GB2139010A - Microwave waveguide switch assembly - Google Patents

Abstract

A microwave waveguide 4-port, 2-way switch comprises a housing having four ports 38 and a cylindrical chamber for housing a rotor 27 having surfaces which, together with the internal surfaces of the chamber, provide coupling passages between selected adjacent pairs of ports. The rotor has a 90 DEG arcuate extension rotating in a 180 DEG arcuate aperture in an end of the housing to limit rotation to 90 DEG between two positions. Alternatively, a third position may be selected in which two opposite ports are coupled by a passage running the length of the rotor. The housing has corner cutouts to reduce its weight. <IMAGE>

Description

SPECIFICATION Microwave waveguide switch assembly This invention relates to the art of microwave waveguide switches, and more particularly concerns an improved motor driven microwave switch having reduced size and weight, but providing superior performance and reliability than prior microwave waveguide switches.

Typical switches used in satellite or other applications have solid circular rotors with semi-circular internal passages for microwave transmission in 90" increments and are driven by large motors. The total weight of such a microwave switch-motor assembly can be as much as five pounds or more, and can occupy a large volume of space. A satellite may require up to 50 or more motor driven microwave waveguide switches, and thus, the heavy weight and large space occupied by prior microwave waveguide switch assemblies in a satellite are very objectionable factors.

According to the invention, a microwave waveguide switch is provided with a greatly simplified rotorwhich permits a much smaller and lighter switch housing, having corner and side cutouts to further reduce the weight of the switch. A motor housing may be integral with the switch housing which contains a rotor limited to 90" increments of rotation. The invention is suitable in all microwave bands, i.e. 10 - 15 gigaherz. The switch may operate with great precision in a prescribed limited range such as 11.2 - 12.2 gigaherz, 12.2 -12.9 gigaherz, 14.0 - 14.5 gigaherz, or other specified narrow band less than the full range of 10 - 15 gigaherz, or full range with less precision in unneeded portions of rotor.

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, 90" apart to act like a double pole, double throw switch, or a single pole, double throw switch. In another version the rotor assembles either of three positions to act as a triple throw.

It is therefore a principle object of the present invention to optimize the switching and transmission performance of a microwave waveguide switch by means of a switch construction having reduced size and weight and thereby requiring a smaller and lighter motor than prior art microwave waveguide 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 is between the switch rotor and the chamber walls in which the rotor rotates.

It is another object of the present invention to provide a microwave waveguide switch of the type described having a lightweight small diameter rotor housed in a small lightweight housing requiring a small drive motor.

It is yet another object of the present invention to provide a microwave waveguide switch of the type described which has a lightweight rotor which will switch faster, is easier to fabricate and is more reiiable.

These and other objects and many of the attendant advantages of th is invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings in which: Figure 1 is a side elevational view of a microwave switch-motor assembly embodying the invention; Figure 2 is an end elevational view taken along line 2-2 of Figure 1; Figure 3, is an end elevational view taken along line 3-3 of Figure 1; Figure 4 is a cross-sectional view taken along line 4-4 of Figure 1; Figure 5 is longitudinal, central sectional view taken along line 5-5 of Figure 3; Figure 6 is a reduced perspective view of the rotor of the assembly of Figure 1-5; Figure 7 is a side elevational view of the rotor; Figure 8 is a plan view of the rotor taken along line 8-8 of Figure 7;; Figure 9 is a side elevational view similar to Figure 1 of another microwave switch-motor assembly embodying another version of the invention; Figures 10 and 11 are cross sectional views taken along lines 10-10 and 11-11 of Figure 9; Figure 12 is an end elevational view taken along line 12-12 of Figure 9.

Figure 13 is a reduced perspective view of the switch portion of the rotor employed in the assembly of Figures 9-12; Figure 14 is a side elevational view of the rotor of Figure 13; and Figure 15 is a plan view of the rotor taken along the line 15-15 of Figure 14; Referring now to the drawings wherein like reference characters designate like or corresponding parts throughout there is illustrated in Figures 1-5 a microwave switch-motor assembly generally designated as reference numeral 20 and having a housing 22 made of lightweight material such as aluminium.

The housing 22 has a generally rectangular end portion 26 which contains a switch portion 27 of a rotor 28 of the switch assembly 20, as best shown in Figures 6-8.

End portion 26 of the housing 22 has rectangular and corner cutouts 30, and central corner cutouts 32, which reduce the weight of the assembly. The housing portion 26 has four flat sides 34 each provided with a rectangular opening 38 affording a direct passage for microwave energy between the hollow interior of the housing 22 and one of four waveguides 40 (shown in dotted lines in Figure 1) attachable by screws 42 engaged in screw holes 44 at corners of the flat sides 34 of the housing portion 26. The hollow housing portion 26 is formed with a cylindrical inside chamber 46, having a wall 47 at which the rectangular openings 38 terminate. A flat end wall 48 of the housing portion 26 has a recessed circular portion 49 which is formed with an arcuate 1800 opening 50 communicating with the chamber 46.Threaded holes 52 in the wall 48 (see Figure 2) receive screws for mounting the assembly 20 on a suitable support 54 indicated by dotted lines in Figure 1. A central opening 56 in the recessed wall portion 49 receives a cylindrical bearing 58 which journals a stub shaft 60 at the outer end of the rotor 28.

The switch portion 27 of the rotor 28 has a pair of axially spaced cylindrical end plates 62, 64 (Figure 7 & 8). Between the end plates 62,64 and integral therewith is a flat central block 66, which has opposite flat parallel sides or walls 68. The thickness of the block 66 is substantially equal to the circumferential spacing between the openings 38 in the chamber 46 to insure that walls of passages for microwave between selected pairs of 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. Grooves 76 in opposite sides of the block 66 serve for fine tuning of the microswitch assembly 58 to pass a prescribed narrow band of microwave frequencies. If desired, other conventional techniques may be used to match the impedance of the rotor to the mating waveguide, i.e. slots, grooves, screws, etc...

The recessed end wall portion 49 of the housing portion 26 is formed with an axial projection 80 extending through 90" circumferentially and rotatably disposed in the semicircular opening 50. Ends 82 of opening 50 serve as abutments or stops to limit rotation of the rotor 28 to 90" in both clockwise and counterclockwise directions as viewed in Figure 2.

A sector 25 may be employed to turn the rotor 28.

This motor may be of conventional type such as described in U.S. Patent No. 3,970,980 attached by screws 101 to the cylindrical end portion 24 ofthe 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 Figure 5 are connectable to theterminals 108 from an external circuit which applies powerto operate the motor 25. Wires 112 inside the housing portion 24 are connected between the terminals 108 and a stationary armature 114 of the motor 25. The armature 114 has inside and outside axial stationary shafts 116, 117. The inside shaft 116 extends through an opening an in end wall 121 of a cup shaped motor housing 122 and contacts a ball bearing 124 engaged in a recess in axial extension 62a of the plate 62. The motor housing 122 is attached to the switch portion of the rotor 28 by screws 126 engaged in holes in the plate or wall extension 62a. A ball bearing 130 is disposed between the rotor 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 62a and rotates 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 screws 101 to an annular flange 142 at the outer end of the cylindrical portion 24 of the housing 22.

Secured inside the cylindrical, cup shaped motor housing 122 are arcuate permanent magnets 144 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 is energized by current of one polarity the rotor 28 rotates in one direction, for example clockwise, to the position shown in Figure 4. Here the arcuate rotor projection 80 will abut and rotation will be stopped by the right end 82 of the 1800 arcuate opening 50 in the wall 48; see Figure 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 Figure 4. Passage P extends between the upper opening 38a, 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 arrows A in Figure 4.This will reverse the passages so that microwave energy passes through one passage between the upper opening 38a 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 20A is shown in Figures 9-12. The assembly 20A is similar to the assembly of Figures 1-8 and corresponding parts are identically numbered.

A rotor 28a shown in Figures 13, 14 and 15 has a pair of thin, narrow, flat parallel plate portions 68a.

Inner adjacent sides are spaced apart a distance substantially equal to the width of each rectangular opening in the chamber 46. Outer sides of the plate portions 68a are spaced apart a distance substantially equal to the circumferential spacing between the openings 38 in the chamber 46. By this arrangement, it is insured that walls of all passages through the chamber 46 register with sides of the openings 38 in the chamber 46 in the two extreme and central positions of the rotor in the housing. A 90" axial, arcuate projection 80a of a circular end wall 64a moves in an arcuate 1800 opening 50a in an end wall 48a of a housing 22a.

When the rotor 28a is turned clockwise 45" to the right from the central position shown in Figures 10 and 12,the rotor28a will have a position similarto that shown in Figure 4. Then the microwaves may flow in one passage between the openings 38a' and 38b', and may flow in another passage between the openings 38c' and 38d'. When the rotor 28a is turned counterclockwise 45" to the left from the central position shown in Figure 10, the rotor 28a will have a position rotated 90" from that shown in Figure 4.

Then microwaves may pass in one passage between the openings 38a' and 38b', and may pass in another passage between the openings 38c' and 38b'. The sector motor in housing 122 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 22a is slightly modified from that of the housing 22 in the assembly 20.

Here an end wall 102a of a housing portion 24a is reduced in mass by removing material between corners leaving four corner ears 166 which register with ears 168 provided on an end plate 102a that carries the motor armature 114 as shown in Figure 5.

Screws 180 engages a shaft 1 17a of the armature 114, see Figure 9.

The switch portion 26a of the housing 24a is modified by removal of material at the corners of the housing 24a to define four ears 170 which have holes 52a to receive screws 172 for mounting the assembly on a support.

It will be clear from the above that assembly 20a serves as a three position switch. There is a straight passage between the openings 38a' and 38c' when the rotor is in the central position, shown in Figure 10. When the rotor is turned 45" in either direction the passages P and P' in Figure 4. The rotor turns a maximum of 90".

Longitudinal slots 74a are also formed at ends of the wall edges and are used for tuning the switch, and matching impedances to connecting waveguides. They also reduce coupling between paths or passages through the switch.

My aforedescribed new and novel rotor design is smaller in diameter, lighter in weight and a consequently enclosed in a smaller housing and is driven by a smaller drivemoter which requires less power then prior art waveguide switches. Moreover my new rotor is easierto 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.

It should be understood that the foregoing relates to only a limited number of preferred 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 scope of the invention.

Claims (5)

1. A microwave waveguide switch assembly, operable in 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 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 wall means thereof 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 wall means of said rotor and the walls of said chamber when said rotor is diposed 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 wall means of said rotor and the walls of said chamber when said rotor is disposed in the other one of said two positions.

2. An assembly as defined in Claim 1, wherein said housing has corner cutouts to reduce its weight.

3. An assembly as defined in Claim 1, further comprising motor means in said housing arranged to drive said rotor between said two positions.

4. An assembly as defined in Claim 1,further including cooperating mechanical means on said rotor and said housing limiting rotation of said rotor between said two positions spaced 90" apart.

5. A microwave waveguide switch assembly substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

5. An assembly as defined in Claim 1, further comprising bearing means in said housing for supporting said rotor to insure free rotation thereof in said housing.

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

7. An assembly as defined in Claim 6, wherein said rotor comprises two flat, parallel, plate portions having inner adjacent sides spaced apart a distance substantially equal to the widths of said openings, and having outer sides spaced apart a distance substantially equal to said circumferential spacing between said openings, so that walls of said passages in said chamber register with sides of said openings in said housing in each of said three positions of said rotor in said housing.

8. An assembly as defined in Claim 7, further comprising motor means in said housing arranged to drive said rotor between said two positions of said rotor in said housing.

9. An assembly as defined in Claim 1, wherein said housing has another cylindrical chambertherein axially aligned with said first named cylindrical chamber, and further comprising electric motor means in said other chamber coupled to said rotor for rotating the same.

10. An assembly as defined in Claim 1, wherein said first named cooperating mechanical means comprises an end wall on said housing having an arcuate 1800 aperture; and an arcuate 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.

11. Microwave waveguide switch assembly substantially as herein before described with reference to and as illustrated in the accompanying drawings.

New Claims Superseded claims all claims New or amended claims:- 1 to 5

1. A microwave waveguide switch assembly, operable in at least two positions, comprising: a hollow housing having a cylindrical hollow cham ber 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 therein between 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 other 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 two positions, and two other separate passages for passing microwaves through said housing between two other 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 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 claimed in Claim 1,wherein said rotor has further wall means to form a further passage for passing microwave through said chamber between a further pair of said openings when said rotor is disposed in a third position mid-way between said two positions.

3. An assembly as claimed 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 claimed in Claim 1 wherein said housing has an end wall formed with an arcuate 1800 aperture; and an arcuate projection on said rotor extending axially into said aperture and subtanding 90" circumferentially of said rotorto limit said rotor to 90 rotation in said housing between said two positions.