Patent Publication Number: US-7714785-B2

Title: GPS antenna module and manufacturing method thereof

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Inventiong 
   The present invention relates to an antenna module and a manufacturing method thereof, and more specifically to an antenna module used in a GPS and a manufacturing method thereof. 
   2. Description of the Prior Art 
   Recently, GPS (Global Positioning System) has become more widely used, especially for navigation positioning. By integrating secondary satellites and communication techniques, accurate positioning, direction and distance can be easily found by anybody; even their speed and time can be known. Hence, the application scope of GPS is very wide. Many kinds of mobile communication devices (such as mobile phones, PDAs, etc.), or relative car electronic devices have been integrated with GPS functions, and GPS has thereby become a necessary function for many devices. 
   However, because of the rapid development of techniques, demands on utility and the need for portability, the size of electronic elements has tended towards becoming smaller and smaller. When integrating multiple functions into a single product, the space occupied by elements must be taken into account. The volume of chips or semiconductor elements can be reduced easily because of the development of packaging processes. However, the volume of prior art GPS antenna modules is difficult to reduce. Please refer to  FIG. 1 , in which a cutaway view of an antenna module frame of a prior art is shown. The antenna module includes a three layered frame that includes a patch antenna  100   a , a PCB (printed circuit board)  300   a , and a shielding case  400   a . One surface of the PCB  300   a  is soldered with a plurality of electronic elements  310   a , and another surface is adhered with the patch antenna  100   a  via double-sided glue  200   a . The patch antenna  100   a  is connected electronically with the soldered dots  500   a  via the antenna pin  101   a  which penetrates the PCB  300   a . Moreover, the shielding case  400   a  is soldered on the side of the PCB  300   a  soldered with a plurality of electronic elements  310   a  via the soldering dots  501   a . Because of the volume of the PCB  300   a  and the shielding case  400   a , the volume of the antenna module is limited and cannot to be further reduced. Hence, it is difficult to satisfy the finesse and demands of small products and devices. Further more, for the processes of the antenna module, there are many soldering dots  500   a ,  501   a  that must be soldered on manually, thus, the efficiency of the processes and costs are affected. 
   If the volume of the antenna module is reduced, costs are lowered, and a steady efficiency and characteristic are maintained, thereby, the antenna module becomes more cost competitive. Hence, the GPS antenna module and the processes thereof can be improved further. 
   Hence, the inventors of the present invention believe that the shortcomings described above are able to be improved upon and suggest the present invention which is of a reasonable design and is an effective improvement based on deep research and thought. 
   SUMMARY OF THE INVENTION 
   An object of the present invention is to provide an antenna module and a manufacturing method thereof. The volumes of the PCB and the shielding case are omitted, and the PCB and the shielding case are substituted by two insulating layers which are coated on a patch antenna. The processes are similar to the semiconductor process. Hence, the volume of the antenna module is reduced, and an optimal high frequency characteristic is achieved. 
   To achieve the above-mentioned object, a GPS antenna module is disclosed. The module comprises a substrate, a first insulating layer, and a second insulating layer. The substrate is set on a bottom surface of a patch antenna. The first insulating layer is coated on the substrate, and a layout circuit is formed on the first insulating layer. A plurality of electronic elements is integrated on the substrate according to the layout circuit. The second insulating layer is coated on the first insulating layer to shield the electronic elements. 
   To achieve the above-mentioned object, a manufacturing method of the GPS antenna module is disclosed. The method comprises providing a patch antenna; coating a first insulating layer on the bottom surface of the patch antenna; forming a layout circuit on the first insulating layer; integrating a plurality of electronic elements on the substrate according to the layout circuit; and coating a second insulating layer on the first insulating layer to shield the electronic elements. 
   To further understand the features and technical contents of the present invention, please refer to the following detailed description and drawings related to the present invention. However, the drawings are only to be used as references and explanations, and not to limit the present invention. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a cutaway view of an antenna module of a prior art; 
       FIG. 2A  is a cutaway view of an antenna module of the present invention; 
       FIG. 2B  is an exploded view of an antenna module of the present invention; 
       FIG. 3  is a flow chart of a manufacturing method of the antenna module of the present invention. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Please refer to  FIG. 2A , in which a cutaway view of an antenna module of the present invention is shown. The antenna module used in a GPS (Global Positioning System) includes a patch antenna  1 , a first insulating layer  2 , and a second insulating layer  3 . Please also refer to  FIG. 2B , in which an exploded view of an antenna module of the present invention is shown. A substrate  10  is set on the bottom surface of the patch antenna  1  and is made of ceramic. The first insulating layer  2  is coated on the substrate  10 , and a layout circuit  20  is formed thereon by semiconductor processes such as using photo resist, developing and etching, etc. The layout circuit  20  can be an antenna amplifier circuit for the GPS receiving signals, or can be a decoding circuit needed by a relative decoding chip. The patch antenna  1  includes an antenna pin  11 , which connects electronically with the layout circuit  20  to transmit the GPS signals. A plurality of electronic elements  201  are integrated on the substrate  10  according to the layout of the layout circuit  20  and the element positions, and are connected with the antenna pin  11  via the layout circuit  20 . The electronic elements  201  are integrated on the substrate  10  via LTCC (Low-Temperature Co-fired Ceramics), printed processes, or heat-transferring processes, etc. The electronic elements  201  are integrated as bare chips, and the packaging method is not required. Hence, the high frequency characteristic is optimized, and the cost of the elements is lowered further. 
   The second insulating layer  3  is coated on the first insulating layer  2  to shield the electronic elements  201 , and thereby prevent the electronic elements  201  from being damaged and signal from suffering interference. The first insulating layer  2  and the second insulating layer  3  can be coated by spin coating, roller coating, ink jet printing, slot die coating, screen printing, or imprinting methods, etc. The material of the first insulating layer  2  and the second insulating layer  3  can be silicon dioxide, plasma nitride, plastic, or glass, etc. 
   Please refer to  FIG. 3 , in which a flow chart of a manufacturing method of an antenna module of the present invention is shown, and also to  FIG. 2B . Firstly, to provide the patch antenna  1  (S 301 ) the substrate  10  is set on the bottom surface of the patch antenna  1  and is made of ceramic. The antenna pin  11  is set on a bottom surface of the patch antenna  1 . Then, the first insulating layer  2  is coated on the substrate  10  of the patch antenna  1 , and the layout circuit  20  is formed on the first insulating layer  2  via semiconductor processes (such as using photo resist, developing and etching, etc.) (S 303 ). 
   The electronic elements  201  are integrated on the substrate  10  of the patch antenna  1  according to the relative element positions on the layout circuit  20  (S 305 ). The integrating method can be LTCC (Low-Temperature Co-fired Ceramics), printed processes, or heat transferring processes, etc. The antenna pin  11  is connected electronically with the electronic elements  201  by forming the layout circuit  20  and integrating the electronic elements  201 . The GPS signal received by the antenna module can be filtered and amplified therein. 
   Finally, the second insulating layer  3  is coated on the first insulating layer  2 , thereby completely shielding the electronic elements  201 , which are integrated on the substrate  10  and exposed on the first insulating layer  2  (S 307 ). Hence, signal interference and damage to the electronic elements  201  can be avoided. 
   In summary, the volume taken up by the PCB and the shielding case of the prior art can be omitted, and thereby the size of the antenna module can be reduced and the cost lowered. Because the distance between the electronic elements  201  and the antenna is shortened, an optimal high frequency character can be achieved. Moreover, the process for manufacturing the antenna module of the present invention is simplified by the SMT method (surface mounted technology), which shortens production time and assembly time. Careless mistakes made by manual soldering can be indirectly reduced, which increases the yield of the products. 
   What is disclosed above are only the preferred embodiments of the present invention, and therefore it is intended that the present invention not be limited to the particular embodiments disclosed. It should be understood by those skilled in the art that various equivalent changes may be made depending on the specifications and the drawings of present invention without departing from the scope of the present invention.