Optical waveguides – With optical coupler – Switch
Reexamination Certificate
1999-03-05
2001-03-13
Healy, Brian (Department: 2874)
Optical waveguides
With optical coupler
Switch
C385S015000, C385S016000, C385S024000, C385S025000, C385S044000, C333S103000, C333S106000
Reexamination Certificate
active
06201906
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to switches for use in waveguide communication systems. More specifically, the present invention relates to a rotatable “T” switch providing at least one primary waveguide path and at least one secondary or cross-connect waveguide path.
BACKGROUND OF THE INVENTION
Waveguide communication systems typically include a number of channels or paths in order to provide system redundancy, thereby enhancing system reliability by permitting redundant systems to be switched in for systems that have failed. In order to facilitate switching between alternate channels, a waveguide switch must be included in the communication system. Presently, waveguide communication systems commonly employ an “R” switch architecture, which does not permit the connection of alternate ports or paths around the primary path configuration. In other words, the orientation of the “R” switch interrupts communication along alternate channels, so that communication is possible only through the chosen primary path linked by the “R” switch orientation. This limitation has given rise to the “T” switch concept.
A “T” switch permits the linking of alternate cross-connect channels around the primary waveguide path, an option that is not possible with existing “R” switch architecture. One such “T” switch is disclosed in U.S. Pat. No. 4,201,963. Unfortunately, prior art “T” switches typically employ existing “R” switch architecture, and therefore must employ an additional external waveguide. Consequently, prior art “T” switch configurations are excessively heavy and bulky, rendering them undesirable for use on spacecraft waveguide communication systems. Accordingly, there exists a need for a more compact and reliable “T” switch architecture.
SUMMARY OF THE INVENTION
A compact waveguide “T” switch according to the present invention provides a four port, three position waveguide switch, yet maintains a size and volume comparable to existing “R” switches. A distinct advantage of the present invention over prior art switching architecture is that the traveling wave tube amplifier (TWTA) can be switched into any channel along the chain without disrupting the operation of any other channel. The three position, four port design permits connection between the alternate waveguides regardless of the position of the primary path. The addition of a double ridge transformer and/or an inductive iris window allows a fixed waveguide to be connected in three states: 1) both waveguides aligned; 2) one waveguide rotated 60° while maintaining a good voltage standing wave ratio (VSWR); and 3) one waveguide rotated −60°.
According to one aspect of the invention, a waveguide switch includes a housing having a pair of ends and an interconnecting sidewall enclosing a cylindrical cavity. One of the housing ends includes an entry port and the sidewall includes a plurality of exit ports. A rotor is rotatably disposed within the cylindrical cavity. The rotor includes an input end having an input port aligned with the entry port and an outer surface having a plurality of output ports. The rotor further includes a first passage connecting the input port to one of the output ports, and also includes a cross-connect passage connecting a pair of the output ports. A motor is provided for rotating the rotor within the cavity to align each of the output ports with an adjacent one of the exit ports, thereby connecting the first passage to a selected one of the exit ports and further connecting the cross-connect passage between a pair of the remaining exit ports.
The housing exit ports preferably are equally spaced circumferentially about the outer surface of the housing sidewall, while the rotor output ports are likewise spaced circumferentially equally about the rotor outer surface. The motor is mounted to the housing at a second end of the housing, opposite the end having the entry port. The housing exit ports and the rotor output ports are located at a common cross-sectional plane, so that each of the output ports can be aligned with a selected one of the housing exit ports.
Preferably, a transformer section, which serves to offset adverse impedance changes due to the partially rotated waveguide interface, is provided at the entry point. The transformer section may be located at the housing entry port, the rotor input port, or at both locations. The transformer section preferably includes a pair of inwardly projecting ridges, with each ridge sloping at an angle relative to the transformer section sidewall. For example, the sloping ridges may be at a 60° angle. Inductive iris windows may be provided to improve response.
Preferably, tightly gapped choke joints are provided in order to reduce wave leakage around the interface between the rotor and the housing. An annular choke joint around the rotor entry port is preferred, as are a series of choke joints spaced circumferentially about the interface between the rotor and the housing.
With the motor mounted to the housing at a point offset from a central axis of the housing a second entry port is possible. A second input port in the rotor aligns with the second entry port, and a second passage in the rotor provides for the connection of the second input port with a selected one of the output ports. Also possible is a second cross-connect passage interconnecting a second pair of the output ports.
According to another aspect of the invention, a switch for a waveguide system includes a housing having a pair of ends and an interconnecting sidewall enclosing a cylindrical cavity. One of the housing ends including an entry port, and the sidewall includes a plurality of exit ports. A rotor is disposed within the housing cylindrical cavity, and includes an end having an input port generally aligned with the housing entry port, and also includes a cylindrical outer surface having three output ports. The rotor defines a primary passage between the input port and one of the output ports, and further defines a cross-connect passage between a pair of the remaining output ports. A motor rotates the rotor within the cavity to thereby align the primary passage with a selected one of the exit ports and to further align the cross-connect passage with a pair of the remaining exit ports.
In accordance with yet another aspect of the invention, a waveguide switch for guiding an electrical field comprises a housing having a pair of ends and an interconnecting sidewall enclosing a cylindrical cavity. The housing includes a plurality of waveguide ports. One of the waveguide ports is disposed adjacent one of the housing ends, while the remaining waveguide ports are spaced equally about the housing sidewall. A rotor is disposed within the housing cylindrical cavity, and includes a pair of ends and an interconnecting outer surface having a plurality of input ports. One of the input ports is located at one end of the rotor, while the remaining input ports are spaced equally about the rotor outer surface. The rotor end input port is generally aligned with the housing end waveguide port, and a motor rotates the rotor within the cavity. A primary waveguide passage is defined between the housing end waveguide port and a selected one of the remaining housing waveguide ports, and a secondary cross-connect waveguide passage is defined between a pair of the remaining housing waveguide ports.
In accordance with yet another aspect of the invention, a switch for a waveguide communication system includes a housing having a pair of ends and an interconnecting sidewall enclosing a cylindrical cavity, with each of the housing ends including an entry port. The sidewall includes a plurality of exit ports. A rotor is rotatably disposed within the cylindrical cavity and includes a pair of ends and an interconnecting outer surface. Each end of the rotor has an input port aligned with an adjacent one of the housing entry ports, and the outer surface includes a plurality of output ports. The rotor also includes a plurality of passages extending therethrough for connecting each of the input po
Ando Michael N.
Kich Rolf
Gudmestad T.
Healy Brian
Hughes Electronics Corporation
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