US2313008A - Electric wave amplifier - Google Patents

Description

March 2, 1943- H. BERGER ET AL ELECTRIC WAVE AMPLIFIER Fild Oct. 25, 1940 4 Sheets-$119M, 1

Figild AIAIA March 2, 1943.

H. BERGER ET AL ELECTRIC WAVE AMPLIFIER Filed Oct. 23, 1940 4 Sheets-Sheet 2 v Inventor: flemzamz Berger f/zlr flerrz 'ger March 2, 1943. H. BERGER ET AL ELECTRIC WAVE AMPLIFIER Filed Oct. 23, 1940 4 Sheets-Sheet 3 'F'ig'. 3a.

Fig.3b

March 2, 1943. H.BERGER ET AL ELECTRIC WAVE AMPLIFIER 4 Sheets-Sheet 4 Filed Oct. 25, 1940 Patented 2 1943 ELECTRIC WAVE Herman Berger and Felix Herrlger, Berlin, Germany; vested in the Alien Property Custodian Application October 23, iaiasenal No. 362,464

In Germany November 30, 1939 4Claims.

In electron tubes used in connection with short waves the current induced in the electrodes by the action of the electron clouds'passing the electrodes is as important as the current having its path determined by conductive means. With electron tubes of the usual construction the induced current and the conducted current cannot be separated from each other and the co-operation of the two currents is dimcult to control.

' According to the present invention, in order to overcome such drawback these two currents are separated from one another by means of an electrode system arranged to emit an electron beam which is modulated as to its velocity or density and is made to enter a chamber, the so- -called Heil chamber.

This comprises a hollow space through which an electron beam is projected and at the entrance portion of which the electrons are velocity modulated and at another portion oflwhich energy is extracted from the moving electrons. In one known arrangement the high frequency energy is derived from the beam by two annular or latticed electrodes enclosed by a metallic envelope or bulb. The electron beam is controlled according to the present invention by an arrangement of grids of the customary type.

In the drawings, Figs. 1a. to 4a are schematic views which each illustrate one embodiment of the invention while Figs. 1b to 4b are diagrammatic views representing respectively the same embodiments as Figs. la to 4a and in which the vacuum vessels are shown to be sectioned at right angles to Figs. 1a to 4a.

The basis of the electrode arrangement, Figs. la, 1b, is a standard pentode system that emits an electron beam which mainly is density-modu lated, that is, modulated as regards the density of the flow of electrons. This beam enters a Heil chamber B of special construction. The electrode that serves to derive the high frequency energy from chamber B comprises two annular or latticed component electrodes A enclosed by a metallic envelope or bulb SE. An aperture D equal in width to that of the electron stream enables currents to pass through the electrodes A, A. Bulb SE is grounded and constitutes the vacuum vessel for the electrode system, and it may be cooled by any suitable means, as water, for instance. The deriving electrodes A, A receive only small currents. The electron clouds produced by the control grid GI act to induce in the electrodes A, A a current that becomes efiective in an oscillatory circuit L.

path in the electrode system itself such currents will be greatly prevented from reacting on the flow of electrons.

The arrangement shown in Figs. 3a, 3b serves mainly to modulate the electron current in its velocity. GI denotes a space charge grid by which the primary current is determined and kept constant. G2 indicates a grid electrode to which a control circuit S is connected. Grid G3 serves as a screening electrode. Thegrids GI, G2, G3 are to produce the velocity-modulated electron beam. For this purpose the electrons travelling between the grids GI, G2 on the one hand and between grids G2, G3 on the other hand must be so timed in their progression that in the second space they always meet with a field of the same direction as in the first space, that is, the electrons are input accelerated and in part checked. The grids are precisely the same as those employed in the standard broadcast tubes. However, in comparison with the operativ wavelength the distances between the grids may be much larger than in the case of density-modulation. Preferably, in order to decrease the grid currents the first three grids are given the same pitch of winding and are mounted that their turns are located one after another. ,The electrodes G4, G5, G6 are connected to positive and negative direct potentials .altemately and serve to concentrate the beam. The space between grid G3 and the electrodes A also serves to conglobate the velocity-modulated electron beam into a density-modulated beam, this action being spoken of as drift effect. Bulb SE and the electrodes A constitute the deriving system more fully involved in Figs. 3a, 312.

What is claimed is:

1. Apparatus for amplifying short wave energy comprising a hollow metal member divided into two chambers by an apertured wall, an elongated electron emissive cathode in one of said chambers extending in a plane parallel to the plane of said wall and adjacent the aperture therein, a multiapertured grid mounted in said last-mentioned chamber between said cathode and said wall, a tubular member in the other of said chambers surrounding the path of electrons which are projected through said aperture, a source of fixed positive potential connected to said tubular member, a resonant circuit coupled to said tubular member and a resonant circuit coupled to-said rid.

2. Apparatus for amplifying short wave energy comprising a hollow metal member dividedinto a central chamber and two side chambers by two spaced parallel apertured walls, an elongated electron emissive cathode. in said central chamber extending in a plane parallel to the planes of said walls and adjacent the apertures therein, a multiapertured arid mounted in said central chamber and surrounding said cathode, a tubular member mounted in each of said side chambers and surrounding the paths of electrons which are projected through said apertures, a source 01' fixed positive potential connected to'said tubular members, a resonant circuit coupled to said tubular mrembers and a resonant circuit coupled to said 8 d.

3. Apparatus according to claim 1 further comprising a second multi-aperture grid mounted between said cathode and said grid, a third multiapertured grid mounted between said last-mentioned grid and said wall, and sources of fixed positive potential connected to said second and third grids.

4. Apparatus according to claim '1 further comprising second andthird grids mounted between said arid and said wall, a source of positive potential connected to said second arid and a source of negative potential connected to said third grid.

nmmsrm BE GER. max HERRIGER'.

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