US2887572A - Directional coupler switches - Google Patents

Description

T. S. SAAD DIRECTIONAL COUPLER SWITCHES May 19, 1959 2 She ets-Sheet 1 I Filed Aug. 26, 1955 9, /Nl/EN7'O/2 THEODORE 6. SAAD ATTORNEY 4 M M LA 5 n 9 r U I N A 2 A AUX/MIR) SWITCH RECEIVER 33 7 Ally/L IAPV TRANSMITTER Maj 19,1959

T. s. SAAD DIRECTIONAL COUPLER SWITCHES 2 Sheets-Sheet 2 Filed Aug. 26, 1955 ATTORNEY United States Patent DIRECTIONAL COUPLER SWITCHES Theodore S. Saad, West Roxbury, Mass., assignor to Raytheon Manufacturing Company, Waltham, Mass., a corporation of Delaware Application August 26, 1955, Serial No. 530,694

15 Claims. (Cl. 250-13) This invention relates to a switching device for selectively permitting or inhibiting electromagnetic energy interchange between two directional couplers or between any pair of three or more directional couplers.

Directional coupler devices are known which have two terminals at each end thereof and which are characterized in that energy supplied to the terminals at one end thereof divides in some ratio between two other terminals at the other end without appearing at the remaining terminal at said one end. Such a directional coupler, using rectangular wave guides, is illustrated and described in the United States Patent No. 2,709,241 of H. J. Riblet and is so constructed that energy divides equally between the two terminals at the end opposite the input end, and the energy so divided is 90 out of phase at the aforesaid two terminals. If two such directional couplers are connected in series, it may be shown that if energy is supplied to a terminal at one end of the first directional coupler, energy of substantially the same magnitude but displaced 90 from the input energy may be derived from one only of the terminals at the output end of the second directional coupler. One or more of such directional coupler assemblies may be employed to advantage in certain communication systems, such as a radar system comprising the usual transmitter, receiver and common antenna. For example, if energy from a transmitter is fed into one of the terminals of a first directional coupler and an antenna is connected to a terminal at the output end of a second directional coupler, the transmitted energy reaching the antenna would be radiated in the usual manner. Reflected wave energy reaching the antenna then returns by the same transmission path through the directional coupler assembly and is available at the input terminal to which the transmitter is connected. By means of a well-known T-R switch, this energy may be supplied to a receiver. In some instances, it is desirable to calibrate the receiver by means of an auxiliary source. lf the latter were connected to the proper input terminal of a third directional coupler connected in tandem with the first directional coupler, energy from this auxiliary source would be available at the terminal of the first directional coupler to which the transmitter and receiver are coupled.

In accordance with this invention, means are provided either for permitting energy to pass through two directional couplers, such as the first and second directional couplers just discussed, or to inihibit the transfer of energy therethrough. Furthermore, means are provided for selectively interconnecting any pair of three or more directional couplers, such as the first and second directional couplers, or the first and third directional couplers just discussed.

In order to transfer energy or block transmission of energy between one more pair of directional couplers, the directional couplers are combined with an electricallyconductive rotary switch member which contains a pair of tubular passages whose transverse dimensions corre- "ice spend to those of the wave guides of the directional couplers. When only two directional couplers are involved, the passages in the rotary switch member may be linear; if more than two directional couplers are spaced about the periphery of the rotary switch member, arcuate passages are necessary which terminate at spaced portions of the periphery of the rotary switch member corresponding to the position of the directional couplers to be interconnected. If the rotary switch member is rotated so that the termination of the passageway therein is aligned with the terminals of the directional couplers to be interconnected, a continuous wave transmission path is'pro vided through both directional couplers. If a solid por tion of the periphery of the rotary switch member is aligned with the directional coupler terminals, or if the opening in the periphery of the rotary switch member is sufliciently small so that the critical dimension of the passage is less than the cut-01f value for the frequency of operation concerned, energy transfer between the two directional couplers is inhibited. If more than twodirectional couplers are used, the rotary switch member may be rotated to a second position at which the passage therein is aligned with another pair of directional couplers and energy transfer through this second pair may be achieved. 1

The rotary switch member may take the form of a slotted tubular housing within which a rotor having a pair of contiguous wave guiding passages is coaxially and rotatably mounted. The various terminals of the d'irec tional couplers are then mounted on the outer periphery of the housing in alignment with the slots in the housing wall. It should be understood that any number of pairs of directional couplers may be interconnected by proper design of the rotary switch member.

To prevent leakages of electromagnetic wave energy in the gap between the rotor and the housing, a number of chokes equal to the number of slots in the housing wall are employed, each of which comprises one or more circular grooves in the periphery of the housing wallsubstantially surrounding the slots therein. The groove is a quarter wave length deep at the operating frequency of the device and is spaced approximately one-quarter wave length from the end of the slot.

Other objects and advantages of the invention may be more clearly understood by referring to the accompanying drawings wherein: 4

Fig, 1 illustrates a partially cut-away isometric view of a top-wall hybrid directional coupler used inthe invention;

Fig. 2 is a view of a first embodiment of a directional coupler switch according to the invention;

Fig. 3 is a view showing a typical microwave system using a second embodiment of a directional coupler switch according to the invention;

Figs. 4 and 5 are views showing the rotor assembly of a directional coupler switch;

Fig. 6 is a detailed view illustrating a typical radio frequency choke used in the rotor assembly housing of Fig. 5; r

Fig. 7 is a view showing a complete directional coupler switch assembly including a rotor assembly and three directional couplers; and I Fig. 8 is a fragmentaryview of a portion of the rotor assembly of Figs. ,4 and 5, showing rotor passages coupling two slots in the wall of the rotor housing.

Referring to the drawing, Fig. 1 illustrates a hybrid directional coupling device 10 "sometimes referred to as an H-plane or top-wall hybrid. This directional con pler is the subject of United States Patent No. 2,709,241 of H. J. Riblet. Briefly, this directional coupler 10 consists of a pair of wave guides 12 and ,llhaving a common wall 13 which forms a wide wall of both guides. Common wall 13 comprises a pair of rectangular slots centrally located along the longitudinal axis of wave guides 12 and 14 and whose longer dimensions are parallel to said longitudinal axis. The portion of common wall 13 lying between slots 15 acts like the central conductor of a coaxial line whose outer conductor is the sides of wave guides 12 and 14 adjacent the slotted section of common wall 13. Directional coupler 10 is characterized in that energy introduced into one end (input end) of one of the wave guides will divide equally between the two wave guides so that the energy available at the other end (output end) of the waveguides will be of equal magnitude. Moreover, the energy derived at the output end of one wave guide will be displaced 90 in phase with respect to the energy available at the outputend of the other wave guide. Theamount of energy returning to the input end of the other wave guide will be negligible. Directional couplervlll operates in identical fashion regardless of which end is the input end. If a directional coupler assembly consisting of two cascaded directional couplers of the type described in Fig. 1 is used and energy is supplied to the input end of one of the wave guides, energy derived at the output end of the directional coupler assembly, that is, at the output end of the second directional coupler, will be substantially equal in magnitude to the incident energy at the input end of the coupling assembly but shifted 90 in phase. Theoretically, no energy is derived-from the output end of the other wave guide of the second directional coupler.

In Fig. 2, a directional coupler switch assembly is disclosed which may be adapted either for transmitting energy from a first location to a second location or for impeding the fiow of energy between the two locations, depending upon the position of the rotary switching member. In Fig. 2, a pair of aligned directional couplers 10 and 10', which may be similar to that shown in Fig. 1, are combined with a rotary switch member 20, which is mounted for rotation about an axis perpendicular to the longitudinal axis of directional couplers 10 and 10'. Rotary switch member is a solid electrically-conductive member containing two wave-guiding passages 22 and 24 whose transverse dimensions correspond to those of wave guide directional couplers 10 and 10. If the switch member 20 is in the position shown in Fig. 2, energy supplied to one of the-directional couplers, such as coupler 10, will impinge upon the solid periphery of rotary switch 20; consequently,transmission of energy from directional coupler 10 to directional coupler 10' is prevented. When rotary switch member 20 is rotated so that the passages 22 and 24 are aligned, respectively, with the wave guides 12 and 12', and 14 and 14, energy fed into one end of wave guide 12 of directional coupler 10, after dividing equally in wave guides 12 and 14, will be transferred through passages 22 and 24 of rotary switch mernber 20 and will be available at the input end of both wave guides of directional coupler 10. The energy at the input end of both wave guides of directional coupler 10' again divides in the two wave guides 12' and 14' in such a manner that cancellations occur in wave guide 12', but energy of magnitude substantially equal to that of the input signal and 90 out of phase therewith will appear at the outputend of wave guide 14' of directional coupler It). The direction of ene y flow is indicated by the arrows in Fig. 2. It

should ,be understood, of course, that if energy is fed into waveguide .14 of directional coupler 10', an output may be obtained from wave guide 12 of directional coupler 10; that is to say, the direction of energy flow maybe opposite to'thatfindicated by arrows. Furthermore, if energy is fed into wave guide 14 of directional coupler 10, energy will be derived from wave guide 12' of directional coupler 10', and vice versa.

Fig. 3 illustrates a typical system utilizing a twoway directional coupler switch consisting of a first directional coupler 10 including wave guides 12 and 14, a second directional coupler 10' comprising wave guides 12 and 14', and a third directional coupler 10" including wave guides 12" and 14". Rotary switch 20 is similar to that shown in Fig. 2, except that the two slots are curved rather than linear in order to intGICOIlIlCClZ the angularly disposed directional coupler. A transmitter 26 supplies energy to wave guide 12 of directional coupler 10. If rotary switch 20 is in the position indicated by dotted lines in Fig. 3, a continuous transmission path is provided between directional couplers it) and 10'. The transmitted energy is divided equally between wave guides 12 and 14 of directional coupler 10, and, after passage through the second directional coupler ,10', energy will be available at the output end of wave guide 14' of directional coupler 10'. An antenna 27 is coupled to wave guide 14 for radiating this energy. Although, theoretically, there is no energy available at the output end of wave guide 12 of directional coupler 10' because of cancellation effects at that end, in practice, a small amount of energy may appear at the output end of this wave guide. In order to absorb any energy appearing in wave guide 12, an auxiliary load 28 is connected to the output end of wave guide 12'. Energy from a remote source, such as energy reflected from a distant object, is received by the same antenna 27 and enters wave guide 14 of directional coupler 10; this energy divides equally between wave guides 12' and 14 and, after passing through the waveguiding passages of rotary switch member 20, enters the ends of wave guides 12 and 14 of directional coupler 10 adjacent to rotary switch member 20 out of phase. Energy is available, theoretically, only at the other end of Wave guide 12, that is, the end remote from rotary switch member 20. A small amount of energy may, in practice, appear at the other end of wave guide 14; an auxiliary load 32 may be coupled to this wave guide to absorb this residual energy. The energy obtained from wave guide 12 is supplied to receive 30 by way of a conventional T-R switch 29.

In order to test the vreceiver ,for proper sensitivity when the transmitter is inactive, the noise source 31 may be coupled to wave guide 14" of directional coupler 10". If rotaryvswitch member 20 is moved 90 clockwise or 180 counter-clockwise from the position indicated by the dottedline in Fig. 3, the directional couplers 10 and 10" are interconnected. Energy from noise source 31 then passes through directional coupler 10", the passages of rotary switch 20, and directional couplerlfi, and is available at the end of wave guide 12 remote from rotary switch member 20 for supplying a test input to receiver 30. An auxiliary load 33 may be connected to the input end of wave guide 12" of directional coupler 10" to absorb any residual energy which may appear at this point. When rotary switch 20 is rotated to an intermediate position such that the slots 22 and 24 therein do not intercouple any of the directional couplers, energy from transmitter 26 fed into wave guide 12 will be reflected from the solid wall of the rotaryswitch member and will be absorbed by auxiliary load 32. This position is suitable While waiting for the system to warm up sufficiently.

Another form of directional coupler switch is shown in Figs. 4 to 8. As shown in Fig. 7, the directional coupler switch assembly includes a rotor 34 mounted within a cylindrical housing 38. Rotor 34 includes a pair of curved slots 35 which connect two regions of the rotors periphery which are displaced approximately apart.

he dir c on l up i h asse a so in de e housing 3%? which contains three projecting portions which may form an integral portion of the housing. Housing 38 includes three slots 40 which pass through the cylindrical wall 37 and projecting portions 39 and are spaced apart along the longitudinal axis of the housing the same amount as passages 35 in rotary 34. Slots 4.0 preferably are of the same transverse dimensions as passages tension, about to be described. The wave guide eatensions, which may he -integral with wave guides 12 and 14, etc, ofthe directional couplers 10, etc., or which maybe fixed thereto, as by brazing, diverge at one end in order to accommodate coupling flanges 44 attached to said one end. Eachof these flanges is mounted to the fiat face of a corresponding projecting portion 39 of housing 38, as by screws, not shown, which are inserted within aligned holes 45in flanges 44 and tapped holes 46 in the projectingportion 39. Wave guide 12 of directional coupler 10, into which energy is supplied, as well as wave guides 14' and 14" of directional couplers and 10'', are connectedto a waveguide coupling flange 47. Wave guide 14 of directional coupler 10 and wave guide 12' and 12" of directional couplers 10' and 10 terminate in a portion 64 closed at the end, and contain therein an energy-absorptive material. Portion 64 may be curved, as shown in Fig. 7, for convenience in mounting the fittings. Flanges .44 have a circular groove 48 in the side (not visible in Fig. 7-) coupled to housing 33. The circular groove is similar to that shown in flanges 47. These grooves and flanges 44 and 47 are approximately one-quarter Wave length deep at a distance of one-quarter wave length from the inner surface of the wave guide near the center of the broader wall of the wave guide where the electric field is greatest, and provide a well known choke joint for preventing radio frequency leakage between the housing 38 and thecorresponding directional couplers, in the case of flanges 44, and between the ,clirectional couplers and microwave transmission leads to various circuit elements, not shown, in the case of flanges 47.

Rotor 34, as shown in Fig. 4, is constructed in the form of a. solid cylinder which. contains a recessed portion 48 at each end into which a cup-shaped element 51 is .positioned. The flange portion 53 .of element 51 is attached, as by rivets, to cylinder 34. Element 51 has a centrally disposed flared portion 52 into which a shaft 54 is mounted. The other end of the rotor cylinder likewise may contain a cup-shaped element to which a shaft is attached. The shafts may be mounted within bearings, not

such as a reduction gear train. The spacing between rotor 34 and housing38 should be as small as possible in order to minimize radio frequency leakage between rotor passages and the directional coupler fittings.

In order to prevent radio frequency leakage in the air gap between-rotor 34 and theinner surface of housing 38, a radio frequency choke 56 is provided in the .vicinity of each slot .40 in housing 38, as shown in Figs. 5 and .6. These chokes comprise a pair of semicircular grooves 57 substantially surrounding each slot 40 and approximately one-quarter wave deep at the operating frequency of the device. These grooves are positioned an average distance of one-quarter wave length from the inner surface of the corresponding slot.

Referring.nowto Fig. .8, if rotordrum 3,4 is in the position indicated, a continuous arcuate transmission path is provided between two of the slots 40 in housing 38. At

the same time, the remaining slot 40 is closed ofiby rotor .drum34 and no energy can be coupled to a directional coupler surrounding this slot. For reasons of clarity, the projecting portions 39 hav e been eliminated in Fig. 8.

It should he understood that these projecting portions are for convenience in mounting and may be omitted if con; cave flanges are used whose curvature conforms to that of the housing. It will be apparent, particularly from inspectionof Figs. 2 and 8, that the openings in the two wave guides of each directional coupler are closed simultaneously. as the solid portion of the rotary switch member 20 of Fig. 2, or the rotor drum 34 of Fig. 8, begins to move past the wave guide openings. In this manner, equal reflections are set up in the directional coupler leading to the input source, thereby avoiding standing waves in this directional coupler which result from reflections of diiierent magnitude.

Eurthermore, the dimension of the wave guides is changed, a direction perpendicular to the voltage vector, that is, in the H-plane. The critical or cut-ofi dimension ilonger transverse dimension) of the wave guides is gradually decreased as the solid portion of the rotorsweeps past the wave guides of the directional couplers until eventually cut-off is reached andtransmission ceases. If the direction of closure were parallel to the longer transverse dimension of the wave guide, as in the case of a side-wall hybrid, instead of perpendicular thereto, the shorter transverse dimension of the wave guide would be gradually decreased as closure was effected, and gradually the distance between the metallic rotor and the wall of the wave guide would decrease. The increasing voltage gradient would eventually become so great as to cause arc-over between the opposed longer transverse walls of the wave guide formed by one long wall of the wave guide and the leading edge of the rotor. For this reason, therefore, the axis of rotation of the rotor should be disposed perpendicular to the longitudinal axis of each directional coupler so that closure in the H-plane maybe efiected.

This invention is not limited to the particular details of construction, materials and processes described, as many equivalents will suggest themselves to those skilled: in the art. For .example, the rotorl20 of Figs. 2 and 3 may be in the form of the rotor assembly shown in Figs. 4 to 7. It is accordingly desired that the appended claims be given a broad interpretation commensurate with the scope of the invention within the art.

What is claimed is:

1. In combination, at least two directional couplers each comprising two wave guides, an electrically-conductive rotor element positioned between said couplers and mounted for rotation about an axis perpendicular to the longitudinal axes of said couplers, said rotor element containing two contiguous wave guiding passages therein whose transverse dimensions and spacing therebetween are comparable with the transverse dimensions and spacing of the wave guides of said couplers, said rotor element presenting a continuous amplitude insensitive wave transmission path between two of said couplers when disposed in a first positionand impeding the transfer of energy between the same couplers when rotated to a second dimensions and spacingtherebetweenare comparable with the transverse dimensions and spacing of the wave guides of said couplers, said rotor element presenting a continuous amplitude insensitive wave transmission path between two of said couplersv/hen disposed in a firstposition and impeding the transfer of energy between the same couplers when rotated to a second position, said solid peripheral portion moving past said wave guides in ,a direction parallel to thecritical dimensionof said wave guides said second position is approached.

3. In combination, at least two directional couplers comprising first and second wave guides each capable of transmitting electromagnetic wave energy of any desired amplitude, an electrically-conductive element positioned between said couplers and mounted for rotation about an axis perpendicular to the longitudinal axes of said couplers, said element containing two contiguous wave guiding passages whose transverse dimensions and spacing therebetween are comparable with the transverse dimensions and spacing of the wave guides of said couplers, said element presenting a continuous amplitude insensitive wave transmission path between two of said directional couplers when disposed in a first position and impeding the transfer of energy between the same directional couplers when rotated to a second position.

4. In combination, at least two directional couplers comprising first and second wave guides each capable of transmitting electromagnetic wave energy of any desired amplitude and having a slotted common wide wall arranged normal to the electric vector of the wave energy within said guides, an electrically-conductive cylindrical element positioned between said couplers and mounted for rotation about an axis perpendicular to the longitudinal axes of said couplers, said cylindrical element containing two contiguous wave guiding passages whose transverse dimensions and spacing therebetween are comparable with the transverse dimensions and spacing of the wave guides of said couplers, said cylindrical element presenting a continuous amplitude insensitive wave transmission path between two of said directional couplers when disposed in a first position and impeding the transfer of energy between the same directional couplers when rotated to a second position.

5. In combination, at least two directional couplers comprising first and second wave guides each capable of transmitting electromagnetic wave energy of any desired amplitude, an electrically-conductive element positioned between said coupling devices and mounted for rotation about an axis perpendicular to the longitudinal axes of said directional couplers, said element containing two contiguous amplitude insensitive wave guiding passages whose transverse dimensions and spacing therebetween are comparable with the transverse dimensions and spacing of the wave guides of said directional couplers, the ends of said wave-guiding passages being in substantial alignment with said directional couplers when said conductive element is in said first position, the critical dimension of that position of the passages presented to the directional coupler being less than the cut-off dimension of the directional coupler wave guides when said conductive element is in said second position.

6. In combination, at least two directional couplers comprising first and second wave guides each capable of transmitting electromagnetic wave energy of any desired amplitude and having a slotted common wide wall arranged normal to the electric vector of the wave energy within said guides, an electrically-conductive cylindrical element positioned between said coupling devices and mounted for rotation about an axis perpendicular to the longitudinal axes of said directional couplers, said cylindrical element containing two contiguous amplitude insensitive wave guiding passages whose transverse dimensions and spacing therebetween are comparable with the transverse dimensions and spacing of the wave guides of said directional couplers, the ends of said wave-guiding passages being in substantial alignment with said directional couplers when said conductive element is in said first position, the longer transverse dimension of that position of the passages presented to the directional coupler being less than the cut-off dimension of the directional coupler wave guides when said conductive element is in said second position.

7. In combination, at least three directional couplers each comprising first and second wave guides capable of transmitting electromagnetic wave energy of any desired amplitude, a tubular cylindrical housing having a plurality of pairs of slots therein spaced about the periphery thereof and having transverse dimensions which conform with those of the wave guides, said wave guides of each directional coupler being attached to said housing in the region of a corresponding pair of slots, an electricallyconductive cylindrical rotor element mounted for rotation within said housing and containing two contiguous wave guiding passages whose transverse dimensions are comparable with those of the wave guides of said directional couplers, said rotor element being adjustable in position for selectively presenting a continuous amplitude insensitive wave transmission path between any selected pair of said directional couplers and impeding the transfer of energy between the other pairs of directional couplers.

8. In combination, at least three directional couplers each comprising first and second wave guides capable of transmitting electromagnetic wave energy of any desired amplitude and having a slotted common wide wall arranged normal to the electric field of the wave energy within said guides, a tubular cylindrical housing having a plurality of pairs of slots therein spaced about the periphery thereof and having transverse dimensions which conform with those of the wave guides, said wave guides of each directional coupler being attached to said housing in the region of a corresponding pair of slots, an electrically-conductive cylindrical rotor element mounted for rotation within said housing and containing two contiguous wave guiding passages whose transverse dimensions are comparable with those of the wave guides of said directional couplers, said rotor element being adjustable in position for selectively presenting a continuous amplitude insensitive wave transmission path between any selected pair of said directional couplers and impeding the transfer of energy between the other pairs of directional couplers.

9. In combination, at least three directional couplers comprising first and second wave guides each capable of transmitting electromagnetic wave energy of any desired amplitude, a tubular cylindrical housing having a plurality of pairs of slots therein spaced about the periphery thereof and having transverse dimensions which conform with those of the wave guide, said wave guides of each directional coupler being attached to said housing in the region of a corresponding pair of slots, a solid electrically-conductive cylindrical rotor element mounted for rotation within said housing and containing two contiguous wave guiding passages whose transverse dimensions are comparable with those of the wave guides of said directional couplers, said rotor element being adjustable in position for selectively presenting a continuous amplitude insensitive wave transmission path between any selected pair of said directional couplers and impeding the transfer of energy between the other pairs of directional couplers, means for preventing leakage of electromagnetic wave energy through the space between said rotor and said housing, said means including an arcuate groove disposed in the inner surface of said housing surrounding each slot in said housing, the depth of said groove and the spacing be tween groove and slot being substantially equal to a quarter wave length at the operating frequency of the device.

10. In combination, at least three directional couplers comprising first and second wave guides each capable of transmitting electromagnetic wave energy of any desired amplitude and having a slotted common wide wall arranged normal to the electric field of the wave energy within said guides, a tubular cylindrical housing having a plurality of pairs of slots therein spaced about the periphery thereof and having transverse dimensions which conform with those of the wave guides, said wave guides of each directional coupler being attached to said housing in the region of a corresponding pair of slots, a solid electrically-conductive cylindrical rotor element mounted for amen-era rotation within said housing --andcontaining two contiguous wave guiding passages whose transverse dimensions are comparable with those of-the wave guides of said directional couplers, said rotor element "being adjustable inwposition for selectively presenting a continuous amplitude insensitive wave transmissionpath between'any selected pair of said directional couplers and impeding the transfer of energy between the other pairs of directional couplers, means for preventing leakage of electromagnetic wave energy through the space between said rotor and said housing, said means including an arcuate groove disposed in the inner surface of said housing surrounding each slot in said housing, the depth of said groove and the spacing between groove and slot being substantially equal to a quarter wave length at the operating frequency of the device.

11. In combination, first, second and third directional couplers comprising two wave guides each capable of transmitting electromagnetic wave energy, a transmitter connected to one end of said first directional coupler, an antenna connected to one end of said second directional coupler, an auxiliary energy source connected to one end of said third directional coupler, an electrically-conductive element positioned adjacent the other ends of said directional couplers and mounted for rotation about an axis substantially transverse to the longitudinal axes of said directional couplers, said element containing two contiguous wave guiding passages whose transverse dimensions and spacing therebetween are comparable with the transverse dimensions and spacing of the wave guides of the directional couplers, said passages of said element interconnecting said first and second directional couplers for effecting radiation from said antenna of energy from said transmitter when said element is in a first position, a receiver connected to said one end of said first directional coupler, said passages interconnecting said first and third directional couplers for applying energy from said auxiliary source to said receiver when said element is in a second position, said element being disposed to transfer energy received by said antenna to said receiver while said element is in said first position.

12. In combination, first, second and third directional couplers comprising two wave guides each capable of transmitting electromagnetic wave energy and having a slotted common wide wall arranged normal to the electric field of the wave energy within said guides, a transmitter connected to one end of said first directional coupler, an antenna connected to one end of said second directional coupler, an auxiliary energy source connected to one end of said third directional coupler, an electricallyconductive cylindrical element positioned adjacent the other ends of said directional couplers and mounted for rotation about an axis substantially transverse to the longitudinal axes of said directional couplers, said cylindrical element containing two contiguous wave guiding passages Whose transverse dimensions and spacing therebetween are comparable with the transverse dimensions and spacing of the wave guides of the directional couplers, said passages of said cylindrical element interconnecting said first and second directional couplers for effecting radiation from said antenna of energy from said transmitter when said cylindrical element is in a first position, a receiver connected to said one end of said first directional coupler, said passages interconnecting said first and third directional couplers for applying energy from said auxiliary source to said receiver when said cylindrical element is in a second position, said cylindrical element being disposed to transfer energy received by said antenna to said receiver while said cylindrical element is in said first position.

13. In combination, first, second and third directional couplers comprising two wave guides each capable of transmitting electromagnetic wave energy and having a slotted common wide wall arranged normal to the electric field of the wave energy within said guides, a transmitter connected to one .end of said rfirst directional coupler, tan antennaconnected to one end of said second directional coupler, :aniauxiliary energy source connected to one end of said third directional coupler, :an electrical conductive cylindrical element positioned adjacent to .the other ends of said directional couplers and mounted for rotation about an axis substantially transverse to the longitudinal axes ofsaiddirectional couplers, said cylindrical element containing two contiguous-waveguiding passages whose transverse dimensions and spacing .therebetwcen are comparable with the transversedimensions and spacing of' the wave guides of the directional couplers, the ends of said wave guiding passages of said rotor element being in substantial alignment with said slots in said housing when said rotor element is in said first and second positions, and means for interposing said rotor element as a barrier across a portion of said slot to prevent energy flow between directional couplers when said rotor element is in some position intermediate the first and second positions.

14. In combination, first, second and third directional couplers comprising two wave guides each capable of transmitting electromagnetic wave energy and having a slotted common wide wall arranged normal to the electric field of the wave energy within said guides, a transmitter connected to one end of said first directional coupler, an antenna connected to one end of said second directional coupler, an auxiliary energy source connected to one end of said third directional coupler, a tubular cylindrical housing having a plurality of pairs of slots therein spaced about the periphery thereof and having transverse dimensions which conform with those of the wave guides, said wave guides of each directional coupler being attached to said housing in the region of a corresponding pair of slots, a solid electrically-conductive cylindrical rotor element mounted for rotation within said housing and containing two contiguous wave guiding passages whose transverse dimensions are comparable with those of the wave guides of said directional couplers, said passages of said rotor element interconnecting said first and second directional couplers for effecting radiation from said antenna of energy from said transmitter when said rotor element is in a first position, a receiver connected to said one end of said first directional coupler, said passages interconnecting said first and third directional couplers for supplying energy from said auxiliary source to said receiver when said cylindrical element is in a second position, said cylindrical element being disposed to transfer energy received by said antenna to said receiver while said cylindrical element is in said first position.

15. In combination, first, second and third directional couplers comprising two Wave guides each capable of transmitting electromagnetic wave energy and having a slotted common wide wall arranged normal to the electric field of the wave energy within said guides, a transmitter connected to one end of said first directional coupler, an antenna connected to one end of said second directional coupler, an auxiliary energy source connected to one end of said third directional coupler, a tubular cylindrical housing having a plurality of pairs of slots therein spaced about the periphery thereof and having transverse dimensions which conform with those of the wave guides, said wave guides of each directional coupler being attached to said housing in the region of a corresponding pair of slots, a solid electrically-conductive cylindrical rotor element mounted for rotation within said housing and containing two contiguous wave guiding passages whose transverse dimensions are comparable with those of the wave guides of said directional couplers, said passages of said rotor element interconnecting said first and second directional couplers for effecting radiation from said antenna of energy from said transmitter when said rotor element is in a first position, a receiver connected to said one end of said first directional coupler, said passages interconnecting said first and third directional couplers for supplying energy f I d auxiliary source to said receiver 11 when said cylindrical element is in a second position, said References Cited in the file of this patent cylindrical element being disposed to transfer energy received by said antenna to said receiver while said cylindri- UNITED STATES PATENTS cal element is in said first position, means for preventing 2,586,993 Riblet Feb. 26', 1952 leakage of electromagnetic wave energy through the space ,5 2,629,048 Dyke et al Feb. 17, 1953 between said rotor and said housing, said means including 2,679,631 Korman et a1 May 25, 1954 at least one arcuate groove disposed in the inner surface of said housing surrounding each slot in said housing, the FOREIGN PATENTS depth of said groove and the spacing between groove and 1,076,926 France Apr. 28, 1954 slot being substantially equal to a quarter wave length at 10 the operating frequency of the device.

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