US2079248A - Ultra high frequency magnetron discharge tube circuit - Google Patents

Description

.May 4, 1937. FRlTz 2,079,248

ULTRA HIGH FREQUENCY MAGNETRON DISCHARGE TUBE CIRCUIT Filed Sept. 19, 1935 s Sheets-Sheet 1 F. 5 5+ F; ,4 A1040 INVENTOR.

ARL FRITZ BY vkz ATTORNEY.

May 4, 1937. 2,079,248

ULTRA HIGH FREQUENCY MAGNETRON DISCHARGE TUBE CIRCUIT I K. FRITZ Filed Sept. 19, 1935 '3 Sheets-Sheet 2 IN\ E\TOR. KARL FRITZ ATTORNEY.

' May 4, 1937.

K. FRITZ ULTRA HIGH FREQUENCY MAGNETRON DISCHARGE TUBE CIRCUIT 3 Sheets-Sheet 5 Filed Sept. 19, 1935 INVENTOR. KARL FRITZ g rv-{A/ ATTORNEY.

Patented May 4, 1937 ULTRA HIGH. FREQUENCY MAGNETRON DISCHARGE TUBE CIRCUIT Karl Fritz, Berlin, Germany, assignor to Telefunken Gesellschaft fiir Drahtlose Telegraphicv m. b. 11., Berlin, Germany, a corporation of Germany Application September 19, 1935, Serial No. 41,223 y In Germany September 4, 1934 11 Claims.

The present invention is concerned with a circuit arrangement designed for the generation, detection, amplification, and multiplication of oscillations, more particularly of ultra-high frequency oscillations. It relates also to electron discharge tubes of the magnetron type and of suitable design for controlling the paths of electrons.

What is meant here by-a magnetron is a charge tube in which a constant or a varying magnetic field governs the path or trajectory of electricity carriers. at least a cathode and an anode 'or plate. Without a magnetic field, it is incapable of fulfilling its function, because it is the magnetic field which produces a useful non-linearity of the tube characteristic in the neighborhood of the working point.

For the production and the reception of radiofrequency oscillations, it 'is known from the prior art that magnetron tubes may be excited by the aid of direct current magnetic fields. It is likewise known that for amplifying relatively lowfrequency oscillations a magnetron may be operated when its magnetic field is excited by an alternating current. The lines'of force of the field are in both cases rectilinear inside the discharge'path and parallel in reference to the axis of the anode system or the heating wire.

Then again it isknown that in an electron tube having a grid an influence over .the passage of electrons from the cathode to the anode may be produced by the magnetic field set up by the current flowing through the heating wire, the said field surrounding, the heater wire annularly (see Barkhausen, Elektronenroehren, Vol. 1, 1931, p.

.- The impress of control currents upon the cathode itself for purposes of field excitation has not proven satisfactory. However, by controllingthe intensity of the magnetic field presenting circular symmetry to the cathode, the paths ofthe electrons in the vicinity of the control electrode may be given such a'curvature that the effective 4 tube characteristic is substantially altered. Radio frequency control of the electrons is then effected by utilizingthe capacitive reactions be-' dis- Such a magnetron contains tween the electrodes. In all cases, however, the cathode is included in the oscillatory circuit.

The magnetron circuit arrangement of this invention is especially well designed for the generation, reception, detection, amplification or fre- 5 quency multiplication of ultra-short waves. It has this outstanding characteristic feature that for the purpose of acting upon the paths of the electrons, recourse is had to a circular-symmetric magnetic field which is set up by the aid of a linear conductor which is normally not heated and which is placed symmetrically'in reference to the anode surface. I

Before entering into a discussion of the special merits of the circuit organization hereinafter to be disclosed, a brief outline will be given of the construction and mounting of the tubes comprised therein. Particularly suited for the present scheme are tubes built as symmetrically as feasible and which comprise at least two anode parts as in an ordinary split anode magnetron. The anodes form an approximately closed hollow surface of revolution. The linear conductor before mentioned (hereinafter called the deflector) which serves to create the circular-symmetric magnetic field forms the axis of rotation of the several anode members. 'Directly or nearly in the electric and the geometric points of symmetry of the system comprised by the-deflector and anode members, at close proximity to the former, are arranged the punctiform or circular electron emission sources.

The chief advantage of circuit schemes as he disclosed resides in the fact that no extraneous magnetic field is required; The heretofore used troublesome. and heavy magnet systems and the source for energization thereof are dispensed with. The circular-symmetric magnetic field is now produced by the aid of a current traversing the'defiector. The incidental expenditure of energy is either reduced to negligible values or no energy at all is supplied, as, for instance, when radio frequency current control-results from a self-oscillatory scheme. v 1

The anode members form an approximately closed surface presenting rotation symmetry. Each of the anode members of the embodiments shown in Figs. 1 to '7 inclusive and 11 to 13 inclusive is preferably conformed to a spherical surface. Theanode' members of the embodiments shown in'Flgsl 8 and 9 are preferably cylindrical in shape. The anodes of the embodiment shown in Fig. 10 are partly cylindrical and partly conical. In every case, however, "the anode members constitute shielding means whereby the discharge path is protected against outside fields. The closed form of anode, moreover, makes conditions so that the radiation resistance of the electrode assembly or system is minimized. Such radiation as may exist is restricted to the breadth of slit. Thus I avoid the wasteful dissipation of a large part of the generated energy.

In contrast with the prior practice, where usually the radio frequency control field and the static accelerator field were superimposed on the same discharge path, the electron paths are maintainedalways in a direction away from the oathode. In other words, the stream of electrons in'the present scheme is caused to proceed by tions of space under conditions which, from the viewpoint of time, have been made non-equivalent by the oscillation process. This point is extremely essential seeing that it renders the use of highemission oxide-coated cathodes (having no pronounced saturation) possible. These cathodes represent an extremely abundant and copious electron source per unit of surface or area. It will be remembered that in practically all ultrashort-wave tube generators, a limitation is imposed upon the load by the cathode rather than by the anode, asis normally true. The dimensions of the cathode grow with the aggregate electron emission. This circumstance, in shortwave tubes, makes itself very disagreeably felt inasmuch as the proportions of the other electrodes grow with the cathode, so that a tube of this kind finally becomes unserviceable for the generation of ultra-short waves for this specific reason that the oscillatory circuit formed by the electrodes and their connections or leads exhibits an unduly low natural frequency. In con-v nection with these problems it has been suggested to use for short-wave tubes, more particularly, magnetron tubes, a vacuum spark-gap,

an are or some other unassisted gas discharge path as a source whence to derive electrons, and

\ this opens up wholly new vistas for the creation 'of novel circuit organizatiofis and for the use of circuit schemes known in the earlier art for the generation of ultra-short waves.

My invention will best be understood from the following detailed description when read in view of the accompanying drawings in which Figure 1 is a circuit diagram of an oscillation generator and amplifier in which the principles of my invention are illustrated;

Figs. 2, 3, 4 and 5 show various modifications suitable for frequency multiplication;

Figs. 6 and '7 show self-sustaining oscillation generators of two different types;

Fig. 8 shows a push-pull type of self-sustaining oscillation generator;

Fig. 9 shows a master controlled radio-frequency amplifier;

Figs. 10 and 11 show two illustrative embodiments in eachof which the oscillation circuit'is combined with the utilizationcircuit; and

Figs. 12 and 13 illustrate two difierent receiving circuits wherein the invention is carried out.

Fig. 1 illustrates the fundamentals of a magnetron type oscillator of the kind here disclosed and designed for master operation and excitation. Control action upon the electrons in a tube R113 obtained by an alternating magnetic field presenting circular symmetry. The cathode I0 is confined to a space as close to the center of the spherical anodes as it is possible to place it. In the figure, it is shown in section and it will be understood to be looped around the conductor S while being insulated therefrom. As is well known in the operation of magnetron tubes, the emission of electrons from a centrally disposed cathode toward a surrounding system-of anodes is such that the electrons describe spiral or hellcal paths under the influence of a polar magnetic field whose axis is coincident with the helical axis. If the polarity of the magnetic field is reversed, then the direction of rotation of the electrons around the polar or helical axis will be reversed. The conductor S is adapted to carry a heavy alternating current. The spiral paths of the electrons emitted from the cathode 10 will be diverted toward first the anode A1 and then the anode A2 in accordance with the reversal of current in the conductor S. Hence, oscillations will be produced in the closed loop circuit including the anodes A1 and A2, together with the inductance L. In the present instance, the control current is assumed to be derived from master os- CillSAiOlbRz. The oscillatory circuit of the master oscillator R2, and the control circuit comprising deflector S and capacitance C of tube R1 are connected by means of a suitable feeder K, having a linear conductor 2| which isdisposed in inductive relation to the conductor 20. The amplified radio frequency energy may be derived from the oscillation circuit consisting of the inductance L and the mutual capacitance between the anode members A1 and A2, or. in any other convenient manner.

The magnetron oscillator of this invention subject to magnetic master control action represents a separately excited ultra-short-wave transmitter which is sensibly free from reactions. In the operation of magnetrons subject to master voltage excitation it has never been possible in the prior art to preclude completely the reactions or the main transmitter upon the master oscillator. Because of the diminutive proportions of the electrode systems under present consideration it is extremely diiiicult in actual practice to prop-' erly locate the neutral symmetry planes or electric bridge points of the system orto accommodate therein the entire means for obtaining voltage control action. The diiliculties attendant upon amplification of ultra-short waves are largely due to the inter-electrode capacitances which produce currents that are improperly phased with respect to the space current energy. Upon attempting to surpass previous limits of high frequency generation, the displacement currents ultiniately exceed the electronic currents so that the amplifier as such becomes useless.

In order to meet these difllculties my inventio 1 may be utilized to considerable advantage. Inastrol circuit C--20S-,-20. In this and in similar schemes the radio-frequency potential between anode members A1 and A2 is immaterial so far as the electron paths M and 12 are concerned.

electrons subject to the influence of an alternating magnetic field I 3 and l4 respectively, during two different alternations. A useful oscillation current may be derived from the amplifier R1 .by coupling a utilization device to the inductance L. This current will not react adversely upon the electron' control action. Moreover, the phase relations between the control current flowing in S and the alternating voltage between A1 and A2 'is immaterial, seeing that the oscillatory cir-- cults are completely separated one from the other. Save for such losses as are generally inevitable, the control action is free from dissipation of energy. Figs, 2 to 5, fundamentally, show magnetron oscillators similar to the one in Fig. 1, though operating as frequency multipliers. The frequency derived at the output end is higher than the frequency put into the control circuit C20S-20.- Frequency multiplication is obtained by virtue of the rotation-symmetric anode surface which is split into a plurality of ring-like members A1, A2, As, etc. These anode members may be conformed to a spherical surface and are inter-connected by way of inductances I! which bear a relationship to the desired output frequency. The connection of the anode members with the plate-potential source may be effected in such a fashion that the oscillations of higher frequencywhich are excited during the various phases of the fundamental input frequency become additively superposed in the load circuit, or in their field in case of direct radiation.

In a frequency-multiplier magnetron it is usual to provide a single cathodeor electron supply source. This cathode is placed in the geometric center of the system consisting of the currentpath and the anode members. The rotationsymmetric surfaces of electron paths in positions sively during each cycle of the fundamental frequency. This electron fan is subject to the control of deflector action of the radio frequency II and I2 represent the paths of two i, 2, 8, l, 8, etc. become eifective succes current flowing through S and produces a sweep of the electrons across the constituent anode splits A1, A2, A: The length of time for which the electron fan stays on each anode member must be uniform and equal. The breadth of the annular anode splits or members must be chosen with due regard for the instantaneous angular speed of the electron fan, and the frequency mu]; tiplier factor is a function of the number of the anode splits.

The useful output energy'at the multiple frequency may be taken over by an inductive coupling between the various loop circuits I1 and the single loop IS, the terminals of which are capacitively coupled at [9 as shown in Fig. 2. In Fig. 3

.the same inductive relationship exists between the loops 22 and the rlng 23, the terminals of which are inter-coupled capacltively at 2'4. The ring 23 may, if desired, comprise a radiator.

In Fig. 4 the frequency multiplier action may be caused to impress the'desired multiple .frequencynpon a coil 15 which is inductively related to a coil IS in a load circuit.

Fig. 5 shows a frequency multiplier wherein the several anode members have output leads 25 all inter-connectedata radio frequency nodal point :5 so as to be supplied with anodepotential from any suitable direct current source as indicated at +3. The separate leads 25 may be inductively coupled to a loop 18 in an output circuit which also ineludes the capacitor i9.

Referringto Fig. 6 I show another modification of my .invention. A self oscillatory magnetron circuit is provided. In this embodiment there are two anode members A1 and A2 of hemispherical formation. The members 29 are capacitively coupled thereto. The capacitive members 29 are in circuit with an inductance 28 from which output energy may be derived in any suitable manner. The oscillator circuit includes the' cathode 10 which is fed by heating current'through the twisted pair of wires 25, this current being de rived from any suitable source as through the transformer 26. A center tap on the secondary of this transformer leads to the negative side of a direct currentsource 27 and the positive side of this source is suitably connected to the deflector conductor S. This circuit is subject to control action by a circular-symmetric alternating magnetic field. The oscillatory circuit of the oscillator consists of the capacities of the anode members A1, A2, and the inductance of the deflector conductor S. The oscillation circuit itself, as will thus be noted, controls the flow or passage of electrons from the source I 0 to the anode splits A1, A2. up by the oscillatory current moves about the conductor S as the axis of circular symmetry. The electron source II) is disposed at a neutral 'point I of the entire system and is formed symmetrically about conductor S. The phase shift required for the self-excitation of oscillations between the controlled electron stream and the plate alternating voltage must be secured by adjustment of the reactions in relation to the transit time of the electrons. Inasmuch as there is usually a phase angle of 90 degrees between current and voltage, it is necessary to. correct the phase relations. The simplest plan is to so adjust the constant current plate voltage with respect to the frequency determined by the oscillatory circuit of the tube that the finite transit time of the electrons will restore the requisite phase relation.

In the case of a magnetron of the self-oscillatory radio-frequency current control type, the presence of a high capacity in the oscillation circuit, as provided by the cooling means 29 adjacent the anode is very advantageous since the ratio L/Cshould be kept low for maintaining a control current of high amplitude.

Fig. 7 shows still another self-oscillatory mag-' netron oscillator subject to audio frequency modulation control. Inside the deflector conductor S, and insulated from the latter by insulation 30 The active magnetic field set is disposed a conductor 3! which may be employed for modulating the currents of the oscillation generator. The modulation source is shown at 32 and is coupled through the transformer 33 to the control circuit including the conductor 38.

The use of a circular-symmetric magnetic field designed to influence the electron paths is not limited to radio frequency current control;

in fact, the same field may be controlled to similar advantage by voltage variations. If in this case a push-pull actionis to be desired, then the anode of the voltage-controlled self-oscillatory magnetron must be split at least twice, as shown in Fig. 8. The oscillatory circuitis interpositioned between the anode members 36 and 31, or corresponding anode groups. The sense of flow of electrons is in this, instance determined byv the direction of a constant magnetic field... The design of the magnetron tube shown in Fig. 3 is such that two cathodes E1 and E2 are provided. Typical electron paths from these electrodes to the surrounding anodes are delineated on the drawingsin one case by solid lines extending from the cathode E1 and in the other case by dotted lines extending from cathode E2. In this embodiment phase shift is unnecessary because the radio frequency potentials which exercise a control action upon the stream of electrons are due to regeneration and to the oscillatory characteristics of the output circuit. I

It is reasonable to assume that in the operation of this embodiment, a cloud of electrons will be concentrated first upon the anode-36 and then upon the two anodes 31, thus producing a radio frequency current in the transformer 35. Suecessful operation of the device is, however, by no means dependent upon the correctness of this theory.

To those skilled in the art, the circuit of Fig. 8 may easily be'modified to include certain of the features of Fig. 1, thus providing a master-controlled, push-pull amplifier. Fig. 9 also suggests 5 a means for accomplishing this end. Here the I I through zero, or twice per cycle of the modulation anode members 38 serve as push-pull exciters under control of energy from the source K. Si: multaneously, the anode member 36 oscillates in phase opposition to the anode members 31.

Upon producing a circular-symmetric and conbe introduced into the oscillator also when the same is subject to magnetic modulation, say, by the agency of a conductor 3| positioned co-axially in reference to the deflector as shown in Fig. '7. So, as seen in Fig. 9, the electron supply sources I!) are slightly displaced from the separating planes between the anode members. Now if the anode splits receive exactly equal direct current voltages, a frequency twice the modulation frequency will arise in the output circuit because the crest of the alternating current wave occurs upon each passage of the modulation current frequency Electric dissymmetry is obtainable by impressing dissimilar potentials upon the platev splits. 'Magnetic dissymmetry is readily securable by a superposed auxiliary field of the desired direction and magnitude.

Delivery of the radio'frequency output current to a' utilization circuit may be made by inductive or capacitive coupling or conductively if -stricted to the exemplified embodiments illusdesired. But the mode of delivery isnot retrated in the drawings. In fact, any suitable and well known transfer means may be employed. Fig. 10 shows an example of capacitive transfer means. applied directly to the deflector conductor S.

Fig. 11 shows a self-oscillatory alternating current-controlled magnetron in which a. spark or are discharge path is used as the source of the electrons? The'pscillation circuit consists of the two anode parts A1 and A'r'and the conductor S.

At the extensions V of the latter, say, outside the discharge vessel, conductor S is fitted with capacia anodes.

tive balls Bby the aid of which the radiation resistance of the dipole arms V can be adjusted to obtain an impedance match with respect to the internal impedance of the oscillator at the working frequency. Inside the conductor S, and separated therefrom by insulation 30, are the two discharge electrodes F. The discharge gap is excited bymeans of a conductor 44 which is brought out at suitable nodal points along the extensions V of conductor S and thence through a resistance 45 to a source of current 46. The electric center of the source of emission is artificially imitated outside the oscillator. Modulation of the oscillator is obtained magnetically. In this instance, also, the deflector or conductor S must carry the modulation frequency in addition to radio frequency. Anode potential is supplied by way of a mid-tap on the secondary winding of a modulation transformer 41 and thence through leads -Z to the anode parts A1 and A2. The conductor S, which in this case surrounds the discharge path, is provided above the electron source with apertures 48 designed to allow of the escape of the electrons. In order to concentrate or focus the fan or beam of electrons, auxiliary electrodes H insulated fromS are provided, and these m be raised to any desired potential.

Figs. 12 and 13 illustrate two different embodiments of receiving circuits. The receiving dipole comprises an extended conductor S. This dipole is arranged tobe excited with electrical energy from end to end as induced therein by received radiant energy. The currents induced in this dipole, therefore, act to deflect the paths of electrons from the cathode I0 to the surrounding When the apparatus is employed as a receiver it is unnecessary for the dipoleconductor S to be electrically'connected to any other portions of the device. Witha view to enhancing the directional properties the entire arrangement may be furnished with a reflector or mirror. The electron source I0 is shown at the center of the system. A1, A2 and A3 are anode members or splits. Adjustments are made so that in the absence of signals substantially the entire electron emission current flows to the central split A3. Hence, the electron fan must be so formed that, when striking the central anode member M, it will roughly have the same width as that member... I

The receiving circuit ,of Fig. 12 comprises a bridge rectifier 49 and a sound responsive device 50 so connected to the anodemembers A1, A2

and A: that full wave rectiflcation'of the modulation frequency. may be impressed across the ;terminals of the sound responsive device. The cathode I0 is energized in the same manner as shown in Fig. 6, while 'anode potential may beimpressed upon the anodes from the direct curradio frequency signal is received upon the dipole antenna S a magnetic fleld will'be produced symmetrically about this conductor so as to control the direction of eiectronic flow, first to the left, "and then to the right, thereby setting up the electronic .fan action as heretofore explained. The amplitude of the electronic swings thus provides,a corresponding response 'in the receiver 50 because only the demodulation currents can traverse .the windings of. the device 5|! when connected through the bridge rectifier as shown.

Fig. 13 shows an embodiment of receiving apparatus which differs from that of Fig. 12 chiefly trol circuit CS,-20. In this-and in similar schemes the radio-frequency potential between anode members A1 and A2 is immaterial so far as the electron paths II and I2 are concerned. electrons subject to the influence of an alternating magnetic field Band I! respectively, during two different alternations. A useful oscillation current may be derived from the amplifier R1 by coupling a utilization device to the inductance L. This current will not react adversely upon the electron control action. Moreover, the phase relations between the control current flowing in S and the alternating voltage between A1 and A2 is immaterial, seeing that the oscillatory circuits are completely separated one from the other. Save for such losses as are generally inevitable, the control action is free from dissipation of energy. 20 Figs. 2 to 5, fundamentally, show magnetron oscillators similar to the one in Fig. 1, though operating as frequency multipliers. The frequency derived at the output end is higher than the frequency put into the control circuit C20-S20. Frequency multiplication is obtained by virtue of the rotation-symmetric anode surface which is split into a plurality of ring-like members A1, A2, Aaetc. These anode members may be conformed to a spherical surface and are inter-connected by way of inductances I! which beara relationship to the desired output frequency. The connection of the anode members with the plate-potential source may be effected in such a fashion that the oscillations of higher frequencywhich are excited during the various phases of the fundamental input frequency become additively superposed in the load circuit, or in their field in case of direct radiation.

In a frequency-multiplier magnetron it is usual to provide a single cathodeor electron supply source. This cathode is placed in the geometric center of the system consisting of the currentpath and the anode members. The rotationsymmetric surfaces of electron paths in positions sively during each cycle of the fundamental frequency. This electron fan is subject to the control or deflector action of the radio frequency II and i2 represent the paths of two' suitable direct current source as indicated at +3.

to a loop l8 in an output circuit which also includes the capacitor l9.

Referring to Fig. 6 I show another modification of my invention. A self oscillatory magnetron circuit is provided. In this embodiment there are two anode members A1 and A2 of hemispherical formation. The members 29 are capacitively coupled thereto. The capacitive members 29 are in circuit with an inductance 28 from which output energy may be derived in any suitable manner. The oscillator circuit includes the' cathode III which is fed by heating current through the twisted pair of wires 25, this current being derived from any suitable source as through the transformer 26. A center tap on the secondary of this transformer leads to the negative side of a direct currentsource 21 and the positive side of this source is suitably connected to the deflector conductor S. This circuit is subject to control action by a circular-symmetric alternating magnetic field. The oscillatory circuit of the oscillator consists of the capacities of the anode members A1, A2, and the inductance of the deflector-conductor S. The oscillation circuit itself, as will thus be noted, controls the flow or i, 2, 6, I, 8, etc. become effective succes current flowing through S and produces a sweep 50 of the electrons across the constituent anode splits A1, A2, A: The length of time for which the electron fan stays on each anode member must be uniform and equal. The breadth of the annular anode splits or members must be chosen with due regard for the instantaneous angular speed of the electron fan, and the frequency multiplier factor is a function of the number of the anode splits.

The useful output energy'at the multiple frequency may be taken over by an inductive coupling between the various loop circuits [1 and the single loop l8, the terminals of which are capacitively coupled at I!) as shown in Fig. 2. In Fig. 3 the same inductive relationship exists between the loops 22 and the ring 23, the terminals of which are inter-coupled capacitively at 2'4. The ring 23 may, if desired, comprise a radiator.

In Fig. 4 the frequency multiplier action may be caused to impress thei'desired' multiple .fre quencyupon a coil [5 which is inductively related to a coil IS in a load circuit.

Fig. 5 shows a frequency multiplier whereinthe several anode members have output leads 25 all inter-connected at"a radio frequency nodal point 35 so as to be supplied with anodepotential from any passage of electrons from the source ill to the anode splits A1, A2. The active magnetic field set up by the oscillatory current moves about the conductor S as the axis of circular symmetry. The electron source I0 is disposed at a neutral point of the entire system and is formedsymmetrically about conductor S. The phase shift required for the self-excitation of oscillations between the controlled electron stream and the plate alternating voltage must be secured by adjustment of the reactions in relation to the transit time of the electrons. Inasmuch as there is usually a phase angle of 90 degrees between current and voltage, it is necessary to correct the phase relations. The simplest plan is to so adjust the constant current plate voltage with respect to the frequency determined by the oscillatory circuit of the tube that the finite transit time of the electrons will restore the requisite phase relation.

In the case of a magnetron of the self-oscillatory radio-frequency current control type, the presence of a high capacity in the oscillation circuit, as provided by the cooling means 29 adjacent the anode is very advantageous since the ratio L/Cshould be kept low for maintaining a control current of high amplitude.

Fig. 7 shows still another self-oscillatory mag-' netron oscillator subject to audio frequency modulation control. Inside the deflector conductor S, and insulated from the latter by insulation 30 The separate leads 25 may be inductively coupled is disposed a conductor 35 which may be employed for modulating the currents of the oscillation generator. The modulation source is shown at 32 and is coupled through the transformer 33 to the control circuit including the conductor 3i.

The use of a circular-symmetric magnetic field designed to influence the electron paths is not limited to radio frequency current control;

in fact, the same field may be controlled to similar advantage by voltage variations. If in this case a push-pull actionis to be desired, then the anode of the voltage-controlled self-oscillatory magnetron must be split at least twice, as shown in Fig. 8. The oscillatory circuit'is interpositioned between the anode members 36 and 31, or corresponding anode groups. 'The sense of flow of electrons is in this instance determined by the direction of a constant magnetic field. The design of the magnetron tube shown in Fig. 3 is such that two cathodes E1 and E2 are provided, Typical electron paths from these electrodes to the surrounding anodes are delineated on the drawings in one case by solid lines extending from the cathode E1 and in the other case by dotted lines extending from cathode E2. In this embodiment phase shift is unnecessary because the radio frequency potentials which exercise a control action upon the stream of electrons are due to regeneration and to the oscillatory character: istics of the output circuit.

It is reasonable to assume that in the operation of this embodiment, a cloud of electrons will be concentrated first upon the anode-36 and then upon the two anodes 31, thus producing a radio frequency current in the transformer 35. Successful operation of the device is, however, by no means dependent upon the correctness of this theory.

To those skilled in the art, the circuit of Fig. 8 may easily be'modified to include certain of the features of Fig. 1, thus providing a master-com trolled, push-pull amplifier. Fig. 9 also suggests a means for accomplishing this end. Here the anode members 38 serve as push-pull exciters under control of energy from the source K. Simultaneously, the anode member 38 oscillates irf phase opposition to the anode members 31.

Upon producing a circuiar-symmetric and constantly unidirectional magnetic field around the be introduced into the oscillator also when the same is subject to magnetic modulation, say, by the agency of a conductor 3| positioned co-axially in reference to the deflector as shown in Fig. 7. So, as seen in Fig. 9, the electron supply sources ID are slightly displaced from the separating planes between the anode members. Now if the anode splits receive exactly equal direct currentvoltages, a frequency twice the modulation frequency will arise in the output circuit because the crest of the alternating current wave occurs upon each passage of the modulation current I through zero, or twice per cycle of the modulation frequency' Electric dissymmetry is obtainable by impressing dissimilar potentials upon the plate splits. 'Magnetic dissymmetry is readily securable by a superposed auxiliary field of the desired stricted to the exemplified embodiments illusdirection and magnitude.

Delivery of the radio'frequency output current to a utilization circuit may be made by inductive or capacitive coupling or conductively if desired. But the mode of delivery isnot retrated in the drawings. In fact, any suitable and well known transfer means may be employed. Fig. 10 shows an example of capacitive transfer means. applied directly to the deflector conductor S.

Fig. 11 shows a self-oscillatory alternating current-controlled magnetron in which a spark or are discharge path is used as the source of the "electrons The, oscillation circuit consists of the two anode parts A1 and Arand the conductor S.

At the extensions V of the latter, say, outside the discharge vessel, conductor S is fitted with capacie tive balls B by the aid of which the radiation resistance of the dipole arms V can be adjusted to obtain an impedance match with respect to the internal impedance of the oscillator at the working frequency. Inside the conductor S, and separated therefrom by insulation 30, are the two discharge electrodes F. The discharge gap is excited by means of a conductor 44 which is brought out at suitable nodal points along the extensions V of conductor S and thence through a resistance to a source of current 46. The electric center of the source of emission is artificially imitated outside the oscillator. Modulation of the oscillator is obtained magnetically. In this instance, also, the deflector or conductor S must carry the modulation frequency in addition to radio frequency. Anode potential is supplied by way of a mid-tap on the secondary winding of a modulation transformer 41 and thence through leads 2 to the anode parts A1 and A2. The conductor S, which in this case surrounds the. discharge path, is provided above the electron source with apertures 48 designed to allow of the escape of the electrons. In order to concentrate or focus the fan or beam of electrons, auxiliary electrodes H insulated from S are provided, and these m be raised to any desired potential.

Figs. 12 and 13 illustrate two different embodiments of receiving circuits. The receiving dipole comprises an extended condu'ctor S. This dipole is arranged to be excited with electrical energy from end to end as induced therein by received radiant energy. The. currents induced in this dipole, therefore, act to deflect the paths of electrons from the cathode iii to the surrounding anodes. When the apparatus is employed as a receiver it is unnecessary for the dipole conduc- -tor S to be electrically conpected to any other portions of the device. Witha view to enhancing the directional properties the entire arrangement may be furnished with a reflector or mirror. The electron source i0 is shown at the center of the system. A1, A2 and A3 are anode members or splits. Adjustments are made so that in the absence of signals substantially the entire electron emission current flows to the central split A3. Hence, the electron fan must be so formed that, when striking the central anode member As, it will roughly have the same width as that member. I

The receiving circuit of Fig. 12 comprises a bridge rectifier 49 and a sound responsive device so connected to the anode members A1, A: and A: that full wave rectification-of the modulation frequency may be impressed across the ;terminals of the sound responsive device. The cathode i0 is energized in the same manner as shown in Fig. 6, while 'anode potential may be impressed upon the anodes from the direct current source 21 and leading through the rectifier bridge 49.

It should be apparent that when an ultra-high radio frequency signal is received upon the dipole in the mode of connectionof the anode members the electron discharge .tube structure.

ALA: and A3 to the sound responsive device 50. There. a full .wave rectifier 5| is suitably connected with the sound responsive device 50 and with the anode membersAi and A2 for demodulating the currents arising upon the reception of the modulated ultra-high frequency signals. This circuit also includes choke coils 52 disposed between the anode potential source 21 and the anode members A1 and A2 so as to avoid the dissipation of ultra-high frequency energy. If desired, auxiliary electrodes 43 may be included in These electrodes will be understood to have impressed upon them a suitable direct current bias potential in order to further control the electronic action within the tube.

I claim: r

1. In an ultra high frequency circuit, a magnetron discharge tube having a plurality of anode members the inner surfaces of which are substantially conformed to a spherical surface, a cathode disposed as near as possible to the center of the spherical system, a magnetic fieldproducing conductor extending diametrically through the spherical system, means for so en-' ergizing the cathode and the anode members as to set-up electronic emission therebetween, means for applying alternating potentials to said fieldproducing conductor for variably controlling the direction of electronic paths within the tube, and means for utilizing the output energy available from different ones of said anode members when in circuit with the cathode 2. A device in accordance with claim 1 ,and

having the anode members conformed to latitudinal zones of the spherical system, and having the field-producing conductor axially disposed with respect to said zones.

3. A device in accordance with claim 1 and having means for multiplying the frequency of the energy impressed upon said field-producing conductor. I 4. A device in accordance with claim 1 in whic 45 said means for applying alternating potentials to said field producing conductor is constituted by a master oscillator. I

5. Adevice in accordance with claim 1 wherein said field producing conductor forms part of a resonantcircuit the impedance values of which are such that self-sustaining oscillations may be generated therein.

6. A self-oscillating magnetron discharge tube circuit having a plurality of spherically segmerited anode members and a centrally disposed cathode included in the electron discharge tube thereof, means including a conductor perpendicularly disposed with respect to the planes of segmentation of said anode members for producing a deflection of electronic emission successively toward different ones of said anode members, and means for compensating for the phase displacement of the anode currents with respect to input currents impressed upon said perpendicularly disposed conductor, which phase displacement is inherently due to the transit time of the electrons from the cathode to each anode member.

'7. A circuit in accordance with claim 6 and having a source of direct current potential connected between the cathode and the anode members and of'such value asto obtain the desired compensation for phase shift.

8. A circuit in accordance with claim 6 and having means including an additional conductor concentric with said perpendicularly disposed conductor for impressing modulations upon the oscillations generated.

9. A circuit in accordance with claim 6 wherein said cathode is divided into ring-like members coaxially disposed with,respect to said perpendicular conductor said ring-like members being so spaced apart longitudinally of said perpendicular conductor that they constitute means for directing the normal flow of electrons toward the gaps betweenadjacent anode members.

" 10. A- circuit in accordance with claim 6 and having means including certain of said anode members for exercising a control action upon the electronic emission which is directed toward others of said anode members.

11. A circuit in accordance with claim 6 and having means including a dipole antenna system for the transmission and reception of ultra-high frequency energy, said means constituting extensions of said perpendicularly disposed con- .ductor.

Images