Patent Application
20070285329
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the general and detailed descriptions of the invention appearing herein, serve to explain the principles of the invention.
The inventors have recognized that addition of beam squint to a feed horn results in an offset beam pattern. This offset beam pattern has been advantageously applied to form a side feed having a longitudinal axis that is parallel to the longitudinal axis of a central feed, but with an offset beam path. Thereby, a multiple feed assembly usable with a range of non-parallel beam paths may be cost efficiently formed via die casting with a high degree of precision.
As shown in
The central, first and second side feeds 12, 16, 18 have a corrugated conical horn 22 extending from the open end of their respective waveguide(s). As best shown in
The corrugation(s) 24 are demonstrated in the exemplary embodiment as generally circular and concentric. Alternatively, the corrugation(s) 24 may be non circular and applied in any of a range of straight and or angled combinations with uniform or varied heights and spacing for the particular application and or operating frequencies desired. Similarly, equivalents to the corrugation(s) 24 may be formed, for example, as steps or a single corrugation represented by the open end 26 of the waveguide 10 or a flared extension of the waveguide 10 end, any of the equivalents having an end angle according to the invention. To prevent interference with the adjacent feed(s) 14, the corrugated conical horn 22 of the central feed 12 may be cut-away from areas of the beam path(s) of the adjacent feed(s) 14.
As shown for example in
In the exemplary embodiment, the first side feed end face angle of the feed horn is 78 degrees with the low and high sides along a horizontal axis of the assembly. Depending upon the offset from the primary beam desired, the end face angle E may be adjusted, for example to any angle less than 90 degrees. Also, to account for changes in the relative elevation of target satellites positioned along a horizon arc in equatorial orbit, with respect to the terrestrial position of the antenna, the vertical spacing of the feeds upon the baseplate 28, for example measured relative to a horizontal axis of septum polarizer(s) 20 positioned in the waveguide(s) 10, may be adjusted. Alternatively, it should also be appreciated that by adjusting the orientation of the end face plane low and high sides, the beam may be configured for varying beam squint in azimuth and or elevation for each of a plurality of different side feeds.
One skilled in the art will recognize that the present invention allows the creation of feed assemblies having multiple feeds with parallel longitudinal axes, the multiple feeds having a range of different beam path(s). Because the longitudinal axes of the multiple feeds and corrugations, if present, are parallel, a feed assembly according to the invention has no overhanging edges, allowing high volume cost efficient fabrication of the feed assembly via molding or die casting. Where a dielectric material such as plastic is used as the material for injection molding, a conductive surface coating may be applied.
Because molding or die casting precisely and permanently orients each of the feeds as desired, the prior manufacturing and or installation steps of separately attaching, interconnecting and or aiming of the sidecar feeds has been eliminated. Where the desired angle of the side feed beam path(s) may change due to sale within different markets and or geographic location, the feed assembly may be adapted to have exchangeable corrugated conical feed horn(s) 22. By exchanging one corrugated feed horn having one end face angle for another, the desired beam path may be quickly changed with a high degree of precision.
Where in the foregoing description reference has been made to ratios, integers, components or modules having known equivalents then such equivalents are herein incorporated as if individually set forth.
While the present invention has been illustrated by the description of the embodiments thereof, and while the embodiments have been described in considerable detail, it is not the intention of the applicant to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will readily appear to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details, representative apparatus, methods, and illustrative examples shown and described. Accordingly, departures may be made from such details without departure from the spirit or scope of applicant's general inventive concept. Further, it is to be appreciated that improvements and/or modifications may be made thereto without departing from the scope or spirit of the present invention as defined by the following claims.
