US2829347A

US2829347A - Selective transfer device for microwave energy

Info

Publication number: US2829347A
Application number: US592231A
Authority: US
Inventors: Tomiyasu Kiyo
Original assignee: Sperry Rand Corp
Current assignee: Sperry Corp
Priority date: 1956-06-13
Filing date: 1956-06-13
Publication date: 1958-04-01
Anticipated expiration: 1975-04-01

Description

April 1, 1958 KIY ToMiYASU 2,829,347

SELECTIVE TRANSFER DEVICE FOR MICROWAVE ENERGY Filed June 13, 1956 5 Sheets-Sheet l INVENTQR K/Yo TOM/msu April r1, 1958 KlYo ToMlYAsu y SELECTIVE TRANSFER DEVICE. FOR MICROWAVE ENERGY Filed June 13, 1956 5 sheets-sheet 2 INVENTOR ATTORNEY April 1, 1958 KlYo 'roMl'YAsu SELECTIVE TRANSFER DEVICE FOR MICROWAVE ENERGY Filed June 13, 195e 5 Sheets-Sheet 5 INVENTQR /Yo TOM/msu l ATTORNEY April 1, 1958 KlYo ToMlYAsU 2,829,347

sELEcTIvE TRANSFER DEVICE FoR MICROWAVE ENERGY Filed June 13, 1956 5 sheets-sheet 4 iNvENToR /BfQ/ 0'7b/w YASU l i@ M April 1, 1958 KlYo 'MlYAsU 2,829,347

SELECTIVE TRANSFER DEVICE RoR MICROWAVE ENERGY Filed June 15, 195e 5 sheets-sheet 5 qfll #M [20 /Z 4/7 IC'- l El l INVENTOR /Bl//Yo 75M A50 ATTO RN EY Unite sntncrivn TRANSFER DEVICE Fon Mrcnowava ENERGY Appucaaaa :ame is, 1956, serial No. 592,231

in ciaims. (ci. ssa- 7) The present invention relates to waveguide apparatus for microwave energy, and is particularly concerned with energy transfer apparatus for selective transfer of energy between a plurality of waveguides. This application is a continuation-in-part of U. S. patent` application S. N. 213,276, by K. Tomiyasu, filed February 2l, 1951.

An object of the invention is to provide improved microwave energy path control apparatus.

More specifically, it is an object to provide improved apparatus for selectively transferring energy from one waveguide to another, and for control of the energytransfer.

A further Objectis to provide improved apparatus for receiving microwave energy through one waveguide and selectively routing it through one or another of plural output waveguide routes.

Another object is to provide improved apparatus for receiving microwave energy through one waveguide and selectively routing it through one and only one of a plurality of output waveguides. l

Yet another object is to provide a compact, improved structure for variable directive coupling between first and second waveguides.

These objectives are met by providing two waveguides xed in adjacent positions with respective waveguide sections thereof parallel, and providing registering openings in the adjacent walls of the parallel kwaveguide sections for energy transfer therebetween.

These openings are made of such breadth and length as to provide complete directional transfer of the microwave energy from one of the waveguides to -the other, inV accordance with the principles of patent application Serial No. 197,064, filed November 22, 1950, in the names of Kiyo Tomiyasu and Seymour B. Cohn:

A movable shutter area of conductive'material is interposed between the guides to obstruct the region of communication therebetween, e. g. to totally block the registering openings and to insure confinement of an energy component arriving in one of the two waveguides to continuance of propagation in that waveguide. The shutter element is arranged in such a way as to be shiftable to unblock the area of said openings, wholly or partially, and to bring about transfer of all or a substantial part of the microwave energy from one waveguide to the other, or from each supplied waveguide to each other.

Representative embodiments of the present invention are illustrated in the drawings.

`Fig. 1 is a perspective View of an energy path control apparatus arranged to serve effectively as a double-throw switch mechanism, for total retention of energy in one wave guide, or for total transfer of energy-thereformf to the other of the two waveguides;

Fig. 2 is a longitudinal sectional'view of the of Fig. l, taken on the line 2 2 in Fig. 3;

Fig. 3 is a cross-sectional view of the structure of Fig..1 taken on the line 3--3 in Fig. 2;

Fig. 4 is a fragmentary cross-sectional view illustrating structure I 2 the same structure as shown in Fig. 3 but with the shutter element positioned for total energy transfer from one waveguide to the other;

Fig. 5 is a plan View of a longitudinally adjustable 5 shutter embodiment of the present invention, parts being broken away and parts shown in section, for clarity of illustration;

Fig. 6 is a side elevation of the embodiment of Fig. 5, parts likewise being broken away for clarity of illustration;

Fig. 7 is a drawing of a modification of the shutter 15 of Figs. 1-4; l Fig. 8 is a plan view of a multi-circuit switching struc ture embodying the present invention;

Fig.- 9 is a cross-sectional View of the structure of Fig. 8, taken on the line 12-12 therein; Fig. 10 is a perspective view, partly in cross-section, of a modified multi-circuit switching structure embodying the present invention;

Fig. 1l is a cross-sectional view, partly broken away, looking up at the structure of Fig. 10; and

Fig. 12 is a cross-sectional view, partly broken away, of the structure of Fig. 11.

The embodiment illustrated in Figs. 1-4 basically ini cludes a first waveguide 11 and a second waveguide 13 rigidly fixed together, with sections of appreciable length in the

respective waveguides

11 and 13 positioned parallel and adjacent to each other. Registering openings are provided in the adjacent walls of the respective sections of

waveguides

11 and 13, and a shutter element 15 is ar- -ranged for transverse sliding movement between these sections of waveguides il and 13.

The slide or shutter element 15 is provided with a longitudinal opening 17, so located that the shutter 15 may be moved to a position at which the opening 17 is situated directly between the parallel and adjacent sections of waveguides i1 and 13, permitting energy communication from one of the two guides to the other through the openings therein.

The openings in the waveguides and the opening 17 in shutter 15 are so arranged that when the shutter opening and the waveguide openings are in register, complete directional energy transfer occurs through the openings, from one waveguide to the other. When the slide element 15 has been moved to the position with opening 17 re"- mote from the openings in the parallel waveguide sections, the passage between the

waveguides

11 and 13 is closed, and accordingly any energy supplied to one end of one waveguide proceeds directly therethrough to the other end thereof with substantially complete freedom from energy transfer over to the other waveguide. The shutter or slide element 1S is illustrated in Figs. 1, 2 and 3 as positioned for this Zero-transfer condition.

The construction chosen for the embodiment illustrated in Figs. 1 4 involves rectangular tubing sections at thc ends ofthe

waveguides

11 and 13, the relatively long parallel middle sections of the

waveguides

11 and 13 being made up as a composite structure including iirst and

secondside plates

21 and 23, upper and lower intermediate longitudinal pieces" 2S and 27, and partition elements 29 and 3l (Fig. 2). The inside surfaces of said

plates

21 and 23, in the space betweenthe left-hand and right-hand rectangular 'tubular portions of the waveguides as seen in Figs. 1 and 2, serve as the interior side wall surfaces of the two waveguides. The upper and lower

intermediate pieces

25 and 27 serve not only to afford a mechanically rigid assembly with the

side plates

21 and 23, but also, these pieces serve as continuations of the narrow wall surfaces of the respective waveguides, between the left-hand rectangular tubing sections and the righthand rectangular tubing sections,

j' 2,829,347 r f Y Partition velement 29 shown in Fig. 2 Serves simultai neously as a portion of the lower interior wall surface of the upper wave guide 11., and a portion of the upper interionwall surface of the lower waveguide 13, reaching to`v the left-hand ends of the

openings

33 and 35 in the upper and lower waveguides 11' and 13, respectively. Similarly, partition element 31 serves as an extension of the adjacent narrow interior wall surfaces of the wave guides, between the ends of the right-hand rectangular` tubing sections of

waveguides

11 and 13 and the righthand ends of the

openings

33 and 35.

The shutter4 15 is supported-at its left edge in milled conformal slots 37 in the

side plates

21 and 23 and partition element 29 and at its right edge, similarly, Vin milled conformal slots 39 inthe side yplates 21' and 273 and partition element31. These slots accurately position shutter 15 and act as guides for the transverse sliding movement j thereof.

Extensive recesses are milled in the middle region of said

plates

21 and 23, in such a Way as to leave anges extending along the regions thereof adjacent the operating location of shutter 15. These flanges are provided with a. series of transverse cuts, in such a Way as to form them into

serrated chokes

22, 2 4, 26 and 28, each comprising a series of transversely extending tines parallel to and spaced slightly from the surface of shutter 15.

The length of the tines of the

serrated chokes

22, 24, 26 and 28 is preferably of the order of one-fourth wavelength, and the width and spacing between tines and spacing of the tines from the shutter 15 are preferably much smaller than one-fourth wavelength. As an example, three or more tines may be included within a disance of one-fourth wavelength along the serrated choke (i. e., transverse the direction of extension of the tines).

Such serrated chokes per se are described and claimed in U. S. patent application Serial No. 197,063, filed No# vember 22, 1950, in the name of the present inventor.

The rectangular tubing sections of the ends of the waveguides preferably are recessed within the ends of `the composite assembly formed of elements 21 2,3,` 25,

ings

33 and 35 in the

respective wage guides

11 and 13 are appreciably longer than the opening 17 in shutter 15. Accordingly, the length of the opening 17 determines theeffective length of the region of intercoupling between the

waveguides

11 and 13 when the shutter is in the position illustrated in Fig. 4 for permitting energy trans-k y fer between

guides

11 and 13. This effective length of the region of communication is of considerable importance to the operation of the structure; and for a given operating frequency, and giveninternal dimensions of the

wave guides

11 and 13, this length of opening 17 may be arranged to provide complete energy transfer from one waveguide to the other with retention of directional energy transmission. With a greater or lesser length of the opening, partial energy transfer is accomplished between thewaveguides, with maintained direction of transmission, the incident energy beingthus divided intoY la transferred component and a component transmitted onward through the guide through which it arrived. Thus, if the structure is to serve primarily as a transfer switch system, the opening 17 must be made to be of that length which provides 100% energy transfer.

The principles of operation of this'type of coupler systemare closely related to thosevsetforth `in, detailin patent application Serial No. 1973064, filed` November 4 22, 1950, in the names of the present inventor and Seymour B. Cohn as joint inventors.

As explained in the application above referred to, the operation of this type of coupler system involves the consideration of two modes of wave energy propagation which prevail in the mutually adjacent waveguide portions whose interiors are exposed to each other through the longitudinally extensive openings in the respective guides. It isV customary to design a rectangular waveguide for efficient transmission of energy` of a known frequency, the mode of transmission being a fundamental mode of the guide usually lreferred to as the TELO mode. This is the dominant transverse electric mode. The a" dimension of the simple rectangular waveguide ordinarily is such as to prevent it from transmitting energy of this frequency in any of the known higher modes.

When two of such waveguides are juxtaposed with their narrower walls mutually adjacent, and these adjacent narrower walls are opened throughout an appreciableflongitudinal extent, the effect is to substantially double the a dimension'of this waveguide portion. This effectively enlarged waveguide portion is then capable of. supporting energy in two modes of propagation, the first being closely related to the simple transverse electric mode TELO described in connection with the basic waveguide section, and the second mode being the asymmetrical mode designated TEM. If inductive loading is provided as by the use of a series of spaced cross-bars each extending across the opening in one of the waveguides (or across the opening in the shutter element), suchl inductive loading brings about a departure of the symmetrical mode from the normal character of a TEU, energy distribution in the enlarged waveguide section.

Whether or not inductive loading is provided, the symmetrical mode and the asymmetrical mode are propagated along the doubled waveguide section at different phase velocities. At the point of entrance of the energy into the doubled wave guide section, they are in phase in the lower guide (i. e., in waveguide 13),assuming this guide only is supplied with energy yat its left-hand end, as by a source S2. At the point of entrance into the doubled waveguide section,V these components are in phase opposition in the upper waveguide (waveguide 11). Farther along the doubled waveguide section, however, the two components approach cophasality in the upper guide, even as they approach Vphase opposition in the lower guide. If the effective length of the opening between the guides is sufficient, complete energy transfer takes place from the lower guide' to the .upper guide with unidirectional propagation being maintained, away from the source end (S2) and toward the opposite end of the structure, i. e., toward the right-hand end of wave guide 1'1.

` If the effective length of the openings is less or greater than the length for complete energy transfer, then the energy will be divided, part ofA it being transferred and proceeding outwardV toward the right-hand end of waveguide 11 to' utilization device U1, the remaining part of the incident energy from source S2 being retained in waveguide 13 and delivered to` utilization device U2.

p If inductance cross-bars are provided across the opening in oneV of the waveguides, or across the opening 17 in shutter 15', asillustrated in Fig. 7, the effective length of the opening for complete energy transfer from one guide to the other must be appreciably greater, for example, three times greater than the effective length of the opening where, no cross-bars are employed. Y

If desired, energy from. two or more sources may be handled by the structure shown in Figs. l-4 simultaneously, For. example, a source S1 may be coupled to the left-hand end ,of waveguide 11 and a source S2 may concurrently supply energy tothe left-hand end of waveguide 13.` These sources needy not be 4of equal frequencies, nor need they be specially relateda's to theirl amplitudes. It is only` necessary that their frequencies bevvithin the design lfrequency. range of operation of the structure." With the shutter positioned in such a way as to completely block the openings, as shown in Figs. 1 3, al1 of the energy from source S1 proceeds directly through to utilization device U1, and all of the energy from source S2 proceeds directly through waveguide 13 to utilization device U2.

A shift of the shutter to situate the opening 17 directly between the wave guides 11 and 13, as illustrated in Fig. 4, brings about a complete interchange of the communication circuits, so that the energy from source S1 is then delivered to utilization device U2 and the energy from source S2 is delivered to utilization device U1. Because of the appreciable longitudinal distribution of the coupling between

waveguides

11 and 13, the transfer of energy proceeding from source S1, over to waveguide 13, is accomplished with negligible leftward propagation (towards source S2), and likewise, the transfer of energy proceeding from source S2, over to waveguide 11, is accomplished with negligible propagation in waveguide 11 toward the left-hand end thereof.

Typical dimensions for an operating frequency of 10,000 megacycles per second are as follows:

Inches Width (I. D.) of each waveguide 0.40 Height (I. D.) of each waveguide 0.90 Width of waveguide openings 0.40 Width of opening 17 in shutter 15 0.40 Length of waveguide openings 3.9 Length of straight sides of opening 17 2.62 Length of opening 17 3.0

The waveguide walls extend close to the surface of the shutter 15, but are slightly spaced therefrom, substantially equally as the tines of the serrated chokes are spaced from the shutter, as is clearly seen in Fig. 3. Preferably, for providing maximum continuity of transmission through the wave guides and avoiding small energy reflection componentsy which could result from the effectively increased a dimension from the lower surface of piece 25 down to the upper surface of shutter 15, and the similarly increased a dimension from the .upper surface of piece 27 to the lower surface of shutter 15, it is desirable to provide a longitudinally extensive boss or plate on each of

pieces

25 and 27 coextensive with the

waveguide openings

33 and 35, and of thickness equal to or slightly less than one-half the thickness ,of partition elements 29 and 31.- By this arrangement, the effective "a dimension throughout each waveguide is substantially uniform when the shutter 15 is positioned as shown in Fig. 3 for preventingH energy transfer between the two waveguides.

' By making the length of the openings in the waveguides appreciably greater than the effective length for full energy transfer, an advantage of simplified construction is realized in that the constructor is enabled to make anexperimental opening 17 in shutter 15, and if such opening proves to be of insuicient length, it may be extended by a relatively simple machining operation, or a series of operations, until the desired result is obtained. Similarly, for a given set of wave guides 11 and 13, various shutters with, different lengths of the openings maybe providedr for complete energy transfer at a plurality of respective wave lengths, or on the other hand, openings of various lengths in the shutters may be provided for various amounts of energy transfer. f

In the embodiment shown in Figs. 5 and 6, upper and

lower waveguides

111 and 113 areriixed together as by

structural elements

118 and 119, and an elongated shutf ter 115 is provided for longitudinal adjustment of its posi? tion between the elongated parallel sections of

waveguides

111 and 113.

Serrated chokes 122, 124, 126, 12S are provided for affording the electrical effect substantially equivalent to direct junctions betweenr shutter 115 and the walls of the upper and lower waveguides, without the requirement` of direct friction contact, and for preventing thev escapel of energy from the. confinement within the waveguides.

The elongated shutter is guided in suitable grooves therefor in the

structural elements

118 and 119, and is slightly spaced from the tines of the

serrated chokes

122, 124, 126, 12S and from the adjacent edges of the

Waveguides

111 and 113.

Matching

openings

133 and 135 are provided in

waveguides

111 and 113, respectively, and an opening 117 which may be of similar configuration and of equal size, if desired, is provided in the shutter 115.

These openings are so situated that the shutter 115, shown set for a position of partial power transfer, may be moved to the right to a position of full register of the three openings, for full transfer, or may be moved to the left to-a position completely preventing energy transfer from one waveguide to the other.

It is not essential for the length of the opening in the shutter to be exactly equal to the length of the openings in the waveguides since in any event the performance of the system is determined by the length of the effective opening for a given shutter setting.

It will be readily appreciated that the embodiment of Figs. 5 and 6 is usable in the same ways in which the embodiment of Figs. l-4 may be used, for providing Aparallel transmission or crossed-over transmission, in two simultaneous communication paths, if desired. The structure of Figs. 5 and 6, however, has the additional feature that the degree of energy transfer may be continuously varied from the condition of substantially complete transmission directly through one waveguide (or in parallel paths through the parallel waveguides), to the condition of complete power interchange between the waveguides. This structure of Figs. 5 and 6 is thus suitedfor all of the applications for which the coupler of U. S. patent application Serial No. 197,064 is suited.

If desired, a scale of calibrations 149 may be provided on the shutter 115, for indicating the degree of power transfer in percentages, or in decibels, or on such other calibration basis as may be desired.

One of the elongated openings in the waveguides or in the shutter may be provided with a loading element or elements such for example as inductance cross-bars, if desired, as described above in connection with the embodiment of Fig. l.

The structure illustrated in Figs. 8 and 9 is a selective microwave energy transfer structure involving the same operating principles as in the previous embodiments, but with a ring-like physical arrangement for employment of a rotary shutter system 315, the principal wave guide system 311being curved into an incomplete ring transmission path. A second waveguide 313 is rigidly positioned above a portion of waveguide 311 and is arcuately conformal therewith over a portion of its length. i

Registering longitudinally extensive openings are provided through the upper interior surface of waveguide 311and the lower interior surface of waveguide 313 for permitting full energy transfer from waveguide 311 to waveguide k313, with directional transmission main-v tained, to convey substantially the entire energy fed into waveguide 311 through flange 361 thereof, out through waveguide 313 and flange 365 thereof. Such complete energy transfer occurs through the registering openings of waveguide 311 and waveguide 313 when rotary shutter 315 is so positioned as to leave these openings totally unblocked.

A plurality offurther wave guides 373 and 375 are similarly rigidly positioned above waveguide 311, and arranged withlongitudinally extensive openings adjacent to similar registering openings in waveguide 311.

A spider frame including a hub 380 and

arms

381, 383, and 385 may be provided for supporting the shutter bearing and for lending rigidity to the system. The

upper waveguides 313,` 373 and 375 are supported on 7

brackets

387, 389 and 391, respectively, extendingupf ward from waveguide 311. These brackets may, 1f desired, comprise extensions of the spider arms 381,383

and 385.

Serrated chokes typied by

chokes

392 and 393 are provided on waveguide 311, over arcuate regions there` of including and extending beyond the longitudinally extensive openings therein; and corresponding serrated chokes are provided along the sides of the arcuate portions of

waveguides

313, 373 and 375, the spacing between the lower waveguide chokes 392, 393 and the chokes of the upper waveguides being slightly greater than the thickness of the shutter 315.

The clockwise end of waveguide 311 beyond the ends ofthe registering openings of

waveguides

311 and 375 is provided with an energy absorber such as a filling of high-loss dielectric material.

With the shutter 315 positioned as illustrated in Fig. 8, blocking the communication path through the registering openings of waveguides 311L and 313, energy entering waveguide 311 at flange 361 is conveyed around to the registering openings of

waveguides

311 and 373,` and transferred from waveguide 311 to waveguide 373 through these openings, and transmitted outward through flange 374. The registering openings ofwaveguides 311 and 375 are blocked when the shutter 315 is positioned as seen in Fig. 8, but this is only incidental, since substantially none of the energy supplied through flange 361 remains untransferred and proceeds in waveguide 311 be-r yond waveguide 373.

Assuming the shutter 315 rotated 120 clockwise from the position seen in Fig. 8, the regions of communication to

waveguides

313 and 373 are blocked, and the energy fed into4 waveguide 311 proceeds on around to the proceeding clockwise through waveguide 311 first encounters a partially opened transfer system, because this results in partial transfer of the energy through such a transfer system, and complete transfer of the energy through the next open transfer system encountered by` the energy continuing clockwise in waveguide 311. For example, assume shutter 315 rotated 90 clockwise from its position illustrated in Fig. 8. As thus repositioned, the shutter would entirely block the registering openings of

waveguide

311 and 313, and would reduce by sub stantially half the effective length of the window or passage comprising the registering openings of

waveguides

311 and 373. A partial energy transfer into waveguide 373 would result, the remaining energy proceeding onward in the clockwise direction in waveguide 311, and all being transferred out through fully open waveguide 375.

Like operation prevails if the shutter is so positioned as to block the registering openings of

waveguides

311 and 375, and partially unblock the registering openings of

waveguides

311 and 313. Such a position is obtained if the shutter 315 is displaced a few degree counterclockwise from the position illustrated in Fig. 8.

With the arrangement of the shutter 315 and the openings as illustrated in Fig. 8, there is always at least one fully open area of communication between waveguide 311 and another waveguide, and hence the power entering at ange 361 is always communicated to one or at most two of the output waveguide ends.

As in all of the previous forms` of the invention, the source and load connections .readily may be interchanged, a load device at ange 361 being supplied by one or another of the respective sources'connected to guides 313,

'

sponding opening

435, 437 or 439.

373 and 375, or by microwave power contributions from f selective microwave energy transfer structure involving operating principles similar to those of the structure of Figs. 5 and` 6. The structure of Figs. l0, ll, 12 differs from the structure of Figs. 8 and 9 in that energy is transferred from the principal waveguide system to one and only one of the output waveguides. The principal waveguide system consists of a waveguide section 411 formed into arcuate shape about a central axis. Waveguide section 411 comprises an annular member 418 and an annular channel member,419. Flanges of annuiarchannel member i519 are joined as by bolting or welding to annular member 418 to form waveguide section 411. A pluralityy of

secondary waveguide sections

413, 415, and 417 are rigidly positioned and tixed to waveguide section 411.

Secondary waveguide sections

413, 415, and 417 comprise separate portions of an arcuate waveguide section formed by an annular member 420 and an annular channel member 421. Outwardly projecting flanges on

annular members

418 and 420 are joined together to form a rigid structure, whereby plane surfaces 425, 427 of

respective channel members

419, 421 are disposed adjacent, but not in contact with each other.

Electromagnetic energy is coupled into waveguide sec tion 411 by means of an input waveguide section 423 which projects into an opening in the wall of each of

members

418, 419 of waveguide section 411. Energy coupled into waveguide section 423 travels counter-clockwise in waveguide section 411 as viewed in Fig. 1l. The extreme counter-clockwise end of waveguide section 411 is terminated in a non-reilective dissipative termination 424. Electromagnetic energy is received from

secondary waveguide sections

413, 415, 417 by means of respective

output waveguide sections

426, 428 and 430. Each of

sections

426, 428, 430 is coupled to its corresponding secondary waveguide section through openings in the walls of

members

420, 421. The extreme clockwise end of each of

secondary waveguide sections

413, 415, and 417 of Fig. 11 is terminated with respective non-reflective

dissipative terminations

431, 432, and 433.

Arcuate openings

435, 437, 439 are provided through the plane surface 425 of waveguide section 411 and the :adjacent plane surface 427 of

secondary waveguide sections

413, 415, 417 for permitting energy transfer from waveguide section 411 to any one

of'waveguide sections

413, 415, and 417.

Openings

435, 437, and 439 are of equalarcuate extent. The arcuate spacing between these openings should be at least as great as the arcuate.

extent of said openings. This is necessary in order that energy be communicated from waveguide section 411 to only one of

secondary waveguide sections

413, 415, and 417.

A shutter 441 is supported for rotation between adjacent surfaces 425, 427 n milled slots in the abutting anges,

of

annularmernbers

418 and 420. Shutter 441 is provided with an opening 442, the arcuate extent of opening 442 being equal to the length of an opening necessary to provide 100% energy transfer between waveguide section 41,1 and one of

sections

413, 415 and 417.' In Fig. 11 shutter opening 442 is shown in registration with opening 437. Electromagnetic energy is transferred from waveguide section 411 to one of

waveguide sections

413, 415, and 417 when opening 442 registers with the corre- When no portion of opening 442 is opposite openings V435, 437 or 439, all of the energy supplied section 411 from input section 423 is transferred to termination 424 where it is dissipated. In this manner, energy is delivered to only one of

output waveguide sections

426, 428, and 430,k or is delivered to termination 424. In no instance is the energy delivered simultaneously to two output waveguide sections. A

`generator delivering energy to input waveguide section 423 'always feeds almatched load, either a load at the end of one of the

output waveguide sections

426, 428, 430 or termination 424. Consequently, there are no switching transients or reflections introduced in the sys-Y tem.

`Serrated chokes, such as chokes 444 and'445 are providedforaording the equivalent of electrical contact between shutter 441 and the adjacent walls of the upper and lower waveguide sections to preventv escape of energy between the shutter and the waveguide sections and to prevent coupling between the waveguide sections other than lthrough shutter opening 442.

' The length of the

openings

43S, 437, and 439 may be made longer, and correspondingly opening 442, by the employment of inductance cross-bars 447 disposed along openingv 442. An indicator 448 may be employed to show the'position of the shutter opening. Holes 449 may be utilized in cooperation with a cog wheel, not shown, for moving the shutter opening 442 from registration with one of

openings

435, 437, and 439 to registration with another of said openings.

While the arcuate extent of opening 442 should be that required to transfer 100% of the energy from waveguide section 411 to one of

secondary waveguide sections

413, 415 and 417, the arcuate extent of

openings

435, 437 and 439 may be equal to or greater than that of opening 442. However, the arcuate spacing between

openings

435, 437 and 439 should be equal to or greater than the arcuate extent 4of opening 442. This is necessary in order that energy be transferred to only one of the secondary waveguide sections. In order to provide the smallest possible structure, it is preferable that the length of

openings

435, 437 and 439 be made exactly equal to the arcuate length necessary for 100% coupling, and that the length of the arcuate spacing between these openings be made the same arcuate length.

As in all of the previous forms of the invention, the source and load connections may be readily interchanged.

Since 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:

1. Selective microwave power transfer apparatus comprising rst and second waveguides respectively including first and second substantially adjacent wall surfaces, wherein said first waveguide is formed as an arc about a predetermined axis to guide energy therein along a path corresponding to a portion of a circle, said first and second waveguides being rigidly fixed together and said first and second surfaces having longitudinally extensive registering openings therein through which the interior of said first and second waveguides are exposed to each other, said rst waveguide including at least one longitudinally extensive opening in said first surface in addition to the opening therein communicating with said second waveguide, and shutter means of conductive material movable substantially along said Walls for selectively blocking or unblocking the region of communication between said first and second waveguides for controlling the transfer of microwave power between said first and second waveguides, said shutter means comprising a rotatable shutter supported for rotation about said axis and having a conductive area interposable between said first and second waveguides according to the angular position of said rotatable shutter.

2. Selective microwave power transfer apparatus as defined in claim l, further including at least one further waveguide adjacent said additional opening in said rst surface of said first waveguide, and having a further opening therein in register with said additional opening in said first surface of said first waveguide, said shutter conductive area being selectively interposable between said first waveguide and said further waveguide.

3. A waveguide switching apparatus comprising a first waveguide section adapted for propagating electromagnetic waves along a first axis, said waveguide section v10 having at least one substantially plane wall parallel to said first axis, said plane wall having at least two -openings extending parallel to said first axis, wherein said first waveguide section is formed into arcuate shape about a second axis perpendicular to a plane including said plane wall; further waveguide sections each adapted for` propagating electromagnetic waves along further cor-k responding axes, each of said further waveguide sections having at least one substantially plane wall parallel to the corresponding axis thereof, the plane wall of each of said further waveguide sections having an opening 'ex-, tending parallel to the corresponding axis of said waveguide section, said further waveguide sections being rigidly fixed with respect to said first waveguide section, wherein the opening in the plane wall of each of said fur ier waveguide sections registers with an opening in the plane wall of said first waveguide section, and whereby said first waveguide section communicates with each of said further waveguide sections; and a substantially plane conductive shutter perpendicular to and adapted for rotation about said second axis, said shutter being further disposed from movement between the registered openings of said further waveguide sections and said rst waveguide section, whereby said shutter selectively blocks communication between said first waveguide section and said further waveguide sections.

4. A waveguide switching apparatus as in claim 3 wherein the plane wall of each of said further waveguide sections is disposed parallel to the plane wall of said first waveguide section and at least the portion of each of said further waveguide sections containing said opening is formed into arcuate shape about said second axis, the radius of curvature of said arcuate shape being equal to the radius of curvature of said first waveguide section.

5. A waveguide switching apparatus comprising a first waveguide section adapted for propagating electromagnetic waves along a first axis, said waveguide section having at least `one substantially plane wall parallel to said first axis, said plane wall having at least two openings of equal extent parallel to said first axis, wherein said first waveguide section is formed into arcuate shape about a second axis perpendicular to a plane including said plane wall; further waveguide sections each adapted for propagating electromagnetic waves along further corresponding axes, each of said further waveguide sections having at least one substantially plane wall parallel to the corresponding axis thereof, the plane wall of each of said further waveguide sections having an opening extending parallel to the corresponding axis of said waveguide section, the extent of the openings of said further waveguide sections being substantially equal to that of the openings of said first waveguide section, said further waveguide sections being rigidly fixed with respect to said first waveguide section, wherein the opening in the plane wall of each of said further waveguide sections registers with an opening in the plane wall of said first waveguide section, and whereby said first waveguide section communicates with each of said further waveguide sections; and a substantially plane conductive shutter disposed perpendicularly to and adapted for rotation about said second axis, said shutter having an opening of arcuate extent not greater than the arcuate spacing between said first waveguide openings, whereby said shutter selectively blocks communication between said frst waveguide section and said further waveguide sections.

6. A waveguide switching apparatus comprising a first waveguide section formed into arcuate shape about a predetermined axis to guide electromagnetic energy therein along a path corresponding to a portion of a circle, a plurality of arcuate openings in the wall of said waveguide section and spaced along said path, said path spacing being not less than a predetermined minimum value; a plurality of second waveguide sections, each of said second waveguide sections having an opening in the wall thereof of arcuate extent no less than said predetermined minimum value and being rigidly fixed with respect to said first waveguide section, wherein each of the openings in said second waveguide sections registers with an opening `of said first waveguide section; and a conductive shutter adapted for rotation about said axis and disposed for movement between the registering openings of said second waveguide sections and said rst waveguide section, said shutter `having an opening of arcuate extent equal to said predetermined minimum value of spacing, whereby said shutter selectively blocks communication between said rst waveguide section and said second waveguide sections, permitting communication from said first waveguide section to no more than one yof said second waveguide sections.

7. A waveguide switching apparatus comprising a first waveguide section formed into arcuate shape about a predetermined axis to guide electromagnetic energy therein along a path corresponding to a portion of a circle, a plurality of openings of equal arcuate extent uniformly spaced along said path, the arcuate spacing between said openings being equal to said arcuate extent; a plurality of second waveguide sections, each of said second waveguide sections having an opening in the wall thereof and being rigidly fixed with respect to said first waveguide section, wherein each of the openings in said second waveguide sections registers with an opening of said first waveguide section; and a conductive shutter adapted for rotation about said axis and disposed for movement between the registering openings of said further waveguide sections and said first waveguide section, said shutter having an opening of arcuate extent equal to that of said first waveguide openings, whereby said shutter selectively permits communication from said first waveguidesection to no more than one of said second waveguide sections.

f8. A waveguide switching apparatus as in claim 6 wherein said predetermined minimum value of arcuate extent is equal to the length of an opening necessary to transfer all of the electromagnetic energy from said iirst waveguide section to a second waveguide section.

9. A waveguide switching apparatus as in claim 6 wherein said rst waveguide section includes means to couple electromagnetic energy `into said section, said means being connected to said section at one extremity thereof, and wherein each of said second waveguide sections `includes means to couple electromagnetic energyvout of said second section, each ofsaid further output coupling means being connected to one of said second waveguide sections `at one extremity' thereof.

10. A `waveguide switching apparatus as in claim ,6 wherein each of said waveguide sections includes means connected at one extremity thereof for coupling electromagnetic energy to said section, and further in cludes a non-reective dissipative termination disposed in the other extremity of said waveguide section.

References Cited in the le of this patent UNITED STATES PATENTS 2,576,943 Jenks Dec. 4, Y1951A 2,735,069 Riblet Feb. 14, 1956 2,762,973 Kallmann Sept. 11, 1956