Patent Application
20120086518
A waveguide coupler may be used combine, sample and/or to detect simultaneous forward and reflected power levels of RF signals within a microwave communication system.
Prior waveguide couplers have applied coupling slot configurations between adjacent waveguides including several slots of precise width, dependent upon a desired operating frequency band of the communications system. Further, to operate in the H signal plane, features along the waveguide sidewalls may be added, also with a high degree of precision, to match the desired operating frequency band. The coupling level between the waveguides may be determined by the number/scale of the coupling slots and/or sidewall features.
The design of a waveguide coupler is typically highly frequency and coupling level specific, requiring a manufacturer to provide a range of different waveguide couplers, each with a specific operating frequency and coupling level, with minimal manufacturing efficiencies between the different designs, in order to satisfy market demands.
Prior waveguide couplers with adjustable coupling levels have utilized complex motorized insertion/retraction elements and/or a plurality of separate elements requiring precision fitting and/or relocation within the waveguides. Such configurations may add significant additional expense and/or operator skill requirements. Further, these complex solutions may provide unacceptable electrical performance and/or environmental seal degradation.
Therefore, it is an object of the invention to provide an apparatus that overcomes deficiencies in the prior art.
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention, where like reference numbers in the drawing figures refer to the same feature or element and may not be described in detail for every drawing figure in which they appear and, together with a general description of the invention given above, and the detailed description of the embodiments given below, serve to explain the principles of the invention.
The inventors have recognized that the prior waveguide couplers incorporate an excessive number of discrete components and/or surface features with minimal parts harmonization between couplers with different coupling levels.
An exemplary waveguide coupler, as shown in
A coupling slot 12 between the inner sidewall(s) 10 communicates between the first trough 4 and the second trough 6. The coupling slot 12 length may be selected according to, for example ½ guide wavelength and waveguide geometry. An inward projecting abutment 14 may be provided in each outer sidewall 8, opposite the coupling slot 12. The coupling slot 12 may be provided with a length along a longitudinal axis of the trough portion 2 that is greater than a width of the first trough 4. A cover 16 seats upon an open top 24 of the trough portion 2 to close the first trough 4 and the second trough 6, forming first and second waveguides 18, 22.
To enable simplified interconnection with adjacent waveguides the first trough 4 and the second trough 6 may be provided with a plurality of bend(s) 24 operative to locate the inner sidewall(s) 10 proximate the coupling slot 12 close to one another and to space the first and second waveguides 18, 22 parallel and apart at interconnection end(s) 26 so that suitable spacing is provided for ease of access to selected interconnection means, such as waveguide flanges or the like, for interconnection of the coupler with further waveguides. Particulars of various waveguide interconnection means are well known in the art and as such are not demonstrated or further described herein.
As best shown in
The step(s) 30 may be provided with a maximum inward extension from the cover 16 and a minimum lateral distance from the coupling slot 12 proximate a center of the coupling slot 12 selected with respect to desired RF performance, such as coupling, return loss and port to port isolation. A height differential between adjacent step(s) 30 may reduce with each step 30 toward the center step 32. A maximum inward extension of the step(s) 30 may be less than half of a height of the first trough 4. In the exemplary embodiment, two step(s) 30 are provided on each side of the center step 32.
For ease of manufacture, the steps in lateral position may be provided with a radius transition 34 between each step 30. Similarly, the steps in height may be provided with a right angle transition 36 between each step 30. Thereby, a machining operation during manufacture of the cover 16 may be performed cost effectively with high precision via standard cutting/grinding tool movements in only three axes.
In a high coupling level configuration, for example 3 dB, the cover 16 may be provided with a flat surface, for example as shown in
Modeled electrical performance for the exemplary 3 dB (
One skilled in the art will appreciate that the trough portion 2 and the cover portion 16 may be cost effectively manufactured with high precision via three axis machining, die casting, metal injection molding and/or a combination of casting/molding followed by machining. Specific dimensions of the coupling slot 12, protrusion(s) 28 and abutment(s) 14 may be selected according to the desired waveguide dimensions, coupling level and operating frequency band. Because of the ability for the coupler to be configured as a 3 dB or 6 dB coupler, prior requirements for design, manufacture and stocking of multiple separate couplers have been eliminated. Further, configuration for use as either a 3 dB or 6 dB coupler may be quickly performed in the field with minimal chance of installation error.
Where in the foregoing description reference has been made to materials, ratios, integers or components 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.
