US2071423A - Ultra high frequency oscillation generator - Google Patents

Description

Feb. 23, 1937. v. J. H. A. NORDLOHNE 7 ULTRA HIGH FREQUENCY OSCILLATION GENERATOR Filed July 25, 1954 n g I 1! INVENTOR P.J.H.A. NORDLOHNE ATTORNEY Patented Feb. 23, 1937 UNITED STATES FA'EENT QFFEQE ULTRA HIGH FREQUENCY OSCILLATION GENERATOR Application July 25, 1934, Serial No. 736,838 In the Netherlands September 14, 1933 4 Claims.

This invention relates to an arrangement for generating ultra-high frequency electric oscillations. I preferably employ a discharge tube connccted to a transmission line the length of which is long relative to the wave-length of the oscillations to be generated. To this transmission line is also connected an oscillatory circuit tuned to the frequency of the oscillations to be generated.

Such a circuit arrangement occurs in those cases in which the load circuit of an oscillator is constituted by the antenna and there is a wide spacing between the discharge tube and the antenna.

In such a circuit arrangement there is the disadvantage that oscillations may be generated whose frequency is governed essentially by the natural frequency of the circuit which is formed by the transmission line and the antenna. As the transmission line is long relative to the wave length of the desired oscillations, the frequency of the oscillations generated will be substantially lower than is desired. According to the invention, in order to obviate this disadvantage, an open oscillatory circuit governing the frequency of the oscillations generated is arranged in the vicinity of the discharge tube. The term open oscillatory circuit is herein used to indicate a system of conductively isolated conductors two of which are disposed in parallel relation to a third conductor so that a capacitive and inductive interaction may be had therebetween.

In addition, the present invention comprises means for preventing radiation of the open oscillatory circuit, at least in one direction.

In order that the invention may be clearly understood and readily carried into effect, one embodiment of the circuit arrangement will now be described more fully with reference to the accompanying drawing, in which only the parts necessary for a correct understanding of the invention are shown.

Referring to the single figure of the drawing, l and 2 designate the anode electrodes of an electronic oscillatory valve having a centrally disposed cathode it. Such a valve may be of the well known magnetron type. The potential applied between the cathode and the anodes is so adjusted that between the electrodes l and 2 there is a negative resistance for the desired oscillations. The load of this oscillator is formed by the two parts of the antenna 3. This antenna is connected by conductors 4 and 5 to the electrode terminals 6 and I of the oscillatory valve.

In order that the electronic oscillatory valve may be suitably energized I preferably provide 2. direct current source which is herein shown as a battery in circuit between the cathode k and the junction points 6 and l in the anode leads of the transmission line.

In order to prevent the generation of oscillations such as would be governed by the natural frequency of the conductors i and 5, an open oscillatory circuit l-d tuned to the frequency of the desired oscillations is provided. This open oscillatory circuit is constituted by wires 8 connected respectively to the conductors 4 and 5 and by a continuous stretch of wire Q disposed in parallel relation to the wires 8 so as to cooperate therewith for producing both inductive and capacitive reactions at the frequency to be gene-rated. The tuning of the open oscillatory circuit 8Q may, of course, be accomplished by suitably predetermining the lengths and by varying the space separation between the conductor 9 with respect to the conductors 8. This can be determined empirically. If the distance between the conductors 4 and 5 is negligible, then the sum of the lengths of the conductors 8 will be substantially the same as the total length of the conductor 9, and in this case the distance between the parallel conductors would preferably be a quarter of a wave length of the generated oscillations as is well known by those skilled in the art. It is, of course, to be understood that the conductor 9 is conductively isolated from all other parts of the system; It is also to be understood that when the reflecting conductor 9 is separated from the radiating conductors 8 by a quarter wave length then it neutralizes radiation in the direction in which it lies with respect to the radiating conductors 8. (See Short Wave Wireless Communication by Ladner and Stoner, page 259, Fig. 144.)

In this circuit arrangement the radiation losses will be fairly high as a considerable quantity of energy is radiated by the circuit 8 by which the frequency is governed.

According to the invention, the oscillatory circuit includes a conductor 9 disposed parallel to the dead-ended conductors 8, the conductor 9 being so dimensioned and arranged at such a distance that the oscillations radiated by the oscillatory circuit 8 are neutralized by the oscillations radiated by the conductor 9, at least in one direction.

Those skilled in the art may readily determine by experiment the proper space separation between the conductors 8 and 9 when their lengths have been fixed. It is theoretically true, however, that when conductor 9is coextensive with conductors 8, it should be separated therefrom by substantially a quarter of a wave length of the generated oscillations.

In the circuit arrangement of the invention, the open oscillatory circuit 8 is preferably connected to such points of the conductors 4 and 5 that the electric distance between these points and the electrodes 3 and 2 is a quarter-wave length of the desired oscillations. In this case, owing also to adjustment of the condensers H and 12, the best matching of the outer impedance to the negative resistance for the desired oscillations between the electrodes l and 2 is obtained, While oscillations of lower frequency are suppressed. The function of the condensers IE and I2 in the transmission lines i and 5 is to obtain, independently of the internal capacity between the electrodes, an ohmic load for the desired oscillation, While at the same time said condensers suppress oscillations of lower frequency than that desired.

What is claimed is:

1. In a device for generating ultrahigh frequency electric oscillations, an electron discharge tube having a cathode and a plurality of anodes, a load carrying structure comprising a transmission line and an antenna system remotely situated with respect to said discharge tube, the length of said transmission line between said discharge tube and said antenna being relatively greater than the wave length of the oscillations to be generated, and means including a system of conductors connected to said transmission line and an inductively and capacitively reactive line paralleling said conductors and electrically insulated therefrom, said means being disposed in the vicinity of said discharge tube for governing the frequency of the oscillations generated.

2. An ultra-high frequency oscillator circuit comprising high frequency apparatus, a load, and

a transmission line which is long relative to the Wave length of the oscillations to be generated connecting said apparatus to said load, and an open oscillatory circuit connected to said transmission line for controlling the frequency of the oscillations generated, said open circuit comprising a pair of coaxially disposed conductors each connected to a different side of said transmission line and a reflecting conductor disposed parallel to the coaxial conductors and electrically insulated therefrom.

3. An oscillation generation circuit comprising an electronic valve generator, a two wire transmission line, having a length which is long relative to the Wave length to be generated, a load, said two wire line being coupled to said valve and to said load, and an open oscillatory circuit comprising the combination of a conductively isolated conductor paralleling two coaxially arranged open-ended conductors, each of the latter conductors being coupled to its respective wire of said line near said valve, said oscillatory circuit being tuned to the frequency of the oscillations to be generated.

4. An oscillation generation circuit comprising a thermionic valve generator, a two wire transmission line having a length which is long relative to the wave length to be generated, an antenna, said two Wire line being coupled to said valve and to said antenna, and an open oscillatory circuit comprising the combination of a conductively isolated conductor paralleling two coaxially arranged open-ended conductors, each of the latter conductors being coupled to its respective wire of said line at a distance substantially one-quarter of a wave length from said valve, said oscillatory circuit being tuned to the frequency of the oscillations to be generated.

PIERRE JANNE HENRI ALPI-IONSE NORDLOHNE.

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