sept l0, 1946- w. w. Mur-:HER Erm. 2,407,318 HIGH FREQUENCY APPARATUS Filed June 1S, 1942 .i , H ` 37 6 l INVENTORS, i WALTER w. msm-:Rand JOHN D_MALLE'H'i Their ATTORNEY. 2,407,318 Patented Sept. l0, 1946 UNITED ySTATES PATENT OFFICE ` „07,318 HIGH-FREQUENCY APPARATUS Walter W. Michel', Mineola, and John D. Mallett. Garden City, N. Y., assignors to Sperry Gyro scope Company, Inc., Brooklyn, N. Y., a corpo ration of New York Application June 18, 1942, Serial No. 447,524 21 Claims. (Cl. 17E-44) l ` The present invention relates to the art in cluding ultra high frequency energy translating ' apparatus. In high frequency systems using frequencies 2 cular wave guide excited by electromagnetic waves of the TM type. Such transformers are bilateral in character; that is, energy may be conducted either from a circular to the rectangular guide, or vice versa. oi' the order or 10’l or 101° or higher cycles per Furthermore, highly eillcient low impedance second it is advantageous to use electromagnetic rotating Joints are provided for conducting high wave guides for the conduction of high frequency frequency energy from one member to a second energy. As is well known, such wave guides may member rotatable with respect thereto, without have many types of cross-section. However, the undesirable modulation oi' the energy passing rectangular type of wave guide has been i’ound to thereacross. be highly advantageous because in its lowest mode In this manner. the desirable characteristics of excitation, corresponding to the transverse elec of 'rE-excited rectangular guides may be used, tric or TE mode, high frequency energy is con where energy is to be conducted around corners, ducted along the wave guide with nxed and den nite orientation of the electric ileld vector, which 16 the wave converters of the present invention pro viding simple and eflicient means for transform is termed the polarization. Accordingly. the po ing such energy to TM mode energy in a cir larization is exactly determined and may be eas cular guide for use with the rotating joints of the `ily controlled, which is not the usual case with invention, whereby increased utility and versa either higher modes of excitation in rectangular tility of such wave guide devices may be ob~ wave guides or with other shapes oi' wave guides. tained. In addition, the rectangular wave guide is easily Accordingly, it is an object of the present in adapted for the conduction of high frequency en vention to provide improved rotating joints for ergy around corners, since sharp angular bends wave guides adapted for the emcient transmis may be formed in rectangular wave guides using proper designs which create little reflection o! 28 sion of high frequency radiant energy with low losses and substantially no modulation due to energy or mismatching in lmpedances, and which relative rotation of the two members of the Joint. do not distort the type of field produced within It is a further object of the present invention the wave guide. to provide improved high frequency translating However, in many applications of such wave guides it is necessary to conduct energy from a 30 devices for conducting high frequency radiant stationary member to a rotating member or vice versa, thus requiring the use of suitable rotat ing wave guide joints. For mechanical reasons these `ioints must be made with the use of cir ‘energy from a round wave guide to a rectangular wave guide, or vice versa, with higher eiliciency, simplicity and compactness. It is a further object o! the present invention cular cross-section wave guides. Furthermore, if 35 to provide improved wave guide apparatus for coupling circular-ly polarized waves with linearly such joints are combined with bends in the cir polarized waves. cular wave guide, undesirable modulations of the Other objects and advantages will become ap intensity of the energy at the frequency of ro parent from the speciñcation, taken in connec tation or harmonics thereof may be produced, as well as undesirable rotations of the directions of 40 tion with the accompanying drawing wherein the invention is embodied in concrete form. polarization with respect to the wave guide, ren Referring to the drawing, dering more diiiicult the problem of efdciently Fig. 1 shows one form of rectangular-to-round conducting energy down through the wave guide energy transformer, ln cooperation with one form and of controllably utilizing this energy. This is especially true where energy in the transverse 45 of rotating joint. Figs. 2 to 5 show modifications of the device of electric or 'I'E mode is transmitted through the Fig. l including modified transformation devices circular wave guide. Such modulation may be and modiñed rotating joints. minimized by use of TM or transverse magnetic Fig. 6 shows a cross-sectional view of a portion waves; The present invention is directed toward im 50 of Fis. 5. As described above, the desirability of round proved devices for overcoming these problems. wave guides energized by the TM type of wave This is done in the present instance by the use for use in rotating joints, and of rectangular wave of suitable "wave transformers" or "wave con guides energized by TE waves for use in corners verters” which couple a rectangular wave guide excited by TE electromagnetic waves with a cir- 55 and bends, necessitates the use of transformation 3 2,407,318 devices for converting from round to rectangular wave guides and simultaneously from TM to TE the snorting plug 8 is made adjustable as by threading it into the outer conductor of stub line waves. and vice versa. l. Any other type of adjustment may be pro One type of such converter is shown in Fig. vided. In addition, the antenna 6', equivalent in l. Here the energy flowing along rectangular function to antenna B, is made adjustable as by wave guide I excites an antenna member B po threading or sliding within a. bore I6 formed in sitioned transversely of wave guide I; that is. plug 8, to obtain maximum energy coupling be along the direction ot the electric vector of the tween rectangular wave guide I and circular wave field within wave guide I. Electromagnetic waves guide 2. are thereby induced in antenna B. 'I'hese waves 10 It has been found that more efficient transfor may be strengthened in intensity by suitably tun mation ci' energy may be obtained by forming ing the antenna 8, as by coupling thereto a stub antennna 6’ oi' larger diameter, since then a short-circuited transmission line ‘I whose short greater surface area is presented for the transmis circuiting plug 8 is positioned at a point to pro sion of the currents along antenna 6', resulting vide maximum amplitude o! induced voltage in 15 in lower losses. Also, the frequency character antenna l. Antenna 8 may also be electrically istics of the system are thereby improved, mak spaced from the end l of wave guide I by sub ing the system eiiiciently responsive to a wider stantially an odd multiple òf a quarter wave range of frequencies. However, it is also desir length of the operating frequency, measured in able to maintain opening Il as small as possible. side the wave guide, to improve the eihciency 20 to prevent excitation of round wave guide 2 by TE oi' transformation. However, this is not entirely waves, caused by the difference in potential which necessary if the antenna i is properly designed. necessarily exists across opening 9 by virtue of Antenna 6 extends through a, suitable open the fact that the potential in the rectangular ing 8 in the wall of guide I and enters the circu guide I must decrease to zero at the closed short lar wave guide 2. being disposed axially and con 25 circuited end 5 of the section. centrically thereof. The presence of the induced Accordingly, antenna B' is formed with two en electromagnetic waves on antenna B thereby gen larged sections I1 and I8 joined by a smaller sec erates corresponding waves in wave guide 2. By tion I9 which passes through opening 9, section virtue of the axial position of antenna 6, the I8 again being approximately a half wave length waves induced in circular wave guide 2 will be of 30 long electrically. the required TM type, which will then be suitably This modiñcation of energy converter is much projected down the length of the wave guide 2. more flexible in operation since both the tuning The length of antenna 3 projecting into wave of the antenna 6', as by means of plug 8. and the guide 2 is preferably electrically equivalent to coupling between the two wave guides 2 and l, substantially a half wave length of the operating 35 as by adjustment within bore I6, may be inde frequency. It is to be understood th'at this device will also operate in the inverse manner to convert a TM wave in guide 2 to a TE wave in guide I. Fig. 1 also shows a suitable rotating joint 3 for coupling a stationary circular wave guide 2 to a rotating circular wave guide l. It will be clear that wave guide l may be made stationary, and wave guide 2 rotating, this being merely an in version of the functions of two elements without 45 changing their inter-relationship. Wave guide 4 is made of the same size and wall thickness as wave guide 2 and is placed as closely as possible to the end of wave guide 2 but not in contact therewith. A flange Il is formed at the end of wave guide l to which is connected a concentric sleeve I2 ci suitable length termi hating at a further flange I3 connected to sleeve I2 but insulated from wave guide 2 by a. very narrow gap Il. The length of sleeve I2 and its inner diameter are so chosen, with respect to the operating fre quency and the outer diameter of wave guide 2, as to present a very low impedance when Viewed pendently adjusted. Fig. 2 also shows another type of rotating joint. Here fiange II’ is shown formed on stationary wave guide 2, although it is clear that it could be formed on rotating wave guide «I in the same manner shown in Fig. 1. Sleeve I2' is formed similar to sleeve I2 of Fig. 1, but flange I3', in stead of simply having its free end closely spaced from Wave guide 2, as in Fig. l, now has its free end turned under to form a further sleeve 2I coaxial with wave guide 4 but not in contact therewith. Wave guide 4 and sleeve 2| form a low im pedance concentric transmission line section which serves to reflect or transform the value of the impedance existing at one end 22 thereof to a different value as seen at the other end, herein designated as 2li. The value of the impedance at end 22, in general, corresponds to the radia tion Limpedance which, in turn, may be influenced by diverse factors, the effect of which is not readily ascertainable. It is desired, however, that the impedance at joint 3 be of a. very low value and substantially independent of any non from the joint 3. whereby joint 3 offers very little ascertainable, unknown. or variable impedance attenuation tc the waves being transmitted along 60 values such as may, from time to time, exist at wave guides 2 and l, and a minimum amount of end 22. This desideratum is accomplished by energy is radiated from gap Il. Effectively the means herein provided as will presently ap flange I3 forms a short circuit for the concentric transmission line formed by wave guide 2 and sleeve I2. Hence preferably sleeve I2 should be electrically one-halt wavelength long, whereby its impedance in parallel with the impedance of gap I l will appear as a low impedance at joint 3. pear. The impedance value existing at end 22, when transformed by means of the transmission line section I, 2i, is effectively in series with the im pedance value presented at the open end of the short-circuited concentric transmission line sec It will be clear that flange II, sleeve I2 and 70 tion formed by sleeve 2I and sleeve I2’. If, as flange I3 may be formed on wave guide 2 instead herein, the length of section 2|, I2' is selected to of wave guide 4 as shown, if desired. be of electrical length substantially equal to one Fig. 2 shows an improved form of rectangular quarter wave length, the impedance seen at its to-round or round-to-rectangular wave guide opening 20 is of a very high, theoretically infinite, converting device. In this case, the position of 75 value. 'I‘hus it will be seen that the total im 9,407,318 5 pedance at end 20, comprising the series connec tion of this theoretically inhalte impedance and the unknown transformed impedance, will be very high. The further section of transmission line comprising wave guide I and sleeve l2’ is also pedance. This process is repeated as many times as is desired or is necessary, until at Joint 3 there is obtained a very low impedance which assures efñcient transmission and small energy loss of the TM energy across rotating Joint 3. This device also provides a broad frequency response adjusted or selected so that the impedance exist for the joint. which is quite desirable, the fre ing at end 20 will be reflected at joint 3 as a very quency response becoming more improved with low impedance, that is, effectively this transmis increase in the number of stages used. sion line section is also a quarter wave section. Fig. 4 shows a rotating joint similar in prin It will be clear, however, because of the shape of l0 ciple to that of Fig. 3. Here a plurality of sleeves this transmission line section that the physical 28, 28’. 2B" are attached to one of the relatively length will be less than one-quarter wavelength. movable wave guides, such as 2, by respective In this way the transformed or reflected im rings 29, 29', 29". A sleeve $0 is connected to pedance at joint 3 will have a very low value upon which the unknown impedance of end 22 15 the other wave guide l and cooperates with sleeves 28, 2B’ and 28", and wave guide 2 in a will have substantially no effect. It is thus as manner similar to that of Fig. 3. Thus, the un sured that the rotating joint lwill present a known impedance at end 3| is transformed by line very low impedance to the transmission of high 30, 28 to end 32 where it is connected in series frequency energy therethrough, which impedance with the high impedance of short-circulted quar will be substantially independent of any un ter wave line 28, 2. The resulting high series known factors existing outside the wave guide. impedance is transformed to a low impedance at Hence, efficient transmission of high frequency end 3|' by quarter-wave line 36, 2, where it is energy across the joint is produced. again transformed to a high impedance at end Fig. 3 shows a further modification of energy converter and rotating joint. Here antenna B" 25 32' by quarter-wave line 30, 28'. At 32’ this high transformed impedance is connected in is made doubly adjustable as in Fig. 2, but instead series with the high impedance of short-circuited of having enlarged rounded portions, it has been quarter-wave line 28', 2, and the resultant is found satisfactory to use cylindrical portions again transformed by quarter-wave line 30, 2 to i1" and IB” having beveled or chamfered ends such as 24, 25, and 26, 21. This yields the fur 30 a low impedance at end 3|". This process may be repeated as many times as desired, deriving a ther advantage of ease of construction while re still lower impedance at each stage, until a suit taining all the electromagnetic advantages of able low impedance is obtained for joint 3. It the device of Fig. 2. will be clear that the present device need not be With the construction of Fig. 3 it has been restricted to three stages, as shown, but may use found that the length of section i8" of antenna 8” may be made substantially non-critical by any desirable number. proper choice of the diameter of section I8" relative to the inner diameter of guide 2, and by proper choice of the chamfer angle. Thus, It is to be noted that the use of more stages, of antenna diameter to inner diameter of wave device for suppressing TE waves in the round guide 2. For this purpose, use is made of the property that TE waves may be propagated in both in Fig. 3 and Fig. 4, and also in Fig. 5 to be described, improves the frequency character as is well-known, a wave guide may be con 40 istics of the joint, and permits its emcient use with more widely varying frequencies as the num sidered to have a characteristic impedance, which ber of stages is increased. is defined as the ratio of the electric to magnetic Fig. 4 also shows another form of wave trans energies in the wave guide. By matching the former for converting TE waves in a rectangular characteristic impedance of the concentric line formed by section IB" and wave guide 2 to the 45 wave guide into TM waves in a round guide. In the present instance no antenna member is used, characteristic impedance of wave guide 2 (or and the production of only TM waves for the 4), and by making the bevel angle of beveled round guide is assured by the use of a filter-type section 24 in the neighborhood of 50° for a ratio guide 2 in the neighborhood of 0.42, it has been found that eñicient excitation of wave guide 2 from antenna 6" may be effected, without re gard to the length of section IB". Fig. 3 also shows a further rotating joint which, in eiïect, exemplifies an extension of the prin ciples of the device of Fig. 2. Thus, the type of impedance matching disclosed in Fig. 2. which 4assures a low impedance at joint 3, is repeated smaller round guides than those in which TM waves may be propagated; that‘is. the 'I'E mode is the lowest mode for round wave guides. Thus, referring to Fig. 4, the rectangular wave guide i is terminated by an adjustable plunger 5' which assures a high wave intensity at the center of the round wave guide 2. Opposite the round wave guide 2 is placed the stub line 1' in number, although it will be clear that any 60 for providing high intensity for the axial TM wave transmission along wave guide 2. Slid desirable number of such stages could be used. ably mounted within stud sleeve 'l' is a thick In the ñrst stage. the impedance existing at end sleeve 3l whose inner diameter is chosen to have 22" due, for example, to radiation of energy and a value at which 'I'M waves cannot occur; that the effect of surrounding objects, is transformed is. the diameter is so chosen that TM waves can by low impedance concentric line 2|", l to end not excite this section of wave guide. Hence 2li", where it is placed in series with the very in several stages, shown in this case as three high impedance of short-circuited quarter-wave concentric line section 2|", I 2’. The resulting high impedance is transformed by quarter-wave all TM wave energy will be reflected from the face 3B of sleeve 3l, which is thereupon adjusted to the position for which high intensity TM line I2', 4 to end 22', where it appears as a very 70 energy will be propagated along guide 2. However, the TE energy still may exist within low impedance. This low'r impedance is trans sleeve 3|, and is therefore conducted down sleeve formed by quarter-wave line 2|', 4 to appear as 24 until reflected by adjustable plug 35, slid a high impedance at end 2li" in series with the very high impedance of short-circuited quarter wave line 2|', i2', to form a still higher im ably mounted therein. Plug 35 is positioned to a position at which the reflected energy substan 7 2,407,31s tially neutralizes any TE energy at the propa gating end of wave guide 2, and hence elîectively in conjunction with rotating joints such as of the type shown in Figs. 1 to 5. suppresses any transmission of TE energy while not affecting the transmission of TM energy, as is desired. It will be clear that this same wave trans former may be used in reverse to convert a cir cularly polarized wave into a TE wave in a rec Fig. 5 shows a further modification of rotating joint. Here in place of the sleeves 28, 28', 28" and rings 29, 23', 23" there are used the solid rings 33, 33’, 33" which cooperate with sleeve 23, similar to that in Fig. 4. These rings 33, 33', 33" are substantially one-quarter wave long, and are severally spaced substantially one-quarter wave length apart. The structure shown in Fig. 5 will tangular wave guide. Preferably this is done in the device of Fig, 5 after the energy is trans ferred across the rotating joint in order that this energy may be conveniently and usefully con ducted to further portions of the circuit without rotational modulation, as discussed above. It will be noted that with such circularly p0 larized waves the diameter of a circular wave be seen to be similar to the ñlter structure dis guide such as 4 may be chosen smaller than the closed in copending Hansen application Serial 15 corresponding value in the preceding figures since No. 417,229, ñled October 31, 1941, to which ref erence is made for an explanation of the theory of operation. In eiïect, the external impedance at end 3| is connected in cascade with a high impedance comprising a filter arrangement 33, 33', 33" and 23, and the resulting high impedance is effectively transformed into a very low series impedance at joint 3. Figs. 5 and 6 also show another type of wave transformer. Thus rectangular wave guide I joins the circular wave guide 4 at right angles. At the junction of these wave guides, and posi tioned obliquely with respect to each of them, is a grid 31 of parallel conductive wires 3B. The orientation of the wires 38 of the grid 31 is pref erably at a 45° angle to the direction of the elec tric vector of the energy in wave guide i, which normally for the lowest mode of ‘I'E energiza tion will be across the shortest dimension thereof as shown by vector 4|. A reñecting conducting plate 39. is positioned parallel to and behind grid 31 separated therefrom by substantially one eighth of the wave length of the electromagnetic energy. In operation, considering for the moment en ergy being transformed from wave guide I to wave guide 4 (although it itis be understood that the device ls fully bilateral) energy flowing along wave by 4| 42 of wires the Wave. although circularly polarized, remains essentially of the TE type, which is adapted to excite a smaller diameter circular wave guide than the TM mode wave used in the circular 20 wave guides of the preceding figures, Although the circular wave guide joints of Figs. 1 to 5 have been described with respect to relatively rotatable wave guide sections, it will be clear that they can be used equally well for rela 25 tively ?ixed wave guide portions which are not in mutual contact. Also, the rotating joints described above need not be restricted to circular wave guides, but may be used wherever high frequency energy is 30 to be conducted between relatively rotatable con ductors, such as in concentric lines or single tu bular lines. In addition, the wave transformers described above may be used to transfer energy between 35 rectangular wave guides and concentric lines, the antenna member 6 then being an extension of the concentric inner conductor of the line. As many changes could be made in the above construction and many apparently widely differ 40 ent 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 draw ings shall be interpreted as illustrative and not guide l having an electric vector as shown will impinge upon grid 31. The component 45 in a limiting sense. the electric vector 4| parallel to the grid What is claimed is: 33 will be reflected thereby, and projected 1. An energy coupling device between a rectan axially into circular wave guide 4, the grid wires gular wave guide and a circular wave guide, com 38 simply acting effectively as a plane mirror with prising an antenna member positioned trans respect to this component. With respect to the 50 versely of said rectangular guide and extending component 63 of the electric vector 4| perpen dicular to grid wires 38, substantially no reñec tion will take place, and the energy will pass coaxially of said circular wave guide, said an tenna member having an enlarged portion with in said rectangular wave guide and a further en through the grid 31. Thereafter this energy will larged portion within said circular wave guide, be reiiected from reñecting plate 39 and, again 55 said enlarged portions being separated by a nar passing through grid 31 with substantially no row connecting portion. hindrance. will be projected also into circular 2. An energy coupling device between a rec wave gui de 4. tangular wave guide and a circular wave guide, It will be noted that the second component of comprising a cylindrical rod antenna member the energy projected into wave guide 4 corre 60 positioned transversely of said rectangular guide sponding to vector 43 is delayed a. quarter wave and extending coaxially of said circular Wave guide and having an enlarged cylindrical portion length or 90 electrical degrees with respect to the within each of said wave guides, said enlarged first component reflected from grid 31. In addi portions being connected to said rod by beveled tion, this second component has a polarization portions having an angle of substantially 50°, the (or electric vector) perpendicular to that of the ratio of the outer diameter of said enlarged cy iirst component. Accordingly. as is well known, lindrical portion within circular wave guide to the net result in wave guide 4 will be a circularly the inner diameter of said circular wave guide polarized wave, that is, one in which the plane of being of the order of 0.4. polarization or the electric vector will be contin 70 3. An energy coupling device between two hol uously rotating at the operating frequency as the low high frequency energy conductors having energy is projected along the wave guide 4. dissimilar modes of propagation of high fre Since this circularly polarized energy is sub quency energy therethrough, comprising an an stantially independent of any rotation of wave tenna member positioned transversely of one of guide 4 about its axis, it may be usefully employed 75 said conductors and extending coaxially into the 2,467,318 other of said conductors, said antennarmember having enlarged portions respectivelyV within 10 said antenna member having an enlarged por tion within said rectangular wave guide and a further enlarged portion within said circular both of said conductors and separated by a nar wave guide, and further including means for row connecting portion therebetween. tuning said antenna member, said tuning means 4. An energy coupling device between two hol comprising an outer conductor, and a movable low conductors having dissimilar modes oi prop snorting plug inserted within said outer con agation. comprising an antenna member posi ductor and having a bore slidably accommodat tioned transversely of one of said conductors and ing said antenna member. whereby said an extending coaxially into the other of said con ductors. said antenna member having an en 10 tenna member is adjustable coupled to said cir cular wave guide. larged portion within each of said conductors, 12. A coupling device comprising a plurality said portions being separated by a narrow con of wave guides having dissimilar modes of propa necting portion therebetween. gation, a common apertured wall connecting said 5. An energy coupling device between two wave guides having dissimilar modes of propa 15 guides, and a metal antenna rod having spaced, sation, comprising an antenna member posi tioned transversely oir one of said wave guides radially expanded portions disposed respectively in each of said guides and on opposite sides of said common wall. and extending coaxially into the other of said 13. A plurality of contiguous hollow high fre wave guides, said antenna member having an enlarged portion within the drst of said wave 20 quency conductors having dissimilar modes of propagation, a common apertured wall connect guides and a further enlarged portion within the ing said conductors, and a metal antenna rod second of said wave guides, said enlarged por having spaced, radially expanded portions dis tions being separated by a narrow connecting posed respectively in each of said conductors and portion between both of said wave guides. on opposite sides of said common wall. 6. An energy coupling device as in claim 5, 14. A microwave device comprising a pair of wherein one oi' said wave guides is excited in hollow wave guides having dissimilar modes of the TE mode and the other of said guides in the propagation, said guides including a common wall TM mode. having an opening therethrough, an antenna ’7. An energy coupling device between a rec tangular wave guide and a circular wave guide 30 member having portions oi dissimilar diameters disposed within said guides, each of said dissimi comprising an antenna member positioned lar diameter portions being disposed within a re transversely of said rectangular guide and ex spective one of said Wave guides.. tending coaxially of said circular wave guide, 15. A coupling device comprising a plurality said antenna member having an enlarged portion of wave guides having dissimilar modes of propa Within said rectangular wave guide and a further gation, a. common apertured wall connecting said enlarged portion within said circular wave guide. guides, a metal antenna rod having spaced, ra 8. An energy coupling device for transferring dially expanded portions disposed respectively in high frequency energy between a rectangular each of said guides and on opposite sides of said TE-excited wave guide and a circular TNI-ex cited wave guide, comprising an antenna member 40 common wall, and means adjustably supporting said antenna rod within said guides. positioned transversely of said rectangular guide 16. A microwave device comprising a plurality and extending coaxially of said circular wave of contiguous hollow wave guides having dis guide, said antenna member having an enlarged similar modes of propagation, said guides hav~ portion within said rectangular wave guide and a further enlarged portion of a length oi' sub 45 ing an apertured common wall, a conductor an tenna rod having spaced, radially expanded por stantially one-half wavelength within said circu tions and positioned transversely of one of said lar wave guide. wave guides and extending through said aper 9. An energy coupling device for transferring high frequency energy between a rectangular tured wall into another oi' said wave guides hav TE-excited wave guide and a circular TM-ex 50 ing dissimilar propagation characteristics, said radially expanded sections being situated respec cited wave guide comprising an antenna member positioned transversely of said rectangular guide tively in each of said wave guides and on oppo and extending coaxially of said circular wave site sides of said common wall, and means for guide, said antenna member comprising a cylin adjusting said rod within said guides, compris drical rod having an enlarged cylindrical portion 55 ing means supporting said rod within said wave connected thereto by conical portions having an guides, and means for adjusting said rod Within apex angle of substantially 50° within each of said supporting means so as to provide substan said wave guides. . tial impedance match between said guides and 10. An energy coupling device between a rec said conductor rod. tangular wave guide and a circular wave guide 60 l'l. Yin energy coupling device between a iirst comprising an antenna member positioned wave guide and a circular wave guide having ldis transversely of said rectangular guide and ex similar modes of propagation, comprising a metal tending coaxially of said circular wave guide, said antenna rod positioned transversely of said ilrst antenna member having an enlarged portion guide and extending into .said circular wave within said rectangular wave guide and a further 65 guide, said rod having enlarged sections formed enlarged portion within said circular wave guide, thereon and integral therewith and placed in and further including means for tuning lsaid an each of said wave guides, said sections having tenna member, said antenna member being sild bevelled end portions and having a diameter ably accommodated and adjustable within said relative to the inner diameter oi' said circular tuning means. 70 guide providing a substantial impedance match 1l. An energy coupling device between a rec between said circular guide and said iirst guide. tangular wave guide and a circular wave guide comprising an antenna member positioned transversely of said rectangular guide and eil:-v 18. .A coupling device as defined in claim 12 wherein said radially expanded portions com prise enlarged rounded members connected t0 tending coaxially of said circular wave guide, 75 said antenna rod. 11 2,407,316 i9. Apparatus for transferring u1tra~high-frequency energy between two wave guides, com prising a ñrst conductor extending completely across one of said wave guides and into the other of said wave guides, a hollow tubular conductor concentrically surrounding said iìrst conductor between said wave guides and forming a concen tric transmission line section therewith, a second hollow conductor concentrically surrounding the 12 wave guide, said apparatus comprising a section of circular wave guide formed of two relatively rotatable portions fixed respectively to said con ductors, whereby said two conductors may be rotated relative to one another without interfer ing with the iiow of ultra-high-frequency energy therebetween, means for coupling said wave guide to one of said conductors in a manner to excite TM waves in said circular wave guide section, and portion of said first conductor projecting on the 1o means for coupling said circular wave guide sec other side of said nrst wave guide and forming a tion to the other of said conductors to transfer concentric transmission line section therewith. said TM energy to said other conductor, one‘of means for adjustably short-circuiting said first said_coupling means comprising an adjustable conductor and said second hollow conductor, and section of concentric transmission line having the means for adjusting the projection oi said ñrst 15 inner conductor thereof extending across said conductor within said other wave guide, whereby rectangular wave guide and coaxially within said ultra-high-frequency energy may be transferred circular wave guide section. between said wave guides substantially without 21. The apparatus defined in claim 20, further reflection or the creation of standing waves by including means for adjusting the amount of pro suitably adjusting said short-circuiting means 20 jection of said inner conductor within said cir and the amount of said projection. cular wave guide. 20. Apparatus for transferring ultra-high-fre quency energy between two ultra-high-frequency energy conductors of which one is a. rectangular WALTER W. MIEHER. JOHN D. MALLETT. Certificate of Correction Patent No. 2,407,318. September l0, i946. WALTER W. MIEHER ET AL. It is hereby certified that errors appear in the printed specification of the above numbered patent requirinîiäorrection as follows: Column l, line 40, for “directions” read direction; column 2, e 4, for “from a” read from the; column 6, line 62, for “stud” read stub; column 7 42, for “it it is" read 'it 'is to; column 10, line l0, for “adjustable” read adjustabiy;line 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 Oüce. Signed and sealed this 1st day of July, A. D. 1947. LESLIE FRAZER, First Assistant üommím'oner of Patents. 11 2,407,316 i9. Apparatus for transferring u1tra~high-frequency energy between two wave guides, com prising a ñrst conductor extending completely across one of said wave guides and into the other of said wave guides, a hollow tubular conductor concentrically surrounding said iìrst conductor between said wave guides and forming a concen tric transmission line section therewith, a second hollow conductor concentrically surrounding the 12 wave guide, said apparatus comprising a section of circular wave guide formed of two relatively rotatable portions fixed respectively to said con ductors, whereby said two conductors may be rotated relative to one another without interfer ing with the iiow of ultra-high-frequency energy therebetween, means for coupling said wave guide to one of said conductors in a manner to excite TM waves in said circular wave guide section, and portion of said first conductor projecting on the 1o means for coupling said circular wave guide sec other side of said nrst wave guide and forming a tion to the other of said conductors to transfer concentric transmission line section therewith. said TM energy to said other conductor, one‘of means for adjustably short-circuiting said first said_coupling means comprising an adjustable conductor and said second hollow conductor, and section of concentric transmission line having the means for adjusting the projection oi said ñrst 15 inner conductor thereof extending across said conductor within said other wave guide, whereby rectangular wave guide and coaxially within said ultra-high-frequency energy may be transferred circular wave guide section. between said wave guides substantially without 21. The apparatus defined in claim 20, further reflection or the creation of standing waves by including means for adjusting the amount of pro suitably adjusting said short-circuiting means 20 jection of said inner conductor within said cir and the amount of said projection. cular wave guide. 20. Apparatus for transferring ultra-high-fre quency energy between two ultra-high-frequency energy conductors of which one is a. rectangular WALTER W. MIEHER. JOHN D. MALLETT. Certificate of Correction Patent No. 2,407,318. September l0, i946. WALTER W. MIEHER ET AL. It is hereby certified that errors appear in the printed specification of the above numbered patent requirinîiäorrection as follows: Column l, line 40, for “directions” read direction; column 2, e 4, for “from a” read from the; column 6, line 62, for “stud” read stub; column 7 42, for “it it is" read 'it 'is to; column 10, line l0, for “adjustable” read adjustabiy;line 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 Oüce. Signed and sealed this 1st day of July, A. D. 1947. LESLIE FRAZER, First Assistant üommím'oner of Patents.