US2272599A - Ultra high frequency system - Google Patents

Description

i /H l MAG/vfr/c Hao l I L Fb. l0, 1942. A, Q CLAvlER r A14; 2,272,599

ULTRA HIGH FREQUENCY SYSTEM Filed April 1, 19:59

Fig. 1.

MAGNET/c I I I Fig-2- Patented Feb. 10, 1942 ULTRA-HIGH FREQUENCY srs-TEM- Andre Gabriel Clavier and Ernest Rosts, Paris, France, assignors to International Standard Electric Corporation, New York, N. Y.

Application April 1, 1939, SerialNo. 265,580 In France April 1, 1938 5 Claims.

The present invention relates to systems generating or utilising electrical oscillations at very high frequency and more particularly to systems for use at extremely high frequencies so-called hyperfrequencies.

In accordance with one of its aspects, the invention relates to new constructions of tubes and associated circuits, the whole being arranged so as to increase the efciency of operation and to facilitate tuning at the operative frequency.

In accordance with one of its characteristics, the invention relates to the combination of a tube generating or utilising electrical waves at eX- tremely high frequencies (so-called hyperfrequencies) with a transmission line with multiple conductors, said transmision line being tuned to the operative frequency by means of a single variable element.

Another characteristic of the invention relates l to generator, utiliser or receiver circuits comprising the provision on the transmission line with multiple conductors of a screen dividing the line into two portions, one of the said portions being included in the high frequency portion of the system, and the other portion being employed to supply the low frequency energy.

In accordance with another characteristic, the invention provides tube structures in which all the electrodes are brought to the outside of the tube by means of substantially parallel conductors forming a transmission line` with multiple conductors; a single tuning member may be provided on the line, such as a reector screen.

Another characteristic relates to generator, utiliser or receiver systems of ultra high frequency electric waves, such that all the connections to the electrodes on at least a portion of their length outside the tube comprise a circuit of a single high frequency, the system involving no other circuit or connection connected to the sources of supply.

The invention is obviously capable of application to Various types of tubes such as diodes, triodes, etc., and to magnetrons with or without split anodes and leads according to the particular case to the use of lines with 3, 4, 5 or more conductors in the composition of the transmission line associated with said tubes.

By way of example, the method of employing the characteristics of the invention is described hereinafter in the case of the tubes of the diode type employed in the form of magnetrons, shown schematically in the attached drawing in which:

Fig. l shows a magnetron tube associated with a three-conductor transmission line;

Fig. 2 represents a magnetron tube with split anode associated with a transmission line with two couples of conductors;

Fig. 3 represents a magnetron tube of the external anode type (that is with an anode forming part of the envelope), associated with a transmission line with three conductors;

Figs. 4 and 5 represent a magnetron tube with three parallel output conductors employed in an experimental embodiment.

Referringto Fig. 1, the magnetron tube shown at I comprises an anode 2 and a filament 3 of which the output connections 4 and 5 respectively are connected by conductors 6, 1, 8 forming a tuned three-wire line and connected to a source of'energy in two parts 9 and I0. A magnetic field H substantially parallel to the lament is created in the tube by any suitable means. This field moveover also exists in the magnetron tubes of Figs. 2 and 3.

A variable resistance I i is indicated in series withv this source, but it is clear that the representation of this supply circuit is arbitrary and may comprise any elements suitable'to the conditions of use of the system.

The two lateral conductors 'l and 8 ofA the three-wire line are connected to the connections 5 of the filament, and they serve as current leads for the supply of the filament. The central conductor 6 of the three-wire line is connected to the plate or anode 2. The tuning of the three- Wire line is effected by displacing a short-circuit bridge l2 in the form of a reflecting mirror suitably insulated from the three conductors 6, 1 and 8 from the point of view of direct potentials or of relatively low frequencies; this bridge l2 may be displaced along the three-wire line.

With an arrangement of this type the radiation of the tuned three-wire line with respect to the radiation which a simple two-conductor line would have is considerably reduced, and the tuned line is therefore more eicient. Moreover, since outside the useful circuit the tube does not comprise any other element capable of being detuned or of absorbing a portion of the power at useful high frequency, the losses in power or disturbances are also considerably reduced.

It will be noted that the lines 4, 5 and screen l 2 are tuned to resonance at the operating frequency. The tuning of cathode or other leads to anti-resonance at the operating frequency to suppress high frequency currents in such leads has already been proposed.

In this arrangement, the short-circuit bridge l2 is outside the tube and permits easy adjustment of the tuning circuit, while in magnetrons whether split or not, even at far lower frequencies the tuned circuit had to be incorporated in the tube for suitable operation, which required the utilisation of the tube at a single Wavelength determined by the construction. On the other hand, with the systems described in the invention, the frequency of the wave generated or treated may be tuned as required and this by the variation of a single element.

Also, the screen or short-circuit bridge I2 isolates the high frequency portion of the system composed of the tube I and that portion of the conductors 6, ll, 8 on the tube side of the screen I2 from the low frequency portion comprising either the supply circuit in the case of the generator shown, or the utilization or reception circuit in the case of receivers or amplifiers for example, since the screen I2 is insulated in a suitable manner from the three-wire line from the point of View of direct potentials or low frequencies.

In this and the following figures, the distances between the conductors of the transmission line employed must be suitably chosen, in particular in the case of tubes operating at very high frequencies (above 5000 megacycles for example) in which the distance between said conductors becomes comparable with a half or a quarter of the operative wavelength.

In an experimental embodiment of Fig. 1, a magnetron tube such as that shown in section in Figs. 4 and 5 has been used. This tube comprises an evacuated envelope I in which are a closed anode cylinder 2 and an axial filament 3. The output connections intended to be used with a three-wire line comprise in the example shown a rigid conductor l on which the anode 2 may be fixed, for example, as indicated at I3. The filament 3 is stretched between the two conductors 5, 5 for example by means of a spring member I4 terminating one of the conductors. The three conductors Il, 5, 5 pass through a foot I5 of the envelope I, As indicated at I6, an absorbent or getter substance may be provided inside the tube to assist in the evacuation.

A magnetron tube with split anode can also be employed in systems incorporating characteristics of the invention, as shown for example in Fig. 2. In this drawing the envelope I of the tube contains a split anode 2 2" and a filament 3 linear with and substantially in the axis of the anode cylinder. The transmission line thus comprises four conductors 6', 6, 'I and 8 which, as indicated, may be directly formed by the leadin conductors of the elements of the tube serving at the same time as supports to the elements. A screen I 2, insulated from the conductors of the transmission line from the point of view of low and continuous frequencies may be displaced along this line in order at the same time to produce the tuning of the four conductors. The two conductors 6 and 6 may be short-circuited at their ends, and this common short-circuited point is connected to the source of supply 9, as in the case of the conductor 6 of Fig. 2.

Fig. 3 shows another form of magnetron tube and transmission line associated therewith comprising an envelope formed by two portions or bulbs I', I" of insulating material and connected by the metallic anode 2 of the tube. This anode may be sealed on the portions I and I and if required may be cooled by a liquid or gas in a manner well known per se. In this case the axial filament 3 and the anode 2 may be connected with a three-wire transmission line similar to that of Fig. 1 and adapted to be adjusted by a screen or short-circuit bridge I2. In this case also the conductors 6, 'I and 8 of the three-Wire line 8 may be directly sealed in the bulbs I' and I" and on the anode 2 of the tube.

The arrangements shown on the drawing by way of example show applications of the invention in the case of a magnetron with two elements, anode 2, lament 3, the anode being either split or not. Such circuits may employ tubes having an anodedivided into multiple portions and/or grid elements. Such tubes with multiple grids may also incorporate characteristics of the invention, their outputs all being provided parallel and conveniently spaced in a common pinch of the envelope of the tube, a single screen or short-circuit bridge I2, insulated from the conductors from the point of view of the low frequency and direct potentials, sucing to regulate the tuning of the transmission line and consequently the frequency of operation of such a tube.

For example, in a triode tube with an undivided anode, the grid conductors, the cathode conductors and the anode conductor may be provided so as to form a transmission line with five conductors with a single short-circuit bridge, which eliminates any possibility of undesirable oscillations proceeding from the existence of elements which are not tuned but capable of entering into resonance at frequencies other than the required frequencies.

It is clear that the devices incorporating characteristics of the invention comprising in association a magnetron tube and a transmission line with single tuning element may be employed in the circuits of oscillators, receivers, frequency changers and amplifiers, the low frequency circuits connected to the ends of the conductors of the transmission lines being separated from the high frequency portion of the arrangement by the short-circuit bridge serving for tuning of the line. Such tubes may be employed for example to reduce the attenuation of the circuit with which they are associated.

What is claimed is:

1. An ultra-high frequency translating system which comprises a shield having apertures, an electron discharge tube having electrodes contained therein, at least three leads including at least one lead from every electrode contained in said tube, said leads all extending parallel to one another from said tube through said apertures and said shield being adjustable along said leads, whereby said shield and said leads constitute the sole high-frequency tuned elements of the sys tem, and potential supply means connected to said leads on the opposite side of said shield from said tube.

2. A system according to claim 1 wherein said leads are also arranged to support the electrodes within said tube.

3. An ultra-high frequency translating system which comprises a shield having apertures, an electron discharge tube having an outside electrode forming part of the tube envelope and at least one further electrode contained therein. at least three leads including at least one lead from said outside electrode and at least one lead from every electrode contained in said tube, said leads all extending parallel to one another from said tube through said apertures and said shield being adjustable along said leads, whereby said shield and said leads constitute the sole highrality of electrodes in said tube comprising a split l0 anode, a plurality of leads connected to said electrodes all of said leads being substantially parallel, means for short-circuiting the leads connected to said split anode, a source of potential connected to said leads, and a. shield provided with apertures and positioned along said leads between said short-circuiting means and said source on one hand and said electrodes on the other hand, said leads extending through said apertures.

ANDRE GABRIEL CLAVIER.

ERNEST RosTs.

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