US2454761A

US2454761A - Ultra high frequency device

Info

Publication number: US2454761A
Application number: US466530A
Authority: US
Inventors: Wilmer L Barrow; Walter W Mieher
Original assignee: Sperry Corp
Current assignee: Sperry Corp
Priority date: 1942-11-20
Filing date: 1942-11-20
Publication date: 1948-11-30
Anticipated expiration: 1965-11-30

Description

NOV'v 30, 1948 w. l... BARRW Erm. 454,761

ULTRA HIGH FREQUENCY DEVICE l mvENToRs E wlLMER I .BARRow j. wALTERwMlEHER NOV. 30, 1948. w, BARROW l-AL 2,454,761

4 V ULTRA HIGH FREQUENCY DEVICE l Filed Nov. 2Q, 1942 y s sheets-sheet 2 7 lll/IIIA I .WILMER L. BARROW WALTER W. M IEHER ATTORNEY NOY. 30, 1948. w"| BARROW ETAL 2,454,761

ULTRA HIGH FREQUENCY DEVICE v Filed Nov.,2o, 1942 A s sheetssheet s INVENToRs WILMER L. BARROW WALTER W. MIEHER Patented Nov. 30, 1948 :Unirse .smi-ies rare-Nr ortica UL'rRA nlcnclcrrcv nevica.

I:Wilmer L. Barrow, 1Concord, Mass., and Walter Micher, Mineola, :N. fY., .assigners to The :Sperryr-LGorporation, a corporation of sDelaware Application November 2o, 1942,.s`eria1N0. 456,530

This invention relates, generallyg'to'ultrahigh frequencyftransmission, and, Ymore particularly, to a type of gas-*discharge resonant tube useful in stopping the flow, through a waveguide or other conductor, of ultra "high frequency energy above a predetermined. adjustable maximum. .amplitude and' in allowingenergy below that amplif tude to flow ,substantially unattenuated, and also I be placed. This Afeature restricts the physical to apparatus for conveniently and removably mounting such'tubes and other apparatus in a wave guide circuit. i 1

Such devices havebeenfound useful in ,ultra high frequency ipulse radiating and .receiving systems. weight considerations .demand that a `single `lievice serve `both as a transmitting .and receiving antenna. The device Aofithe lpresent.invention makes it possible for high energy transmitter pulses to be introduced into a waveguide also utilized-by the receiver, in. such a manner that the yreceiver is "not paralyzedor permanently damaged Vby the-high energy ofthe transmitted pulses.

In common penance, thisgasdischarge device has come to he' known as ar T-Rhox, an abbreviation for the 'term transmissionreception box, and willibe referred to"inthe`.following specicationas such. y

The T-R'boxes of theiprior art-have been,pro vided with a gas-enclosing `metallic! resonant` cas]- ing or enclosure having glass or otherceramic walls or'windowsthrough whichthe Aradio frequency energy enters or leaves vuthebox. The enclosure also contains discharge electrodes which are adapted `to provide 'a ygas discharge within the -enclosure in response to highiintensity received energy, to-destroy -theresonant condition of the lenclosure and thereby-tohlock `the passage of such-energythrough the device. `In such devices itiis a practical necessity ,toiform the glass or ceramic windowsvvithinthe casing walls before `fully enclosing the casing, `as by soldering,V hrazing` or` welding the metalto-metal joints. t

In previous devices of lthis-,type Ythe `forming or the metaljointswas extremely difficult, since particular painshadtol-lloc' taken to` preventy damage to the 'glass'or'ceramic'windows. This'is especially the'casefsince lprior -art TeRboxes have been designed forvoperationy withelectrical resonance ofthe'fundamentalor dominant resonant mode, lfor `which 4the operating'ffrequency is the lowest permissible for 4resonance" to f occur. In suchT-Rboxes,:there-iseonly one 'point of voltage maximum, Aat whichlthe windows should Y In many suchrsystems, space .and

shapeanddimensions of the casing and the location ;.o`ffthewindows`, so thatthe above-discussed disadvantages -in the electrical and f mechanical design andmanufacture are present.

" Alsoftloe gas discharge between the `electrodes tends to evaporatesome of the material of these electrodes, so that afilm vof this metal, ,or other material `formed by interaction of the metal vapor andthe gas, is deposited on'the glass or other ceramic walls.` This film continues to build up with the continued use oi the T-R box,;and harmfully affectsthe entrance or egress of radio frequency energy fromthe box while also causing serious power losses. Eventually this film renders the T-R box unusable and makes replacement necessary.

In prior art systems, it has been the practice to ,solder-orotherwise permanently seal the T-R box directly into its connecting wave guides or other high frequency energy conductors, in order toprevent loss of energy yatt-he joints. However, the finite life of these devices due to the causes just described makes the permanent installation of the device in-the conducting system impracticable.

According to thepresent invention, theseprior art'defects are substantially overcome. An improvedtype of T-R box isprovided in which resonanceoccurs .ata higher mode of resonance than the fundamental modes, so that more points of voltage maximum'areobtained, wherebythe glass `or ceramic windowsmay .be spaced from the metaljoints whereby the required soldering, brazing or Welding. of thesemetal joints will have little .effect upon the windows, and a .greater flexibilitydnelectrical and mechanical designl and manufacture may be obtained.` Furthermore,` the discharge electrodes are so located as toreduce and delay formation of the harmful film on the windows, lthus `providing longer life and lower losses. In addition, an improved form of holder for 'suchdevicesisprovided, adapted toremovablysupport such`T`RboXes or other similar devices, with a minimum ofenergy `loss and impedance mismatch at' the improved j ointsforrning a part of theholder.

It is therefore a principal object ofthe present inventlonto provide improved form of T-R box having a rugged typek of construction suchthat damage is unlikelyeven under roughmilitary, navalor other service conditions.

It is another object of the present invention to provide ran .improved .construction of LTR boxes or other similar devices in which neces- 3 sary glass-metal seals are relatively removed from soldered, brazed or welded metal joints, whereby the construction of the device is improved and its manufacture is facilitated.

It is still another object of the present invention to provide an improved form of T-R box adapted to be plugged into a wave guide or other high frequency energy conductor system, and to be easily removable therefrom.

It is yet another object of the present invention to provide an improved T-R box operating at a higher mode of resonance whereby advantages in electrical and mechanical design and manufacture are obtained. Y

It is a further object of the present invention to provide a socket or holder means in' a wave guide or high frequency energy conductor system for removably supporting a T-R box or other ultra high frequency device, without permitting energy to leak through the joints therein into space or to bypass the device, and to provide minimum impedance discontinuity at the joints.

A still further object of the present invention is to provide improved impedance matching means at joints presented to the flow of high frequency energy, whereby impedance discontinuities to the energy leakage are avoided.

Other objects and advantages will become apparent from the specification taken in connection with the accompanying drawings, wherein the invention is embodied in concrete form.

In the drawings,

Fig. 1 is a schematic block diagram, showing a system in which a T-R box according to the present system may be used.

Fig. 2 is a longitudinal cross-sectional view of a preferred form of the T-R box of the present invention.

Fig. 3 is a perspective cross-sectional view of a T-R box or other wave guide accessory holder according to the present invention.

Fig. 4 is a fragmentary cross-section View taken along the lines 4-4 of Fig. 2.

Fig. 5 is an explanatory graph.

Fig. 6 is a fragmentary longitudinal crosssection view of an alternate form of a portion of Fig. 2.

Fig. 7 is a partial cross-section view of another form of the invention.

Fig. 8 is a cross-sectional view taken along the lines 8-8 of Fig. 7 with the structure 'l' rotated slightly.

Fig. 9 is a cross-sectional view of an alternate form of the device of Fig. 7.

Fig. 10 is a fragmentary cross-sectional view taken along the line IIl-ID of Fig. 9.

Fig. 11 is a fragmentary cross-sectional view of another modification of the device of Fig. 7.

Fig. 12 is a fragmentary cross-sectional view taken along the line I 2-I2 of Fig. 11.

Fig. 13 is a fragmentary cross-sectional view of a further modification of the invention.

Fig. 14 is a fragmentary cross-sectional view taken along the line I4I4 of Fig. 13.

Fig. 15 is 'a partial longitudinal cross-sectional View of still another form of the invention.

Fig. 16 is a plan cross-sectional view of yet another form of the invention.

Fig. 17 is a longitudinal sectional View of another form of high frequency device cooperating with the holder of the present invention.

Similar characters of reference are used in all of the above figures to indicate corresponding parts.

Referring now to Fig. 1, there is shown a block diagram of an illustrative system using a T-R box, shown as a pulse-type object location system. High energy pulses from a pulsed transmitter 2 are fed by means of a wave guide 3 or other high frequency energy conductor into the wave guide 4, and thereby to a reflector or other antenna arrangement 4. Wave guide 4 forms a T-joint with guide 3, and is also connected to the T-R box I, whose other end is connected to a Wave guide 5 leading to a receiver 6. T-R box I is so designed that when a pulse is emitted by transmitter 2, the T-R box is made non-conducting, as will be described, so that substantially all the energy of the transmitted pulse is rejected by the T-R box I and substantially none is introduced into the receiver 6. This transmitted pulse is emitted by antenna 4', and, in the illustrative system used, may be reflected by any object within the radiation pattern of the antenna 4. Depending upon the size of the object and the distance between the system and the object, the transmitted pulse is reflected and returns to the antenna 4' somewhat attenuated and after a time delay corresponding to the distance between antenna 4 and the reflecting object. The energy of this received pulse is considerably smaller than the transmitted energy. T-R box I is accordingly made conducting to this lesser energy, so that this received pulse is transmitted directly through the T-R box I substantially unattenuated, to be received and utilized by the pulse receiver 6. Pulse transmitter 2 is designed so that its admittance to the received pulse is low, so that little of the reflected pulse energy is absorbed by transmitter `2. T-R box I thus serves to protect' the receiver from high energy intensities. 'It will be clear that many uses exist for such T-R boxes other than the illustration just given.

As seen in Fig. 2, the T-R box I consists, in a preferred form, mainly of v`a resonant chamber or resonator'l. The two wave guides 4 and 5 xedly terminate in an external holder or socket 8, and which removably supports resonator l. The resonant `chamber 'I itself is 'preferably made cylindricaLlits cylindrical wall l -being of some such alloy as the commercially well-known alloy Kovar, Vand has" its external and internal Surfaces plated with material of high electrical conductivity, such as silver Ior copper. In the form of the invention shown in Fig. 2, the resonator l is closed at one end with a rigid wall 9 and at its opposite end by a flexible diaphragm I0.

Reentrant from a 4central aperture in end wall 9 is .a tube` I5 which extends into the resonator 1 nearly toend wall I D. The internal end of tube I5 is conical, and has a small hole I7 centrally positioned at the apex thereof. Coaxially positioned within tube I5 is a conducting rod 2D, which terminates in a conical point 2l just inside of hole I l. Rod ZIJ is positioned with respect to and electrically insulated from tube I5 by a metal-to-glass seal 22. Centrally fastened in a central aperture in the diaphragm ID is a conical bluntly-pointed conduc'tor 2.3, which reaches to within a short distance of the hole Il. Rod 23 is extended through the diaphragm I 0 and .threaded outside of the diaphragm IIJ, as at 24, to be axially adjustably moved by rotation of a nut 25 which is fixed axially relative to the outer cylindrical wall 'l' of resonator 'l by means of end bracket 26 fixed to Wall l', whereby the operating point of .the T-R box may be adjusted, vas will be seen. Bracket 26 also serves as a mounting device for the T-R box. A pairuof openings II and II2 .are made in the to a very low level, as shown by the portion 32 of the curve 3l' of Fig. 5. In this way, the high intensity pulse 30 is substantially blocked by the T-R. box.

When the main pulse is over, this high-current discharge between l1 and 23 ceases, the T-R box becomes tuned again, so as to be capable of passing energy from the low energy reflected pulse to the receiver 6.

The gap between electrodes l5 and 23 is preferably placed as far as possible from windows Il, l2, so as to prevent any metal sputtered from electrodes i5 and 23 during the interval when the discharges occur, from condensing on windows Il, l2, thus preventing aging of the device by increasing the attenuation of these windows.

The breakdown point of chamber 'l and hence the point of demarcation between the pulses transmitted and blocked thereby may be adjusted by means of knob 25.

The T-R box just described is adapted to be removably held within a holder fastened permanently to the remainder of the system, in order to permit ready replacement upon deterioration or damage. In the past, great difculty has been experienced in providing removable devices for connection in an ultra high frequency system such as the present system, since the necessary joints required to provide removability introduce undesirable and harmful impedance discontinuities and also permit leakage of energy outside the system and around the removable device, which may be a T-R box as in the present illustration, or any other type of high frequency device similarly' insertable in the system.

According to the present invention, these former difliculties are overcome by the provision of special features in such a holder for a removable device, which minimize the effects noted above. A mounting is provided in which the coupling between T-R box and wave guides takes place without surface-to-surface contacts playing any part in the electrical operation, thus removing entirely any variations, irregularities or losses associated with such contacts. In the present illustration, the T-R box described above, or any other similar device, is adapted to be removably held within a holder or socket arrangement 8, as by means of suitable fastening members 26 holding bracket 26 firmly but removably against the thick wall 4t of holder 8. Wall 40 is made of highly conductive material with its in'- ner conducting surface 4I of slightly greater diameter than the outside diameter of resonator l, and is substantially of the same length as that of resonator l.

Wave guides 4 and 5 are rigidly positioned in wall and extend therethrough to form openings directly opposite windows H and I2. Above and below wave guides 4 and 5, at a distanc-e of substantially one-duarter-wavelength of the operating frequency, are placed annular grooves 4l and 42 extending radially for a distance of a quarter-wavelength of the operating frequency. These grooves 4i and 42 and the space between resonator 'l and cylindrical wall 4l] form a filter and impedance matching system, to prevent high frequency energy from leaking from the interior of wave guides 4 and 5 out of the top or the bottom of the socket or holder 8, and to minimize the impedance discontinuities at the joint between the holder 8 and the T-R box.

To explain the operation of this portion of the device, grooves 4I and 42 may be considered to constitute quarter-wave sections of a two-conductor transmission line, short-circuited at their remote ends, such as at 43, by the conductive material of wall 40. As is Well known, such a short-circuit quarter-wave transmission line presents a very high impedance at its open end, as at 44. In the apparatus of Fig. 2, this high impedance is effectively in series with the unknown impedance which is characteristic of the space between holder 8 and resonator 7.l The series connection of such a high impedance with an unknown impedance necessarily yields a resultant very high impedance. The quarter-wave transmission line formed by the concentrically disposed inner wall 4i of holder 8 and the outer wall 'l' of the T-R box transforms this resultant high impedance into a very low impedance at point 45. Accordingly, the gap at 45 presents an extremely low impedance to the iiow of energy through wave guide 4 into the T-R box. By virtue of this condition, the physically necessary discontinuity at this point has little effect upon the system, and little or no energy leaks outwardly from the joint, at least in the longitudinal or axial direction of the T-R box. Even though the dimensions herein referred to are not held to exactly, a substantial blocking of the egress of energy will result.

It will be clear that the explanation offered for slot 4I and wave guide 4 applies equally well to the remaining slots and wave guides.

As seen more clearly in Fig. 3, means `are provided to prevent whatever high frequency energy is propagated longitudinally from the joint from r travelling around annular grooves 4l, 42, which are similar to wave guides extending around and bypassing the resonator l, and thereby out from guide 5 Substantially 20 displaced from the wave guides 4 and 5, and a quarter-wave from the edges of the guides, is placed a vertical slot 46 which has a depth of a quarter-wavelength. VThe crossover points between annular grooves 4| and 42 and vertical slot 46 are blocked to high frequency energy by means of conducting pins 4l and 48, or by other conducting means, so that there can be no communication of energy between the annular grooves 4l, 42 and the slots 46. Also, pins 47, 48 prevent the ow of energy through grooves 4 I, 42. Slot 46 then acts in a manner similar to that of the grooves 4l and 42, to prevent energy from bypassing the resonator l. If the circumferential distance between adjacent edges of wave guides 4,

5 is substantially greater than a half-wavelength,

a pair of slots, placed a quarter-wavelength respectively from wave guides 4 and 5, may be used in place of the single slot 46.

In order to more easily construct'l the holder and to conserve material, it is not necessary that the filter grooves 4| and 42 be formed in a solid block of metal 4U as shown in Figs, 2 and 3. They may also be made by simply fastening the lter structure to a thin wall tube 53 forming the outside of holder 8, as in Fig. 7. In Fig. '7, annular quarter-

wave deep'sections

54 and 55 are provided on opposite sides of the wave guides 4 and 5, and in; side of Wall 53, the open ends 58, 51 of the

sections

54, 55 being located a quarter-wave distance from the upper and lower conducting surfaces 60, 6| of

the'guides

4 and 5. These

sections

54, 55 operate in exactly the same manner as explained in Fig. 2 to prevent axial leakage and to provide minimum impedance at the joint.

As shown in Fig. 8, if the Windows Il and l2 are rotated relative to the openings of the wave guides 4 and 5, the coupling between

guides

4 and 5 may i rae-bepm be altered, thus effectively varying thef'Qand the coupling o'f the system. As shown, `an equal change in the coupling of the T-R box to the'two wave guidesis provided by any rotational adjustment of the T-R box. Obviously, it fcouldbe arranged to change the coupling to one guide only if desired, as by providing a variable angle between the axes of the two guides terminating in the holder, and by other means readily apparent to one skilled in the art.

As seen in Fig. 8, :filter means, similar to that shown in Fig. 7 to suppress leakage of energy out of the top and bottom of holder 8, may be also placed vertically on each side of the .resonator 'I in order to prevent energy from bypassing the resonator. For this purpose, in the annular space between shell 53 and the casing I of T-R box I there are placed two members 66, 66' formed as longitudinal sections of a cylinder and concentric with respect to shell 53. each of these members, such as l[i4 and 64', are spaced from the edges 65, 65' of the wave guides l and 5 by substantially a quarter-wavelength. Connecting members 6E, 55 with shell 53 are members 63, 63 which are chosen to have such a width that the members, 66 `provide a quarterwavelength short-circuited line sections in a mann ner similar to that shown in Fig. -3. It will-be clear that these devices will perform in the same manner as those of Fig, 3 to prevent bypassing of the rll-R box -I by the 4high .frequency energy flowing between wave guides 4 -and 5. Members 66, B6' may be formed integrally with

ilanges

54, 55 of Fig. 7, whereby members 63, 63 prevent bypassing cf T-R box 'l through the

sections

54, 55.

Figs. 9, l1 and 13 show several modications of the arrangement of Fig. 7, all operating upon the same general principle. Thus, in Fig. 59, the quarter-wave short-circuited line section -12 is formed outside of shell 53 and communicates with" the interior thereofbyannular slot 10. Asbefore, section 'I2 is separated from wave guide 4 by substantially a quarter-wavelength. InFig. 1,1, section l2 is shown folded downward instead of upward, but otherwise similar to that of Fig. 9. Fig. i3 is similar to Fig. 7, merely reversing the direction in which the short-circuited quarter-wave section 54 extends. It will be clear that each `of these modifications will operate in the same manner as Fig. '7 and Fig. 2 to prevent axial leakage of high frequency energy and tomaintain a minimum impedance at the joint between thehol-der and T-R box I. Obstructions equivalent in function to pins 48 of Fig. 3 may also be used in these figures.

Figs. l0, 12 andll show modifications of Fig. '8, corresponding to their respective i'lgures,"9, 1l and 13. In each of these cases again theintermedi'ate external leakage impedance is connected in series with a short-circuited quarter-wave 'line section and the resultant series impedance is transformed at the opening of the 'wave guide 'to a very low impedance to provide minimum impedance at 4the joint and to prevent energy leakage. These lfigures are otherwise self-explanatory.

If desired, the windows II, I2 of Figsbl and 7 need not be oppositely located, but maybe placed at any suitable orientation or location relative to each other, as `pointed out above. In Fig. 15., wave guide A is `shown fastened into fa rotatable lter structure I05 opposite window fII., while wave guide 5 is shown positioned in 'a iilter structure IBS opposite a window laterally, and if desireclfalso angularly, displaced from window I I'. Filter structures |05 and :IUE are `shown .similar to the `The lea-ding edges of J 310 Ettf-'pe described in T9, `but may-be of any suitable Filter fstructures -III5 and `IIlI may be made individually-rotatable withrespect *toichamber 'I lsothat waveguides!! and A5i' maybedisposed at any desired "angle, The construction of this 5modilisation-ha`s the advantage of `separating rlater'allythe filter structures of a'the two wave guides and Windows, and thus decreasing the likelihood 4of transfer-of 'energy 1from 'one guide tothe other throughthe holder without passage through the further means for `preventing energy `from bypassing fthe resonator Jl is shown 'in Fig. -16, fwhich describes the application of a type of 4iilter structure first 'shown in a coaxial-line type yof ultra high frequency filter "in copending applicavtion Serial iNo. 417,229, entitled A high fre- 'duency `tube structure, led October 31, 1941, in the 'name of William W. Hansen. `External I'holier Wall 53, into which wave guides 4 and 5 are inserted opposite windows II, I2 in T-R vbox l, expands in thickness at alternate quarter-wave intervals around the circumference to form ap- -proximately `quarter-wave long conducting members lI'I'U with `slightly greater inner diameter ithan T-'R box 'I with similar unexpanded memlbers "III-2. AIn designing the lter, the lengths of sections III) and II2 are selected by experi- .'ment .if inecessary, yto provide an impedance inyversion.'irom section `'to section by means of the vusual'quarter-wave 4transm'ission-line action such vthat .a 'very :low effective impedance is caused to appear between -the

wave guide

4 or 5 and the oppositelydisposed T-Rrbox 1 or other device.

In the -illustration'shown'in Fig. 16, the impedance appearing, for example, between guide 4 and T-R box 'I will be transformed by 'the `first adjoining quarter-wave' section vto 'a different impedance. The following pairs Vof quarter-wave sections, being alternately of low and high characteristic impedance, will transform this higher impedance to 'a very low effective impedance appearing between -guide'5 and T-Rbox l. Thus, fthe wave energy -is forced to travel between the rguides and the interior 'resonant 'space of the device without an appreciable amount circumventing-the device.

`In the modification :shown in Fig. 16, an odd Inumber of quarter-wave sections are provided. Other numbersand arrangements of sections, in- 4cluding even `sections of lengths different from a quarter-wave, may be devised -by well known transmission-line theory by those skilled inthe It -is seen -that without the filter devices herein shown, including that 4of Fig. 16, the high frequency -energy will be propagated in the annular channel between wall -53 and resonator .'I :so as .to bypass the 'If-R box at least in part. Any desired combination of the `iilter -means herein shown `may 1be utilized with T-R box holders, to prevent both axial `and `peripheral leakage yof energy. The socket devices here shown are also applicable -to other types of tubes or `to other ultrahigh frequency devices, such as mixers, 'deteotora and the like, without Ibeing necessarily limited to use with T-R boxes.

For -example,l?ig. 157 lillustrates the -use of "a .holder similar Vto lthat of Fig. 7 with Van ultra :high-frequency velocity modulation electron discharge device, such as `of the Klystron type `described in Varian Patent No. 2,242,275, issued May 20,1941. In `this gure, the -two wave guides d and 5 cooperate with respective -resonators +20 `and :.I2'I which are respectively the input and out put circuits of the Klystron device, here shown as being an amplifier as disclosed in the abovementioned patent, and having a cathode |22.

It will beclear that many other types of high frequency device could be substituted for the T-R box or the Klystron device described in the present specification. Also, the holders of the remaining figures, such as Figs. 2, 9, 11, 13, or 16 could be utilized in the same fashion as shown in Fig. 7. It is also evident that the T-R box herein disclosed may be rigidly fastened tothe Wave guides, or may be used in any other manner not described in the present disclosure. In particular, it is evident that the Wave-guide filter means of Fig. 16 may be used in many types of Wave guide applications.

Wherever distance is given in terms of wavelength in the above, it is to be understood that the actual dimension is such as to give the same electrical effect as the given dimension would in vacuum, since all wavelengths given are those occurring in vacuum. v

As discussed above, the term higher mode of resonance (or equivalent expressions) when used in the appended claims, signifies that the resonant frequency of the cavity resonator is higher than the lowest (fundamental mode) resonant frequency thereof.

As many changes could be made in the above construction and many apparently widely different embodiments of this invention could be made Without departing from the scope thereof, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

What is claimed is:

l. A gas discharge device for ultra high frequencies comprising a cavity resonator having a gas-filled casing of a length for resonance at a higher mode, said casing having a rigid end wall, a flexible end wall, and a'cylindrical side wall having a pair of apertures located substantially a quarter-wavelength from said rigid end Wall and respectively providing an entrance and an egress in said resonator for high frequency energy; a reentrant tube coaxial with said casing and extending from said rigid end wall toward said flexible wall, 'said tube having an aperture in the end thereof adjacent said iiexible wall; a first electrode fixed to said flexible wall; means operably connected to said first electrode for adjusting said rst electrode toward and away from the end of said tube; la second electrode disposed Within said tube and insulated therefrom; and means for maintaining a cold discharge between said second electrode and the apertured end of said tube, whereby a high intensity energy pulse entering one of said apertures will break down said gas to detune said cavity and prevent passage of said energy to the other of said apertures, while a low intensity energy pulse will pass through said cavity substantially unattenuated, the break-down level of said cavity being adjustable under the control of said adjusting means.

2. A gas discharge device for ultra high-frequencies, -comprising a gas-filled cavity resonator resonant at the operating frequency of said device, means operably connected to said resonator for coupling ultra high frequency energy to said -cavity at a voltage anti-nodal position thereof, means operably connected to said resonator for abstracting energy from said cavity also at a voltage anti-node, and means connected to said resonator for maintaining a cold discharge therein at a voltage anti-node thereof spaced from said coupling and abstracting means.

3. A gas discharge device for ultra high frequencies, comprising a gas-filled casing providing a cavity having dimensions for providing a higher mode of resonance at the operating frequency of said device, means including a window in said casing for coupling lhigh frequency energy thereto at a voltage anti-nodal position of the field within said cavity, and means within said casing responsive to high frequency energy of sufliciently high amplitude for causing a gas discharge in said cavity and thereby detuning said resonant cavity, said last-named means being spaced from said coupling means to prevent deterioration of said window by the action of said discharge.

4. A gas discharge device for ultra high frequencies comprising a gas-filled casing providing a cavity resonant at the operating frequency of said device, means including a window in said casing for coupling thereto energy at said operating frequency, and means Within said casing responsive to high frequency energy of suiciently high amplitude for providing a gas discharge within said cavity to detune said cavity, said last means being spaced from said Window to prevent deterioration of said window by the action of said gas discharge.

5. Apparatus for use with ultra high frequencies comprising means providing a cavity resonator for an operating frequency higher than the lowest resonant frequency thereof, means coupled to said cavity resonator at a voltage antinodal position thereof for supplying energy thereto of said operating frequency, means coupled to said resonator for abstracting energy from said cavity resonator also at a voltage anti-node thereof, and means in said cavity resonator for preventing said abstraction of energy in response to high frequency energy input to said cavity above a predetermined value.

6QA gas4 discharge device for ultra high frequencies, comprising a gas-filled cavity resonator resonant at the operating frequency of said device, means coupled to said resonator for supplying ultra yhigh frequency energy to said cavity resonator, means coupled to said resonator for abstracting energy from said resonator, and means operably connected to. said reso-nator for maintaining a cold discharge within said resonator` at a' voltage anti-node thereof spaced from said energy supplying and abstracting means.

7. High frequency apparatus comprising an enclosed, gas-filled cavity resonator, means including a window in the wall of said resonator for coupling high` frequency energy thereto at a voltage anti-node thereof and means including a second window in the wall of said resonator for coupling high frequency energy therefrom, said resonator having a higher mode of resonance at the operating frequency of said device, and said 13 prising means forming .a quarter-wave transmission line section having said joint as a termination, said section being connected at its outer end to a quarter-wave short-circuited transmission line section in series with a leakage gap E whereby leakage of high frequency energy through said gap is minimized.

9. A -high frequency system wherein a cylindrical high frequency device is removably coupled guides, comprising a hollow cylindrical holder body surrounding saidl device and having said rectangular guides communicating with'the interior thereof, a quarter-wave deep annular groove extending radially in saidbody at a distance of a g quarter-wavelength above and belowsaid guide, whereby leakage of highfrequency energy axially of Vsaid device Vdue rto clearance between said holder and saiddevice is minimized.

10. A'high frequency system, wherein a cylinto a pair of waveguides, comprising a hollow cylindrical holder body adapted to surround said device and having said guides communicating with the interior thereof, said body having au.;

quarter-wave deep slot formed .therein extending parallel to one edge of one.of .said .guides and spaced a quarter-wavelength therefrom, whereby leakage of high frequency energy due to clearance between-said holder and saidtdevice is minimized.

1l. The combination as in `claim 10 wherein the depth of said slot is formed axially and wherein said slot extends annularly about said holder to prevent leakage axially of said holder `and device.

vice, a high frequency energy conductor xed to said holder and communicating with the interior thereof, and a high frequency device removably and rotatably supported by said holder and comprising a casing having an opening therein for passage of high frequency energy, said opening being normally opposite the end of said high frequency energy conductor communicating with said holder and being adapted to cooperate varia,- bly therewith according to the rotary position of said device in said holder.

i4. Apparatus comprising a high frequency device adapted to have high frequency energy flow therethrough, a hollow holder removably supporting said device, said holder surrounding said device and having high frequency energy conductors communicating with the interior thereof, said holder being spaced from said device, and means in said holder for preventing leakage of high frequency energy between said conductors and around said device.

l5. High frequency apparatus wherein an enclosed high frequency device having apertures for the passage of high frequency energy is removably coupled to high frequency conductors, comprising a holder for said device including a hollow holder body surrounding said device and having a pair of rotatable sections, each opposite one of said apertures, each of said sections being fixed to one of said conductors to permit said holder to be utilized with any one of a plurality of devices having differing circumferential locations of said apertures.

to a pair of rectangular high lfrequency ywave :1,0

drical high frequency device is removably `coupled 16'. `The combination as in claim 15 further including meansat the joint between said conductors and said apertures for preventing leakage of fenergy therefrom.

` `1'7. High frequency apparatus comprising an enclosed, gas-filled cavity resonator having a cylindrical inner wall and two ends, and means 4including a Iwindow in said cylindrical wall for coupling `high frequency energy thereto, said .resonator having a higher mode of resonance at Ithe operating frequency of 'saiddevica and said rwindow being located remote `from said ends of said resonator to facilitate fabrication thereof. `18. High frequency apparatus comprising a .high frequency energy utilization device having .openings for the entrance and egress of high frequency energy,and a holder removably supporting said device `positioned adjacent to and Vspaced ffrom said device, said holder support-- ing high frequency energy conductors opposite said openings and spaced therefrom by gaps, said holder including means therewithin for prevent- @ing leakage-of high frequency energy at said gaps .betweensaid:conductors and said openings.

19. -High yfrequency apparatus comprising a .thigh :frequency energy utilization device having an opening for coupling high frequency energy thereto, `a holder removably supporting said vde- .vice positioned adjacent to and spaced from said device, `and a high frequency energy conductor `fixedly supported by said holder opposite said ripening, said holder including means therewithin lfor preventing leakage of high frequency energy at the gap between said conductor and said iopening.

20. A high frequency system wherein a high frequency device is removably coupled to a high frequency conductor, comprising means coupling said conductor to said device, said coupling means comprising means removably holding said device in a predetermined relation to said conductor to form an effective junction therebetween, and including means therewithin for minimizing the impedance of the joint between said conductor and said device.

21. Apparatus as in claim 20, wherein said last named means comprises means forming a quarter-wave transmission line section having said junction as a termination, said section being connected at its outer end to a quarter-wave shortcircuited transmission line section in series with the leakage gap between said device and said holding means, whereby leakage of high frequency energy through said gap is minimized.

22. High frequency apparatus wherein an enclosed high frequency device having apertures for the passage of high frequency energy is removably coupled to a pair of high frequency conductors, comprising a holder for said device including a hollow holder body surrounding said device and having a pair cf sections each opposite one of said apertures, each of said sections supporting one of said conductors, whereby high frequency energy may be led toward and away from said device.

23. High frequency apparatus wherein an enclosed cylindrical high frequency device having axially displaced apertures in the cylindrical wall thereof for the passage of high frequency energy is removably coupled to high frequency conductors, comprising a holder for said device including a hollow holder body surrounding said device and having a pair of sections each opposite one of said apertures, each of said sections carrying one of said conductors.

24. High frequency apparatus comprising a high frequency energy utilization device having openings for the entrance and egress of high frequency energy, and a holder for removably supporting said device and positioned adjacent to and spaced from said device, said holder supporting high frequency energy conductors opposite said openings and spaced therefrom by gaps and including means therewithin for preventing leakage of high frequency energy at said gaps between said conductors and said openings, said leakage preventing means including resonant transmission line means.

25. A high frequency system, wherein a cylindrical high frequency device is removably coupled to a pair of wave guides, comprising a hollow cylindrical holder body adapted to surround said device and having said guides communicating with the interior thereof, said body having a quarter-wave deep slot formed therein, the depth of said slot being formed radially of said body, said slot extending annularly of said body and parallel to one edge of one of said guides and spaced a quarter-wavelength therefrom, Where by leakage-of high frequency energy axially of said holder due to clearance between said holder and said device is minimized.

26. A high frequency system, wherein a cylindrical high frequency device is removably coupled to a pair of wave guides, comprising a hollow cylindrical holder body adapted to surround said device and having said guides communicating with the interior thereof, said body having a quarter-wave deep slot formed therein, the depth of said slot being formed radially of said 16 body, said slot extending axially of said body and parallel to one edge of one of said guides and spaced a quarter-wavelength therefrom, whereby leakage of high frequency energy circumf entially of said holder due to clearance betwe n said holder and said device is minimized.

27. Apparatus comprising a high frequency device adapted to have high frequency energy ow therethrough, a hollow holder removably supporting said device, said holder surrounding said device and having high frequency energy conductors communicating with the interior thereof, said holder being spaced from said device, and means in said holder for preventing leakage of high frequency energy between said conductors and -around said device, said leakagepreventing means comprising quarter-Wave sections of alternately wide and narrow clearance between said device and said holder, whereby said energy is prevented from flowing in the space between said device and said holder.

WILMER L. BARROW. WALTER W. MIEHER.

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

UNITED STATES PATENTS Number Name Date 2,106,770 Southworth et al. Feb. 1, 1938 2,106,771 Southworth Feb. 1, 1938 2,128,234 Dallenbach Aug. 30, 1938 2,153,728 Southworth Apr. 11, 1939 l2,300,052 Lindenblad Oct. 27, 1942 Certificate of Correction Patent No. 2,454,761. November 80, 1948.

WILMER L. BARROW ET AL.

It is hereby certied that errors appear in the printed specification of the above numbered patent requiring correction as follows:

Column 11,line 56, claim 1, after means insert coupled to said second electrode; line 58, after the Word tube strike out the comma and insert instead a period; same line beginning with whereby strike out all to and including the Word and period means in line 66 same claim; column 13, line 64, beginning with 15. High frequency strike out all to and including the Word and period therefrom. in line 4, column 14, and insert instead the following:

15. High frequency apparatus comprising an enclosed, gas-filled cavity resonator having a cylindrical wall, and means in said wall for coupling thereto energy oj' a frequency required to form voltage antinodes at a plurality of positions therein, said coupling means being located adjacent one of said positions.

16'. Apparatus as in claim 15, wherein said resonator includes a pair of opposed reentrant portions providing an internal gap near one end of said resonator.

and that the said Letters Patent should be read With these corrections therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 5th day of July, A. D. 1949.

THOMAS F. MURPHY,

.Assistant Commissioner of Patents.