Abstract:
A mobile communication apparatus includes a printed circuit board (PCB) and a global positioning system (GPS) antenna. The GPS antenna is made of a metal sheet, and vertically inserted into the PCB.

Description:
[0001]     This application claims the benefit of Taiwan application Serial No. 93139231, filed Dec. 16, 2004, the subject matter of which is incorporated herein by reference.  
       BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The invention relates in general to a mobile communication apparatus and global positioning system (GPS) antenna thereof, and more particularly to a mobile communication system, which utilizes a small-scale metal sheet for the GPS antenna design, and GPS antenna thereof.  
         [0004]     2. Description of the Related Art  
         [0005]      FIG. 1  is a schematic structure diagram of a conventional mobile communication apparatus having a GPS chip antenna. Referring to  FIG. 1 , the mobile communication apparatus  100 , such as a personal digital assistant (PDA), a PDA phone, a smart phone, or a mobile phone, includes a GPS chip antenna  110  and a printed circuit board (PCB)  120 . The GPS chip antenna  110  is disposed in a GPS antenna design region  130  of the PCB  120 . The specification of the design region  130  is generally 18 mm×3 mm. The GPS antenna includes a ceramics part  112  and an antenna body  114 . The antenna body  114 , a printed circuit disposed on the surface of the ceramics part  112 , can miniaturize the antenna  110  by using the ceramics  112  of high dielectric constant and provide a GPS operational frequency of 1575 MHz. The GPS chip antenna  110  is for example, a Hitachi SMA-15011C1 small ceramic antenna for GPS.  
         [0006]     However, the chip antenna  110  having ceramics material is very easily damaged and broken in a drop test, and the performance of the antenna body  114  in receiving signals will be reduced due to high dielectric constant of the ceramics part  112 . In addition, because the antenna body  114  is mainly disposed in parallel with the PCB  120 , the antenna body  114  is easily interfered by circuits and other antennas on the PCB  120 , thereby influencing the performance of the antenna body  114  in receiving signals. Using ceramics material to design antenna structure also increases manufacturing cost.  
       SUMMARY OF THE INVENTION  
       [0007]     It is therefore an object of the invention to provide a mobile communication apparatus and GPS antenna thereof. By designing a number of declined slots on a metal sheet as an antenna, the metal antenna can be miniaturized and configured in the above-mentioned GPS chip antenna design region. Moreover, the antenna surface is perpendicular to the PCB. Therefore, not only a better antenna radiation field can be generated but also the manufacturing cost of GSP antenna can be reduced.  
         [0008]     The invention achieves the above-identified object by providing a GPS antenna disposed on a PCB of a mobile communication apparatus. The GPS antenna is made of a metal sheet, and the metal sheet includes a number of slots.  
         [0009]     The invention achieves the above-identified object by providing a mobile communication apparatus including a PCB and a GPS antenna. The GPS antenna is made of a metal sheet for vertically inserting into the PCB.  
         [0010]     Other objects, features, and advantages of the invention will become apparent from the following detailed description of the preferred but non-limiting embodiments. The following description is made with reference to the accompanying drawings. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]      FIG. 1  is a schematic structure diagram of a conventional mobile communication apparatus having a GPS chip antenna.  
         [0012]      FIG. 2A  is a schematic structure diagram of a mobile communication apparatus according to a preferred embodiment of the invention.  
         [0013]      FIG. 2B  is a structure diagram of a GPS antenna according to a preferred embodiment of the invention.  
         [0014]      FIG. 2C  is a comparison diagram between the radiation field of the conventional chip antenna and the radiation field of the GPS antenna of the invention in  FIG. 2A . 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0015]     Referring to  FIG. 2A  and  FIG. 2B  simultaneously, a schematic structure diagram of a mobile communication apparatus and a structure diagram of a GPS antenna according to a preferred embodiment of the invention are shown. The mobile communication apparatus  200 , such as a PDA, a PDA phone, a smart phone, or a mobile phone, includes a GPS antenna  210 , a PCB  220 , and other components (not shown in the figure). The GPS antenna  210  is disposed in the GPS antenna design region  230  of the PCB  220 . The GPS antenna  210  includes a rectangle body  212 , a positioning part  213 , a support sheet  215 , an adsorption sheet  217 , and a feed-in part  219 . The body  212  is for vertically inserting into the PCB  220 . The metal sheet  212  further includes a number of declined slots  214  in parallel with each other and having the same slot width. The openings of two adjacent slots are formed in opposite direction.  
         [0016]     The positioning part  213  is disposed at the bottom side A of the body  212 . There are totally disposed two positioning parts in the preferred embodiment. The positioning part  213  is for inserting into the corresponding hole (not shown in the figure) of the PCB  220 . The hole contains solder, and the solder is melt away to weld the positioning part  213  in the PCB  220  when a surface mount technology (SMT) is performed to weld the antenna  210  onto the PCB  220 . The support sheet  215  is connected to a short side B of the body  212  without disposing any declined slots  214 , for welding onto the PCB  220  and supporting the body  212  to be vertical with the PCB  220 . In manufacturing process, the support sheet  215  can be welded onto the PCB  220  by SMT The adsorption sheet  217 , connected to a top side C of the body  212 , is disposed in parallel with the PCB  220  and vertical to the surface of the body  212 . The SMT machine can mount the GPS antenna  210  on the PCB  220  by adsorbing the adsorption sheet  217 . The feed-in part  219  is connected to a short side D of the metal sheet  212  opposite to the support sheet  215 , for connecting with the PCB  220  and receiving GPS signals of operational frequencies. The feed-in part  219  is welded onto the PCB  220  by SMT.  
         [0017]     As mentioned above, the GPS antenna design region  230  has a scale of 18 mm×3 mm. An ordinary metal antenna should have a length of  40 mm in order to generate resonance modes in a GPS operational frequency  1575  MHz. However, the GPS antenna having the body  212  structure of four declined slots  214  and one triangular slot  216  in the embodiment can be miniaturized and disposed in the design region  230 , and generate resonance modes having the required GPS operational frequency in test.  
         [0018]     As shown in  FIG. 2B , the length of GPS antenna  210  is calculated about  15  mm with respect to the length of the body  212 , and the width of GPS antenna  210  is determined to be about  2 . 75  mm according to the width of the support sheet  215 . Therefore, the GPS antenna  210  can be disposed in the above-mentioned GPS antenna design region  230 . In the embodiment, each declined slot  214  has a included angle about 30 degrees with respect to the short side D of the rectangle body  212  and the slot angle of the triangular slot  216  is also designed 30 degrees.  
         [0019]     Besides, the slot width D of each declined slot  214  is about 0.8 mm. The induced currents  11  and  12  in opposite direction are respectively generated at two sides of the declined slot  214  after the antenna  210  receives a signal, so if the slot width of the declined slot  212  is too small, such as smaller than 0.8 mm, it will happen that the induced currents  11  and  12  are canceled out by each other.  
         [0020]     The feed-in part  219  is disposed at the short side D of the body  212 . When the antenna  210  receives a signal in a GPS operational band, the induced current can flow through the longest effective path, that is, from the short side D, pass the five turning parts  218  of the body  212  to the short side B. Although the total length of the rectangle body  212  is only 15 mm, resonance modes in a GPS operational band can be generated by smart design of the declined slots  214 . In the invention, the triangular slot  216  is close to the short side D and the five turning parts  218  are formed respectively between two adjacent slots. The first turning part  218  is formed between the triangular slot  216  and the adjacent declined slot  214 . The other four turning parts  218  are respectively formed between two adjacent declined slots  214 .  
         [0021]     The above-mentioned GPS antenna  210  can be designed a monopole antenna so as to improve performance in receiving signals. Moreover, the GPS antenna  210  can be a nickel silver material, or other materials having enough strength in order that the antenna  210  is not damaged in the drop test.  
         [0022]     Referring to  FIG. 2C , a comparison diagram between the radiation field of the conventional chip antenna (a Hitachi SMA-15011C1 small ceramic antenna for GPS)  110  and the radiation field of the GPS antenna  210  of the invention in  FIG. 2A  is shown. The upper diagram of  FIG. 2C  shows the radiation fields generated by the conventional chip antenna  110  respectively on the H surface (i.e. the XZ-plane in the figure), the E 1  surface (i.e. the YZ-plane in the figure), and the E 2  surface (i.e. the XY-plane in the figure). The lower diagram of  FIG. 2C  shows the radiation fields generated by the GPS antenna  210  respectively on the H surface, the E 1  surface, and the E 2  surface. From  FIG. 2C , the radiation field of GPS antenna  210  is closer to an ellipse polarization field than that of the chip antenna  110  in prior art. It implies that the small-scale metal antenna vertically disposed on the PCB  220  can really reduce the interference from circuits or other antennas on the PCB  220 , and thus effectively improve the performance in receiving signals.  
         [0023]     As described above, although the GPS antenna of the invention is exemplified to have a rectangle body composed of four declined slots and one triangular slot, the GPS antenna of the invention can also be any other metal sheet structure having slots. As long as the slot is suitably designed so that the antenna can be miniaturized and generate resonance modes in a GPS operational band, it will not be apart from the skill scope of the invention.  
         [0024]     The mobile communication apparatus and GPS antenna thereof disclosed by the above-mentioned embodiment of the invention has the following advantages. The metal antenna having a rectangle body composed of several declined slots can be miniaturized and disposed in the design region for GPS chip antenna, and generate the required resonance modes in a GPS operational band. Therefore, the antenna of the invention can provide higher performance, and generate better ellipse polarization field. Furthermore, the antenna will not be damaged in the drop test and thus reduce manufacturing cost for its metal material has the features of high strength, easy production and low cost.  
         [0025]     While the invention has been described by way of example and in terms of a preferred embodiment, it is to be understood that the invention is not limited thereto. On the contrary, it is intended to cover various modifications and similar arrangements and procedures, and the scope of the appended claims therefore should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements and procedures.