CA1225128A - Microwave waveguide switch assembly - Google Patents

Abstract

MICROWAVE WAVEGUIDE SWITCH ASSEMBLY

ABSTRACT

A microwave waveguide switch assembly comprises a stationary housing having four openings and a cylindrical chamber for housing a rotor which has a microwave switch section formed with two cylindrical axially spaced plates at ends of an integral bar to contain the microwave energy between the walls of the rotor and the chamber wall during transmission of microwave energy through selected passages in the housing. The plates and the bar along with the chamber wall provide an essentially sealed microwave passageway thus minimizing transmission losses and at the same time, preventing leakage of microwave energy between passageways.

Description

SLY
This invention chelates to the at of microwave wave guide switches, and more particularly concerns an improved motor driven microwave switch having reduced size and weight, but providing supecio~ performance and reliability than error microwave wave guide switches.
Typical wave guide switches have solid circular rotors with semi-circular internal passages for microwave transmission in 90 increments. This type of rotor construction contains the following disadvantages:
1) The size of the rotor it inherently of larger diameter, with a higher inertia which requires a larger housing and a larger motor to drive the rotor between positions. Move electrical energy will be needed and the speed of switching will be impacted. Weight and size are obviously effected by this larger rotor.

2) Typically, microwave energy is transmitted in hollow, rectangular metal conductors known as wave guides. Discontinuities in the walls such as air gaps or seams interrupt the flow of energy causing losses in energy and undesirable leakage. In the conventional solid circular rotor, microwave energy it transmitted from the stationary housing through a rectangular air gap into the rotor.
The energy exits the rotor through a second rectangular air gap into the housing. Energy losses and leakages occur within the air gaps.
According to the invention, a microwave wave guide switch is provided with a greatly simplified rotor which permits a much I, I
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~Z;~51Z8 smaller and lighter switch housing, having corner an side cutouts to further reduce the weight of the switch. Furthermore, in the invention a vertical wall within the rotor has been eliminated.
The energy is transmitted through the rotor which consists of three sides only, and the fourth wide is provided by the stationary housing chamber wall thereby eliminating the two vertical gaps typical of eke conventional rotor. Losses and leakages associated with these air gaps have been eliminated improving the performance of the switch. The small rotor provides a reduced path length also resulting in lets insertion losses.
Some prior art wave guide switches have had a rotor con6istinq of only the rectangular plate, but since the plate must rotate within the chamber, the air gaps at the top and bottom produce discontinuities in the vertical wall, resulting in losses and leakages of energy between passages.
This invention describes a wave guide switch which it suitable for all miccowave6 bands and whose design will provide superior transmisfiion properties over a limited band or the pull band ox microwave fcequencie6 at a substantial savings in weight, size, inherent heating, cost, drive-motor prime power. All of these improved properties ace vital for such applications as satellites where requirements or 50 or more motor driven wave guide switches per satellite are common. When the switch operates to transmit microwaves at right angles; microwave propagation within the switch is between the rotor and the walls of a chamber in the switch housing wherein the rotor rotates. In this version of the microwave switch, the rotor assumes either of two positions, OWE
apart to act like a I.'....

' l -`- : 128 YO-YO' ' : Doyle pole, double throw switch, or a single pole, dollble . throw switch. In another version the rotor as~emke~ either - . ox three potion to act as a triple throw . It is therefore a principal object of the present 5 : invention to optimize the switching and transmission porks mange of a microwave wavegui~ switch by means of a witch construction having reduced ire and weight and thereby rev squiring a smaller and lighter motor than prior art microwave . wave guide switches.
It is still another object of the present invention to provide a microwave switch of the type described wherein microwave propagation within the switch it between the switch rotor and the chamber walls in which the rotor rotates.
It is another object of the prevent invention to provide a microwave wived switch of the type dockyard having a lightweight small diameter rotor housed in a small lightweight housing requiring a small drive motor.
It it yet another object of the pronto invention to provide a microwave wave guide witch of the type described which ha a lightweight rotor which will witch fatter, it canter to fabricate and is more reliable.
These and other oh~ects and many of the attendant , advantages of this invention wow be readily appreciated as _ Jo Iota tame becomes better understood by reference Jo the follow-in detailed description when considered in connection with the accompanying drawings in which:
Fig 1 it a I de elevation Al view of a microwave with motor assembly embodying the invention, Fig 2 it an end elevation Al view taken along line I ox Pig 1, I

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-ire-; I I I it an end elevation Al view taken along line

3 3 ox Fig. 1, ¦ Fig 4 it a cross ~ctional view taken along line ¦ 4-4 of Fig. 1:
I Fix. 5 it longitudinal, central sectional view taken : I along line 5-5 of ~ig7 3:
Fig 6 it a reduced perspective view of the rotor of the assembly of Fig. 1-5:
¦ Fig 7 it a side ~levational view of the rotor, ¦ Fig 8 is a plan view of the rotorjt~ken lung line : I ¦ ~8-8 ox Fig. 7:
. I Fig 9 it a wide elevation Al view similar to Fig. 1 l ox another microwave switch-motor amiably embodying anywhere ¦ version ox Thea invention:
1 ¦ Fig. 10 and 11 are cross sectional vow taken along ¦ lye 10-L0 and ~1-11 of Fig. 9:
Fig 12 it an end elevation Al view taken along line 12 I of Fig 9.
Fig 13 is a reduced perspective view of the switch . 20 7.. ¦ -I lion of the rotor employed in the amiably of Fig. 9-12:
¦ Fig. 14 is a side elevation Al view of the rotor of Fog 13: and ¦ Fig. 15 it a plan view of the rotor taken along the ¦ line 15 15 of Fig. 14 I ¦ Referring now to the drawings wherein like reverence ¦ characters designate like or corresponding pats throughout ¦ there it illustrated in Fugue 1-5 a microwave switch-mot~r amiably generally de~ignatQd as reference numeral I and have ¦ it a housing 22 made of lightweight metal Suckle a aluminum it ,. A Jo .. ., ."~ f,: Swahili . wish Howe amok or 25 of ho switch assembly 20. The Hugo 22 has a generally rectangular end portion I which . Continue a witch portion 27 of a rotor 28 of the witch as-: symbol 20, as best shown it Figs. 6-8.
.; End portion 26 of the housing 22 has rectangular and ' ~oxn~r cutouts 30D and central corner cutouts it which reduce the wright of the assembly. The housing portion 26 ha four flat tides 34 each provided with a rectangular opening 38 aft . fording a direct passage fox microwave energy betweeJI the hollow interior of the housing 22 and one of your waveg~ides 40 .. .. . Sheehan in dotted liner in Fig. 1) attachable by Casey 42 engaged in strew holes 44 at corners of thy slat sides I ox the housing portion 26. The hollow housing portion I it formed , with a cylindrical inside chamber avowing a wall I at which . two rectangular openings 38 terminate. A flat end wall 48 of the housing portion 26 has a recessed circular portion I
which it formed with an arcuate 180 opening 50 communicating with the chamber 46. Threaded hole 52 in the wall 48 see Fog. 2) receive screws for mounting the assembly 20 on a suit-.- 20 able support 54 indicated by dotted lines in Fig. I A eon-trial opening 56 in the recessed wall portion 49 receives a cylindrical beaning 58 which journals a tub shaft 60 at the outer end of the rotor 28.
The witch portion 27 of the rotor I has a pair of US axially spaced cylindrical end plats 62, 64 fig. 7 & 8).
Between the end plates 62, 64 and integral therewith is a flat central bloc 66, wow ha opposite flat parallel sides or wall 680 The thlckn~s~ of the block 66 it equal to the circus-. I frontal spacing of the openings 38 at the chamk~r 46 to insure 1 that wall ox passages for microwaves between selected pair of .__ 2~i~2 I

the openings 38 via the chamber 46 register with the sides of the openings 38. All the openings 38 are of equal length and width.
The length of each wall 68 equals the length of each of the openings 38. The width of each wall 68 is equal to the diameter of each end plate 62, 64 which is precisely fitted to rotate inside the chamber walls 47. The diameter of the chamber 46 is thus substantially equal to that of the circular end plates 62, 64, and of the width of the walls 68 of the block 66. The cylindrical end plates 61, 64 and the block 66 provide continuity by eliminating gaps to reduce louses and prevent leakage of microwave energy beyond the end plates in the chamber 46 axially of the rotor 28 and the housing 22. The integral joining of the ends of the block 66 with the plates 62, 64, reduces losses and prevents leakage of microwave energy between passages in the chamber 46 separated by the block 66. Outer wall 74 of the block 66 as shown in Fig. 4 are convex to fit flush with the concave side walls of the chamber 46. Grooves 76 in opiate side of the block 66 serve for fine tuning ox the micro switch assembly 58 to past a prescribed broad band of microwave frequencies. The reduction of gap losses and prevention of microwave leakage by the plates 62, 64, and the block 66 insures that faithful propagation of microwave frequencies through the rotor will be maintained.
End plate 64 it formed with an axial projection 80 extending 90 circumferential and rotatable disposed in the semi-circular opening 50. Ends 82 of opening 50 in the recessed end wall portion 49 of the housing 22 serve a abutments or stop for the projection I to limit rotation of the rotor 28 to 90 in both clockwise and counterclockwise directions as viewed in Fig. 2.

So A sector motor Z5 may be employed to turn the rotor 28. This motor may be of conventional type such as described in US. Patent No. 3,970,980 attached by screws 101 to the cylindrical end portion 24 of the housing 22 is a circular plate 102 provided with an opening 104 in which is fitted an insulated plug 106. Circuit terminals 108 are fitted in the plug 106 wires 110 indicated by dotted lines in Fig. 5 are connectable to the terminals 108 from an external circuit which applies power to operate the motor 25.
Wire 112 inside the housing portion 24 are connected between the terminals 108 and a stationary armature 114 of the motor 25. The armature 11~ has inside and outside axial stationary shafts 116, 117. The inside shaft 116 extends through an opening in end wall 121 of a cup shaped motor housing 122 and contacts a belaboring 124 engaged in a souses in axial extension aye ox the plate 62.
The motor housing 122 it attached to the switch portion of the rotor 28 by screw 126 engaged in holes in the plate or wall extension aye. A ball bearing assembly 130 is disposed between the motor housing wall 122 and the plate 62. The outer bearing race 132 is held stationary at the inside wall of the chamber 46. The inner race is force fitted to the plate extension aye and rotate with the rotor 28. The outer mounting shaft 117 of the armature 114 is secured in a bore 134 by set screw 137. The bore 134 is formed in axial projection 136 of the stationary end plate 102 which is secured by screw 101 to an annular flange lg2 at the outer end of the cylindrical portion 24 of the housing 22.
Secured inside the cylindrical, cue shaped motor housing 122 are arcuate permanent magnets I which rotate with the rotor 28 around the stationary armature 114.
The assembly 20 operates as a double pole switch in the following manner. When the motor 25 it energized by current PAT 9861~1 'I

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of one polarity the rotor 28 Wright in one direction, for example, clockwise, to the position shown in Fig. 4. Here the arcuate rotor projection 80 will abut and rotation will be stopped by the right end 82 of the 180 arcuate opening 50 in the wall 48;
see Fig. 2. There will now be two passages P and P' through the microwave switch, between the switch portion 27 of the rotor 28 and the chamber wall 47 as indicated in Fig. 4. Passage P extends between the upper opening aye, the chamber wall 47 and the side opening 38b. Passage P' extends between the bottom opening 38C
and the side opening 38d. If the direction of current flow is reversed in the armature 114, the rotor 28 will turn counterclockwise as indicated by arrow in Fig. 4. This will reverse the passages so that microwave energy passes through one passage between the upper opening aye and the side opening 38d via the chamber wall 47, and through another passage between the bottom opening 38c and the side opening 38b via the chamber wall 47.
A triple position microwave switch motor assembly AYE is shown in Figs. 9-12. The assembly AYE is similar to the assembly 20 of Figs. 1-8 and corresponding parts are identically numbered.
A rotor aye shown in Figs. 10, 13, 14 and 15 has a pair of thin, narrow, flat, parallel plate portions aye. Inner adjacent sides 158 are spaced apart a distance equal to the width of each rectangular opening in the chamber 46. Outer tides of the plate portions aye are spaced apart a distance equal to the circumferential spacing of the opening 38~ in the chamber I
By this arrangement, it is insured that walls of all passages through the chamber I register with sides ox the openings 38 in the chamber 46 in the two extreme and central positions of the color in the housing. 90 axial, arcuats projection aye of a circular end wall aye moves in an arcuate 180 opening aye in an end wall aye of a housing aye.

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When the rotor Zoo is turned clockwise OWE to the right from the central the position shown in Figs. 10 and 12, the color aye will have a position similar to that shown in Fig. 4. Then the microwaves may flow in one passage between the openings aye' and 38b', and may flow in another passage between the openings 38c' and 38d~. When the rotor aye is turned counterclockwise 45 to the left from the central position shown in Fig. 10, the Roy aye will have a position rotated 90 from that shown in Fig. 4. Then microwaves may pass in one passage between the openings aye' and dunned may pass in another passage between the openings 38c' and 38b'. The sector motor in housing 12Z will reverse the position of the rotor in response to the polarity of current applied to the motor armature 114 as described above in connection with the assembly 20.
The structure of the housing aye is slightly modified from that of the housing 22 in the assembly 20. Here an end wall aye of a housing portion aye it seduced in mass by removing material between corners leaving four corner ear 166 which register with ears 168 provided on an end plate aye that carries the motor armature 114 as shown in Fig. 5. Screws 180 engages a shaft aye of the armature 114, see Fig. 9.
The switch potion aye of the housing aye is modified by removal of material at the corners of the housing aye to define four ears 170 which have holes aye to receive screws 172 for mounting the assembly on a support.
It will be clear from the above that assembly aye serves as a three position switch. There is a straight passage between the openings aye' and 38c' when the rotor is in the central position, shown in Fig. 10. When the rotor is turned ~5 in either direction the passages P and Pi in Fig. 4. The rotor turns a maximum of 90.

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L2~3 Longitudinal slots aye are also formed at ends of the wall edges and ace used for tuning the switch, and match-in impedances to connecting wave guides. They also reduce coupling between paths or passages through the switch.
My aforedescribed new and novel cotoc design is smaller in diameter, lighter in weight and a consequently enclosed in a smaller housing and is driven by a smaller drive motor which Lucas less power then prior art wave guide switches. Moreover, my new rotor is easier to fabricate (straight lines) and is more reliable and can handle microwave power energy more efficiently since self heating effects due to insertion loss are reduced.
That is the thermal expansion of my rotor, being smaller in diameter is less than one of a larger diameter: and therefore less prone to expand to where it seizes in the housing chamber. The rotor construction insures that these will be no gap losses ox undesired leakage of microwave energy out of the housing chamber axially beyond the cylindrical end plates, and no leakage of microwave enecqy between passages in the chamber separated by the block integral with the end plates.
It should be understood that the foregoing relates to only a limited number of pcefecred embodiments of the invention which have been by way of example only, and that it is intended to cover all changes and modifications of the examples of the invention herein chosen for the purpose of the disclosure which do not constitute departures from the spirit and score of the invention.

PAT 9~61-1 I. .
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Claims (4)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A microwave waveguide switch assembly operable in at least two positions, comprising:
a hollow housing having a cylindrical hollow chamber therein;
a rotor axially rotatable in said chamber;
said housing having four sides disposed at right angles to each other, with a rectangular opening in each of said sides communicating with said chamber for passing microwaves therethrough;
each of said openings having the same length and width and each of said openings being equally spaced circumferentially of said chamber;
said rotor having a pair of axially spaced cylindrical end plates integrally formed with a wall means thereinbetween extending axially of said chamber, said end plates extending perpendicular to the axis of rotation of said rotor to open two separate passages for passing microwaves through said housing between adjacent pairs of said openings, each of said separate passages being formed by said cylindrical end plates and said wall means of said rotor and by said walls of said chamber when said rotor is disposed in one of said two positions, and two other separate passages for passing microwaves through said housing between two other adjacent pairs of said openings each of said other separate passages being formed by said cylindrical end plates and said wall means of said rotor and said walls of said chamber when said rotor is disposed in the other one of said two positions; the diameters of said end plates and width of said wall means being substantially equal to the diameter of said chamber to prevent leakage of microwaves out of said chamber beyond said end plates axially of said housing and rotor, and to prevent leakage of microwaves between said passages in said housing in each of said positions of said rotor, and to provide a rotor path presenting less discontinuities to the propagation of microwaves.

2. An assembly as defined in claim 1, wherein said rotor has further wall means to form a further passage for passing microwaves through said chamber between a further pair of said openings when said rotor is disposed in a third position midway between said two positions.

3. An assembly as defined in claim 1, wherein said wall means of said rotor comprises two flat, parallel plate portions between said end plates and having inner adjacent sides spaced apart a distance substantially equal to the width of said openings so that walls of said passages in said chamber register with sides of said openings in said housing in each of said positions of said rotor in said housing.

4. An assembly as defined in claim 1, wherein said housing has an end wall formed with an arcuate 180° aperture; and an accurate projection on said rotor extending axially into said aperture and subtending 90° circumferentially of said rotor to limit said rotor to 90° rotation in said housing between said two positions.