Abstract:
A patch antenna includes: a dielectric layer made of an insulation material, and having upper and lower surfaces, and a through hole; a radiation metal layer disposed on the upper surface of the dielectric layer, and having a first plate body, a first aperture aligned with the through hole, and a first protruding portion extending from a peripheral edge of the first aperture into the through hole; and a grounding metal layer disposed on the lower surface of the dielectric layer, and having a second plate body, a second aperture aligned with the through hole, and a second protruding portion extending from a peripheral edge of the second aperture into the through hole. The first and second protruding portions contact each other in the through hole so that the radiation and grounding metal layers are electrically connected. A method of making a patch antenna is also disclosed.

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
       [0001]    This application is a Divisional of U.S. Ser. No. 12/157,659 filed 12 Jun. 2008, which claims benefit of Serial No.  096150529 , filed 27 Dec. 2007 in Taiwan and which applications are incorporated herein by reference. To the extent appropriate, a claim of priority is made to each of the above disclosed applications. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to a patch antenna for receiving satellite signals, more particularly to a patch antenna and a method of making the same that involves relatively simple manufacturing processes. 
         [0004]    2. Description of the Related Art 
         [0005]    A commercially available patch antenna for receiving satellite signals (frequency of approximately 2.32˜2.3325 GHz) includes a dielectric layer formed from a fluoropolymer substrate (such as a Teflon® substrate), and a radiation layer and a grounding layer made of copper foil and adhered respectively to opposite surfaces of the fluoropolymer substrate. A through hole is formed in a center of the resulting plate structure, and a wall defining the through hole is covered with a copper layer to thereby establish an electrical connection between the radiation layer and the grounding layer. 
         [0006]    Referring to  FIG. 1 , a process for manufacturing a conventional patch antenna utilizing a fluoropolymer substrate includes the following steps. First, in step  901 , opposite surfaces of the fluoropolymer substrate are cleaned, and then the surfaces are corroded using a chemical agent to activate the surfaces. Next, in step  902 , the two surfaces of the fluoropolymer substrate are covered with hot melt adhesive films, respectively. In step  903 , the hot melt adhesive films are covered respectively with copper foils, and the copper foils are pressed and heated such that the adhesive films melt and the copper foils and the fluoropolymer substrate are bonded together to thereby form a tri-layer plate. In step  904 , a hole-punching process is performed on the tri-layer plate to thereby form a through hole therein. Since the fluoropolymer substrate includes fibrous material, when forming the through hole, rough edges and unevenness in a wall defining the through hole may result. Therefore, in step  905 , the wall defining the through hole is made even through a chemical corrosion process. Subsequently, in step  906 , a copper layer is formed on the wall defining the through hole using an electroplating process, such that the copper layer on the wall of the through hole is connected to the two copper foils. Finally, in step  907 , an outer shape of a patch antenna is formed by a stamping process to thereby complete manufacture of the patch antenna. 
         [0007]    In the above manufacturing process, chemical etching is required since it is difficult to work with the surfaces of the fluoropolymer substrate. This not only complicates manufacture but also results in the generation of chemical liquid waste. In addition, the material costs associated with the fluoropolymer substrate are high, the fluoropolymer substrate is not easily recycled, and a substantial amount of non-recyclable waste material is generated when punching the fluoropolymer substrate. 
         [0008]    Therefore, the manufacture of patch antennas using a fluoropolymer substrate not only results in complicated manufacture and high production costs, but also results in the generation of a significant amount of waste material that adversely affects the environment. 
       SUMMARY OF THE INVENTION  
       [0009]    Therefore, an object of this invention is to provide a patch antenna that is low in cost. 
         [0010]    According to one aspect, the patch antenna of this invention includes: a dielectric layer made of an insulation material, and having an upper surface, a lower surface, and a through hole; a radiation metal layer disposed on the upper surface of the dielectric layer, and having a first plate body, a first aperture aligned with the through hole, and a first protruding portion extending from the first plate body at a peripheral edge of the first aperture into the through hole; and a grounding metal layer disposed on the lower surface of the dielectric layer, and having a second plate body, a second aperture aligned with the through hole, and a second protruding portion extending from the second plate body at a peripheral edge of the second aperture into the through hole, the first protruding portion and the second protruding portion contacting each other in the through hole to establish an electrical connection between the radiation metal layer and the grounding metal layer. 
         [0011]    Another object of this invention is to provide a method of making a patch antenna that involves simple processes, that is low in cost, and that is environmentally friendly. 
         [0012]    According to another aspect of this invention, the method of making a patch antenna includes the steps of: stamping a first metal plate to form a first plate body having a predetermined shape, and simultaneously, a first aperture in the first plate body and a first protruding portion that extends from a peripheral edge of the first aperture to thereby form a radiation metal layer; stamping a second metal plate to form a second plate body having a predetermined shape, and simultaneously, a second aperture in the second plate body and a second protruding portion that extends from a peripheral edge of the second aperture to thereby form a grounding metal layer; placing the radiation metal layer and the grounding metal layer in a mold in such a manner that the first protruding portion and the second protruding portion are coupled together; and introducing an insulation material into the mold to form a dielectric layer that is interposed between the radiation metal layer and the grounding metal layer. 
         [0013]    According to yet another aspect, the method of making a patch antenna includes the steps of: stamping a metal plate to form a first plate body having a predetermined shape, and simultaneously, a first aperture in the first plate body and a first protruding portion that extends from a peripheral edge of the first aperture to thereby form a radiation metal layer; stamping a second metal plate to form a second plate body having a predetermined shape, and simultaneously, a second aperture in the second plate body and a second protruding portion that extends from a peripheral edge of the second aperture to thereby form a grounding metal layer; preparing a dielectric layer having a through hole; and attaching the radiation metal layer and the grounding metal layer to opposite surfaces of the dielectric layer and in such a manner that the first protruding portion and the second protruding portion are coupled together. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS  
         [0014]    Other features and advantages of the present invention will become apparent in the following detailed description of the preferred embodiments with reference to the accompanying drawings, of which: 
           [0015]      FIG. 1  is a flowchart of a conventional method of making a patch antenna; 
           [0016]      FIG. 2  is a flowchart of a method of making a patch antenna according to a first preferred embodiment of the present invention; 
           [0017]      FIG. 3  is a perspective view of a radiation metal layer according to the first preferred embodiment of the present invention; 
           [0018]      FIG. 4  is a perspective view of a grounding metal layer according to the first preferred embodiment of the present invention; 
           [0019]      FIG. 5  is a perspective view, illustrating the radiation metal layer and the grounding metal layer of the first preferred embodiment maintained in a parallel state in a mold; 
           [0020]      FIG. 6  is a perspective view of a patch antenna according to the first preferred embodiment of the present invention; 
           [0021]      FIG. 7  is a sectional view, illustrating protruding portions of the radiation metal layer and the grounding metal layer coupled together according to the first preferred embodiment of the present invention; 
           [0022]      FIG. 8  is a top plan view, illustrating a shape and various dimensions of the patch antenna of the first preferred embodiment of the present invention; 
           [0023]      FIG. 9  is an S11 S-parameter plot of the patch antenna of the first preferred embodiment of the present invention; 
           [0024]      FIG. 10  is a Smith chart of the patch antenna of the first preferred embodiment of the present invention; 
           [0025]      FIG. 11  is a directivity diagram of the patch antenna of the first preferred embodiment; 
           [0026]      FIG. 12  is a perspective view, illustrating a plurality of prominence portions of the first preferred embodiment; 
           [0027]      FIG. 13  is a fragmentary enlarged view of  FIG. 12 , illustrating one of the prominence portions thereof; 
           [0028]      FIG. 14  is a sectional view of  FIG. 12 , illustrating one of the prominence portions embedded in a dielectric layer; 
           [0029]      FIG. 15  is a flowchart of a method of making a patch antenna according to a second preferred embodiment of the present invention; 
           [0030]      FIG. 16  is an exploded perspective view of a radiation metal layer, a grounding metal layer, and a dielectric layer according to the second preferred embodiment of the present invention, illustrating relative positions among these elements before being bonded together; and 
           [0031]      FIG. 17  is a perspective view of a patch antenna according to the second preferred embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0032]    A method of making a patch antenna according to a first preferred embodiment of the present invention will now be described with reference to  FIG. 2  and other drawings as specified below. 
         [0033]    Referring to  FIG. 3 , a first metal plate (not shown) is stamped to form a first plate body  211  of a predetermined shape in step  101 . In the first preferred embodiment, an outer periphery of the first plate body  211  is substantially circular. Further, a center area of the first plate body  211  is stamped to form a first aperture  212 , and a first protruding portion  213  that extends at substantially a right angle from a peripheral edge of the first aperture  212 . In addition, a first sub-feed-in hole  214  is formed in the first plate body  211 , a guide groove  215  is formed in the first plate body  211  extending from the outer periphery and toward a center of the first plate body  211 , and four first indentations  216  are formed in the outer periphery of the first plate body  211  extending inwardly and spaced apart along the outer periphery of the first plate body  211 , thereby completing the formation of a radiation metal layer  21 . 
         [0034]    Referring to  FIG. 4 , a second metal plate (not shown) is stamped to form a second plate body  221  of a predetermined shape in step  102 . In the first preferred embodiment, an outer periphery of the second plate body  221  is substantially circular, and a size of the second plate body  221  corresponds to a size of the first plate body  211 . Further, a center area of the second plate body  221  is stamped to form a second aperture  222 , and a second protruding portion  223  that extends at substantially a right angle from a peripheral edge of the second aperture  222 . In addition, a second sub-feed-in hole  224  is formed in the second plate body  221 , and four second indentations  225  are formed in the outer periphery of the second plate body  221  extending inwardly and spaced apart along the outer periphery of the second plate body  221 , thereby completing the formation of a grounding metal layer  22 . 
         [0035]    Referring to  FIGS. 3 ,  4 , and  5 , in step  103 , the radiation metal layer  21  and the grounding metal layer  22  are placed in a mold (not shown), such that the first plate body  211  and the second plate body  221  are parallel to each other. Further, four first positioning bars  41  are passed respectively through the first indentations  216  to abut against the second plate body  221 , and four second positioning bars  42  are passed respectively through the second indentations  225  to abut against the first plate body  211 . Additionally, outer side surfaces of the first plate body  211  and the second plate body  221  abut against the mold. Hence, the first plate body  211  and the second plate body  221  are maintained in a parallel state in the mold to thereby prevent the first plate body  211  and the second plate body  221  from being displaced and deformed when a molten insulation material is introduced into the mold. Moreover, an inner diameter of the first protruding portion  213  is similar to an outer diameter of the second protruding portion  223 , such that the first protruding portion  213  and the second protruding portion  223  are coupled fittingly (see  FIG. 7 ). Further, the first sub-feed-in hole  214  and the second sub-feed-in hole  224  are aligned with each other. 
         [0036]    Referring to  FIGS. 5 ,  6 , and  7 , in step  104 , a molten insulation material is introduced into the mold, such that the insulation material fills a space between the radiation metal layer  21  and the grounding metal layer  22 . However, an unfilled area  201  is formed by the first protruding portion  213  and the second protruding portion  223 , and a bolt (not shown) is passed through the first sub-feed-in hole  214  and the second sub-feed-in hole  224 , such that the insulation material is not able to fill these areas, thereby resulting in the formation of through holes after the insulation material hardens. After the insulation material hardens, the elements are removed from the mold. As a result, a dielectric layer  23  is formed interposed between the radiation metal layer  21  and the grounding metal layer  22 , and a patch antenna  2  having a through hole  201  and a feed-in hole  202  is obtained. The feed-in hole  202  and the guide groove  215  of the radiation metal layer  21  are used to control the frequency band and field pattern received by the patch antenna  2 . Moreover, the end of the first protruding portion  213  and the end of the second protruding portion  223  overlap such that an electrical connection is established between the radiation metal layer  21  and the grounding metal layer  23 . 
         [0037]    Preferably, a metal material having a low impedance and that is easily soldered is used for making the radiation metal layer  21  and the grounding metal layer  22 . In the first preferred embodiment, the metal material is SPTE (electrolytic tin plate) that is manufactured to a thickness of 0.2 mm and that complies with the Japanese JIS G3303 industrial standard. 
         [0038]    As for the insulation material for forming the dielectric layer  23 , a plastic material is preferably used that may be easily injection molded, and that has a dielectric constant (Df) less than 2.5, a dielectric strength (Dk) less than 0.001, and a heat deflection temperature (HDT) higher than 110° C. In the first preferred embodiment, Noryl RF1132 resin manufactured by the General Electric Company is used for the insulation material. 
         [0039]    To prevent the efficiency of the patch antenna  2  from being adversely affected, the first and second indentations  216 ,  225  are preferably formed extending from the outer peripheries of the first and second plate bodies  211 ,  221  and toward centers thereof by a distance that does not exceed 0.5 mm. 
         [0040]    Referring to  FIG. 8 , a radius  203  of the patch antenna  2  of the first preferred embodiment is approximately 23 mm, a radius  204  of the through hole  201  is approximately 3.25 mm, a diameter  205  of the feed-in hole  202  is approximately 1 mm, a length  206  of the guide groove  215  is approximately 6 mm, a width  207  of the guide groove  215  is approximately 2 mm, an overall thickness (not indicated) of the patch antenna  2  is approximately 2 mm, and a distance  208  from the feed-in hole  202  to the center of the patch antenna  2  is approximately 7.65 mm. The frequency band and field pattern of the patch antenna  2  obtained through computer simulation are shown in  FIGS. 9 ,  10 , and  11 . 
         [0041]    Referring to  FIGS. 12 ,  13 , and  14 , when stamp-forming the first plate body  21 ′, a plurality of prominence portions  217  may be formed in the first plate body  21 ′ in proximity to the outer periphery thereof and that extend in the same direction as the first protruding portion  213 ′ thereof. In the first preferred embodiment, the prominence portions  217  are frustoconical in shape and are formed respectively with through holes  218  in centers thereof. When the molten insulation material is introduced into the mold, the molten insulation material fills the through holes  218 . After the insulation material hardens, the prominence portions  217  are embedded in the dielectric layer  23 ′ to thereby enhance the connecting force between the first plate body  21 ′ and the dielectric layer  23 ′. Likewise, when stamp-forming the second plate body  22 ′, a plurality of prominence portions  217  may be formed in the second plate body  22 ′. A detailed description of the prominence portions  217  of the second plate body  22 ′ is dispensed with for the sake of brevity. 
         [0042]    A method of making a patch antenna according to a second preferred embodiment of the present invention will now be described with reference to  FIG. 15  and other drawings as specified below. As shown in steps  601 ˜ 604 , the difference between the method of the first preferred embodiment and the method of the second preferred embodiment is that, in the second preferred embodiment, the dielectric layer is manufactured separately from the radiation metal layer and the grounding layer before being bonded with these latter two elements. 
         [0043]    Referring to  FIG. 16 , in step  601 , a first metal plate (not shown) is stamped to form a first plate body  511  of a predetermined shape. In the second preferred embodiment, an outer periphery of the first plate body  511  is substantially circular. Further, a center area of the first plate body  511  is stamped to form a first aperture  512 , as well as a first protruding portion  513  that extends at substantially a right angle from a peripheral edge of the first aperture  512 . In addition, a first sub-feed-in hole  514  is formed in the first plate body  511 , and a guide groove  515  is formed in the first plate body  511  extending from the outer periphery and toward a center of the first plate body  511 , thereby completing the formation of a radiation metal layer  51 . 
         [0044]    In step  602 , a second metal plate (not shown) is stamped to forma second plate body  521  of a predetermined shape. In the second preferred embodiment, an outer periphery of the second plate body  521  is substantially circular, and a size of the second plate body  521  corresponds to a size of the first plate body  511 . Further, a center area of the second plate body  521  is stamped to form a second aperture  522 , as well as a second protruding portion  523  that extends at substantially a right angle from a peripheral edge of the second aperture  522 . In addition, a second sub-feed-in hole  524  is formed in the second plate body  521 , thereby completing the formation of a grounding metal layer  52 . 
         [0045]    In step  603 , a molten insulation material is introduced into a mold (not shown), such that after the insulation material hardens, a dielectric layer  53  of a predetermined shape and that has a through hole  531  in a center area thereof and a feed-in hole  532  is formed. 
         [0046]    Referring to  FIGS. 16 and 17 , in step  604 , opposite surfaces of the dielectric layer  53  are applied with an adhesive, which may be performed by coating the surfaces of the dielectric layer  53  with an adhesive or by applying adhesive droplets to the surfaces of the dielectric layer  53 . It is preferable that the adhesive is able to maintain its dielectric properties and does not deteriorate after being subjected to high temperatures (e.g., 300° C. or higher). Next, the radiation metal layer  51  and the dielectric layer  53  are placed opposing each other in such a manner that the first aperture  512  and the through hole  531  are aligned, as are the first sub-feed-in hole  514  and the feed-in hole  532 . Subsequently, the first plate body  511  is attached to the upper surface of the dielectric layer  53  such that the first protruding portion  513  is disposed in the through hole  531 . In addition, the grounding metal layer  52  and the dielectric layer  53  are placed opposing each other in such a manner that the second aperture  522  and the through hole  531  are aligned, as are the second sub-feed-in hole  524  and the feed-in hole  532 . Subsequently, the second plate body  521  is attached to the lower surface of the dielectric layer  53  such that the second protruding portion  523  is disposed in the through hole  531 . An inner diameter of the first protruding portion  513  is similar to an outer diameter of the second protruding portion  523  such that the first and second protruding portions  513 ,  523  may be coupled fittingly together. Moreover, the end of the first protruding portion  513  and the end of the second protruding portion  523  overlap such that an electrical connection is established between the radiation metal layer  51  and the grounding metal layer  53 . After the radiation metal layer  51  and the grounding metal layer  53  are attached to the dielectric layer  53 , a patch antenna  5  having a through hole  501  and a feed-in hole  502  is obtained. 
         [0047]    From the aforementioned, in the method of making a patch antenna of the present invention, an insulation material that is injection molded is used and made to correspond to the structures of the radiation metal layer  21 ,  51  and the grounding metal layer  22 ,  52  to thereby simplify manufacture. Compared to the conventional process using a fluoropolymer substrate, the present invention significantly simplifies manufacture of the patch antenna  2 ,  5 , reduces manufacturing costs, and is environmentally friendly. Hence, the objects of the present invention are realized. 
         [0048]    While the present invention has been described in connection with what are considered the most practical and preferred embodiments, it is understood that this invention is not limited to the disclosed embodiments but is intended to cover various arrangements included within the spirit and scope of the broadest interpretation so as to encompass all such modifications and equivalent arrangements.