Patent Publication Number: US-7898368-B2

Title: Filter unit

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates generally to satellite communications and, more particularly, to a filter unit for satellite communications. 
     In satellite communications, signal quality may be susceptible to communication environments such as terrestrial topology and weather conditions. A filter may usually be used to suppress interference or noise in received signals. 
       FIG. 1A  is a schematic cross-sectional view of a conventional filter unit  1 . Referring to  FIG. 1A , the filter unit  1  may include a base  11  and a number of tuning pins  12  each corresponding to one of a number of grooves  112  of the base  11 . The depth of each groove  112  may be adjusted by a corresponding one of the tuning pins  12  so as to filter signals at frequencies of interest. However, the conventional filter unit  1  may generally include an alloy of aluminum and zinc, in which the weight percentage of aluminum is greater than that of zinc. Such weight percentage may result in undesirable surface roughness of the grooves  112 , which may adversely affect the function of a filtering space  111  defined by the grooves  112  and in turn the performance of the filter unit  1 . 
     BRIEF SUMMARY OF THE INVENTION 
     Examples of the present invention may provide a filter unit that comprises a cover including a number of first grooves, and a base including a number of second grooves aligned with the first grooves. 
     Some examples of the present invention may also provide a filter unit that comprises a cover including a number of first grooves, and a base including a number of second grooves aligned with the first grooves, wherein the cover includes an alloy of zinc and aluminum, and the weight percentage of zinc is greater than that of aluminum. 
     Examples of the present invention may further provide a filter unit that comprises a cover including a number of first grooves, and a base including a number of second grooves aligned with the first grooves, wherein the base includes an alloy of zinc and aluminum, and the weight percentage of zinc is greater than that of aluminum. 
     Other objects, advantages and novel features of the present invention will be drawn from the following detailed embodiments of the present invention with attached drawings, in which: 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       The foregoing summary as well as the following detailed description of the preferred embodiments of the present invention will be better understood when read in conjunction with the appended drawings. For the purposes of illustrating the invention, there are shown in the drawings examples which are presently preferred. It is understood, however, that the invention is not limited to the precise arrangements and instrumentalities shown. In the drawings: 
         FIG. 1A  is a schematic cross-sectional view of a conventional filter unit; 
         FIG. 2A  is an unfolded, perspective view of a filter unit in accordance with an example of the present invention; 
         FIG. 2B  is a folded, perspective view of the filter unit illustrated in  FIG. 2A ; 
         FIG. 2C  is a cross-sectional view of the filter unit illustrated in  FIG. 2B ; and 
         FIG. 3  is a perspective view of a communication device in accordance with an example of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Reference will now be made in detail to the present examples of the invention illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like portions. 
       FIG. 2A  is an unfolded, perspective view of a filter unit  2  in accordance with an example of the present invention. Referring to  FIG. 2A , a filter unit  2  may include a base  21  and a cover  22 . At least one of the base  21  or the cover  22  may include an alloy of aluminum (Al) and zinc (Zn), wherein the weight percentage of zinc may be greater than that of aluminum. Experiments reveal that surface roughness or surface texture of a filter unit comprising an Al—Zn alloy may be improved when zinc is greater than aluminum in weight percentage. The surface roughness or surface texture may be measured by several methods such as roughness average (R a ), root-mean-square (rms) and maximum height of profile (R max ). 
     In one example, the weight percentage of zinc is equal to or greater than approximately 90%. In another example, the weight percentage of zinc is equal to or smaller than approximately 99%. In still another example, the weight percentage of aluminum is equal to or greater than approximately 1%. In yet another example, the weight percentage of aluminum is equal to or smaller than approximately 10%. In yet still another example, the alloy may include approximately 90% to 99% of zinc and approximately 1% to 10% of aluminum by weight. 
     Furthermore, in one example, the weight percentage of zinc is equal to or greater than approximately 95%. In another example, the weight percentage of zinc is equal to or smaller than approximately 96%. In still another example, the weight percentage of aluminum is equal to or greater than approximately 3.9%. In yet another example, the weight percentage of aluminum is equal to smaller than approximately 4.3%. In yet still another example, the alloy may include approximately 95% to 96% of zinc and approximately 3.9% to 4.3% of aluminum by weight. 
     The base  21  may include a first support  212 , a second support  213 , and a body  211  between the first and second supports  212  and  213 . The body  211  may include a recessed portion “R” with a bottom surface (not numbered). A number of protrusions  2111  may protrude from the bottom surface and may be separated from one another by a groove “G 1 ”. The first support  212  may include a first opening  212 A for signal input and the second support  213  may include a second opening  213 A for signal output. 
     The cover  22  may include a raised portion  220  with a number of grooves “G 2 ”. In the present example, each of the raised portion  220  and the recessed portion R may have a rectangular shape. When the recessed portion R and the raised portion  220  engage with one another, the grooves G 1  and G 2  may be aligned with one another. Each of the grooves G 1  and G 2  may extend in a first direction, which may be orthogonal to a second direction in which a signal to be filtered transmits from the first opening  212 A to the second opening  213 A. 
       FIG. 2B  is a folded, perspective view of the filter unit  2  illustrated in  FIG. 2A . Referring to  FIG. 2B , a number of fastening means  23  such as screws, bolts and rivets may be used to engage the cover  22  with the base  21 . 
       FIG. 2C  is a cross-sectional view of the filter unit  2  illustrated in  FIG. 2B  taken along a line AA′. Referring to  FIG. 2C , the grooves G 1  and G 2  and a space “S” defined by the engaged base  21  and the cover  22  may function as a filter that allows a signal at a frequency within a predetermined range to pass the outlet  213 A. 
       FIG. 3  is a perspective view of a communication device  3  in accordance with an example of the present invention. Referring to  FIG. 3 , the communication device  3  may include a transceiver module  31 , a feeding module  32  coupled to the transceiver module  31  and a reflection module  33 . The transceiver module  31  may include a transducer  311 , a filter unit  322  which may be similar to the filter unit  2  described and illustrated with reference to  FIGS. 2A to 2C , and a waveguide  323 . The transducer  311  may include an orthogonal mode transducer (OMT) coupled between the filter unit  322  and the waveguide  323 . 
     In describing representative examples of the present invention, the specification may have presented the method and/or process of operating the present invention as a particular sequence of steps. However, to the extent that the method or process does not rely on the particular order of steps set forth herein, the method or process should not be limited to the particular sequence of steps described. As one of ordinary skill in the art would appreciate, other sequences of steps may be possible. Therefore, the particular order of the steps set forth in the specification should not be construed as limitations on the claims. In addition, the claims directed to the method and/or process of the present invention should not be limited to the performance of their steps in the order written, and one skilled in the art can readily appreciate that the sequences may be varied and still remain within the spirit and scope of the present invention. 
     It will be appreciated by those skilled in the art that changes could be made to the examples described above without departing from the broad inventive concept thereof. It is understood, therefore, that this invention is not limited to the particular examples disclosed, but it is intended to cover modifications within the spirit and scope of the present invention as defined by the appended claims.