Abstract:
Provided is an RF plug connector which includes: a conductive terminal portion; and an annular conductive coaxial portion that is arranged around the terminal portion, wherein a pair of conductive lead portions extending in the same direction is provided at the outer circumference of the coaxial portion, the terminal portion comprises a lead portion that is arranged between the pair of lead portions so as to be parallel to an extension direction thereof, and impedance control is performed by adjusting the distance between the lead portion of the terminal portion and the lead portions of the coaxial portion.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation application based on a PCT Patent Application No. PCT/JP2010/000559, filed Jan. 29, 2010, whose priority is claimed on Japanese Patent Application No. 2009-020264 filed Jan. 30, 2009, the entire content of which are hereby incorporated by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to a structure of a connector for connecting an RF module and an antenna in an internal component of an electronic device, and relates to a structure of a connector in which the high-frequency characteristics are improved compared to a conventional connector, and further high-frequency response is possible. 
         [0004]    2. Description of the Related Art 
         [0005]    As a type of coaxial connector, a coaxial connector is known in which an annular space and a cable housing portion are in communication, a cable is exposed in the annular space, the distal end of a cylindrical portion of a counter connector can be inserted into the annular space until the vicinity of the cable housing portion, at least a portion of an inner lid is accommodated between standing walls upwardly extending from the hollow portion edge of the insulator, a terminal is disposed on the upper plane of the hollow portion edge of the main body of the insulator, and a contact portion is provided sagging downward from a wire connection portion (refer to Japanese Unexamined Patent Application, First Publication No. 2006-318936). Also, as this type of coaxial connector, a coaxial connector that is constituted from a housing, a bushing mounted in the housing, a socket held in the bushing, and a semi-rigid cable mounted in the socket is known(refer to Japanese Unexamined Patent Application, First Publication No. 2001-307842). 
         [0006]    In a conventional RF connector (compact coaxial connector), impedance matching of the coaxial portion (cylindrical portion) is mainly performed. However, in the conventional RF connector, since the distance of the lead attachment portion is short, impedance matching thereof was not performed. In particular, in the soldered portions of the ground shell lead portion, a reinforcing role for ensuring the soldering strength has generally served as the object. 
         [0007]    However, in a conventional RF connector, as stated above, remarkable reflection occurred in the soldered portions due to impedance matching of the soldered portions not being particularly performed. 
         [0008]    Also, with the increasing performance of electronic devices in recent years, RF connectors corresponding to use in higher-frequency ranges are required. 
       SUMMARY 
       [0009]    In order to solve the aforementioned issues, the first aspect of the present invention is an RF plug connector including: a conductive terminal portion; and an annular conductive coaxial portion that is arranged around the terminal portion, wherein a pair of conductive lead portions extending in the same direction is provided at the outer circumference of the coaxial portion, the terminal portion includes a lead portion that is arranged between the pair of lead portions so as to be parallel to an extension direction thereof, and impedance control is performed by adjusting the distance between the lead portion of the terminal portion and the lead portions of the coaxial portion. 
         [0010]    In the first aspect of the present invention, it may be arranged such that the end faces of the pair of lead portions and the end face of the lead portion of the terminal portion are arranged on substantially the same plane. Moreover, it may be arranged such that the end faces of the pair of lead portions project out of the end face of the lead portion of the terminal portion in the extension direction of each lead portion. 
         [0011]    A second aspect of the present invention is an RF receptacle connector including: a conductive terminal portion; and an annular conductive coaxial portion that is arranged around the terminal portion, wherein a pair of conductive lead portions extending in the same direction is provided at the outer circumference of the coaxial portion, the terminal portion includes a lead portion that is arranged between the pair of lead portions so as to be parallel to an extension direction thereof, and impedance control is performed by adjusting the distance between the lead portion of the terminal portion and the lead portions of the coaxial portion. 
         [0012]    In the aforementioned second aspect, it may be arranged such that the end faces of the pair of lead portions and the end face of the lead portion of the terminal portion are arranged on substantially the same plane. Moreover, it may be arranged such that the end faces of the pair of lead portions project out of the end face of the lead portion of the terminal portion in the extension direction of each lead portion. 
         [0013]    A third aspect of the present invention is an RF connector including: a receptacle connector that includes a receptacle-side signal contact portion that includes a lead portion and a terminal portion that is installed in a protruding manner in a portion thereof, and a receptacle-side ground shell portion that includes a pair of lead portions that are arranged on both sides of the receptacle-side signal contact portion and that extend in the same direction and a cylindrical coaxial portion that is connected to the lead portions, and that is integrated with the receptacle-side signal contact portion via an insulating portion so that the terminal portion of the receptacle-side signal contact portion is arranged in the center of the coaxial portion; and a plug connector that includes a plug-side signal contact portion that includes a lead portion and a terminal portion that is installed in a protruding manner in a portion thereof, and a plug-side ground shell portion that includes lead portions that are arranged on both sides of the plug-side signal contact portion and that extend in the same direction and a cylindrical coaxial portion that is connected to said leads, and that is integrated with the plug-side signal contact portion via an insulating portion so that the terminal portion of the plug-side signal contact portion is arranged in the center of the coaxial portion, wherein the terminal portion of the receptacle connector and the terminal portion of the plug connector are capable of being connected by fitting together the coaxial portion of the receptacle connector and the coaxial portion of the plug connector, the lead portion of the receptacle-side signal contact portion is arranged between the pair of leads of the receptacle-side ground shell portion so as to be parallel to an extension direction thereof, and the lead portion of the plug-side signal contact portion is arranged between the pair of leads of the plug-side ground shell portion so as to be parallel to an extension direction thereof. 
         [0014]    In the third aspect of the present invention, it may be arranged such that all of the lead portion of the receptacle-side signal contact portion and the lead portions of the receptacle-side ground shell portion are formed to have a plate shape, the lead portions of the receptacle-side ground shell portion project out in a perpendicular direction with respect to the center axis of the coaxial portion of the receptacle-side ground shell portion, and the lead portion of the receptacle-side signal contact portion and the lead portions of the receptacle-side ground shell portion are arranged to be flush. Moreover, it may be arranged such that all of the lead portion of the plug-side signal contact portion and the lead portions of the plug-side ground shell portion are formed to have a plate shape, the lead portions of the plug-side ground shell portion project out in a perpendicular direction with respect to the center axis of the coaxial portion of the plug-side ground shell portion, and the lead portion of the plug-side signal contact portion and the lead portions of the plug-side ground shell portion are arranged to be flush. 
         [0015]    In the third aspect of the present invention, it may be arranged such that one surface of the lead portion of the receptacle-side signal contact portion and the lead portions of the receptacle-side ground shell portion, or one surface of the lead portion of the plug-side signal contact portion and the lead portions of the plug-side ground shell portion is arranged to be flush, and the receptacle connector or the plug connector is capable of being connecting to a pattern of a circuit board with these one surfaces serving as soldered surfaces. Moreover, it may be arranged such that the end faces of the lead portions of the receptacle-side ground shell portion and the plug-side ground shell portion and the end faces of the leads of the receptacle-side signal contact portion and the plug-side signal contact portion are arranged on substantially the same plane, respectively. Further, it may be arranged such that the end faces of the lead portions of the receptacle-side ground shell portion and the plug-side ground shell portion project out of the end face of the leads of the receptacle-side signal contact portion and the plug-side signal contact portion, respectively, in the extension direction of each lead portion. 
         [0016]    In the connector according to the present invention, matching of impedance is easy in the portion between the terminal portion and the coaxial portion since the lead portions of the coaxial portion are arranged on both sides of the lead portion of the terminal portion, and impedance control is performed by adjusting the distance between the lead portion of the terminal portion and the lead portions of the coaxial portion. As a result, it is possible to achieve a structure that is advantageous for use in the high-frequency range by suppressing the generation of signal reflections in the portion. 
         [0017]    Further, the receptacle connector is constituted by the receptacle-side signal contact portion and the receptacle-side ground shell portion being integrated so that the terminal portion is arranged in the center of the coaxial portion, and the lead portion of the signal contact portion is arranged between the pair of lead portions that are provided in the ground shell portion and that extend in the same direction. Also, the plug connector is constituted by the plug-side signal contact portion and the plug-side ground shell portion being integrated so that the terminal portion is arranged in the center of the coaxial portion, and the lead portion of the signal contact portion is arranged between the pair of lead portions that are provided in the ground shell portion and that extend in the same direction. Thereby, it is possible to perform impedance control by adjusting the distance between the lead portions, i.e., between either of the lead portions of the receptacle connector and the lead portions of the plug connector. As a result, matching of impedance is easy in both the receptacle connector and the plug connector, and it is possible to achieve a structure that is advantageous for use in the high-frequency range by suppressing the generation of signal reflections in these portions. 
         [0018]    Moreover, since the lead portions of the signal contact portions and the lead portions of the ground shell portions are flush, it is possible to accurately and reliably perform impedance control by adjustment between the lead portions, which is advantageous in the high-frequency range. Accordingly, it is possible to significantly improve the high-frequency characteristic (VSWR). Further it is possible to enable use in a higher-frequency range (for example 16 GHz) than previously. 
         [0019]    Moreover, if the one surface of the lead portions according to the present invention serves as soldered surfaces, it is possible to perform impedance matching of the soldered portions while maintaining the soldering strength and achieve excellent high-frequency characteristic, compared to a conventional RF connector. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0020]      FIG. 1  is a perspective view showing a receptacle connector that constitutes the RF connector according to an embodiment of the present invention. 
           [0021]      FIG. 2  is a perspective view showing a plug connector that constitutes the RF connector according to the embodiment. 
           [0022]      FIG. 3  is a perspective view showing a receptacle-side signal contact portion according to the embodiment. 
           [0023]      FIG. 4  is a perspective view showing a plug-side signal contact portion according to the embodiment. 
           [0024]      FIG. 5  is a longitudinal sectional view showing the RF connector in the engaged state according to the embodiment. 
           [0025]      FIG. 6  is a perspective view seen from the receptacle connector side showing the RF connector in the engaged state according to the embodiment. 
           [0026]      FIG. 7  is a perspective view seen from the plug connector side showing the RF connector in the engaged state according to the embodiment. 
           [0027]      FIG. 8  is a perspective view showing a receptacle connector that constitutes the RF connector according to the embodiment. 
           [0028]      FIG. 9  is a perspective view showing a plug connector that constitutes the RF connector according to the embodiment. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0029]    Hereinafter, an RF connector according to an embodiment of the present invention shall be described. 
         [0030]    Note that the embodiment is described in detail in order to better comprehend the gist of the invention, and unless otherwise noted, shall not serve to limit the present invention. 
         [0031]      FIG. 1  and  FIG. 2  are figures that show outlines of the RF connector according to the embodiment of the present invention. The RF connector of the present embodiment consists of a receptacle connector  1  and a plug connector  2 . The receptacle connector  1  and the plug connector  2  are mounted on separate circuit boards. When the receptacle connector  1  and the plug connector  2  are integrally joined, the substrates on which the connectors are mounted become electrically connected.  FIG. 3  and  FIG. 4  show schematic exploded perspective views of the receptacle connector  1  and the plug connector  2 . 
         [0032]    The receptacle connector  1  is constituted from a receptacle-side signal contact portion  10  shown in (a) of  FIG. 3 , a receptacle-side ground shell portion  20  shown in (b) of  FIG. 3 , and an insulating portion  30  shown in (c) of  FIG. 3 . The receptacle connector  1  may be obtained by integrally molding the receptacle-side signal contact portion  10 , the receptacle-side ground shell portion  20  and the insulating portion  30  by insert molding. 
         [0033]    A lead portion  11  of the receptacle-side signal contact portion  10  is formed from a conductor such as copper alloy having substantially a rectangular plate shape. One surface of the lead portion  11  is a soldered portion  12  that is soldered to the circuit board. On a surface on the opposite side of the lead portion  11 , a terminal portion  13  having substantially a cylindrical shape is provided so as to project out toward the opposite side of the soldered portion in the normal direction of the surface. This terminal portion  13  may be integrally formed with the lead portion  11  by drawing, or they may be integrally joined after being formed as separate components. 
         [0034]    A lead portion  22  of the receptacle-side ground shell portion  20  is formed from a plate-shaped conductor having substantially a U-shape such as a copper alloy. One surface of each lead portion  22  is a soldered portion  25  that is soldered to the circuit board. On the surface on the opposite side a coaxial portion  21  with a cylindrical shape is provided so as to project out toward the opposite side of the soldered portion in the normal direction of the surface. Moreover, a semicircular portion  22   a  of the U-shaped lead portion  22  and the outer circumference of the coaxial portion  21  are formed so as to be integrated. This coaxial portion  21  may also be integrally formed with the lead portion  22  by drawing, or they may be integrally joined after being formed as separate components. 
         [0035]    The insulating portion  30  is formed in a plate shape by an insulator such as resin or the like, and houses the receptacle-side signal contact portion  10  and the receptacle-side ground shell portion  20  so that the terminal portion  13  of the receptacle-side signal contact portion  10  and the coaxial portion  21  of the receptacle-side ground shell portion  20  are arranged in a coaxial manner while electrically insulating them from each other. 
         [0036]    The lead portion  22  of the receptacle-side ground shell portion  20  is arranged so as to be separated by a predetermined distance from the lead portion  11  on both sides of the lead portion  11  of the receptacle-side signal contact portion  10 . Also, an end face  14  of the lead portion  11  and end face  23  of the lead portion  22  project out of the side surface of a main body portion  30   a  of the insulating portion  30  toward the outer side along the longitudinal axis (extension direction) of the lead portion  11 . The end face  14  and the end face  23  of the respective lead portions are arranged on the same plane. 
         [0037]    The insulator  30  has a hole portion  30   b  that is formed in the center of the plate-shaped main body portion  30   a,  and is integrated with the receptacle-side ground shell portion  20  by inserting the coaxial portion  21  of the receptacle-side ground shell portion  20  into the hole portion  30   b.  Also, a groove portion  30   c  that partially contains the lead portions  22 ,  22  is formed on both sides of the bottom surface of the insulator  30  that faces the receptacle-side ground shell portion  20 . In the state of the insulator  30  and the receptacle-side ground shell portion  20  being integrated by inserting the coaxial portion  21  of the receptacle-side ground shell portion  20  in the hole portion  30   b,  the lead portion  22 ,  22  partially project out of the insulator  30  at the both sides thereof. Also, a doughnut-plate shaped insulating member  30   d  is inserted inside the coaxial portion  21  that is placed inside the hole portion  30   b,  and the terminal portion  13  is inserted into a hole portion  30   e  in the center of the insulating portion  30   d,  whereby the receptacle-side signal contact portion  10  is mounted on the insulator  30 . Also, a housing groove  30   f  is formed in the middle of the bottom portion of the insulating portion  30  so as to be positioned between the groove portions  30   c,    30   c,  and the lead portion  11  of the receptacle-side signal contact portion  10  is fitted in the housing groove  30   f.  The distal end portion of the lead portion  11  projects out slightly of the insulator  30 . 
         [0038]    On the other hand, the plug connector  2  consists of a plug-side signal contact portion  40  shown in (a) of  FIG. 4 , a plug-side ground shell portion  50  shown in (b) of  FIG. 4 , and an insulating portion  60  shown in (c) of  FIG. 4 . The plug-side signal contact portion  40  and the plug-side ground shell portion  50  have a complementary shape with the receptacle-side signal contact portion  10  and the receptacle-side ground shell portion  20 , respectively. Also, the plug connector  2  may be obtained by integrally molding the plug-side signal contact portion  40 , the plug-side ground shell portion  50 , and the insulating portion  60 . 
         [0039]    A terminal portion  43  of the plug-side signal contact portion  40  is provided so as to project from the surface of the opposite side of a soldered portion  42  of a lead portion  41 , which is formed with a conductor having substantially a rectangular plate shape, toward the opposite side of the soldered portion in the normal direction of the surface. The terminal portion  43  is substantially cylindrical, but it may be split into a plurality of portions at equal angles along the center axis of the terminal portion  43  in the radial direction (it is split in the example of (a) of  FIG. 4 ). The terminal portion  43  may be integrally formed with the lead portion  41  by press working or the like, or they may be integrally joined after being formed as separate components. 
         [0040]    A coaxial portion  51  of the plug-side ground shell portion  50  is provided so as to project out of the surface on the opposite side of a soldered portion  55  of a lead portion  52 , which is formed with a plate-shaped conductor having substantially a U-shape, toward the opposite side of the soldered portion in the normal direction of the surface. The coaxial portion  51  is also substantially cylindrical, and is split into a plurality of portions at equal angles along the center axis of the coaxial portion  51  in the radial direction. Moreover, the semicircular portion of the lead portion  52  and the circular arc of the coaxial portion  51  are formed so as to match. This coaxial portion  51  may also be integrally formed with the lead portion  52  by press working or the like, or they may be integrally joined after being formed as separate components. 
         [0041]    The insulating portion  60  is formed in a plate shape by an insulator such as resin or the like, and houses the plug-side signal contact portion  40  and the plug-side ground shell portion  50  so that the terminal portion  43  of the plug-side signal contact portion  40  and the coaxial portion  51  of the plug-side ground shell portion  50  are arranged in a coaxial manner while electrically insulating them from each other. 
         [0042]    The insulating portion  60  has a cylindrical projection portion  60   b  in the center of a plate-shaped main body portion  60   a,  and a fitting hole  60   c  that allows insertion of the coaxial portion  51  of the plug-side ground shell portion  50  is formed on the outer periphery side of the projection portion  60   b.  The terminal portion  43  of the plug-side signal contact portion  40  is capable of being inserted into the inner side of the projection portion  60   b.  A round hole portion  60   d  inside the projection portion  60   b  has an inner diameter that allows insertion of the terminal portion  13  of the aforementioned receptacle-side signal contact portion, and four vertical groove portions  60   e  are formed on the inner circumference portion of the hole portion  60   d.  The terminal portion  43  of the plug-side signal contact portion  40  that is divided into four is inserted into the groove portions  60   e.  That is, by fitting the upper portion of the coaxial portion  51  of the plug-side ground shell portion  50  into the fitting hole  60   c  of the insulating portion  60 , and inserting the upper portion of the terminal  43  of the plug-side signal contact portion  40  in the groove portions  60   e,  the insulating portion  60 , the plug-side ground shell portion  50 , and the plug-side signal contact portion  40  are integrated as shown in  FIG. 2 . Note that in the state shown in  FIG. 2 , the lead portion  52  of the plug-side ground shell portion  50  and the lead portion  41  of the plug-side signal contact portion  40  slightly project out from the insulating portion  60 . 
         [0043]    The lead portion  52  of the plug-side ground shell portion  50  is also arranged to be separated by a predetermined distance d from the lead portion  41  (refer to  FIG. 1  and  FIG. 2 ) on both sides of the lead portion  41  of the plug-side signal contact portion  40 . Also, an end face  44  of the lead portion  41  and end face  53  of the lead portion  52  slightly project out of the side portion of the insulating portion  60  to the outside along the longitudinal axis (extension direction) of the lead portion  41 . The end face  44  and the end faces  53  are arranged on the same plane. 
         [0044]    The RF connector according to the present invention can perform impedance matching of the lead portions by adjusting the aforementioned distance d. By changing this distance d, it is possible to adjust the impedance of the lead portions to a desired value. 
         [0045]    Also, according to the results of electromagnetic field simulations that the inventors have performed using the structure of the present embodiment, it is found that the high-frequency characteristic is improved if the lead end faces  23 ,  53  of the ground shell portions  20 ,  50  project out approximately 0.5 mm from the end faces  14 ,  44  of the signal contact portions  10 ,  40  in the extension direction of each lead portion. Accordingly, the lead end faces  23 ,  53  of the ground shell portions  20 ,  50  may project out approximately 0.5 mm from the end faces  14 ,  44  of the signal contact portions  10 ,  40  in the extension direction of each lead portion. 
         [0046]    Moreover, a groove portion  26  is formed on the outer circumferential surface of the coaxial portion  21  of the receptacle-side ground shell portion  20 , and one or more projection portion  56  may be formed on the inner circumferential surface of the coaxial portion  51  of the plug-side ground shell portion  50  at a height corresponding to that of the groove portion  26 . When the receptacle connector  1  and the plug connector  2  are fitted together (refer to  FIG. 5 ,  FIG. 6 , and  FIG. 7 ), the projection portion  56  fits into the groove portion  26 , whereby unexpected detachment between the receptacle connector  1  and the plug connector  2  is prevented. 
         [0047]    In the connector according to the present invention, since the lead portions  22 ,  52  of the coaxial portions are arranged on both sides of the lead portions  11 ,  41  of the terminal portions, and impedance control is performed by adjusting the distance between the lead portions  11 ,  41  of the terminal portions and the lead portions  22 ,  52  of the coaxial portions, matching of impedance is easy in the portion between the terminal portions  13 ,  43  and the coaxial portions  21 ,  51 , and it is possible to achieve a structure that is advantageous for use in the high-frequency range by suppressing the generation of signal reflections in the portion. 
         [0048]    Also, the receptacle connector  1  is constituted by the receptacle-side signal contact portion  10  and the receptacle-side ground shell portion  20  being integrated so that the terminal portion  13  is arranged in the center of the coaxial portion  21 , and the lead portion  11  of the signal contact portion is arranged between the pair of lead portions  22 ,  22  that are provided in the ground shell portion and that extend in the same direction. Moreover, the plug connector  2  is constituted by the plug-side signal contact portion  40  and the plug-side ground shell portion  50  being integrated so that the terminal portion  43  is arranged in the center of the coaxial portion  51 , and the lead portion  41  of the signal contact portion is arranged between the pair of lead portions  52 ,  52  that are provided in the ground shell portion and that extend in the same direction. Thereby, it is possible to perform impedance control by adjusting the distance between the lead portions, i.e., between either of the lead portions of the receptacle connector  1  and the lead portions of the plug connector  2 . As a result, matching of impedance is easy in both the receptacle connector  1  and the plug connector  2 , and it is possible to achieve a structure that is advantageous for use in the high-frequency range by suppressing the generation of signal reflections in these portions. 
         [0049]    Moreover, since the lead portions  11 ,  41  of the signal contact portions and the lead portions  22 ,  52  of the ground shell portions are flush, it is possible to accurately and reliably perform impedance control by adjustment between the lead portions, which is advantageous in the high-frequency range. Accordingly, it is possible to significantly improve the high-frequency characteristic (VSWR). Further, it is possible to enable use in a higher frequency range (for example 16 GHz) than previously. 
         [0050]    Moreover, if the one surface of the lead portions according to the present invention serves as soldered surfaces, it is possible to perform impedance matching of the soldered portions while maintaining the soldering strength and achieve excellent high-frequency characteristic, compared to a conventional RF connector.