US2545073A - Device for amplifying or generating electric oscillations of very high frequency - Google Patents

Description

March 13, 1951 DEVICE FOR AMPLIFYING OR GENERATING ELECTRIC (5 DE VRIES 2,545,073

OSCILLATIONS 0F VERY HIGH FREQUENCY Filed Feb. 12, 1947 got: VRIES INVENTOR A GEN T charge tube having a wall Patented Mar. 13, 1951 PATENT o FF1cE fj- DEVICE FOR AMPLIFYING OR GENERATING ELECTRIC OSCILLATIONS F VERY HIGH FREQUENCY Gerrit de Vries, Eindhoven, Netherlands, assignor to Hartford National Bank and Trust Company, Hartford, Conn., as trustee Q Application February 12, 1947, Serial No. 728,044 e In the Netherlands June 14, 1944 This invention relates to a device for generating or amplifying electric oscillations of very high frequency; this device comprises an electric dismade at least in part of insulating material, the flow of electrons passing through the tubewith variable intensity and inducing high-frequency currents in a circuit arranged outside the tube and comprising a slit. 'The'term',circuit"suggests either two conduc- "t'or's" separated fromeach other by a slit and connected by an impedance or a cavity resonator which in a simple form is constituted by a solid of revolution formed by a single circular conductor, a slit being left between the ends of the conductor.

In such a device the flow of electrons is controlled in such manner that the number of electrons passing through a given tube section varies with the frequency. If such a pulsating flow of electrons is conducted along a slit in a circuit of the form as described before, high frequency currents are set up in this circuit. It has now been found that at the areas where conductive parts of the said circuit are adjacent the tube wall discharge phenomena may occur between these parts and the wall made of glass, quartz or like material. It is not impossible that the spray and ionization phenomena occurring in the case of very high frequencies involve losses which cause undesirable heating apt to lead to damage of the device.

This difliculty can be avoided entirely by the use of a device for amplifying or generating electric oscillations of very high frequency, said device being provided with an electric discharge tube having a Wall made at least in part of insulating material, on the outside of which is arranged a circuit having a slit and an insulating part of the wall of the tube opposite to the adjacent conducting parts of this circuit, being 10- cally provided with conductive coatings each of which is conductively connected to a part of the said circuit.

The term local coating is to be understood to mean a layer which is so mounted on the tube wall that this layer and the tube wall are no longer separated by an air layer, the said coating being only, applied to those parts of the tube wall which face the said conductors of the circuit.

It has now been found that the use of this means avoids any trouble from discharge phenomena liable to cause damage to parts of the device.

The conductive coating may be made of differin materials and applied in various ways,

I section 1,'rubuc Law 690, August 8, 194a 1 .iil'latent expires June 14, 1964 i V ,1; 2'Claims. (Cl.3155) thus, for example, the tube may be coated with small plates of metals, such as nickel, copper or the like; alternatively, the coatings may be arranged in the shap of rings to surround the tube. The application of the coatings may be effected in a simple manner by applying a metal compound to the wall, dissociating it by heat and burning-in the meta] precipitate thus formed. A metal which. is especially suitable to be applied in thismanner-is platinum, it being possible to start with a readily dissociated platinum compound, for example platinum chloride dissolved in nitrocellulose or platinum resinates which are applied in the form of any suspension and dissociated by heat, the platinum precipitate being then burnt-in.

The invention may be used with devices for generating or amplifying electric oscillations of very high frequency, a circuit which, as already set out hereinbefore, may have widely difiering shapes, but which at any rate must have a slit in the proximity of the tube wall, bein arranged on the outside of the tube. A very simple form of construction is that in which the tube is surrounded by a so-called cavity resonator, that is to say a solid of revolution which is formed by a single circular conductor which comprises a slit; on either side of the slit the conductor may have a flange which is just opposite the tube wall, these flanges being connected, according to the invention, to conductive coatings of the tube wall.

According to a particular form of construction of the device according to the present invention the connection of the conductive Wall coatings to the parts of the circuit is established by means of flexible elements which may be formed, for example, by arcuate or corrugated rings, a plurality of bent strips or the like.

In order that the invention may be clearly understood and readily carried into effect, it will now be set out more fully with reference to the accompanying drawing which illustrates part of the device according to the invention.

Referring to the single figure of the drawing, I designates a part of the wall of an electric discharge tube, said part being made of insulating material. The wall I is surrounded by two conducting parts 2 separated by a slit 3 and united to form a circular conductor 4 which constitutes a cavity resonator. A heater [0 for a cathode source of electron emission H, is provided at one extremity of the tube wall I, and the electron beam is formed by the focusing electrode l2 and the accelerating electrode l3 and passes along the insulating wall portion of th tube to the collector plate It. In order to avoid discharge omena between the conducting parts .2 and the wall *lyth'e wall is "provided," accordingto the invention, with coatings 5 and 6 which are formed in the shape of rings and which are connected by a esnlatineawall:portion-Q said envelope surr und ging said electron beam over a;portion of the travel of said beam, --a-ci-rcu-it having conductive pcritions closely adjacent the outer side of said in- ,jsulati-ng-wall portion and havin {a slit between said conduci ive portions to efiect ,inductive .cou- :pli-ng between the saidcircuit'and the said electron beam, and econductive Ecoatings on said in- .sulating wall portion interposed between said insulating wall portion-andrsaidconductive portions of said circuit, said coatings being in elecztrical connectionxwithzsaidjconductivejportions.

:2. Adevice for generating 501 amplifying high frequency oscillations comprising an electric -discharge tube having an envelope, a cathode source of an electron beam within said envelope,

an insulatin wallportion of said envelope surrounding saideleetron beam over a portion of the travel of said beam, a cavity resonator adjacent the outer side of the said insulating wall portiqnand having conductive end portions and a slit closely adjacent said insulating portion to effectjin'ductive coupling between the said resonator-iandthe said electron beam, and conductive coatings on said insulating wall portion interposed between'said insulating wall portion and said conductive end portions of .said cavity resonatorpsaid coatings being in electrical connection with said conductive end portions.

7 GERRIT .DE VRIES. EFE ENCES CI E z'Ifh-e following references are bf record the file of this patent:

"UNITED STATES PATENTS Number Name v Date 2,240,229 cscharli a, Apr. .29, 19.41

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