US2399325A - High-frequency-oscillation generator or amplifier - Google Patents

Description

April v30, 1946.

- E. U.- CONDON HIGH FREQUENCY OSCILLATION GENERATOR OR AMPLIFIER Filed Marci 14, 1940 WITNESSES:

INVENTOR 'A ORNEY Patented Apr. 30, 1946- rncnrascmsucr-oscmm'rrou assurance on AMPLIFIER Application March 14, 1940, Serial-No. 323,912

10 i'llaims.

My invention relates to electrical oscillators, and has particular relation to apparatus for generating oscillations having a wave length oi the order of decimeters.

It is an object of my invention to provide a decimeter-wave length oscillator of simple structure.

Another object of my invention is to provide a decimeter wave length oscillator capable of delivering substantial power.

An incidental object of my invention is to promovement is impressed on a stream of electrical charges by the electric field of a hollow body resonator. As the stream vibrates laterally, it traces a path backward and forward across a periodicelectromagnetic field, the instantaneous spacial distribution of which is such as to oppose the longitudinal movement of the charges.

Energy is thus derived from the stream and may be radiated from a suitable antenna.

The novel features that I considericharacteristic of my invention are set forth with particularity in the appended claims. The invention itself, however, both as to its organization and.

its method of operation, together with additional objects and advantages thereof, will best be understood by referringv to the following description taken in connection witlr the accompanying drawing, in which the single figure is a diagrammatic viewillustrating a preierred embodiment of my invention.

The apparatus-shown in the drawing comprises a vacuum-tight container in the form of an elongated ellipsoid of revolution tempered of a metal such as copper or stainless steel or an insulator such as glass or a ceramic substance. If the container iscomposed of insulating material,-a conducting layer should preferably be deposed on' its inner surface. The container is in the preferred practice of my invention highly evacuated, although it may contain an inert gas or mercury vapor at a pressure of several microns to several millimeters of mercury.

filament is partially enclosed within a dishshaped metallic shell 5 having a small opening? in its base. The shell 5 is preferably grounded and a high negative potential 9 (shown sym bolically as a battery) is impressed between the filament s and ground. The electrons emitted from the filament 3 are accelerated by the potential difierence between the shell 5 and the filament, and concentrated into a narrow beam as they pass through the opening i. To avoid unnecessarily complicating the explanation, I have shown and described only the filament and the accelerating shell. In the construction of oscillators in accordance with my invention, additional electrodes such as are common in the cathode-ray tube art will be found to be desirable. Where such electrodes are used in the practice of my invention they are to be regarded as falling within the scope thereof.

The stream of electrons emitted from the open} ing 3 is transmitted through an electrical resonator i i which has the form of a hollow dumbbell. The resonator is so disposed that the electron stream passes through the center of the constrlcted portion i ii in a direction perpendicular to the longitudinal axis. dumbbell are not of spherical shape but are preferably ellipsoids of revolution'having a substantial eccentricity with the axes of revolution perpendicular'to the longitudinal axis of the dumbbell. course take other forms than ellipsoids oi revolution. However, whatever form is selected, it is essential that the major axis of an end should be substantially diflerent than the minor axes in the plane perpendicular to the longitudinal axis 0f the dumbbell. Thus a parallelopiped, the base of which is a rectangle, is one possible form.

Because the ends of the dumbbell lack spherical symmetry. the mode of electrical oscillation of the dumbbell in which the electric field is parallel to the direction of the stream is different from its mode of oscillation in which the electric field is perpendicular to the stream. The

frequency corresponding to the latter mode of oscillation is selected for use in the present connection, and the field produced when the resonator is excitedto oscillate in this mode is impressed on the stream. The stream, accordingly, is laterally deflected as indicated by the diverging arrow lines I! and i9 which-represent" two of its positions. The deflection is periodic and its frequency is equal to the frequency corresponding to the selected mode of oscillation of the resonator.

The ends i5 of the The ends of the dumbbell may of To cause the resonator to oscillate in a predetermined manner, the corresponding frequency must be impressed thereon. Where a system according to my invention is used for amplifying purposes, a potential corresponding to the frequency ofthe desired mode of oscillation is impressed from an external source. However, in general, my invention is used for the conversion of direct current energy into oscillatory energy. and in such a case a feed-back coupling from the emitter oi the oscillating energy is provided. For the present, it may be assumed that resonator H is excited to oscillate at the proper frequency and impresses a periodic deflection on the electron stream.

After the stream leaves the resonator II, it has a substantial component of velocity along its original direction in addition to the lateral periodic component. A second hollow body resonator 2| which is preferably in the form of a narrow box with the smaller dimension along the original direction of motion of the stream is disposed in the path of the stream and the stream enters the resonator through an elongated grid 23 in its incident surface.

The resonator 2|. is so dimensioned that the the upper region the electric field has one polarity. as indicated by an arrow labeled E and in the lower region, it has the opposite polarity as indicated by another arrow. The resonators II and -.2l are so spaced and the electric fields at which they are excited to oscillate is so phased that the stream passes through the latter resonator II at any instant at the time when the electric field in the region in which it passes is such as to oppose the forward motion of the electrons. The field thus absorbs energy from the electrons while varying at the frequency correspondingto its lateral movement.

' The energy derived from the electron stream is to a large extent radiated from an antenna 21 which passes through a hollow tube 23 extending from the resonator 2|. In the region in which it is connected to the resonator 2|, the antenna 21 is provided with a loop 3|, the plane of which is such that the magnetic field corresponding to the electric field which derives energy from the electrons threads the area bounded by the loop. The loop 3| may be properly oriented in a plane perpendicular to the plane of the arrows 33. a Where the system is to be used for producing oscillations, there is an interchange of energy between the energy deriving resonator 2| and the deflecting resonator 'i I. The transfer of energy take place through a conductor extending from a loop 31, properly oriented in the deflecting resonator II to a loop 39 properly oriented in the deriving resonator 2|. The conductor is ing the resonators. In the deflecting resonator II, the position of the loop 31 may be determined by considering the direction of the magnetic field corresponding to the excited mode of oscillation of the resonator. The direction of the magnetic field at a series of points is represented by the curvilinear arrow 43 labeled below the resonator II. The plane of the loop 31 should be such that it is threaded by the magnetic field represented by the ,arrow 43. The loop in the deriving resonator 2| should be oriented to be threaded by the magnetic field represented by the arrows 33. For the purpose of adjusting the positions of the loops 3|, 31 and 39 and timing the resonators H and 2|, magnetically or thermally actuable levers may be provided.

In the direction in which the resonators II and 2| are threaded by the stream of electrons, their dimensions should be so small that the proper deflection of the stream and the efficient derivation of energy is not impaired by the subiection of the electrons to the held for prolonged time intervals. These dimensions are determined by taking into consideration the selected frequency of oscillation of the resonators and the speed of the electrons. The time interval during which an electron of average velocity i present within the deflecting resonator II should be so move against the electric field in the region through which they are passing.

After the electrons pass through the absorbing resonator, they are deflected from a conducting several decimeters may, accordingly, be radiated.

To improve the operation of the resonators, they may be filled with a low loss dielectric material such as rutile.

Although I have shown and described a certain specific embodiment of my invention, I am fully aware that many modifications thereof are possible. My invention, therefore, is not to be restricted except insofar as is necessitated by the prior art and by the spirit oi the appended claims.-

I claim as my invention: 1. A hollow body resonator comprising a dumbbell shaped bell, the end portions of which have major axes in a plane perpendicular-to the longitudinal axis of the shell, said axes being of substantially different length,

2. A generator, detector or amplifier of electrical oscillations comprising a conducting'shell constituting an electromagnetic resonator, means for projecting a stream of electrical charges through said shell, said shell being so oriented with respect to the line of said charges that the electrical field corresponding to one mode of oscillation of said shielded by a conducting tube 4| interconnect. 76 shell imposeson said stream a periodic lateral-deflection corresponding to said mode of oscillation, and another shell, constituting an electromagnetic resonator having a mode of oscillation of a frequency substantially equal to that of said one mode mounted to receive said charges after said stream has been deflected, said last named shell being so oriented that the electrical field corresponding to said mode of oscillation of said last named shell is parallel to said stream and is manifested as a standing wave extending between the terminal points between which said stream oscillates laterally and having a nodal point intermediate of said terminal points, the polarities of the fields at different points of said standing wave being such as to oppose the motion of the charges in said stream.

3. A generator of electrical oscillations comprising a conducting shell constituting an electromagnetic resonator, means for projecting a stream of electrical charges through said shell, said shell being so oriented with respect to the line of said charges that the electrical field corresponding to one mode of oscillation of said shell imposes on said stream a periodic lateral deflection corresponding to said mode of oscillation, another shell constituting an electromagnetic resonator and having a mod of oscillation of a frequency substantially equal to that of said one mode disposed to receive said charges after said stream has been deflected, said last-named shell being 50 disposed that the electrical field corresponding to said mode of oscillation of said lastnamed shell is parallel to said stream and is manifested as a standing wave extending between the terminal points between which said stream oscillates laterally and having a nodal point intermediate of said terminal points, the polarities of the .fields at different points of said standing wave being such as to oppose the motion of the changes in said stream, and means for coupling said shells so that there is an interchange of energy between them.

4. A generator of electrical oscillations comprising a conducting shell constituting an electromagnetic resonator, means ior projecting a stream of electrical charges through said shell. said shell being so oriented with respect to the line of said charges that the electrical field corresponding to one mode of oscillation of said shell imposes on said stream a periodic lateral deflection corresponding to said mode of oscillation. and another shell constituting an electromagnetic resonator and having a mode of oscillation of a frequency substantially equal to thatof said one mode disposed to receive said charges after said stream has been deflected. said last-named shell being so disposed that the electrical field corresponding to said mode of oscillation of said last-named shell is parallel to said stream and is manifested as a standing wave extending between th terminal points between which said stream oscillates laterally and having a nodal point in termediate of said terminal points. the polarities of the fields at different points of said standing wave being such as to oppose the motion of the charges in said stream, said shells being so dimensioned in the region in which they are penetrated by said stream with reference to the velocity of said stream that the charges of said stream reacts with an electrical field which is substantially constant for all practical purposes during the time that said charges are subjected to said field.

5. Apparatus for generating electrical oscillations comprising means for projecting a stream of electrical charges, means for swinging said stream laterally at the periodicity of said oscillations, and means for producing a periodic electromagnetic field having the periodicity of said oscillations in the path of said stream, the electric vector of said field being substantially along the line of said stream and having a polarity opposite to that of said stream in the region .in which said stream impinges on said field at any instant and having the opposite polarity at the same instant in a contiguous region.

6. In combination, a conducting shell constitutin an electromagnetic resonator and having two end portions and a constricted portion join-a ing said two end portions, mean for passing a stream of electrons through said constricted portion of said shell only, said shell being so shaped that the electric field corresponding to one mode of oscillation of the shell is at substantially right angles to said stream, and means for producing oscillations in said shell in said'one mode whereby a periodic lateral deflection of said stream is effected.

'7. In combination, a conducting shell constituting an electromagnetic resonator and having a constricted portion. means for passing a stream of electrons through said constricted portion of said shell only, said shell being so shaped that the electric field corresponding to one mode of oscillation of the shell is at substantially right angles to said stream, means for producing oscillations in said shell in said one mode whereby a periodic lateral deflection of said stream is effected, and means for producing a periodic electromagnetic field having the periodicity of said oscillations in the path of said stream after it has passed through said shell, the electricvector of said field being substantially along the line of said stream and having a polarity opposite to that of said stream in the region in. which said stream impinges on said field at any instant and having the opposite polarity at the same instant in a contiguous region.

8. In combination, aconducting shell constituting an electromagnetic resonator and having a constricted portion, means for passing a stream of electrons through said constricted portion of said hell only, said shell being so shaped that the electric field'correspondlng to one mode of oscillation of the shell is at substantially right angles to said stream, means for producing oscillations in said shell in said one mode whereby a periodic lateral deflection of said stream is effected, and another shell constituting an electromagnetic resonator having a corresponding mode of oscillation of a frequency substantially equal to that of said one mode mounted to receive said stream of electrons after deflection thereof, said last named shell'being so oriented that the electrical field of said corresponding mode of oscillation is parallel to said stream and is manifested as a standing wave extending between the terminal points between which said stream oscillates laterally and having a nodal point intermediat of said terminal points, the polarities of the fields at different points of said standing wave' being such as t oppose the motion of the electrons in said stream.

9. The combination of a hollow body resonator comprising a dumb-bell shaped shell having a constricted center portion and a pair of end portions, the end portions having major axes in a plane perpendicular to the longitudinal axis of the shell. said axes being of substantially different length, means for projecting a stream of electrical charges through said constricted center portion in a direction perpendicular to the electric field corresponding to one of the modes of oscillation of said shell, and means for producing oscillations in said shell in said one mode whereby a periodic lateral deflection of said stream is efiected.

10. The combination 0! a hollow body resonator.

comprising a dumb-bell shaped shell having a constricted center portion and a pair or end portions, the end portions having major axes in a plane perpendicular to the longitudinal axis or the shell, said axes being or substantially different length, means for projecting a stream of electrical charges through said constricted center portion in a. direction perpendicular to the electrio field corresponding to one of the modes of oscillation of said shell, means for producingoscillations in said shell in aid one mode whereby a periodic lateral deflection of said stream is tiguous region.

EDWARD U. CONDON.

Images