US2415962A

US2415962A - Automatic switch for ultra high frequency

Info

Publication number: US2415962A
Application number: US462261A
Authority: US
Inventors: Ernest C Okress
Original assignee: Westinghouse Electric Corp
Current assignee: CBS Corp
Priority date: 1942-10-16
Filing date: 1942-10-16
Publication date: 1947-02-18
Anticipated expiration: 1964-02-18

Description

Feb. S, 1947. E. c. oKREss M5962 AUTOMATIC SWITCH FOR ULTRA HIGH FREQUENCY Filed oct. 1e, 1942 l Ecs/VER INVENTOR 12 14 Eg 4f 'E c. @Kee-5s Wre- Gs/Emmz BY AM m ATTORNEY atenter Feb. i8,

D STTES 'ENE apron/merc swrrcn ron ULTRA inea FREQUENCY Application Gctober 16, 1942,Serial No'. '462;261

This invention relates to electricity of ultrahigh frequency, and more particularly, to an automatic switch for controlling the ow of such energy in a wave guide.

The principal object of my invention, generally considered, is an improved automatic ultra-high frequency switch of the type generally designated as a TR box, whereby such an instrument is adapted to be put together by welding certain parts. l

Another object of my invention is to construct a TR box with an annularly corrugated flexible metal diaphragm wall carrying an electrode movable by means of an adjusting cap or drum head, to flex the diaphragm wall for tuning the cavity, and simultaneously vary the position of the electrode carried thereby with respect to an associated electrode on a xed wall of said cavity.

Another object of my invention is to construct an automatic switch, of the type designated as a TR box, in such a manner that parts may be put together by welding, thereby' substan-l tially eliminating the use of glass and reducing the amount of solder used in its construction.

Other objects and advantages of theinvention, relating to the particulararrangement and construction of the various parts, will become apparent as the description proceeds.

Referring to the drawing:

Fig. l is an axial vertical sectional view, after assembly and Welding, of a Wave guide and associated TR bo-x embodying my invention.

Fig. 2 is a plan of the combined structure shown in Fig. 1.

Fig. 3 is a horizontal axial sectional view on the line III- III of Fig. l, in the direction of the arrows.

Fig. 4. is a horizontal sectional view o-n the line .IV- 1V of Fig. 1, in the direction of the arrows.

Fig. 5 is an enlarged fragmentary view corresponding t0 a portion of Fig. 1, before the welding is elected. f

Fig. 6 is a View corresponding to Fig. 5 but showing a modiiication.

Fig. '7 is an elevational view of the switch of my invention and mechanism normally associated t-herewith.

In the Okress et al. application, Serial No. 451,356, led July 17, 1942, and owned by the assignee of the present application, there is described and claimed an automatic switch for controlling the flow of ultra-high frequency electricity in a wave guide to thereby protect associated apparatus; The automatic switcher TR `box of said application comprisesmeans for tuni Claims. (Cl. 1178-44) ing the'box cavity and adjusting the spacing of spark gap electrodes. The maintenance or" the box cavity in an evacuated condition includes the use of glass-to-metal seals.

In accordance with the present invention, the construction of such a switch or TR boxis improved by the substantial elimination of glassto-metal seals and the employment instead of welded connections, such connections being sufficiently removed and electrically isolated from .first .considering the diagrammatic showing YFig..', the reference character li designates a wave generator for producing energy ofxa desired ultra-high frequency which is transmitted along a metal Wave guide l2, which in the present embodiment is of hollow rectangular cross section, to an antenna I3, which is shown as a .parabolic device for directing a beam in a desired direction toward an object. The invention is to be used With ultra-high frequency radio waves which may be projected and reflected in substantially the same manner as light Waves.

' Accordingly the projected wave energy may be directed toward some object, reflected' therefrom, and on its return course intercepted by the same antenna which concentrates and causes it to reenter the guide i2 and travel therein and through a branch tubeV i4 to excite a receiver it. bviously the returning wave energy will be very weak compared to the transmitted energy and a TR box i6 is, therefore, interposed in the branch tube M to check the flow o-f any high-powered energy and yet permit the receiver to be actuated by the vrelatively weak energy of 'a returning sign311.

The switch or TR box of the present invention comprises a cylindrical body il of conductive material', preferably metal such as Kovan which may be welded. The body -i'l intersects the conductive, preferably metal wave guide branch It, as shown most clearly in Figs. 1 to 5, inclusive, and is united thereto, as by means ci solder it, This cylindrical member also carries quarter wavelength conductive cylindrical, preferably metal, sections i9' and" 2i, each having inner' outstanding annular portions 22 andlv united tothel inner surface of the cylindrical member I1, or formed integral therewith. The mode of' connection may be soldering if not formed integral. This means that the cylindrical member I1 carries a pair of coaxial cylindrical portions, the free edges of which extend outwardly away from one another and the inner edges of which are connected to said cylindrical portion in line with the upper and lower walls of the wave guide I4, as shown most clearly in Fig. 1. l

The cylindrical portion I1 also carries

windows

24 and 25 of suitable dielectric material such as No-loss glass which serves to pass the micro-wave energy in the guide I4 through the TR box I8. Said windows are suitably dimensioned, both as to diameter and thickness and with due consideration to their dielectric constant, to introduce a minimum of disturbance and still give suicient coupling between the TR box cavity and the wave guide. These windows are shown convex outwardly in order to better withstand the outside pressure when the box cavity is evacuated, desirably generally circular, and disposed with their centers on the axis of the Wave guide I4. They are desirably as small as practicable for obtaining the desired energy transfer without undue lessening of the surface continuityv of the resonator volume of the box. These windows are made vacuum tight as by sealing in place in the cylindrical member I1.

In the present embodiment, Vtuning of the resonator chamber of the TR1 box I6 is effected by making the upper wall of said chamber 26 as a flexible conductive or metal diaphragm 21, desirably provided with concentric annular corrugations, as shown most clearly in Figs. 1 and 4. To the central portion of the diaphragm 21 is secured an adjustable electrode 28 provided with a threaded stem 29 outstanding therefrom, and carried by the hub portion 3l of an adjusting drum head, cap or nut member 32 threadably engaging the cylindrical member I1, as indicated at 33. The threads on the electrode extension and cylindrical member I 1, if both right handed, for example, are necessarily of different pitch in order to provide for adjustment'of the electrode 28 and diaphragm 21 by turning the head 32', the peripheral portion of which is desirably knurled, as indicated at 34. From a practical standpoint it is preferable to have thepitch of the threads on the extension 29 greater than that of the threads 33. i 1

The bottom wall 35 of the resonant cavity 26 is desirably rigid and carries a hollow electrode 36, the lower portion of which may be closed by a block of material 31, such as glass, carrying a probe 38 one end of which is impregnated with a salt of radium or other radio-active material 39, for inducing the generation of photo-electrons to decrease the breakdown potential between the

electrodes

28 and 36. Other keepalive means may be substituted for the radio-v active probe.

The ilexible wall 21 and the relatively rigid wall 3.5 are carried by hollow cylindrical members 4I and 42, of Kovar or other weldable conductive material, provided with outstanding

annular flanges

43 and 44 respectively welded to the outer edge portions of the cylindrical inember I1, as indicated at 45 and 46. The

outstanding anges

43 and 44 may initially have annular corrugations or bosses 51 extending toward the adjacent edges of the cylindrical member I1 to facilitate the formation of welds therebetween, as illustrated in Fig. 5. By virtue of having these welds disposed at a relatively great distance from the wave guide I4 and with what amount to filters or choke plates therebetween, there is no danger of any undesired action, such as spark over, adjacent the joints, as might be the case if said joints were disposed close to or not electrically isolated from, the resonant cavity dened by the cylindrical member I1 and the

portions

21 and 35.

The sections I9 and 2i both have lengths corresponding to a quarter wave whereby a high impedance is induced at the openings 41 and 48, as the impedance of the spaces 49 and 5i) is equal to where Q is the merit factor of said spaces and Zo the characteristic impedance, which is high because Q is high. This high impedance at 41 and 48 is transformed, through the characteristic impedance of the spaces 5I and 52, to a very low impedance at the

annular gaps

53 and 54, causing the same to act electrically shorted although mechanically no metallic contact exists. The Q of the resonant cavity 26 is somewhat reduced by this construction, but not seriously.

After connecting the cylindrical portion I1 with the associated cylindrical portions I9 and 2l to the Wave guide i4, and welding the

flanges

43 and 44 to the cylindrical portion I1, to assemble the

wall portions

21 and 35 and their associated electrodes therewith, the adjusting drum or nut 34 may be applied in any desired manner, as by turning in place on the ends of the associated threads respectively carried by the cylindrical portion I1 and the electrode extension 29, starting with the

electrodes

28 and 38 either touching or very closetogether so that upon turning on the adjusting drum said electrodes are gradually separated until in the position illustrated in Fig. 1 where they are in approximately the correct adjustment, with the flexible wall 21 disposed substantially parallel to the xed wall 35.

As'an alternative the drum may be formed in two parts adjustably connected as by screws 55. after the parts have been individually turned in place on the cooperating

threads

33 and 29. This latter construction avoids the necessity of initially flexing the diaphragm 21.

Any desired means may be provided for evacuating the chamber 26, such as an exhaust tube 56 extending from the glass block 31.

Referring now to the embodiment of Ymy invention illustrated in Fig.I 6, the cylindrical member I1a is there shown with an outstanding peripheral annular flange 58, and the cylindrical member 42a is likewise provided with an annu lar flange 44@1 corrugated as indicated at 51a for uniting with the flange 58 as an alternative to the welded connection 46 of the rst embodiment. A similar welded construction may be substituted for the welds 45 of the iirst embodiment.

From the foregoing disclosure, it willbe seen that I have provided for the use of welds to hasten and cheapen the manufacture of "TRY boxes. Such welds are separated from the resonant box cavity by parts of sufiicient impedance, so that the welded joints are isolated and prevented from interfering with the resonant characteristics.

In operation, when high power tends to pass down the wave guide I4 toward the receiver I5,

the potential diierence developed between

uthe electrodes

28 and 35, after proper tuning of the cavity 26 and adjustment between the electrodes, the breakdown potential therebetween being lowered by the keep alive probe 38, is sufficient to cause sparking between said electrodes, Iresulting in a large impedance mismatch which acts as an excellent reflector of energy attempting to get through to sensitive receiving apparatus l5.

When, however, a signal is being received, the

tersecting said guide structure, hollow inner metal` members having inner electrode-carrying closure portions cooperating with said outer metal member to define a resonant cavity and terminating in flanges extending outwardly and welded to said metal member, and lter means disposed between said outer and inner members and extending from the guide structure toward the welds for electrically isolating the latter from said resonator cavity.

2. In combination, an elongated hollow conductive structure adapted to function as a guide for electricity of ultra-high frequency, and a resonator comprising a hollow outer metal member intersecting said guide structure and enclosing coaxial spark-gap electrodes, each electrode being carried by a wall of said resonator, each wall being bordered by portions extending outwardly from its periphery and terminating in a flange overlying and welded to an end portion of said outer metal member.

3. In combination with an elongated hollow conductive structure adapted to function as a guide for electricity of ultra-high frequency, a resonator comprising a hollow outer'inetal member intersecting said guide structure and enclosing coaxial spark-gap electrodes, each electrode being carried by a wall of said resonator, each wall being bordered by portions extending outwardly from its periphery and terminating in an outwardly extending flange welded to an end portion of said outer metal member, and means for tuning said resonator and adjusting the distance between said electrodes.

4. In combination with an elongated hollow conductive structure adapted to function as a guide for electricity of ultra-high frequency, a resonator comprising a hollow outer metal member intersecting said guide structure and enclosing coaxial spark-gap electrodes, a iiexible diaphragm carrying one of said electrodes, a fixed wall portion carrying the other of said electrodes, and hollow metal portions extending away from one another and the peripheries of said diaphragm and xed wall portions and each terminating in an outwardly extending flange welded to end portions of said outer metal member.

5. In combination with an elongated hollow conductive structure adapted to function as a guide for electricity of ultra-high frequency, a resonator comprising a hollow outer metal member intersecting said guide structure and enclosing coaxial spark-gap electrodes, each electrode being carried by a wall of said resonator, each wall being bordered by portions extending outwardly from its periphery and terminating in a flange overlying and welded to an end portion of said outer metal member, one of said electrodes being hollow, and a probe disposed coaxially within said electrode and insulated therefrom, and means associated with said probe for lowering the breakdown potential between said electrodes.

6. In' combination with an elongated hollow conductive structure adapted to function as a guide for electricity of ultra-high frequency, means intersecting said guide structure andv defining therewith a resonator chamber enclosing coaxial spark-gap electrodes, each el-ectrode being carried by a wall 0f said resonator coplanar with a wall of said guide exterior of said chamber, and means providing for exhausting said resonator chamber and making it vacuumtight.

'7. In combination with an elongated hollow conductive structure adapted to function as a guide for electricity of ultra-high frequency, means kintersecting said guide structure and defining a resonator chamber enclosing coaxial spark-gap electrodes, each electrode being carried by a wall of said resonator, one of said electrodes being hollow, and means communicating with rthe interior of said hollow electrode for exhausting said resonator chamber.

8. In combination with an elongated hollow conductive structure adapted to function as a guide for electricity of ultra-high frequency, a resonator comprising a hollow outer metal member intersecting said guide structure and enclosing coaxial spark-gap electrodes, each electrode being carried by a wall of said resonator, each wall being bordered by portions extending outwardly from its periphery and terminating in a flange overlying and welded to .an end portion of said outer metal member, and filter means dis-- posed between the cavity of said resonator and said welds for isolating the latter and preventing them from interfering with the characteristics of the former.

9. In combination with an elongated hollow conductive structure adapted to function as a guide for electricity of ultra-high frequency, a resonator comprising a hollow generally cylindrical outer metal member intersecting said guide structure and enclosing coaxial spark-gap electrodes, means associated with one of said electrodes for lowering the breakdown potential, a flexible diaphragm carrying one of said electrodes, a fixed wall portion carrying the other of said electrodes, hollow cylindrical portions extending outwardly from the periphery of said diaphragm and fixed wall portions, each terminating in an annular fiange extending outwardly and welded to an outer portion of said outer metal member, filter plates disposed between said guide structure and welds for isolating the latter from the resonant cavity defined by the guide structure and cylindrical portion, and means for tuning said resonator and adjusting the distance between said electrodes comprising a drum head threadably mounted on said outer metal portion and threadably receiving an extension of the electrode carried by said flexible metal member, the threaded portions on the lcylindrical member and electrode extensions differing in pitch whereby turning of said drum head adjusts the position of the flexible metal wall portion and electrode carried thereby with respect to the other electrode.

10. A TR box comprising a hollow body resonator with a cavity'denedby' portions of the walls of a hollow conductive structure adapted to function as a guide for electricity of ultra-high frequency and `t1, hollow outer metal member intersecting said guide structure, with lateral eX- tensions from walls of said guide structure welded to end portions of said outer metal member at points remote from the resonator cavity.

il. In combination with an elongated hollow conductive structure adapted to function as a guide for electricity of ultra-high frequencyfa, TR boX intersecting said guide structure and comprising a hollow body resonator, opposed spark-gap electrodes enclosed thereby, and means for flexing a wall of said resonator which is generally coplanar with a, wall of vsaid guide to simultaneously tune the same and; adjust the gap between said electrodes.

12. A TR box comprising a hollow body resonator, opposed spark-gap electrodes enclosed thereby, means for flexing a wall of said resonator to simultaneously tune the same and adjust the gap between said electrodes, and means associated with one of said electrodes for lowering the breakdown potential therebetween.

13. A TR box comprising a hollow body resonator, opposed spark-gap electrodes enclosed thereby, meansassociated with one of said eleotrodes for exhausting the resonator cavity, and means for exing a wall of said resonator to simultaneously tune the same and adjust the gap between said electrodes.

VV8 t 14. A "TR box comprising a hollow body res#4 onator, opposed spark-gap electrodes enclosed thereby, means for flexing a wall of said resonator to simultaneously tune the same and adjust the gap between said electrodes, Welds connecting the resonator body to an associated wave guide, and means for electrically isolating said welds from said wave guide to eliminate their inuence on the characteristics of the resonator cavity. v

ERNEST C. OKRESS.

REFERENCES CITED The following references are of record in the ie of this patent:

UNITED STATES PATENTS Number Name Date 2,1062770 Southworth Feb. 1, 1938 2259,690 Hansen Oct. 21, 1941 2,108,640 Bieling Feb. 15, 1938 2,263,648 Salzberg Nov. 25, 1941 2,190,668 Llewellyn Feb. 20, 1940 2,242,275 Varian May 20, 1941 1,304,868 Franklin May 27, 1919 FOREIGN PATENTS Number Country Date 277,666 German Sept. 3, 1914