Patent Publication Number: US-9899740-B2

Title: Hybrid antenna

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a Continuation of application Ser. No. 13/868,383, filed on Apr. 23, 2013, the entirety of which is incorporated by reference herein. 
    
    
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The disclosure generally relates to a hybrid antenna, and more particularly, relates to a hybrid antenna comprising a stamping element for improving antenna bandwidth and antenna efficiency. 
     Description of the Related Art 
     Nowadays, 2G or 3G communications system technology is applied in notebooks, tablet computers, or mobile phones. An RF (Radio Frequency) antenna incorporated in a PCB (Printed Circuit Board) is well known in the art. PCB antenna structures are widely used in wireless communications devices because they are relatively inexpensive to manufacture yet effective for low power communications. However, the drawbacks of PCB antenna structures are narrow bandwidths and poor antenna efficiencies. On the other hand, stamping antenna structures can overcome some drawbacks of PCB antenna structures, but have more complicated manufacturing processes and are more expensive. 
     BRIEF SUMMARY OF THE INVENTION 
     In one exemplary embodiment, the disclosure is directed to a hybrid antenna, comprising: a main radiator, a first holder, a second holder, a feeding element, an extension branch, a first trace, and a first via. The main radiator is substantially disposed above the dielectric substrate. The first holder is coupled to a first end of the main radiator. The second holder is coupled to a second end of the main radiator. The feeding element is coupled to a signal source. The extension branch is substantially disposed below the dielectric substrate, and is coupled between the second holder and the feeding element. The first trace is disposed on a second surface of the dielectric substrate, and the first via is formed through the dielectric substrate, and coupled between an end of the first trace and the first holder. 
     In another embodiment, the disclosure is directed to a method for manufacturing a hybrid antenna, comprising  20 . A method for manufacturing a hybrid antenna, comprising the steps of: providing a dielectric substrate, a stamping element, a first trace, and a first via, wherein the stamping element comprises a main radiator, a first holder, a second holder, a feeding element, and an extension branch, wherein the first holder is coupled to a first end of the main radiator, the second holder is coupled to a second end of the main radiator, and the extension branch is coupled between the second holder and the feeding element, wherein the first trace is disposed on a second surface of the dielectric substrate, and wherein the first via is formed through the dielectric substrate, and is coupled between an end of the first trace and the first holder; and performing an SMT (Surface Mounted Technology) process to fix the stamping element to the dielectric substrate, wherein the main radiator is substantially disposed above the dielectric substrate, the extension branch is substantially disposed below the dielectric substrate, and the feeding element is coupled to a signal source. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       The invention can be more fully understood by reading the subsequent detailed description and examples with references made to the accompanying drawings, wherein: 
         FIG. 1A  is a pictorial drawings for illustrating a hybrid antenna according to an embodiment of the invention; 
         FIG. 1B  is a pictorial drawings for illustrating a hybrid antenna according to an embodiment of the invention; 
         FIG. 1C  is a side view for illustrating a hybrid antenna according to an embodiment of the invention; 
         FIG. 2  is a diagram for illustrating a hybrid antenna and the manufacturing thereof according to an embodiment of the invention; 
         FIG. 3A  is a diagram for illustrating a hybrid antenna and the manufacturing thereof according to an embodiment of the invention; 
         FIG. 3B  is a diagram for illustrating a hybrid antenna according to an embodiment of the invention; 
         FIG. 4  is a diagram for illustrating return loss of a hybrid antenna according to an embodiment of the invention; 
         FIG. 5  is a diagram for illustrating antenna efficiency of a hybrid antenna according to an embodiment of the invention; and 
         FIG. 6  is a flowchart for illustrating a method for manufacturing a hybrid antenna according to an embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     In order to illustrate the purposes, features and advantages of the invention, the embodiments and figures thereof in the invention are described in detail as follows. 
       FIGS. 1A and 1B  are pictorial drawings for illustrating a hybrid antenna  100  according to an embodiment of the invention.  FIG. 1C  is a side view for illustrating the hybrid antenna  100  according to an embodiment of the invention. The hybrid antenna  100  may be applied to a variety of mobile devices, such as a smart phone, a tablet computer, and a notebook computer. The hybrid antenna  100  at least comprises a dielectric substrate  110 , a ground plane  120 , and a stamping element  130 . The dielectric substrate  110  may be a PCB (Printed Circuit Board), such as an FR4 (Flame Resistant 4) substrate. The ground plane  120  and the stamping element  130  may be made of conductive materials, such as silver, copper, or aluminum. Note that in a preferred embodiment, the stamping element  130  is fixed to the dielectric substrate  110  ( FIGS. 1B and 1C ), but they are shown as two separate components ( FIG. 1A ) to be understood easily. 
     The dielectric substrate  110  has a first surface E 1  and a second surface E 2 . The first surface E 1  is opposite to the second surface E 2 . In some embodiments, at least a portion of the stamping element  130  is disposed on the first surface E 1  of the dielectric substrate  110 , and the ground plane  120  is disposed on the second surface E 2  of the dielectric substrate  110 . In other embodiments, the ground plane  120  and the portion of the stamping element  130  are disposed on a same surface of the dielectric substrate  110 . The dielectric substrate  110  may be further known as “a virtual plane” in the disclosure. 
     The stamping element  130  comprises a main radiator  140 , a first holder  150 , a second holder  160 , a feeding element  170 , and an extension branch  180 . The main radiator  140  is separate from and substantially parallel to the dielectric substrate  110 . In some embodiments, the main radiator  140  substantially has a straight-line shape. The first holder  150  is coupled to a first end of the main radiator  140 , and the second holder  160  is coupled to a second end of the main radiator  140 , wherein the first end is opposite to the second end. The first holder  150  and the second holder  160  are soldered on the first surface E 1  of the dielectric substrate  110 , and are both substantially perpendicular to the main radiator  140 . In some embodiments, the main radiator  140  further comprises a first meandering structure, which may substantially have an S-shape, a W-shape, or a U-shape. The feeding element  170  is coupled to a signal source  199 . The signal source  199  is configured to excite the hybrid antenna  100 . The extension branch  180  is coupled between the second holder  160  and the feeding element  170 . In some embodiments, the extension branch  180  further comprises a second meandering structure, which may substantially have an S-shape, a W-shape, or a U-shape. The feeding element  170  comprises a feeding platform  172  coupled to the signal source  199 . The feeding platform  172  is soldered on the first surface E 1  of the dielectric substrate  110 , and is substantially disposed between the main radiator  140  and the dielectric substrate  110 . In some embodiments, the feeding platform  172  substantially has a rectangular shape. A resonant current path of the hybrid antenna  100  is from the feeding element  170  through the extension branch  180 , the second holder  160 , and the main radiator  140  to the first holder  150 . Note that the stamping element  130  is configured as a main radiation portion of the hybrid antenna  100 . In a preferred embodiment, the main radiator  140  of the stamping element  130  is substantially disposed above the dielectric substrate  110 , and the extension branch  180  of the stamping element  130  is substantially disposed below the dielectric substrate  110 . In comparison to a convention design including all antenna elements disposed above a PCB, the design of the invention can effectively reduce the total height of the hybrid antenna  100 . 
     In some embodiments, the hybrid antenna  100  may further comprise a taper element  190 . The taper element  190  is disposed on the first surface E 1  of the dielectric substrate  110 , and is coupled between the feeding platform  172  and the signal source  199 . In some embodiments, the taper element  190  substantially has a triangular shape. More particularly, a narrow portion of the taper element  190  is coupled to the signal source  199 , and a wide portion of the taper element  190  is coupled to the feeding platform  172 . The taper element  190  is an optional conductive component configured to increase the bandwidth of the hybrid antenna  100 , and it may be eliminated in other embodiments. 
     In some embodiments, the hybrid antenna  100  may further comprise a first via  111 , a second via  112 , a third via  113 , a first trace  121 , and a second trace  122 . The first trace  121  is disposed on the second surface E 2  of the dielectric substrate  110 . In some embodiments, the first trace  121  substantially has a U-shape. The first via  111  is formed through the dielectric substrate  110 , and is coupled between an end of the first trace  121  and the first holder  150 . The second trace  122  is disposed on the second surface E 2  of the dielectric substrate  110 . In some embodiments, the second trace  122  substantially has a straight-line shape. The second via  112  is formed through the dielectric substrate  110 , and is coupled between a first end of the second trace  122  and the feeding platform  172 . The third via  113  is formed through the dielectric substrate  110 , and is coupled between a second end of the second trace  122  and the second holder  160 . The second trace  122  is coupled in parallel to the extension branch  180 , and provides an additional resonant current path. In some embodiments, any of the first trace  121  and the second trace  122  further comprises a third meandering structure, which may substantially have an S-shape, a W-shape, or a U-shape. In some embodiments, the first holder  150  comprises a first protrusion  152 , and the second holder  160  comprises a second protrusion  162 . The first protrusion  152  is soldered on the first surface E 1  of the dielectric substrate  110  and is coupled to the first via  111 . The second protrusion  162  is soldered on the first surface E 1  of the dielectric substrate  110  and is coupled to the third via  113 . The first protrusion  152  and the second protrusion  162  may extend toward each other. In some embodiments, each of the first protrusion  152  and the second protrusion  162  substantially has a rectangular shape. In another embodiment, the first trace  121  and the second trace  122  are both disposed on the first surface E 1  of the dielectric substrate  110  (not shown), and are respectively directly coupled to the first holder  150  and the second holder  160 , instead of being coupled through the first via  111 , the second via  112 , and the third via  113 . The first via  111 , the second via  112 , the third via  113 , the first trace  121 , and the second trace  122  are optional conductive components configured to adjust impedance matching of the hybrid antenna  100 , and they may be eliminated in other embodiments. 
     In the invention, the stamping element  130  is designed to be partially above and partially below the dielectric substrate  110  (or a virtual plane) to reduce the total height of the hybrid antenna  100 . The main radiator  140  of the stamping element  130  is supported by the first holder  150  and the second holder  160  such that the hybrid antenna  100  is robust and the manufacturing of SMDs (Surface Mount Devices) is simplified. When an input signal is fed to the hybrid antenna  100 , the main radiator  140  has the largest current density among the hybrid antenna  100 . Since the main radiator  140  is separate from the dielectric substrate  110  and is almost not negatively affected by metal components disposed on the dielectric substrate  110 , the radiation efficiency and bandwidth of the hybrid antenna  100  is effectively improved. Furthermore, one or more traces disposed on the dielectric substrate  110  may be included and integrated with the stamping element  130 , and accordingly the hybrid antenna  100  has advantages of a stamping antenna structure and a PCB antenna structure. To be brief, the invention has at least the advantages of a small antenna size, low cost, a simple manufacturing process, robustness, and good radiation performance. The invention may suitably be applied to a variety of small mobile devices. 
     In some embodiments, an SMT (Surface Mounted Technology) process may be performed to solder one or more portions of the stamping element  130  onto the dielectric substrate  110 . As to the SMT process, soldering paste is first attached to one or more specific positions of the dielectric substrate  110 , and after the stamping element  130  is appropriately located, the soldering pastes are heated and melted to fix the stamping element  130 . The manufacturing of the invention may be further improved during the SMT process. Please refer to the following embodiments. 
       FIG. 2  is a diagram for illustrating a hybrid antenna  200  and the manufacturing thereof according to an embodiment of the invention.  FIG. 2  is similar to  FIGS. 1A, 1B, and 1C . In the embodiment, the hybrid antenna  200  further comprises a plastic fixture  210 . The plastic fixture  210  is disposed between the main radiator  140  and the feeding platform  172 , and touches both of them. When an SMT process is performed to fix the stamping element  130  to the dielectric substrate  110 , the plastic fixture  210  is configured to maintain the desired shape of the stamping element  130  and to increase stability of the stamping element  130 . In some embodiments, the plastic fixture  210  may be eliminated after the SMT process. Other features of the hybrid antenna  200  of  FIG. 2  are similar to those of the hybrid antenna  100  of  FIGS. 1A, 1B, and 1C . Accordingly, the two embodiments can achieve similar performances. 
       FIGS. 3A and 3B  are diagrams for illustrating a hybrid antenna  300  and the manufacturing thereof according to an embodiment of the invention.  FIGS. 3A and 3B  are similar to  FIGS. 1A, 1B, and 1C . In the embodiment, the first holder  150  and the second holder  160  are fixed to the dielectric substrate  110  by a first location pin  311  and a second location pin  312 , respectively. As shown in  FIG. 3A , the extension branch  180  comprises a slight bend  182  which is originally not parallel to the main radiator  140 . As shown in  FIG. 3B , when an SMT process is performed to fix the stamping element  130  to the dielectric substrate  110 , the slight bend  182  of the extension branch  180  is forced to be parallel to the main radiator  140  and the dielectric substrate  110 , and generates elastic force to increase stability of the stamping element  130 . Other features of the hybrid antenna  300  of  FIGS. 3A and 3B  are similar to those of the hybrid antenna  100  of  FIGS. 1A, 1B, and 1C . Accordingly, the two embodiments can achieve similar performances. 
       FIG. 4  is a diagram for illustrating return loss of the hybrid antenna according to an embodiment of the invention. The horizontal axis represents operation frequency (MHz), and the vertical axis represents return loss (dB). According to the criterion of 6 dB return loss, the hybrid antenna of the invention at least covers a first band FB 1  and a second band FB 2 . In a preferred embodiment, the first band FB 1  is approximately from 824 MHz to 960 MHz, and the second band FB 2  is approximately from 1710 MHz to 2170 MHz. 
       FIG. 5  is a diagram for illustrating antenna efficiency of the hybrid antenna according to an embodiment of the invention. The horizontal axis represents operation frequency (MHz), and the vertical axis represents antenna efficiency (dB). As shown in  FIG. 5 , the hybrid antenna of the invention has good antenna efficiency in both of the first band FB 1  and the second band FB 2 , thus, the antenna efficiency may meet various application requirements. 
       FIG. 6  is a flowchart for illustrating a method for manufacturing a hybrid antenna according to an embodiment of the invention. To begin, in step S 610 , a dielectric substrate and a stamping element are provided, wherein the stamping element comprises a main radiator, a first holder, a second holder, a feeding element, and an extension branch, wherein the first holder is coupled to a first end of the main radiator, the second holder is coupled to a second end of the main radiator, and the extension branch is coupled between the second holder and the feeding element. Finally, in step S 620 , an SMT (Surface Mounted Technology) process is performed to fix the stamping element to the dielectric substrate, wherein the main radiator is substantially disposed above the dielectric substrate, the extension branch is substantially disposed below the dielectric substrate, and the feeding element is coupled to a signal source. Note that every detailed feature of the embodiments of  FIGS. 1-5  may be applied to the method of  FIG. 6 . 
     It should be understood that the above-mentioned element size, element shapes, and frequency ranges are not used to limit the invention. An antenna designer can adjust these settings according to different requirements. 
     Use of ordinal terms such as “first”, “second”, “third”, etc., in the claims to modify a claim element does not by itself connote any priority, precedence, or order of one claim element over another or the temporal order in which acts of a method are performed, but are used merely as labels to distinguish one claim element having a certain name from another element having a same name (but for use of the ordinal term) to distinguish the claim elements. 
     While the invention has been described by way of example and in terms of the preferred embodiments, it is to be understood that the invention is not limited to the disclosed embodiments. To the contrary, it is intended to cover various modifications and similar arrangements (as would be apparent to those skilled in the art). Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements.