the aid of a directional coupling arrangement into an evacuated hollow waveguide 40 of preferably rectangular cross-section supplied, which has a closed end 41 and an opposite end 42 that against the Atmosphere is closed by a glass window 43, which, however, allows the removal of vibration energy. At this end 42 is the waveguide 40 is connected to a waveguide 44 through which the vibration energy is guided to the consumer 38 will. At the shorted end 41 of the waveguide 40 is a pointed dielectric with lost material coated block 45 arranged to a broadband reflection-free termination obtain. The waveguide 40 encloses a portion of the tube housing 10, preferably one of the Broad sides is in contact with the housing. To provide directional coupling between the waveguide 40 and the tube for obtaining the vibrational energy from the π / 2 shape are four connections 51, 52, 53 and 54 provided with the same degree of coupling, the z. B. are of the same type as the Absorption waveguide 30 used. Each link has a cavity coupling loop and a Waveguide coupling loops that are bent in the same sense. However, the coupling connections are for the direction-dependent coupling of the π / 2 form

in the tube a quarter, a half and a quarter of the waveguide wavelength apart. Since adjacent cavity resonators in the tube are πΙ2 apart, the desired relationship is achieved by connecting coupling connections 51 and 52 and 53 and 54 to adjacent cavities, with a cavity between connections 52 and 53 not being coupled. Furthermore, this object is achieved by loading this coupling area with transverse plates 55 in order to obtain such a wavelength in this area that the spacing in the waveguide corresponding to the distance from adjacent cavities in the tube is a quarter of a waveguide wavelength. After this coupling area, the metal sheets 55 gradually decrease in length in order to obtain a transition to the smooth rectangular waveguide at the end 42. An examination of this coupling arrangement, as it is carried out in the above-mentioned article by Surdin, shows that this arrangement results in a rectified coupling, ie waves which circulate clockwise in the tube induce a wave in waveguide 40 which is also only clockwise and, conversely, waves traveling counterclockwise in waveguide 40 create a wave traveling counterclockwise in the resonant cavity. Accordingly, in the oscillator shown, the directions of the radial electric field and the axial magnetic field are chosen so that a favorable interaction only takes place with a clockwise wave propagating in the tube to prevent the oscillation energy from propagating in the waveguide 40 in a clockwise direction to obtain.

In many respects, the operation is similar to that of a standard magnetron oscillator. In the The resonance chamber creates vibrations that are characteristic of the non-degenerate π / 2 shape. The various means described serve to suppress vibrations of all others To shape. The vibrational energy of the desired shape is given to the tube by several coupling connections taken only for propagation in waveguide 40 in the direction of load 38 are determined. The energy possibly reflected by the load 38 is either in the final part 45 destroyed or otherwise fed back into the tube in such a direction that it reaches the Annihilation only progresses in a non-synchronous clockwise direction and, as a result, one has little effect on the desired waveform.

As a further exemplary embodiment, FIG. 3 shows a magnetron oscillator which is intended to operate with a phase difference of 2 jt / 3 between adjacent cavities. For the sake of simplicity, the parts corresponding to FIGS. 1, 2 are denoted by reference numerals which differ by a hundred. Accordingly, the housing designated by the reference number in FIGS. 1 and 2 is provided with the reference number 111 in FIG. The other designations are carried out in a corresponding manner. In order to emphasize the desired 2π / 3 shape, it is advantageous in this case to connect all third segments to one another in accordance with the principles recognized as being correct. Furthermore, an absorption waveguide piece 130 is used to suppress the shapes, which is coupled to three consecutive cavities by three connections 132, 133 and 134 with the same degree of coupling, but the cavity and waveguide coupling loops of the coupling connections 132 and 134 are bent in the same sense, while those of the coupling connection 133 are bent in the opposite direction in order to obtain a phase inversion. Furthermore, the waveguide 130 is loaded by radial plates 135 in order to obtain a wavelength of the conductor for the 2π / 3 waveform which is twice as large as the distance between adjacent coupling connections in the waveguide 130, so that adjacent coupling connections by half Conductor wavelength are separated. In order to obtain the desired directional properties, the waveguide 140 is provided with three connections 151, 152 and 153 with the same degree of coupling, which belong to three consecutive cavities. In the case of the central coupling connection 152, the cavity and waveguide loops are bent in the opposite direction, while the loops of the coupling connections 151 and 153 are bent in the same direction. Furthermore, the waveguide 140 is loaded in the coupling area by radial plates 155 in order to obtain a wavelength for the desired 2π / 3 form of the oscillation energy such that the coupling connections 151, 152 and 153 in the waveguide are spaced apart by a third of this wavelength . As a result, there is a same direction directed coupling between the tube ^and: the waveguide 140. In addition, the field strengths of the radial electric field and the axial magnetic field and the geometry of the resonators are directed so that an interaction of the electrons takes place with this desired waveform. Thereafter, the operation of this oscillator is analogous to that of the oscillator shown in FIGS.

From the preceding explanation it can be seen that the embodiments described are only examples for the general principles of the invention. Various other designs, e.g. B. those that are intended for operation with other non-degenerate waveforms or with other Forms of directional couplings, resonant cavities and suppression arrangements for non desired waveforms used can be determined by those familiar with the art Those skilled in the art can be proposed without departing from the spirit and aim of the invention.

Claims (5)

Claims, 1. Ultra-high frequency oscillator using a magnetron the spoke wheel Design in which the anode segments are in the form of radially extending planar structures are attached to an outer cylinder in such a way that cavity resonators arise and in which the Outer cylinder at several points coupling options for the exit in the cavity circles has generated vibrations in an outer circle adjoining the anode cylinder, characterized in that the tube is operated in an oscillator circuit in which the magnetic field and the bias voltage between the centrally located cathode and the anode cylinder are chosen so that adjacent cavity resonators are neither in phase nor in antiphase work and that the outer circle is in shape a rectangular waveguide is formed, which the anode only on part of its circumference surrounds, and that the coupling between the anode compartment and the waveguide (outer circle) is designed as a directional coupling, such that the energy generated is fed to a consumer which is at the end of the waveguide. 2. Ultra high frequency oscillator according to claim 1, characterized in that the directional coupling element has such a critical distance that the interaction space of the oscillator in a Direction of circulating high-frequency waves are selectively coupled into the waveguide, to proceed along it towards the consumer end of the waveguide, and that the ultrahigh frequency waves reflected from the consumer end selectively in the oscillator interaction space are coupled, where they proceed in the opposite direction. 3. Ultra-high frequency oscillator according to one of the preceding claims, characterized in that that a hollow waveguide piece that is closed at both ends and at both ends in the essentially anechoic terminations has to be arranged around part of the oscillator anode, the is different from the part occupied by the other waveguide, and that a plurality of Coupling connections the closed waveguide piece with cavity resonators of the oscillator couple in such a way that the oscillator selectively wave energy from the desired Frequency deviating frequencies is withdrawn. 4. Ultra-high frequency oscillator according to claim 3 for an oscillation of the π / 2 shape, characterized in that a plurality of webs which connect the respective fourth anode segments are provided that one of the broad sides of the hollow rectangular waveguide piece closed at both ends Outside of the anode cylinder rests on a part extending at least over three anode segments, so that three coupling connections are provided with a mutual distance of πΙ2, which are coupled to successive cavities and of which the middle one is twice as large as the other two coupling connections and has opposite directions that one of the broad sides of the hollow rectangular waveguide piece connected to the consumer rests against another part of the surface of the anode cylinder and that four directional coupling elements are connected to the hollow waveguide piece, which are of the same size, one after the other have a distance of a quarter, half and a quarter of the guide wavelength and each couple two successive anode cavities lying on both sides of a non-coupled anode cavity with the waveguide connected to the consumer. 5. Ultra-high frequency oscillator according to claim 3 for oscillations of the 2 π / 3-shape, characterized in that a plurality of webs which connect the respective third anode segments are provided that one of the broad sides of the hollow rectangular waveguide piece closed at both ends Outside of the anode cylinder rests on a part extending at least over three anode segments, so that three coupling connections are provided with a mutual distance of 2π / 3 , each of which couples the waveguide piece closed at both ends with one of three successive anode resonance cavities and which are of the same size , wherein the direction of the central coupling connection is opposite to the direction of the two outer coupling connections, so that one of the broad sides of the hollow rectangular waveguide piece intended for connection to the consumer rests against another part of the outside of the anode cylinder , and that three directional coupling elements are connected to the hollow waveguide section, which are of the same size and are coupled to three other successive anode cavities, the direction of the central coupling element being opposite to the direction of the two outer coupling elements. Considered publications:
German Patent No. 839 950;
U.S. Patent No. 2,611,110. 1 sheet of drawings © 709 510/305 5.57