US2521818A - Wave guide coupling - Google Patents

Description

Sept. 12, 1950 w. A. ARON ETAL WAVE cum: COUPLING 2 Sheets-Sheet 1 Filed Feb 8, 1945 WAL rm A. ARON CHARLES H 0,4 m LOWELL M. HOLL/NGSWORTH INVENTORS BY WW Q z/fi wg Sept. 12, 1950 w. A. ARON EIAL WAVE GUIDE COUPLING 2 Sheets-Sheet 2 Filed Feb. 8, 1945 FIG. l

228, 23 24& 4

WALTER A. ARON 7 CHARLES H. DAVIS LOWELL HOLLINGSWORTH IN VEN TORS- ATTORNEY Patented Sept. 12, 1950 UNITED STATES PATENT OFFICE WAVE GUIDE COUPLING Application February 8, 1945, Serial No. 576,844

This invention relates to a transmission line for high frequency energy and more particularly to a transmission line having substantial rotational flexibility. The present line maybe twisted relative to its longitudinal axis within a wide range without introducing substantial transmission losses.

It has been proposed, in copending application of Joseph E. Coyle and Elmer L. Younker, Serial No. 534,324, filed May 5, 194.4, to provide a flexible length of line capable of being bent and also rotatable about its axis. The flexible length according to this copending application comprises a substantial number of relatively short wave guide sections, mounted in a flexible rubber tube in spaced relation to each other. Each section is in the form of a metallic disk having a central opening therein, corresponding to the dimensions of a rectangular or circular wave guide. An annular quarter wave channel constituting a high frequency choke is provided in one face of each wave guide section.

As in the prior device mentioned above, the present invention relies upon the fact that microwave energy may be transmitted from one section of a wave guide to another without substantial loss, providing some means are used between each section to prevent radiation. In the prior disclosure such a means takes the form of'a quarter-wave annular cavity with the space between spaced Wave guide sections providing the channel communicating with the wave guide apertures so as to act as a high frequency choke whereas in the present invention the wave guide sections are in abutting relation, with one face of each section undercut to provide the space communicating with the annular cavity. The prior device, however, is principally designed to permit bending of the line, while the present invention is concerned principally with oscillatory rotation of one length of a wave guide relative to a stationary length of wave guide about their common axis.

The principal object of the present invention is to provide a length of Wave guide type of transmission line which is capable of rotational oscillation within a, wide angular range wherein the standing wave ratio and losses will be maintained at a satisfactorily low level.

Anothe object of the invention is to provide a coupling structure or joint between two lengths of wave guide to permit one of the lengths to be rotated with respect to the other on an axis common to both lengths.

13 Claims. (Cl. 178-44) Still another object of the invention is to provide means for permitting rotation between two aligned wave guides wherein the means is adapted to provide a uniform twisting action to maintain the desired continuity of propagation or transmission of high frequency energy from one wave guide to the other.

Another object of the invention is to provide a length of wave guide transmission line or a coupling structure embodying a plurality of abutting sections, each being rotatable relative to its adjacent section in a progressively limited manner towards one end of the length of line or coupling. Any desired number of sections may be used, the number depending upon the degree of twist or rotation contemplated.

Other novel features and advantages of the invention will become apparent as the description proceeds.

In the drawings:

Fig. l is an elevational view of a wave guide transmission line coupling structure according to one embodiment of the invention;

Fig. 2 is a right end view of the coupling structure of Fig. 1;

r Fig. 3 is a longitudinal horizontal sectional view of said coupling structure, taken along the line 3-3 of said Fig. l, the elbows and some parts beyond them being omitted;

Fig. 4 is a transverse vertical sectional view of said coupling structure, taken along the line 4-4 of Fig. 3;

Fig. 5 is a longitudinal sectional view, similar to Fig. 3, of a modified form of one of the intermediate sections shown in Fig. 3;

Fig. 6 is a right end view of the intermediate section of Fig. 5;

Fig. 7 is an enlarged, slightly exaggerated top view, partly broken away, of the intermediate section of Fig. 5, with a pin and wire in place; and

Fig. 8 is a fragmentary sectional view taken along the line 8-8 of Fig. '7.

Referring now to Figs. 1-4, a length of standard rectangular type metallic wave guide it) is joined to another length of wave guide It by a coupling structure, joint or rotationally flexible wave guide length generally designated by H.

Coupling structure l2 as shown in Fig. 3 generally comprises an end section 13, an intermediate section a center section i5, another intermediate section I 6 and an end section l-I. It will be understood that any number of intermediate sections may be provided, preferably an equal number being positioned on each side of center section I5, depending upon the degree of oscillatory rotation desired.

Each of the aforesaid sections I3I| preferably is in the general form of a disk or oylindrical member of brass, aluminum or other suitable metallic substance. In a preferred embodiment (Figs. 1-4) the center section I5 is substantially one-half wavelength in axial length and the intermediate sections are approximately a quarter wavelength long. The sections are rotatable relative to each other and each section is provided with a rectangular central aperture I8 (Fig. 3) corresponding in size to the wave guide dimensions used. Coupling stru-ctiu'e I2 is so assembled that each of sec tions I3, I4, I5, I6 and I! abuts its adjacent section and all of the sections are in aligned relation so that the axes of the central apertures I8 are in substantial alignment.

Each of the aforesaid end and intermediate sections i3, I4, I6, I! is formed to provide a radio-frequency choke to prevent radiation, but in the preferred embodiment the center section I5 is not formed as a choke section. The choke comprises an annular channel or cavity I9 formed in one face of each section around aperture I8, this face being designated as the front face. In

4 general, the inner diameter of channel I9 is just sufiicient to exceed the diagonal dimension of aperture I8 as shown more clearly in Fig. 4. The radial width and axial depth of channel I9 must be of proper dimensions to provide the desired choke action. Such a channel is known as a quarter-wave choke, although in practice the depth of the cavity generally is somewhat less than a quarter wavelength. Proper dimensions for such a choke cavity are well-known in the art.

In order that channel l9 may function as a choke, it is necessary that there be communication between aperture or opening I8 and channel I9. Inasmuch as the sections are in abutting relation, with the front face of one section engaging the rear face of the adjacent section, resort is had to a channel 23 communicating with channel I9. undercutting the front face of each of sections I 3, I4, I6 and I! so that there is a disk-shaped space between the undercut portion of the front face of one section and the rear face of the adjacent section. This is more clearly shown in Fig. 5 with respect to an individual section, here shown as a modified form of the intermediate section I l. It will be understood that while the following description is directed to the intermediate section M, the structure and operation thereof applies also to the other sections except when specifically mentioned otherwise.

Disposed in the circumferential surface portion of section I4 is at least one circular recess or socket 2|, adapted to receive a pinmember 22a (see Figs. 3 and 4). In a preferred form two, recesses 2! are disposed diametrically opposite each other although it will be understood that any desired number of recesses 2I and pins 22a may be used desirably spaced equally about the circumference of the section. Pins 22a are herein shown as being generally cylindrical in shape with their axes colinear with the radii of section I4 and are free to rotate about their axes within recesses 2|. A neck portion 23a of each of pins 22a extends out of the recesses 2I. This neck portion 23a may be of the same diameter as that of the larger body portion 24a located within a recess 2|.

A diametrical bore 26 isdisposed through neck Channel 29 is formed by circularly over and slidably engage the top surface of each of pins 22a to prevent outward movement thereof, as hereinafter described.

Fig. 3 illustrates the joint or coupling structure I2, according to the preferred embodiment, in assembled position and shows the several sections I3, I4, I5, I6 and IT in aligned abutting relation. with bores 26 of pins 22 also in normally aligned relation. As the center section I5 is not usually provided with a choke channel, sections I 4 and I6 are in reverse relation with each other so that their front faces abut the smooth parallel faces of section I5.

As shown, terminal or end sections I3 and I! may be provided with slightly larger apertures I! for receiving in firmly fitting relation the ends of rectangular wave guides I0 and I I respectively, and which may be secured within apertures I8 in any suitable manner.

Sections I3 and II are also provided at their end portions with outstanding annular flanges 33. The diameter of flanges 33 is substantially equal to the diametrical distance between the outer or top surfaces of pins 22a. A hollow cylindrical sleeve 28 is mounted on flanges 33 to surround the several sections I3-I1 of the joint or coupling structure I2 for substantially the entire length thereof to provide a housing therefor. Sleeve 28 is adapted to slidably engage the tops of pins 22 on each of the sections [3, I4, I5, I6 and I1, thereby maintaining the same in position and serving to make the joint or coupling structure I2 substantially stable.

Mounted on the free end of section I3 is an annular end plate or looking ring 34, secured to section I3 by several screws 35. A rabbet 3B is provided in the peripheral portion of the face of plate 34 adjacent section I3 for engaging and receiving one end of sleeve 28, thus preventing longitudinal movement thereof relative to the individual sections. Sleeve 28 may be maintained in position at the opposite end of joint I2 by providing an outstanding flange 31 on the righthand end of flange 33 of section I1. Flange 31 and sleeve 28 may be secured in position by a nut 38 having an inwardly extending annular flange 33 overlapping a portion of the outside face of section I! and flange 37. Nut 38 is externally knurled and internally threaded to engage an externally threaded portion 59 at the end of sleeve 28. The nut 38 is so positioned longitudinally relative to the sleeve 28 that the end section I! is free to rotate relative to said nut and sleeve and that the several sections I1, I3, I5, I4 and I3 are free to rotate relative toeach' other. If desired, a lock ring 4| also may be provided for threaded engagement with sleeve 28.

We may consider the left-hand end of joint or coupling structure I2 as the stationary end as it is usually associated with a stationary wave guide I0 while the right-hand end may be assumed to be the oscillatory end as it is associated with wave guide I i. which is rotatable in an oscillatory manner, about its longitudinal axis.

As wave guide II oscillates about its longitudinalv axis, section H which is secured to wave uide [I rotates with it in the same direction and for the same degree of rotation. This movement carries each pin 22a of section I! in the same direction, and by pressure of said pins 22a. upon wires 2'! which are slidably engaged in the bores 26 of aligned pins 220. tends tocause wires 21 to bend. This tendency is somewhat offset due to the fact that pressure on wires 2i causes the aforesaid pins 22: to rotate about their axes within the recesses or sockets 2|. Continued twisting or rotation of wave guide II' increases the tendency of the wires .21 to bend. However, the wires 2.1 are preferably of sufficiently' strong material, such as music wire, to resist bending and consequently the wires serve as lever arms against the pins 220. in the next adjacent section I6. to. impart a rotational movement to section I6. Similar motion is imparted by rotation of section I6 to the next adjacent section I and successively to section I4 and similarly to any additional sections which may be included within the coupling structure i2. It will be noted that the rotation of each succeeding section lags that of the preceding section slightly, and that the degree of rotation of each succeeding. section is less than that of each preceding adjacent section.

It will therefore be. understood that the wires or rods 21 serve the dual purpose of imparting rotation to the succeeding sections and of limiting the degree of rotation between adjacent sections, It will also be noted that as rotation occurs the wires 21 have a tendency to slide in bores 28 of pins 2211, Or expressing it another way, the pins 22a. tend to slide longitudinally relative tothe wires 21 as they rotateupon their axes and as the pins of adjacent sections become angularly offset relative to each other in the direction of angular movement. In order to prevent disengagement of the wires 27 from pins 22a in end sections I3 and I1 and to insure the proper degree of rotation, wires 2'! are made sufiiciently long to extend beyond the pins 220 in sections I3 and IT. The wires 21 may also be provided with enlarged portions or knobs at their ends. Also, if desired, each Wire 27 may be soldered or other- Wisesecured or anchored within the bore 26 of one of the pins 22a, more desirably of the pin 22a associated with the center section it to insure that wire 21 will remain centered with respect to the coupling structure I2, and will not be displaced longitudinally in either direction.

It is apparent that with sections I3 and I1 firmly secured to wave guides I0 and I I, respectively, and with the four rotatable sections I4, I5, I6, and I"! arranged as shown in Fig. 1, rotation in one direction of wave guide II and thus of end section I I will result in a proportional relative rotation between adjacent sections. Furthermore, this proportionality of rotation between adjacent sections will maintain desired continuity of propagation or transmission of energy through the coupling structure or joint I2 and will result in a proportional rotation of the direction of polarization of the transmitted energy while maintaining the standing wave ratio and losses at a satisfactory low level.

It will, of course, be understood that the rotatable sections of the coupling structure or joint I-2- are adapted to. rotate in both clockwise and counterclockwise direction relative to thencrmal fat rest position as wave guide .I I is rotationauy oscillated relative to its longitudinal axis; also, that considerably prolonged and rapid oscillation is possible in the construction described without damage to the coupling structure or joint. I2 and without substantial transmission loss.

A modification of the present invention, directed particularly to the pins and means of retaining them, is shown in Figs. 5-8. As there shown each pin 22b is similar to the pins 22a (of Figs. 3 and 4) already described, except that, the neck portion 23b, of each pin 22b, extending beyond the section I3-I"I in which it is positioned, is of smaller diameter than that. of the larger body portion 24?), located within one of the recesses 2|, thereby defining an annular shoulder 25 (Fig. 8).

It is preferred to retain the pins 221) by mountingrelatively thin rings 36 of metal or other suitable rigid material upon the circumferential surface of the sections, section I4 being shown for purposes of illustration (Figs. 5-8) Ring 3d may be mounted on section I4 in any suitable manner, such as by screws 3 I, or by keying, welding, etc., and its outside circumferential surface should make a sliding fit Within the sleeve 28.

Substantially circular apertures 32 corresponding to the number of recesses 2|, are provided in ring 36 and extend through the radial width of ring 36 with the center of. apertures 32- lying on the radii of the individual section I13 through the centers of recesses 21. The axial dimension of ring is preferably less than the axial length of section I4 and less than the diametersof recesses 2| and of the body portions 24b of the pins 221). Thus, portions of ring. 30 adjacent apertures 32 will overlap shoulders 25 and hold pins 222) in place within recesses 2|. The diameter of apertures 32 is preferably less than the diameter of recesses 2 I, but larger than the axial length of ring 36; thus in effect, if section 24 isprovided with two recesses 2|, ring 36 is divided into two equal parts by two apertures 32, leaving diametrically opposite spaces between said two parts. The remaining arc-shaped walls at the opposing ends of the said two parts of ring 36, which define apertures 32, partially surround and embrace the extending neck portions 231) of pins 2217, thereby permitting pins 22b to rotatewithin apertures 32. The radial width of ring 36; is

;. preferably substantially equal to the length of neck portion 23b.

While preferred embodiments of the present invention have been illustrated and described, it will be understood these are capable of modification and improvement without departing from the spirit of the invention. Therefore it is not desired that the scope of the invention be limited.

to the precise details set forth.

Having thus described the invention what we claim as new and desire to secure by Letters Patent is:

1. A coupling structure for connecting a length. of stationary wave guide to a length of rotatable wave guide for transmission ofhigh-frequency energy comprising, in combination, a plurality of substantially disc-shaped sections in aligned abutting relation, said sections being rotatable relative toeach other in planes perpendicular to a common axis and having a plurality of equally spaced circular recesses disposed in the circumferential surface portions of each of said sections, said sections also having radio-fre-- quency choke cavities associated with Opposing faces thereof and aligned central apertures correspending to the dimensions of said wave guides,

Said stationary wave guide and said rotatable wave guide being connected to opposite end sec,- tions of said coupling structure in communica-, tion with said apertures in said end sections, a substantially cylindrical pin member disposed in each of said recesses in said sections with the axes of said pin members colinear with radii of said sections, said pin members being free to rotate about their axes within said recesses, a portion of each of said pin members extending radially beyond the circumference of saidsections and having a bore diametrically disposed therein, the axis of each such bore being normally parallel with the longitudinal axis of said structure, and a relatively flexible wire extending sub.- stantially the length of said abutting sections and being in slidable engagement through said bores in aligned pin members, said wire being adapted to impart limited rotational movement successively to said sections upon rotation in either direction of said oscillating wave guide, said pin members rotating within their associated recesses due to angular displacement of said wire and thereby reducing the tendency of said wire to bend.

2. A coupling structure as claimed in claim 1 wherein a hollow cylindrical sleeve is mounted in closely fitting relation around the sections and is adapted to slidably engage the top surfaces of the pin members, thereby holding said pin members in position in their recesses.

3. A coupling structure as claimed in claim 1 wherein the sections comprise two end sections respectively secured to the stationary wave guide and the rotatable waveguide, a center section having smooth parallel faces, the axial width between said parallel faces being half the wavelength of the transmitted energy, and at least one intermediate section between said center section and each of said end sections, the axial width of such intermediate section being a quarter of the wavelength of said energy.

4. A coupling structure as claimed in claim 1 wherein a substantially ring-shaped member is mounted on the circumferential surface of each of the sections, the axial width of said ringshaped member being less than the diameters of the recesses and of the pin members in each of said sections, said ring-shaped member having a plurality of circular openings extending through the radial dimension of said ring-shaped member with the axes of said openings coinciding with the axes of said pin members, the diameter of each of said openings being greater than the axial width of said ring-shaped member whereby said openings effectively divide said ring-shaped member into a plurality of spaced arcuate portions, the walls of said openings partially sur-- rounding reduced extending portions of said pin members and overlapping the portions of said pin members within said recesses, thereby maintaining said pin members in position.

- 5. A coupling structure for connecting a length of stationary wave guide to a length of rotatable wave guide adapted to transmit high frequency energy comprising, in combination, a plurality of relatively short substantially cylindrically shaped sections in aligned abutting relation, said sections being rotatable relative to each other in planes perpendicular to a common axis, said sections having radio frequency choke cavities associated with opposing faces thereof and aligned central apertures corresponding to the dimensions of said wave guides, said stationary wave guide and said rotatable wave guide being connected to opposite end sections of said coupling structure in communication with said apertures in said end sections, each of said sections having a plurality of angularly spaced recesses in the circumferential portion thereof, pin means loosely mounted in said recesses, and flexible means slidably engaging said pin means, said flexible means being adapted to impart limited rotation to said sections in either direction upon rota-- tional oscillation of said rotatable wave guide.

6. A coupling structure for connecting a length of stationary wave guide to a length of rotatable wave guide adapted to transmit high frequencyenergy comprising, in combination, a pluralityof relatively short substantially cylindricallyshaped sections in aligned abutting relation, said sections being rotatable relative to each other in planes perpendicular to a common axis, said sections having radio frequency choke cavities associated with opposing faces thereof and aligned central apertures corresponding to the dimensions of said wave guides, said stationary wave guide and said rotatable wave guide being con-- nected to opposite end sections of said coupling structure in communication with said apertures in said end sections, each of said sections having at least one recess in the circumferential portion thereof, said recesses in adjacent sections being in substantial alignment, rotatable means carried in each of said recesses and means connecting said rotatable means for imparting limited rotation to said sections in either direction upon rotational oscillation of said rotatable wave guide.

7. A joint for coupling two lengths of wave guide comprising, in combination, a plurality of abutting joint sections, means for transmitting energy through said joint sections, choke means associated with said transmitting means for preventing leakage of energy from said joint sec-' tions, and means slidably mounted relative to said sections for imparting and permitting progressively limited rotational oscillation to said sections relative to one end of said joint while maintaining continuity of energy transmission through said joint.

8. In a structure for coupling together two wave guides which have opposing extremities disposed in spaced coaxial relationship and relatively rotatable about said common axis, a plurality of coupling sections, said sections including two end sections respectively joined to and rotatable with the two extremities of said wave guides, and a plurality of intermediate sections disposed between said end sections, the consecu tive sections abutting each other, and each of said sections being provided with wave guidev means extending therethrough and coaxial with the common axis aforesaid; means to maintain said sections in their abutting relationship and to maintain the wave guide means thereof in their coaxial relationship and to allow said sections to rotate relative to each other about said common axis; and means joining consecutive sectionsand adapted to transmit angular displacements of the end sections relative to each other to the intermediate sections in progressively limited amounts so that the angular displacements between consecutive sections is relatively small.

9. In a coupling structure as defined in claim 8, wherein choke means are provided to substantially prevent losses of energy between successive sections.

length of a wave guide for interconnecting sections thereof, comprising a series of relatively rotatable individual members each having an opening generally corresponding in size and shape to the inside contour of the wave guide, a housing containing said members and means for effecting rotation of said members successively and progressively in the event of relative rotation of the interconnected wave guide sections, thus locating the openings in said members in different angular positions to produce the effect of a twisted guide.

11. A device adapted to be inserted in the length of a wave guide for interconnecting sections thereof, comprising a series of relatively rotatable individual members each having an opening generally corresponding in size and shape to the inside contour of the wave guide, a housing containing said members, and means interconnecting said members and capable of rotating the same successively and progressively in the event of relative rotation of the intercom nec'ted wave guide sections, thus locating the openings in said members in different angular positions to produce the effect of a twisted guide.

12. A device adapted, to be inserted between wave guide sections for interconnecting the same, comprising a series of plates maintained in faceto-face relationship and rotatable with respect to each other about a common axis, each of said plates having an opening generally corresponding in size and shape to the inside contour of said sections, each of said plates further having re-- cesses therein, and means including elements disposed in the recesses of said plates for effecting rotation of the plates successively and progressively in response to relative rotation of the interconnected wave guide sections.

13. In a device adapted to be inserted between wave guide sections for interconnecting the same, a series of abutting rigid apertured members arranged for relative rotation about a common axis and cooperatively forming a wave guide, and means interlinking said members and operable to effect relative rotation thereof, to produce a twisting of the wave guide formed by said members, in response to relative rotation of the interconnected wave guide sections.

WALTER A. ARON. CHARLES H. DAVIS. LOWELL M. HOLLINGSWORTH.

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

UNITED STATES PATENTS Zaleski D80. 23, 1947

Images