Patent Publication Number: US-8542159-B2

Title: Cable connector and antenna component

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This is a Continuation Application of International Application No. PCT/JP2009/006942, filed on Dec. 16, 2009, which claims priority to Japanese Patent Application No. 2008-319520, filed on Dec. 16, 2008, and Japanese Patent Application No. 2008-319946, filed on Dec. 16, 2008. The contents of the aforementioned applications are incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a cable connector for connecting an RF module with an antenna in the internal components of electronic equipment, and also relates to an antenna component in which the cable connector is connected with the antenna. More particularly, the present invention relates to a cable connector and an antenna component which eliminate complicated steps of assembling a connector with a transmission line, which are capable of reducing assembly steps in number and a manufacturing cost more than the conventional cable connectors and antenna components, and which are capable of making a connector connection portion thinner. 
     2. Description of the Related Art 
     In conventional RF connectors (small-size coaxial connectors), electrically connecting a coaxial cable with an RF module in a method as shown, for example, in  FIG. 11A  to  FIG. 13  is dominant (for example, see Japanese Unexamined Patent Application, First Publication No. 2001-307842 and Japanese Unexamined Patent Application, First Publication No. 2006-318936). In this method, a coaxial cable  141  is first stripped as shown in  FIGS. 11A and 11B  to expose an internal conductor  142  and an external conductor  143 . Next, as shown in  FIG. 11D , the internal conductor  142  of the coaxial cable  141  is soldered to a contact terminal  140  as shown in  FIG. 11C . Next, as shown in  FIG. 12A , a housing  122  is assembled into a shell terminal  121  to fabricate an assembly  120 . Next, as shown in  FIG. 12B , into the assembly  120 , the coaxial cable  141  soldered to the contact terminal  140  is assembled. Next, as shown in  FIGS. 12C and 12D , the external conductor  143  of the coaxial cable  141  is caulked into the shell terminal  121 , and also an outer cladding  144  of the coaxial cable  141  is caulked into the shell terminal  121 . The assembly  120  connected with the coaxial cable  141  is attached to an RF module  130  as shown in  FIG. 13 , to thereby electrically connect the coaxial cable  141  with the RF module  130 . 
     However, in the case where a conventional RF connector is used, the number of assembly steps is large as shown in  FIGS. 11A to 12D . In addition, the assembly requires a sophisticated skill. 
     Furthermore, because the coaxial cable has a large diameter, it is difficult to make thin (low-profile) the connection portion (the connector connection portion) between the coaxial cable and the RF connector (that is, make thin the assembly  120  shown in  FIG. 12D ). 
     Furthermore, with numerous steps for assembling the RF connector with the coaxial cable, their manufacturing cost becomes high. 
     The present invention has been achieved in view of the above circumstances, and has an object to provide a cable connector and an antenna component with a reduced number of assembly steps and a reduced manufacturing cost, and also capable of making the connector connection portion thin. 
     SUMMARY 
     To solve the above problems and achieve such an object, the present invention adopts the followings. 
     (1) A cable connector of the present invention includes: a wiring board with a signal transmission line; and a plug connector that is provided on one surface of the wiring board and that is electrically connected with the signal transmission line. The wiring board comprises a first conductor, an insulating material, and a second conductor laminated in this order. In a slit formed in the second conductor, the signal transmission line that is a part of the second conductor cut out from the second conductor is arranged at a predetermined distance from the second conductor. The second conductor and the signal transmission line are arranged on the same plane. 
     (2) In the case of the above (1), it is preferable that the wiring board comprises the first conductor, the second conductor, and the third conductor laminated in this order respectively via an insulating material. 
     (3) In the case of the above (1) or (2), it is preferable that on the one surface of the wiring board, a coaxial cable that is electrically connected with the signal transmission line be disposed. 
     (4) In the case of the above (1) or (2), it is preferable that a first notch portion be formed at a position facing the signal transmission line of the first conductor. 
     (5) In the case of the above (4), it is preferable that a second notch portion be formed at a position facing the plug connector of the first conductor. 
     (6) An antenna component of the present invention includes: a first wiring board with a signal transmission line; a plug connector that is provided on one surface of the first wiring board and that is electrically connected with the signal transmission line; and a second wiring board that has an antenna electrically connected with the signal transmission line and that is coupled to the first wiring board. The first wiring board comprises a first conductor, an insulating material, and a second conductor laminated in this order. In a slit formed in the second conductor, the signal transmission line that is a part of the second conductor cut out from the second conductor is arranged at a predetermined distance from the second conductor. The second conductor and the signal transmission line are arranged on the same plane. 
     (7) In the case of the above (6), it is preferable that the first wiring board comprises the first conductor, the second conductor, and the third conductor laminated respectively via an insulating material. 
     (8) In the case of the above (6) or (7), it is preferable that a first notch portion is formed at a position facing the signal transmission line of the first conductor. 
     (9) In the case of the above (8), it is preferable that a second notch portion is formed at a position facing the plug connector of the first conductor. 
     According to the cable connector as set forth in the above (1), the second conductor and the signal transmission line are placed on the same plane, and the second conductor is placed on both sides of the signal transmission line. This can make the connection portion between the plug connector and its mating connector thin. Therefore, it is possible to make thin the electronic equipment that uses the cable connector. 
     Furthermore, the plug connector can be installed on the wiring board with ease, which makes it possible to simplify the assembly steps. As a result, the manufacturing cost of the cable connector can be reduced. Furthermore, because the assembly steps can be simplified, the manufactured cable connectors are unlikely to suffer from performance variations, making it possible to provide stable products. 
     In addition, with the change such as in width and length of the signal transmission line, in a gap between the signal transmission line and the second conductor, and in thickness of the first conductor and the second conductor, it is possible to control the characteristic impedance of the signal transmission line with ease. Therefore, impedance of the wiring board can be optimized with ease in accordance with the communication characteristics (frequency band, communication distance, and the like) at high frequencies of the equipment and the antenna that are to be connected with the cable connector. 
     According to the antenna component as set forth in the above (6), it is possible to make thin the connection portion between the plug connector and its mating connector, the connection portion between the first wiring board and the second wiring board, and the antenna. Therefore, it is possible to make thin the electronic equipment that uses the antenna component. 
     Furthermore, the plug connector can be installed on the first wiring board with ease, which makes it possible to simplify the assembly steps. As a result, the manufacturing cost of the antenna component can be reduced. Furthermore, because the assembly steps can be simplified, the manufactured antenna components are unlikely to suffer from performance variations, making it possible to provide stable products. 
     In addition, with the change in width and length of the signal transmission line, in a gap between the signal transmission line and the second conductor, and in thickness of the first conductor and the second conductor, it is possible to control the characteristic impedance of the signal transmission line. Therefore, impedance of the first wiring board can be optimized with ease in accordance with the communication characteristics (frequency band, communication distance, and the like) at high frequencies of the antenna of the second wiring board. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  is a perspective view showing a first embodiment of a cable connector according to the present invention. 
         FIG. 1B  is a plan view of the embodiment. 
         FIG. 1C  is a side view of the embodiment. 
         FIG. 1D  is a cross-sectional view of  FIG. 1B , taken along the A-A line. 
         FIG. 1E  is a cross-sectional view of  FIG. 1B , taken along the B-B line. 
         FIG. 2A  is a plan view of a second conductor used in the embodiment. 
         FIG. 2B  is a plan view of a first conductor used in the embodiment. 
         FIG. 3  is a schematic perspective view showing one example of use of the cable connector of the embodiment. 
         FIG. 4  is a schematic perspective view showing a second embodiment of the cable connector according to the present invention. 
         FIG. 5A  is a perspective view showing a third embodiment of the cable connector according to the present invention. 
         FIG. 5B  is a plan view of the embodiment. 
         FIG. 5C  is a cross-sectional view of  FIG. 5B , taken along the A-A line. 
         FIG. 5D  is a cross-sectional view of  FIG. 5B , taken along the B-B line. 
         FIG. 6  is a plan view showing an arrangement of a second conductor and a signal transmission line of the embodiment. 
         FIG. 7  is a schematic perspective view showing one example of use of the cable connector of the embodiment. 
         FIG. 8  is a schematic perspective view showing a fourth embodiment of the cable connector according to the present invention. 
         FIG. 9  is a perspective view of a first embodiment of an antenna component according to the present invention. 
         FIG. 10  is a perspective view showing a second embodiment of the antenna component according to the present invention. 
         FIG. 11A  is a process diagram showing how to electrically connect a coaxial cable with an RF module in the case where a conventional RF connector is used. 
         FIG. 11B  is a process diagram showing how to electrically connect the coaxial cable with the RF module in the case where the conventional RF connector is used. 
         FIG. 11C  is a process diagram showing how to electrically connect the coaxial cable with the RF module in the case where the conventional RF connector is used. 
         FIG. 11D  is a process diagram showing how to electrically connect the coaxial cable with the RF module in the case where the conventional RF connector is used. 
         FIG. 12A  is a process diagram showing how to electrically connect the coaxial cable with the RF module in the case where the conventional RF connector is used. 
         FIG. 12B  is a process diagram showing how to electrically connect the coaxial cable with the RF module in the case where the conventional RF connector is used. 
         FIG. 12C  is a process diagram showing how to electrically connect the coaxial cable with the RF module in the case where the conventional RF connector is used. 
         FIG. 12D  is a process diagram showing how to electrically connect the coaxial cable with the RF module in the case where the conventional RF connector is used. 
         FIG. 13  is a process diagram showing how to electrically connect the coaxial cable with the RF module in the case where a conventional RF connector is used. 
     
    
    
     EMBODIMENTS FOR CARRYING OUT THE INVENTION 
     Embodiments of a cable connector according to the present invention will be described. 
     The embodiments will be specifically described for better understanding of the spirit or scope of the invention, and hence, do not limit the present invention unless otherwise specified. 
     First Embodiment 
       FIGS. 1A to 1E  are schematic diagrams showing a first embodiment of a cable connector according to the present invention.  FIG. 1A  is a perspective view of the present embodiment.  FIG. 1B  is a plan view of the present embodiment.  FIG. 1C  is a side view of the present embodiment.  FIG. 1D  is a cross-sectional view of  FIG. 1B , taken along the A-A line.  FIG. 1E  is a cross-sectional view of  FIG. 1B , taken along the B-B line. 
     A cable connector  1 A ( 1 ) of the present embodiment comprises: a wiring board  10 A ( 10 ); and a plug connector  20 . 
     The wiring board  10 A has a first conductor  13 , an insulating material  15 , and a second conductor  14 , which are laminated in this order with a substantially equal thickness. As the insulating material  15 , for example a polyimide resin, a polyethylene terephthalate resin, an aramid resin, a liquid crystal polymer (LCP), or the like may be used. 
     In the second conductor  14 , a part of it is cut off to form a slit  11 . In the slit  11 , a signal transmission line  16 , which is made of the same material as that of the second conductor  14 , is arranged with a predetermined space s from the second conductor  14  (see  FIG. 2A ). The second conductor  14  and the signal transmission line  16  are placed on the same plane. That is, the signal transmission line  16  is placed so that its two sides and its front end side (plug connector  20  side) is surrounded by the second conductor  14 . 
     A plug connector  20  is provided on one surface  10   a  of the wiring board  10 , and is electrically connected with the signal transmission line  16 . 
     In the cable connector  1 A of the present embodiment, the first conductor  13  and the second conductor  14  form ground conductor for the signal transmission line  16 . That is, in the wiring board  10 A, the signal transmission line  16  is arranged so as to be on a wide ground conductor (the first conductor  13 ), and another ground conductor (the second conductor  14 ) is arranged on the same plane as the signal transmission line  16  so as to surround the two sides and the front end side of the signal transmission line  16 . With this construction, the radiated noise from the signal transmission line  16  is diminished. 
       FIG. 2A  is a plan view schematically showing the second conductor  14  and the signal transmission line  16 . 
     The second conductor  14  and the signal transmission line  16  are made of a foil of metal such as copper. 
     As shown in  FIG. 2A , the signal transmission line  16  is provided in the longitudinal direction of the second conductor  14 , along the slit  11  provided in the central portion of the second conductor  14 . The signal transmission line  16  has its base end in the vicinity of an end portion of a region  14   a  of the second conductor  14  that faces the plug connector  20 . The signal transmission line  16  extends as far as to one end  14   b  of the second conductor  14 . The signal transmission line  16  is electrically connected with, for example, an antenna or the like at the one end portion  14   b  of the second conductor  14  (not shown in the figure). 
     Furthermore, the signal transmission line  16  is arranged at a predetermined space s from the second conductor  14 . 
       FIG. 2B  is a plan view schematically showing the first conductor  13 . 
     The first conductor  13  is made of a foil of metal such as copper, similarly to the second conductor  14  and the signal transmission line  16 . 
     In the first conductor  13 , there are formed a plurality of rectangular first notch portions  13   a  at positions facing the signal transmission line  16 . Furthermore, at a position of the first conductor  13  that faces the plug connector  20 , there is formed a second notch portion  13   b  that is larger than the first notch portion  13   a . With the first notch portions  13   a  and the second notch portion  13   b  formed at these positions, impedance matching of the wiring board  10 A can be obtained, reflection loss of the electric signals are diminished, and transmission characteristics of the signals flowing through the signal transmission line  16  can be improved. Without the first notch portions  13   a  and the second notch portion  13   b , there is a possibility that use of a thin substrate such as an FPC will cause the C component increase and its impedance decrease, resulting in insufficient transmission of signals. 
     The first notch portion  13   a  has a size of, for example, 0.5 mm×0.5 mm. 
     The second notch portion  13   b  has a size of, for example, 2.1 mm×1.05 mm. 
     Along the edge portions of the first conductor  13  and the second conductor  14 , and along the edge portion of the insulating material  15  that is placed therebetween, there are provided a plurality of through-holes  12  at their respective corresponding positions, which are spaced a predetermined distance apart from each other. That is, the through-holes  12  penetrate the wiring board  10 A ( 10 ) in its thickness direction to electrically connect the first conductor  13  with the second conductor  14 . 
     The distance d between the through-holes  12  is a length corresponding to ½ or less of the wavelength of the frequency of the antenna to be connected with the cable connector  1 A. 
     The space s between the second conductor  14  and the signal transmission line  16 , the length and the width w of the signal transmission line  16 , the thicknesses of the first conductor  13 , the second conductor  14 , and the insulating material  15 , and other dimensions are appropriately adjusted in accordance with the impedance required for the wiring board  10 A. As a result, impedance of the wiring board  10 A can be adjusted, and also the impedance can be optimized in accordance with the communication characteristics (frequency band, communication distance, and the like) at high frequencies of the antenna to be connected with the cable connector  1 A. 
     For example, in portable communication equipment on a radio system that communicates in the 12 GHz band, the impedance required for the wiring board  10 A is 50Ω. Therefore, for example, the space s between the second conductor  14  and the signal transmission line  16  is set to 200 μm, the length of the signal transmission line  16  is set to 20 mm or less, the width w of the signal transmission line  16  is set to 450 μm, the thickness of the first conductor  13  is set to 18 μm, the thickness of the second conductor  14  is set to 18 μm, and the thickness of the insulating material  15  is set to 70 μm. Thereby, a wiring board  10 A with an impedance of 50Ω is obtained. 
     The plug connector  20  comprises: a contact terminal  21 ; an insulator  22 ; and an external conductor  23 . 
     The contact terminal  21  is brought into contact with a contact portion of a mating connector (a receptacle connector), to thereby be electrically connected with the receptacle connector. In addition, the contact terminal  21  is electrically connected with the signal transmission line  16 . That is, the signal transmission line  16  is to be electrically connected with the contact portion of the receptacle connector via the contact terminal  21 . 
     The insulator  22  comprises: a flat plate portion  22   a ; and a bump portion  22   b  formed on one surface of the flat plate portion  22   a . The bump portion  22   b  supports the contact terminal  21  as if surrounding the contact terminal  21 . The plug connector  20  is arranged on the one surface  10   a  of the wiring board  10  via the flat plate portion  22   a  of the insulator  22 . The insulator  22  is made of, for example, a liquid crystal polymer (LCP). 
     The external conductor  23  is arranged so as to surround the bump portion  22   b  of the insulator  22  from its outer circumference, and is electrically connected with the first conductor  13  and the second conductor  14 . 
     When the cable connector  1 A of the present embodiment is used, the plug connector  20  of the present embodiment is connected with a receptacle connector  33  provided on one surface  31   a  of the insulating substrate  31 , as shown in  FIG. 3 . More particularly, a contact terminal  34  of the receptacle connector  33  is fitted into the contact terminal  21  of the plug connector  20 , and also an external conductor  35  of the receptacle connector  33  is fitted into the external conductor  23  of the plug connector  20 . Thereby, each pair is electrically connected. It is preferable that through-holes  32  be provided in the insulating substrate  31  similarly to the wiring board  10 A of the present embodiment. At this time, the distance between the through-holes  32  is a length corresponding to ½ or less of the wavelength of the frequency of the antenna to be connected with the cable connector  1 A, similarly to the case of the through-holes  12  provided in the wiring board  10 A. 
     According to the cable connector  1 A of the present embodiment, the aforementioned wiring board  10 A is used instead of a conventional coaxial cable. This eliminates the necessity of taking the outer diameter of the coaxial cable into consideration. Hence, the thickness of the connection portion between the plug connector  20  and the receptacle connector  33  can be made thin. Therefore, it is possible to make thin the electronic equipment that uses the cable connector  1 A of the present embodiment. 
     Furthermore, impedance of the wiring board  10 A can be adjusted, and also the impedance can be optimized in accordance with the communication characteristics (frequency band, communication distance, and the like) at high frequencies of the antenna to be connected with the cable connector  1 A. 
     Furthermore, if the plug connector  20  is installed at a predetermined position of the wiring board  10 A, the cable connector  1 A of the present embodiment is obtained. Therefore, this can be assembled more easily than conventional RF connectors, thus making it possible to simplify the assembly steps. That is, with reference to  FIG. 11A  to  FIG. 12D , the conventionally required steps include: stripping the coaxial cable  141 ; connecting the coaxial cable  141  with the contact terminal  140 ; fabricating the assembly  120 ; assembling the assembly  120  into the coaxial cable  141 ; caulking the external conductor  143  of the coaxial cable  141  into the shell terminal  121 ; and caulking the outer cladding  144  of the coaxial cable  141  into the shell terminal  121 . On the other hand, according to the present embodiment, it is only required that the first conductor  13 , the insulating material  15 , and the second conductor  14  and the signal transmission line  16  be laminated (in a batch) to fabricate the wiring board  10 A, and then that the plug connector  20  be installed at a predetermined position of the wiring board  10 . This makes it possible to assemble the cable connector  1 A more easily than ever. As a result, special devices and jigs required for the assembly become unnecessary. Therefore, the manufacturing cost of the cable connector  1 A can be reduced. In addition, the manufactured cable connectors  1 A are unlikely to suffer from performance variations, making it possible to provide stable products. 
     Second Embodiment 
       FIG. 4  is a schematic perspective view showing a second embodiment of the cable connector according to the present invention. 
     In  FIG. 4 , like constituent parts to those of the first embodiment shown in  FIGS. 1A to 2B  are designated with same reference numerals and are not repetitiously explained. 
     A cable connector  1 B ( 1 ) of the present embodiment is different from the aforementioned cable connector  1 A ( 1 ) of the first embodiment in that a plug connector  20  is provided on one surface (the other surface  10   b  of the wiring board  10 A) of a first conductor  13 , and in that a coaxial cable  41 , which is electrically connected with a signal transmission line  16 , is disposed on the one surface of the first conductor  13  at one end portion of the wiring board  10 A. 
     The coaxial cable  41  comprises: a central conductor  42  composed of a single-core line, a twisted line, or the like; an insulator  43  that covers the outer circumference thereof; an external conductor  44  that is coaxially placed outside the insulator  43 ; and an outer cladding  45  that covers the outside of the external conductor  44 . 
     The coaxial cable  41  is arranged on the one surface of the first conductor  13  that constitutes the wiring board  10 A, with its central conductor  42  being exposed. The central conductor  42  is electrically connected with the signal transmission line  16  via, for example, a conducting member  46 . The conducting member  46  is arranged in a first notch portion  13   a  formed in the first conductor  13 . The conducting member  46  is not particularly limited so long as it is capable of electrically connecting the central conductor  42  with the signal transmission line  16 . It may be a metal foil, a solder, a conductive adhesive, or the like. 
     Furthermore, the external conductor  44  of the coaxial cable  41  is electrically connected with the first conductor  13 . 
     According to the cable connector  1 B of the present embodiment, similar advantages to those of the aforementioned first embodiment are obtained. In the present embodiment, the coaxial cable  41  is connected with the wiring board  10 A. To be more specific, the coaxial cable  41  is spaced from the plug connector  20 , and is electrically connected with the plug connector  20  via the signal transmission line  16 . Therefore, the thickness of the connection portion between the cable connector  1 B and the receptacle connector  33  of the present embodiment is equal to the total thickness of the wiring board  10 A and the plug connector  20 , similarly to the case of the first embodiment. Consequently, it is possible to make the thickness of the connection portion thinner than ever. 
     Furthermore, in the cable connector  1 B of the present embodiment, the coaxial cable  41  which is electrically connected with the signal transmission line  16  is disposed on the other surface  10   b  (the one surface of the first conductor  13 ) of the wiring board  10 A. Therefore, it is possible to route the signal transmission line (the coaxial cable  41 ) in the housing of the electronic equipment in a more complex manner over a longer distance than the case of the first embodiment. Consequently, with the signal transmission line (the coaxial cable  41 ) excellent in high-frequency characteristics being routed, it is possible to suppress deterioration of the communication characteristics at high frequencies. 
     Third Embodiment 
       FIGS. 5A to 5D  are schematic diagrams showing a third embodiment of the cable connector according to the present invention.  FIG. 5A  is a perspective view of the present embodiment.  FIG. 5B  is a plan view of the present embodiment.  FIG. 5C  is a cross-sectional view of  FIG. 5B , taken along the A-A line.  FIG. 5D  is a cross-sectional view of  FIG. 5B , taken along the B-B line. 
     In  FIGS. 5A to 5D , like constituent parts to those of the aforementioned first embodiment are designated with same reference numerals and are not repetitiously explained. 
     A cable connector  1 C ( 1 ) of the present embodiment is different from the aforementioned cable connector  1 A ( 1 ) of the first embodiment in that a wiring board  10 B ( 10 ) comprises a first conductor  13 , a second conductor  14 , and a third conductor  17  laminated in this order respectively via an insulating material  15 . The first conductor  13 , the second conductor  14 , and the third conductor  17  are electrically connected via through-holes  12  which are formed along the edge portion of the wiring board  10 B. Also in the present embodiment, a distance d between the through-holes  12  is a length corresponding to ½ or less of the wavelength of the frequency of the antenna to be connected with the cable connector  1 C. 
     The third conductor  17  is made of, for example, a foil of metal such as copper, similarly to the first conductor  13  and the second conductor  14 . 
     On one surface of the third conductor  17  (the one surface  10   a  of the wiring board  10 B), there is provided a first conductive portion  24  at a position corresponding to a signal transmission line  16  via an insulating film  26 . On the first conductive portion  24 , there is placed a plug connector  20 . The first conductive portion  24  is electrically connected with a contact terminal  21  of the plug connector  20  via a conductive portion (not shown in the figures) that extends through an insulator  22  of the plug connector  20 . 
     Furthermore, the first conductive portion  24  is electrically connected with the signal transmission line  16  via a second conductive portion  25  that extends through the third conductor  17 , the insulating film  26 , and the insulating material  15 . 
     Furthermore, the external conductor  23  is electrically connected with the third conductor  17 . 
       FIG. 6  is a plan view schematically showing the second conductor  14  and the signal transmission line  16  of the present embodiment. Also in the present embodiment, the signal transmission line  16  is provided in the longitudinal direction of the second conductor  14 , along the slit  11  provided in the central portion of the second conductor  14 , similarly to the aforementioned first embodiment. At this time, the signal transmission line  16  is arranged with a predetermined space s from the second conductor  14 . 
     In the vicinity of the end portion on the plug connector  20  side of the signal transmission line  16 , there is provided a through-hole  16   a . With a second conductive portion  25  being arranged in the through-hole  16   a , the signal transmission line  16  and the first conductive portion  24  are electrically connected with each other. 
     As for the cable connector  1 C of the present embodiment, for example in portable communication equipment on a radio system that communicates in the 12 GHz band, impedance required for the wiring board  10 B is 50Ω. Therefore, the space s between the second conductor  14  and the signal transmission line  16  is set to 100 μm, the length of the signal transmission line  16  is set to 50 mm or less, the width w of the signal transmission line  16  is set to 85 μm, the thickness of the first conductor  13  is set to 18 μm, the thickness of the second conductor  14  is set to 18 μm, the thickness of the third conductor  17  is set to 18 μm, the thickness of the insulating material  15  placed between the second conductor  14  and the third conductor  17  is set to 70 μm, the thickness of the insulating material  15  placed between the first conductor  13  and the second conductor  14  is set to 67 μm. 
     Also in the present embodiment, it is preferable that first notch portions be provided at positions facing the signal transmission line  16  of the first conductor  13  and that a second notch portion be provided at a position facing the plug connector  20  of the first conductor  13  (not shown in the figures), similarly to the aforementioned first embodiment. Furthermore, similarly to the third conductor  17 , it is preferable that the first notch portions be provided at positions facing the signal transmission line  16  of the third conductor  17  and that the second notch portion be provided at a position facing the plug connector  20  of the third conductor  17  (not shown in the figures). With the first notch portions and the second notch portion being provided, impedance matching of the wiring board  10 B can be obtained, reflection loss of the electric signals is diminished, and transmission characteristics of the signals flowing through the signal transmission line  16  can be improved. Without the first notch portions and the second notch portion, there is a possibility that use of a thin substrate such as an FPC will cause the C component increase and its impedance decrease, resulting in insufficient transmission of signals. 
       FIG. 7  is a perspective view showing an example of use of the cable connector  1 C of the present embodiment. Similarly to the first embodiment, when the cable connector  1 C of the present embodiment is used, the plug connector  20  of the present embodiment is connected to a receptacle connector  33  provided on one surface  31   a  of an insulating substrate  31 . More particularly, a contact terminal  34  of the receptacle connector  33  is fitted into the contact terminal  21  of the plug connector  20 , and also an external conductor  35  of the receptacle connector  33  is fitted into the external conductor  23  of the plug connector  20 . Thereby, each pair is electrically connected. 
       FIG. 7  illustrates an insulating substrate  31  with a construction without through-holes. However, the insulating substrate  31  may be provided with through-holes, similarly to the case of the first embodiment. At this time, the distance between the through-holes is a length corresponding to ½ or less of the wavelength of the frequency of the antenna to be connected with the cable connector  1 C. 
     According to the cable connector  1 C of the present embodiment, similar advantages to those of the aforementioned first embodiment are obtained. At this time, in the present embodiment, the connection portion between the plug connector  20  and the receptacle connector  33  is thicker than that of the first embodiment by the total thickness of the third conductor  13  and one layer of the insulating material  15  because the wiring board  10  comprises the first conductor  13 , the second conductor  14 , the third conductor  17 , and the insulating materials  15  arranged therebetween. However, compared with the case where a conventional coaxial cable is used, the connection portion is still sufficiently-thin. 
     Furthermore, as shown in  FIG. 5D , the signal transmission line  16  is surrounded by the ground conductors (the first conductor  13 , the second conductor  14 , and the third conductor  17 ). This can diminish the radiated noise more than the cable connector  1 A of the first embodiment, improving the transmission characteristics of signals. As a result, it is possible to route the wiring board  10 B longer than that of the first embodiment. Therefore, the cable connector  1 A or  1 C according to the first embodiment or the third embodiment may be used in accordance with the size, the route length of the signal transmission line, and the desired radiated noise characteristics of the electronic equipment to be used. 
     Fourth Embodiment 
       FIG. 8  is a perspective view showing a fourth embodiment of the cable connector according to the present invention. 
     A cable connector  1 D ( 1 ) of the present embodiment is different from the aforementioned cable connector  1 C ( 1 ) of the third embodiment in that a coaxial cable  41 , which is electrically connected with a signal transmission line  16 , is disposed on one surface of the third conductor  17  at one end portion of the wiring board  10 B. 
     As the coaxial cable  41 , one similar to that used in the second embodiment can be used. Also in the present embodiment, a central conductor  42  of the coaxial cable  41  is electrically connected with the signal transmission line  16  via a conducting member  46 , and an external conductor  44  of the coaxial cable  41  is electrically connected with the third conductor  17 . In the present embodiment, there is placed a conducting member  46  in a through-hole that penetrates the third conductor  17  and the insulating material  15  placed between the third conductor  17  and the second conductor  14 . The conducting member  46  is similar to one in the second embodiment. 
     According to the cable connector  1 D of the present embodiment, similar advantages to those of the aforementioned second embodiment are obtained. At this time, in the present embodiment, the connection portion between the plug connector  20  and the receptacle connector  33  is thicker than that of the first embodiment by the total thicknesses of the third conductor  13  and one layer of the insulating material  15  because the wiring board  10 B comprises the first conductor  13 , the second conductor  14 , the third conductor  17 , and the insulating materials  15  arranged therebetween. However, compared with the case where a conventional coaxial cable is used, the connection portion is still sufficiently-thin. 
     Furthermore, the signal transmission line  16  is surrounded by the ground conductors (the first conductor  13 , the second conductor  14 , and the third conductor  17 ). This can diminish the radiated noise more than the cable connector  1 B of the second embodiment, improving the transmission characteristics of signals. As a result, it is possible to route the signal transmission line (the coaxial cable  41 ) longer than that of the second embodiment. Therefore, the cable connector  1 B or  1 D according to the second embodiment or the fourth embodiment may be used in accordance with the size, the route length of the signal transmission line, and the desired radiated noise characteristics of the electronic equipment to be used. 
     &lt;Antenna Component&gt; 
     Next is a description of embodiments of an antenna component according to the present invention. 
     The embodiments will be specifically described for better understanding of the spirit or scope of the invention, and hence, do not limit the present invention unless otherwise specified. 
     First Embodiment 
       FIG. 9  is a schematic perspective view showing a first embodiment of an antenna component according to the present invention and how it is used. 
     An antenna component  50 A ( 50 ) of the present embodiment comprises: the aforementioned cable connector  1 A (the wiring board  10 A and the plug connector  20 ) of the first embodiment; and a second wiring board  60 A ( 60 ). Hereinafter, the wiring board  10 A of the cable connector  1 A is sometimes referred to as the first wiring board  10 A. 
     The second wiring board  60  is coupled to the first wiring board  10 A. On the second wiring board  60 A, there is provided an antenna  65 A ( 65 ) that is electrically connected with the signal transmission line  16  of the first wiring board  10 A. 
     As for a plurality of through-holes  12  provided along the edge portion of the first wiring board  10 A, a distance d therebetween is set to a length corresponding to ½ or less of the wavelength of the frequency of the antenna  65 A. 
     The second wiring board  60 A comprises: a flexible substrate  62 ; and the antenna  65 A including an electric conductor  63  and a ground electric conductor  64 , which are provided on one surface  62   a  of the substrate  62 . 
     The electric conductor  63  is electrically connected with the signal transmission line  16  of the first wiring board  10 A. The electric conductor  63  may be integrated with the signal transmission line  16 . 
     The ground electric conductor  64  is electrically connected with the first conductor  13  of the first wiring board  10 A. The ground electric conductor  64  may be integrated with the first conductor  13  as shown in  FIG. 9 . 
     As the substrate  62 , a film-like or sheet-like resin made of: a polyimide resin, a polyethylene terephthalate resin, an aramid resin, or the like may be used. 
     As the electric conductor  63  and the ground electric conductor  64 , a predetermined pattern formed on the one surface  62   a  of the substrate  62  may be used. Its formation methods include screen printing by use of a conductive paste, etching a conductive foil, and metal plating. 
     As the electrically conductive paste that forms the electric conductor  63  and the ground electric conductor  64 , one in which conductive fine particles such as silver powder, gold powder, platinum powder, aluminum powder, palladium powder, rhodium powder, carbon powder (such as carbon black and carbon nanotubes) is blended with a resin composition may be used. 
     As the conductive foil that forms the electric conductor  63  and the ground electric conductor  64 , a copper foil, a silver foil, a gold foil, a platinum foil, an aluminum foil, or the like may be used. 
     As the metal plating that forms the electric conductor  63  and the ground electric conductor  64 , copper plating, silver plating, gold plating, platinum plating, or the like may be used. 
     As shown in  FIG. 9 , when used, the antenna component  50 A of the present embodiment is connected with the receptacle connector  33 , similarly to the aforementioned cable connector  1 A. At this time, it is preferable that through-holes  32  be provided also in the substrate  31  on which the receptacle connector  33  is provided, in a manner spaced from each other by a distance corresponding to ½ or less of the wavelength of the frequency of the antenna  65 A. 
     According to the antenna component  50 A of the present embodiment, the first wiring board  10 A is provided, instead of a conventional coaxial cable, for electrically connecting the antenna  65 A with the plug connector  20 . Therefore, the connection portion between the plug connector  20  and the receptacle connector  33  can be made thin, similarly to the case of the aforementioned cable connector  1 A. Furthermore, the second wiring board  60 A on which the antenna  65 A is provided is coupled to the first wiring board  10 A, and the antenna  65 A is electrically connected with the signal transmission line  16 . As a result, the connection portion between the first wiring board  10 A and the second wiring board  60 A is approximately as thick as the total thickness of the first wiring board  10 A and the second wiring board  60 A. Therefore, it is possible to make the connection portion between the antenna  65 A and the first wiring board  10 A significantly thinner than the connection portion between an coaxial cable and an antenna in the case where a conventional coaxial cable is used. In addition, the antenna  65 A (the second wiring board  60 A) itself is approximately as thick as the substrate  62 , and hence, is also made thin. Taking this fact into consideration, electronic equipment can be made thin by mounting the antenna component  50 A of the present embodiment on the electronic equipment. 
     Furthermore, in the antenna component  50 A of the present embodiment, the aforementioned cable connector  1 A is used. Therefore, as described above, impedance of the first wiring board  10 A can be adjusted and the impedance can be optimized in accordance with the communication characteristics (frequency band, communication distance, and the like) at high frequencies of the antenna  65 A of the second wiring board  60 A. Consequently, it is possible to efficiently transmit electric power, and secure a sufficient communication distance. 
     Furthermore, it is possible to install the plug connector  20  on the first wiring board  10 A with ease, that is, only an installation of the plug connector  20  on the FPC on which the antenna  65 A is formed fabricates the antenna component  50 A of the embodiment. Therefore, its assembly steps can be simplified, similarly to the case of the aforementioned cable connector  1 A. As a result, special devices and jigs required for the assembly become unnecessary. Therefore, the manufacturing cost can be reduced. In addition, the manufactured antenna components  50 A are unlikely to suffer from performance variations, making it possible to provide stable products. 
     Second Embodiment 
       FIG. 10  is a schematic perspective view showing a second embodiment of the antenna component of the present invention and how to use it. 
     An antenna component  50 B ( 50 ) of the present embodiment is different from the aforementioned antenna component  50 A of the first embodiment in that a second wiring board  60 B ( 60 ) is coupled to the aforementioned cable connector  1 C (the wiring board  10 B and the plug connector  20 ) according to the third embodiment and in that an antenna  65 B ( 65 ) comprises: a first electric conductor  66 ; a second electric conductor  67 ; and a third electric conductor  68 . Hereinafter, the wiring board  10 B of the cable connector  1 C is sometimes referred to as the first wiring board  10 B. 
     The second wiring board  60 B ( 60 ) of the present embodiment comprises: a flexible substrate  62 ; and the antenna  65 B ( 65 ) including the first electric conductor  66 , the second electric conductor  67 , and the third electric conductor  68  that are provided on one surface  62   a  of the substrate  62 . 
     Of these electric conductors, the first electric conductor  66  is electrically connected with the first conductor  13  of the first wiring board  10 B, and functions as a ground conductor. On the other hand, the second electric conductor  67  and the third electric conductor  68  are electrically connected with the signal transmission line  16  of the first wiring board  10 B. The length of the first electric conductor  66 , the second electric conductor  67 , and the third electric conductor  68  that constitute the antenna is set to a length corresponding to ¼ of the wavelength of the frequency of the electronic equipment in which the antenna component  50 B of the present embodiment is used. The first electric conductor  66 , the second electric conductor  67 , and the third electric conductor  68  can be formed on the one surface  62   a  of the substrate  62 , similarly to the electric conductor  63  and the ground electric conductor  64  which are used in the antenna component  50 A of the first embodiment. 
     As shown in  FIG. 10 , when used, the antenna component  50 B of the present embodiment is connected with the receptacle connector  33 , similarly to the case of the aforementioned cable connector  1 C. At this time, although not shown in  FIG. 10 , through-holes may be provided also in the substrate  31  on which the receptacle connector  33  is provided, in a manner spaced from each other by a distance corresponding to ½ or less of the wavelength of the frequency of the antenna  65 B. 
     According to the antenna component  50 B of the present embodiment, similar advantages to those of the aforementioned antenna component  50 A of the first embodiment are obtained. At this time, in the present embodiment, the connection portion between the plug connector  20  and the receptacle connector  33 , and the connection portion between the first wiring board  10 B and the second wiring board  60 B are thicker than that of the first embodiment by the total thickness of the third conductor  13  and one layer of the insulating material  15  because the wiring board  10 B comprises the first conductor  13 , the second conductor  14 , the third conductor  17 , and the insulating materials  15  arranged therebetween. However, compared with the case where a conventional coaxial cable is used, the connection portions are still sufficiently-thin. 
     Furthermore, the signal transmission line  16  is surrounded by the ground conductors (the first conductor  13 , the second conductor  14 , and the third conductor  17 ). This can diminish the radiated noise more than the antenna component  50 B of the first embodiment, improving the transmission characteristics of signals. As a result, it is possible to route the signal transmission line (the first wiring board  10 B) longer than that of the first embodiment. 
     Therefore, the antenna component  50 A or  50 B according to the first embodiment or the second embodiment may be applied in accordance with the size, the route length of the signal transmission line, and the desired radiated noise characteristics of the electronic equipment to be used. 
     According to the cable connector of the present invention, a connection portion between a plug connector and its mating connector can be made thin. Furthermore, the plug connector can be installed on a wiring board with ease, which makes it possible to simplify the assembly steps. As a result, the manufacturing cost of the cable connector can be reduced. Furthermore, because the assembly steps can be simplified, the manufactured cable connectors are unlikely to suffer from performance variations, making it possible to provide stable products. In addition, impedance of the wiring board can be optimized with ease in accordance with the communication characteristics (frequency band, communication distance, and the like) at high frequencies of the equipment and the antenna that are connected to the cable connector. 
     According to the antenna component of the present invention, the connection portion between the plug connector and the receptacle connector, and the connection portion between the first wiring board and the second wiring board can be made thinner than when a conventional coaxial cable is used. Furthermore, only an installation of the plug connector onto the FPC on which the antenna is formed fabricates the antenna component of the embodiment. Therefore, its assembly steps can be simplified. As a result, the manufacturing cost can be reduced, and the manufactured antenna components are unlikely to suffer from performance variations, making it possible to provide stable products. In addition, impedance of the first wiring board can be lowered, and also the impedance can be optimized in accordance with the communication characteristics (frequency band, communication distance, and the like) of the antenna at high frequencies. Therefore, according to the antenna component of the present invention, it is possible to efficiently transmit electric power, and secure a sufficient communication distance.