US3089976A

US3089976A - Thermally tuned reflex klystron

Info

Publication number: US3089976A
Application number: US22235A
Authority: US
Inventors: Jr Thomas Dawley Fentress; Shepherd William Gerald; Wurthmann Gunther Ernest
Original assignee: Bendix Corp
Current assignee: Bendix Corp
Priority date: 1960-04-14
Filing date: 1960-04-14
Publication date: 1963-05-14
Anticipated expiration: 1980-05-14

Description

May 14, 1963 T. D. FENTRESS, JR., ETAL 3,089,976 THERMALLY TUNED REFLEX KLYSTRON Filed April 14, 1960 INVENTORS 7:0. FENTRESSIR. we. SHEPHERD BY GE. WURIHMANN ATTORNEY United States Patent 3,089,976 THERMALLY TUNED REFLEX KLYSTRON Thomas Dawley Fentress, Jr., Eatontown, N.J., William Gerald Shepherd, St. Paul, Minn., and Gunther Ernest Wurthmann, Red Bank, N.J., assignors to The Bendix Corporation, a corporation of Delaware Filed Apr. 14, 1960, Ser. No. 22,235 3 Claims. (Cl. 315-523) The present invention relates to electron discharge devices and more particularly to reflex oscillators of the cavity resonator type.

In reflex oscillators of the klystron type, due to operation at very high frequencies, the dimensions of the critical components are of necessity small in physical size. Further, as the frequency is raised, the components become smaller in size. If an attempt is made to thermally tune a reflex klystron at very high frequencies by means of a conventional diode type tuner, the small size of the resonant cavity so limits the size of the tuning diaphragm that it is diflicult to achieve the compliance and movement required to cover the desired frequency range without making the diaphragm extremely thin and fragile.

The present invention provides a novel thermally tuned device in which two diaphragms or flexible members are utilized. One of the diaphragrns is relatively large in diameter and is located outside of the resonant cavity.

It is an object of the present invention to provide an improved electron discharge device.

Another object of the invention is to provide an improved reflex oscillator.

Another object of the invention is to provide an improved =klystron.

Another object of the invention is to provide an improved thermally tuned klystron.

Another object of the invention is to provide novel means for thermally tuning a reflex oscillator of the cavity resonator type.

Another object of the invention is to provide a novel diode tuner for a klystron.

The above and other objects and features of the invention will appear more fully hereinafter from a consideration of the following description taken in connection with the accompanying drawing, wherein one embodiment of the invention is illustrated by way of example.

In the drawing, the single FIGURE is a cutaway section of a device embodying the invention.

Referring now to the drawing wherein an electron discharge device is indicated generally by the numeral 1, which may, for purposes of illustration, be a klystron of the reflex type. The device 1 has an envelope 2 which may be of the conventional type and is merely shown by dashed lines. Enclosed in the envelope 2 is a plate 3 of metal which has a circular opening 4 defining a part of a cavity resonator. A slot or cut-out portion 5 extends from the opening 4 and defines a wave-guide output section for the device. A choke joint 6 is provided to minimize loss of energy propagated through the wave guide 5 and a window 7 mounted in the envelope 2.

A=flixed to one face of the plate 3 is a circular, metallic frame or support 8 having a frusto-conical portion 9 upon which is mounted a grid 10 which may be of fine wire. An annular metallic diaphragm 11 is secured to the other face of the plate 3 and may be provided with concentric corrugations 12. The diaphragm 11 carries a grid 13 which is concentric with the grid 10.

Cooperatively associated with the cavity resonator, are an electron gun 14 and a repeller electrode 15 to constitute a reflex oscillator therewith. The electron gun 14 includes a cathode 16 and focusing electrode 17. The gun 14 is secured to the block 3 by means of an insulating ring 18 and flanged cylinder 19. An accelerating grid 20 may be provided between the cathode 14 and grid 10.

The plate 3 has an axially extending flange 21 which supports a tuner focusing electrode 22 on an insulating washer 23. A top plate 24 is also supported by the plate 3 and clamps the electrode 22, washer 23 and insulating member 25 therebetween. The top plate 21 may have a plurality of openings 26 to aid in the evacuation of the device. The repeller electrode 15 extends through an opening 27 in the top plate 24 and is supported therein by an insulating collar 28, insulating washer 29, spacer 30 and nut 31. A repeller electrode shield 32 is secured by the collar 28 and spacer 30.

A ring-like cathode 33 is positioned in the space between the tuner focusing electrode 22 and repeller electrode shield by metal tabs 34. The cathode 33 is of the conventional type and includes a heater 35. A diaphragm 36, which serves as the anode for the tuner diode, is supported at the outer edge on a step 37 on the plate 3 and has an opening 38 therein concentric with the grid 13. The diaphragm 36 is connected to the diaphragm 11 by a ring 39 to which the two diaphragms are brazed. The diaphragm 36 is of a stubstantially larger diameter than the diaphragm 11 and by virtue of its size it possesses the necessary compliance to yield the desired motion, using thermal means, without being so fragile as to move by mechanical environments. The diaphragm 36 is of a material having good thermal expansion characteristics together with good creep strength, for example, a stainless steel known as Carpenter 347.

In operation, the diaphragm 36 serves as the anode of a diode tuner and is moved by thermal expansion caused by heating resulting from the collection of current from the cathode 33. This motion causes the diaphragm 36 to move the diaphragm 11 to change the grid spacing of the resonant cavity with a corresponding change in frequency.

The connections to the various elements in the device have been omitted for simplicity, however, it is understood that they would be made in a conventional manner.

Although only one embodiment of the invention has been illustrated and described, various changes in the form and relative arrangement of the parts, which will now appear to those skilled in the art, maybe made without departing from the scope of the invention.

What is claimed is:

1. A reflex klystron comprising an envelope enclosing a resonant cavity, a fixed grid, a movable grid, a first diaphragm for mounting said movable grid in one wall of said cavity, a second diaphragm member concentric with said first diaphragm and positioned external of said cavity, means for connecting said diaphragms together, and means including a cathode for causing a thermal change in said second diaphragm thereby to tune said cavity.

2. A thermal tuned reflex klystron comprising a resonant cavity, a fixed grid mounted in one wall of said cavity, a movable grid, means including a flexible memsaid second flexible member is of a material having a high thermal coefi'icient of expansion.

References Cited in the file of this patent UNITED STATES PATENTS Clifford et a1 Nov. 23, 1948 La Rue Dec. 9, 1952 Gardner Mar. 10, 1953 Svensson Ian. 15, 1957

Claims

1. A REFLEX KLYSTRON COMPRISING AN ENVELOPE ENCLOSING A RESONANT CAVITY, A FIXED GRID, A MOVABLE GRID, A FIRST DIAPHRAGM FOR MOUNTING SAID MOVABLE GRID IN ONE WALL OF SAID CAVITY, A SECOND DIAPHRAGM MEMBER CONCENTRIC WITH SAID FIRST DIAPHRAGM AND POSITIONED EXTERNAL OF SAID CAVITY, MEANS FOR CONNECTING SAID DISPHRAGMS TOGETHER, AND MEANS INCLUDING A CATHODE FOR CAUSING A THERMAL CHANGE IN SAID SECOND DIAPHRAGM THEREBY TO TUNE SAID CAVITY.