Patent Publication Number: US-2009224986-A1

Title: Radio apparatus and antenna device having element formed on casing material

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2008-55350 filed on Mar. 5, 2008; the entire contents of which are incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a radio apparatus and an antenna device, and in particular to a radio apparatus and an antenna device having an antenna element formed on a casing material of the radio apparatus. 
     2. Description of the Related Art 
     It is generally known that a radio apparatus, e.g., a mobile phone has a built-in antenna device contained in a casing material these days instead of an antenna device that may be extended outside of the casing material, e.g., a whip antenna that used to be popular. The radio apparatus may enjoy improved design and operability by employing the built-in antenna. In recent years, however, as the radio apparatus is required to have multiple functions and high performances and to be downsized and slim at the same time, the antenna device faces difficulty in performing as required in a condition such as contained in limited space of the casing material. 
     In order to deal with the above difficulty, e.g., it has been developed to form a conductive pattern on a casing material of a radio apparatus by using a method of, e.g., plating and to feed the conductive pattern as an antenna. Such an antenna may generally be fed through a feed pin in contact with the conductive pattern, instead of a feed line soldered to the conductive pattern, as it should be taken into account that the casing material often made of plastic has limited heat-resistance. 
     There is a problem, however, that a relative position between a printed board on which an antenna feed circuit is mounted and the casing material may affect where to put the feed pin and may limit a degree of freedom, as the feed pin has to be put in a fixed direction. In addition, in order to simplify assembly work in a manufacturing process, it is preferable to reduce the number and the size of the feed pins as much as possible. It is not known how to solve the above problem or how to meet the above manufacturing process requirement. 
     An antenna built-in module formed by an antenna feed circuit and an antenna combined with each other is disclosed in Japanese Patent Publication of Unexamined Applications (Kokai), No. 2005-5866. 
     According to JP 2005-5866, the antenna built-in module has a circuit board on which a radio circuit is provided, a cover made of sheet metal arranged in such a way as to almost entirely cover the circuit board, and an exclusive shield case made of sheet metal arranged in such a way as to cover a specific area on the circuit board. 
     The cover is not limited to be made of sheet metal and may be shaped as a lid of a box made of plastic and provided with a conductive layer on a surface of the box lid. In that case, a portion of the conductive layer formed on an upper plate of the box lid may work as a radiation conductor, and a portion of the conductive layer formed on a side wall of the box lid may work as a feed conductor and a grounded conductor. 
     The antenna built-in module of JP 2005-5866 is configured in such a way that the conductive layer formed on the side wall of the box lid may connect the radio circuit provided on the circuit board to the conductive layer formed on the upper plate of the box lid made of plastic. 
     As it is generally known that a printed board of a radio apparatus, e.g., a mobile phone, on which an antenna feed circuit is provided and a casing material of the radio apparatus may hardly be formed as one piece, the antenna built-in module of JP 2005-5866 may not be applied to such a radio apparatus. 
     SUMMARY OF THE INVENTION 
     Accordingly, an object of the present invention is to feed an antenna element formed by a conductive pattern formed, e.g., plated, on a casing material by using a small number of short feed pins located with a high degree of freedom. 
     To achieve the above object, according to one aspect of the present invention, a radio apparatus including a printed board having an antenna feed circuit, a casing material provided with an antenna element, an antenna feed material, and an electric connection between the antenna feed circuit and the antenna element is provided. The antenna element is formed by a conductive pattern formed on a face of the casing material facing the printed board. The antenna feed material is arranged between the face of the casing material and the printed board. The electric connection connects the antenna feed circuit and the antenna element through the antenna feed material. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a radio apparatus of a first embodiment of the present invention. 
         FIG. 2  is a cross sectional view of a portion of a section of the radio apparatus of the first embodiment. 
         FIG. 3  is a cross sectional view of a portion of a section of a modification of the radio apparatus of the first embodiment. 
         FIG. 4  is a diagram showing an antenna feed connection of a radio apparatus of a second embodiment of the present invention. 
         FIG. 5  is a diagram showing another antenna feed connection of the radio apparatus of the second embodiment of the present invention. 
         FIG. 6  is a diagram showing a modification of the antenna feed connection of the radio apparatus of the second embodiment shown in  FIG. 4 . 
         FIG. 7  is a diagram showing a modification of the antenna feed connection of the radio apparatus of the second embodiment shown in  FIG. 5 . 
         FIG. 8  is a diagram showing another modification of the antenna configuration and the antenna feed connection of the radio apparatus of the second embodiment, including an additional conductive pattern formed on the antenna feed material. 
         FIG. 9  is a diagram showing yet another modification of the antenna configuration and the antenna feed connection of the radio apparatus of the second embodiment, including the additional conductive pattern formed on the antenna feed material. 
         FIG. 10  is a diagram showing an antenna feed connection of a radio apparatus of a third embodiment of the present invention. 
         FIG. 11  is a diagram showing a modification of the antenna feed connection of the radio apparatus of the third embodiment. 
         FIG. 12  is a diagram showing another modification of the antenna feed connection of the radio apparatus of the third embodiment. 
         FIG. 13  is a cross sectional view of a portion of a section of a radio apparatus of a fourth embodiment of the present invention. 
         FIG. 14  is a diagram showing an antenna feed connection of the radio apparatus of the fourth embodiment. 
         FIG. 15  is a diagram showing an antenna configuration and an antenna feed connection of a radio apparatus of a fifth embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Hereinafter, embodiments of the present invention will be described in detail. In following descriptions, terms such as upper, lower, left, right, horizontal or vertical used while referring to a drawing shall be interpreted on a page of the drawing unless otherwise noted. A same reference numeral given in no less than two drawings shall represent a same member or a same portion. 
     A first embodiment of the present invention will be described with reference to  FIGS. 1-3 .  FIG. 1  is a perspective view of a radio apparatus  1  of the first embodiment. The radio apparatus  1  has a first section  11 , a second section  12  and a connection  13  movably connecting the first section  11  and the second section  12  in such a way as to open or close the two sections to each other.  FIG. 1  shows a state that the first section  11  and the second section  12  are closed to each other. The first section  11  has an auxiliary display  14  made of, e.g., a liquid crystal display device. 
       FIG. 2  is a cross sectional view of the first section  11  along a line with arrows A-A shown in  FIG. 1  partially showing an end portion of the first section  11  that is farther from the connection  13 . The first section  11  is formed by an upper piece  11   a  and a lower piece  11   b  both made of dielectric material and mechanically joined in a vertical direction. 
     The first section  11  contains a radio circuit that is not shown and a printed board  15  in which a feed line formed by a conductive pattern that is not shown is provided. The radio circuit and the conductive pattern are called an antenna feed circuit together. 
     The upper piece  11   a  has an inner face facing the printed board  15 , and a conductive pattern  11   c  is formed on the inner face of the upper piece  11   a.  More specifically, the inner face of the upper piece  11   a  is provided with an adhesive layer (not shown) made of dielectric material being different from the material of the upper piece  11   a.  The conductive pattern  11   c  may be plated through the adhesive layer. 
     Owing to existence of the adhesive layer, the upper piece  11   a  may be provided with the conductive pattern  11   c  no matter what kind of material the upper piece  11   a  is made of. Thus, the material of the upper piece  11   a  may be selected from reinforced dielectric material that is necessary for the radio apparatus  1  to be stiff and thinner. 
     The upper piece  11   a  may have a conductive pattern that is not shown and formed on an outer face of the upper piece  11   a.  The conductive pattern on the outer face may be connected to the conductive pattern  11   c  by turning around an edge of the upper piece  11   a  or though a via hole that is not shown and penetrates between the inner and outer faces of the upper piece  11   a.    
     The upper section  11  contains an antenna feed material  16  arranged between the inner face of the upper piece  11   a  and the printed board  15 . The antenna feed material  16  is made of nonconductive material, e.g., plastic, and has a feed conductor  16   a  shown by a dashed line. The feed conductor  16   a  may be formed, e.g., by being plated on a surface of the antenna feed material  16 , or as a via hole that penetrates inside the antenna feed material  16 . 
     An end of the feed conductor  16   a  that is nearer to the printed board  15  is connected to the antenna feed circuit (more specifically, the conductive pattern that is not shown) of the printed board  15  through a first feed pin  17 . Another end of the feed conductor  16   a  that is nearer to the upper piece  11   a  is connected to the conductive pattern  11   c  through a second feed pin  18 . 
     The first feed pin  17  and the second feed pin  18  are a means of electrical connection, generally called a spring pin, having a plunger through a spring arranged in a metallic pipe. A tip of the plunger may be pressed against a conductive face of the other party of connection so as to obtain electrical conduction. 
     The first feed pin  17  may be provided on the printed board  15  and the tip of the plunger may be pressed against the end of the feed conductor  16   a  that is nearer to the printed board  15 . The first feed pin  17  may be provided on the antenna feed material  16  and connected to the end of the feed conductor  16   a  that is nearer to the printed board  15 , and the tip of the plunger may be pressed against the antenna feed circuit of the printed board  15 . 
     The second feed pin  18  may be provided on the antenna feed material  16  and connected to the end of the feed conductor  16   a  that is nearer to the upper piece  11   a,  and the tip of the plunger may be pressed against the conductive pattern  11   c.  The second feed pin  18  may be provided on the upper piece  11   a  and the tip of the plunger may be pressed against the end of the feed conductor  16   a  that is nearer to the upper piece  11   a.    
     According to the above configuration, the conductive pattern  11   c  is connected to the antenna feed circuit of the printed board  15 , and may be fed as, e.g., a monopole antenna. As shown in  FIG. 2 , a portion of the antenna feed material  16  that is connected to the antenna feed circuit of the printed board  15  is separated from the printed board  15 . The separation may be made so small that the first feed pin  17  may be made short enough to improve assembly work efficiency. 
     The antenna feed material  16  may be formed in such a way that a short feed pin may be used as the second feed pin  18  after the antenna feed material  16  is arranged in place. As shown in  FIG. 2 , a portion of the antenna feed material  16  that is connected to the conductive pattern  11   c  through the second feed pin  18  may be shaped in accordance with a shape of the upper piece  11   a,  so that where to arrange the antenna feed material  16  may be selected more freely although the second feed pin  18  has to be put in a fixed direction. 
     As being arranged in such a way as to fill space around the end portion of the first section  11  that is farther from the connection  13 , the antenna feed material  16  may mechanically reinforce the first section  11 . 
     A modification of the first embodiment will be described with reference to  FIG. 3 .  FIG. 3  is a cross sectional view of a portion of a first section  11   m,  i.e., a modification of the first section  11  described above and shown in  FIG. 2 . Each of portions shown in  FIG. 3  which is a same as the corresponding one shown in  FIG. 2  is given the same reference numeral ( 11   a,    11   b,    15  and  18 ) and its explanation is omitted. 
     An antenna feed material  16   m  is put on a face of the printed board  15  facing the inner face of the upper piece  11   a  of the first section  11 . The antenna feed material  16   m  is made of nonconduct material, e.g., plastic, and has a feed conductor  16   n  shown by a dashed line. The feed conductor  16   n  may be formed, e.g., by being plated on a surface of the antenna feed material  16   m,  or as a via hole that penetrates inside the antenna feed material  16   m.    
     An end of the feed conductor  16   n  that is nearer to the printed board  15  is connected to the antenna feed circuit of the printed board  15  through a connector  19 . The connector  19  is a pair of connectors put on the antenna feed material  16   m  and the printed board  16   n  and joined to each other. 
     An end of the feed conductor  16   n  that is nearer to the upper piece  11   a  is connected to the conductive pattern  11   c  through the second feed pin  18 . 
     According to the above modified configuration, the conductive pattern  11   c  is connected to the antenna feed circuit of the printed board  15 , and may be fed as, e.g., a monopole antenna. The first section  11   m  may lack the first feed pin  17  included in the first section  11  shown in  FIG. 2 , and thus may further improve the assembly work efficiency. 
     According to the first embodiment of the present invention described above, a radio apparatus that may use a conductive pattern formed on a casing material as an antenna element may feed the antenna element through a small number of short feed pins located with a high degree of freedom. 
     A second embodiment of the present invention will be described with reference to  FIGS. 4-9 . A radio apparatus of the second embodiment is a same as the radio apparatus  1  given the same reference numeral of the first embodiment for convenience of explanation, having a conductive pattern formed on a casing material configured to be fed by an antenna feed circuit provided on a printed board through an antenna feed material and feed pins, as described with respect to the first embodiment. Each of portions of the radio apparatus  1  of the second embodiment is given the same reference numeral as shown in  FIG. 2 . 
     The conductive pattern  11   c  of the second embodiment, however, may be used as an antenna such as an inverted F antenna that may be fed and grounded at one and another portions of the antenna, respectively.  FIG. 4  is a diagram showing an antenna feed connection of the radio apparatus  1  of the second embodiment. 
     As shown in  FIG. 4 , the first feed pin  17  is formed by a signal side and a ground side paired with each other, and so are the feed conductor  16   a  and the second feed pin  18  (each of the pairs is shown as surrounded by a dashed ellipse in  FIG. 4 ). The conductive pattern  11   c  may be used as an inverted F antenna. A portion of the conductive pattern  11   c  is connected to a signal side of the antenna feed circuit through the signal sides of the second feed pin  18 , the feed conductor  16   a  and the first feed pin  17 . Another portion of the conductive pattern  11   c  is connected to a ground side of the antenna feed circuit through the ground sides of the second feed pin  18 , the feed conductor  16   a  and the first feed pin  17 . 
       FIG. 5  is a diagram showing another antenna feed connection of the radio apparatus  1  of the second embodiment. In  FIG. 5 , as similarly shown in  FIG. 4 , the first feed pin  17  is formed by a signal side and a ground side paired with each other, and so are the feed conductor  16   a  and the second feed pin  18  (each of the pairs is shown as surrounded by a dashed ellipse in  FIG. 5 ). The conductive pattern  11   c  may be used as a folded monopole antenna having a grounded end. A portion of the conductive pattern  11   c  is connected to a signal side of the antenna feed circuit through the signal sides of the second feed pin  18 , the feed conductor  16   a  and the first feed pin  17 . Another portion of the conductive pattern  11   c  is connected to a ground side of the antenna feed circuit through the ground sides of the second feed pin  18 , the feed conductor  16   a  and the first feed pin  17 . 
     As described above, the conductive pattern  11   c  may be used as an antenna of a type that may be fed and grounded at one and another portions of the antenna, respectively, by using the first feed pin  17 , the feed conductor  16   a  and the second feed pin  18  formed by the pairs of the signal side and the ground side. The first feed pin  17  may be formed by a pair of short feed pins that are similar to the short feed pins of the first embodiment, and so may be the second feed pin  18 . 
     A modification of the second embodiment will be described with reference to  FIGS. 6-7 .  FIG. 6  is a diagram showing a modification of the antenna feed connection of the second embodiment shown in  FIG. 4  that the first feed pin  17  is replaced by the connector  19  (i.e., a pair of connectors joined to each other as described with respect to the modification of the first embodiment) as similarly shown in  FIG. 3 . Each of portions of the modification shown in  FIG. 6  is given a same reference numeral as shown in  FIG. 3  for convenience of explanation. 
     As shown in  FIG. 6 , the connector  19  is formed by a signal side and a ground side paired with each other, and so are the feed conductor  16   n  and the second feed pin  18  (each of the pairs is shown as surrounded by a dashed ellipse in  FIG. 6 ). The conductive pattern  11   c  may be used as an inverted F antenna. A portion of the conductive pattern  11   c  is connected to a signal side of the antenna feed circuit through the signal sides of the second feed pin  18 , the feed conductor  16   n  and the connector  19 . Another portion of the conductive pattern  11   c  is connected to a ground side of the antenna feed circuit through the ground sides of the second feed pin  18 , the feed conductor  16   n  and the connector  19   
       FIG. 7  is a diagram showing a modification of the different antenna feed connection of the second embodiment shown in  FIG. 5  that the first feed pin  17  is replaced by the connector  19  similarly as shown in  FIG. 3 . In  FIG. 7 , as similarly shown in  FIG. 6 , the connector  19  is formed by a signal side and a ground side paired with each other, and so are the feed conductor  16   n  and the second feed pin  18  (each of the pairs is shown as surrounded by a dashed ellipse in  FIG. 7 ). The conductive pattern  11   c  may be used as a folded monopole antenna having a grounded end. A portion of the conductive pattern  11   c  is connected to a signal side of the antenna feed circuit through the signal sides of the second feed pin  18 , the feed conductor  16   n  and the connector  19 . Another portion of the conductive pattern  11   c  is connected to a ground side of the antenna feed circuit through the ground sides of the second feed pin  18 , the feed conductor  16   n  and the connector  19 . 
     As described above, the conductive pattern  11   c  may be used as an antenna of a type that may be fed and grounded at one and another portions of the antenna, respectively, by using the connector  19 , the feed conductor  16   n  and the second feed pin  18  formed by the pairs of the signal side and the ground side. The antenna feed connection shown in  FIG. 7  may lack the first feed pin  17  included in the antenna feed connection of the second embodiment shown in  FIG. 4  or  FIG. 5 , and thus may further improve the assembly work efficiency. 
     The antenna that may be fed and grounded at one and another portions of the antenna is not limited to the above examples of the inverted F antenna or the folded monopole antenna having a grounded end. 
     Another modification of the second embodiment will be described with reference to  FIGS. 8-9 . This modification has an additional conductive pattern formed on a surface of or inside the antenna feed material  16  and connected to a separate feed system. The above additional conductive pattern may be used for an application other than an application of the antenna formed by the conductive pattern formed on the casing material. That is, e.g., the former is applied to a mobile phone use and the latter is applied to a wireless local area network (WLAN) use. 
       FIG. 8  is a diagram showing an antenna configuration and an antenna feed connection of the modification described just above. Location of each portion of the modification shown in  FIG. 8  may be divided into three areas, i.e., on the printed board  15 , on the antenna feed material  16  and on the upper piece  11   a  as divided by vertical dashed lines. Additional conductive patterns, i.e., a ground pattern  16   g  and an antenna element pattern  16   x,  are formed on the antenna feed material  16 . 
     As shown on a left side of  FIG. 8 , the printed circuit  15  includes two kinds of radio circuits. One is a “radio circuit- 1 ” connected to the paired first feed pin  17 . The signal side and the ground side of the first feed pin  17  are connected to a feed portion and a ground portion of the conductive pattern  11   c  forming an inverted F antenna through the feed conductor  16   a  and the ground conductor  16   g,  respectively. Another one is a “radio circuit- 2 ” connected to the antenna element pattern  16   x  through another feed pin  20  provided in the printed board  15 . 
     As what is shown in  FIG. 9  is a same as shown in  FIG. 8  except that the conductive pattern  11   c  forms a folded monopole antenna, its explanation is omitted. 
     According to the modifications shown in  FIGS. 8-9 , an antenna element for an additional system may be formed on the antenna feed material  16  and the two systems may have the ground pattern in common so that an additional effect may be obtained that the additional system may lack a feed pin of the ground side. 
     According to the second embodiment of the present invention described above, a radio apparatus that may use a conductive pattern formed on a casing material as an antenna element and partially grounded may feed and ground the antenna element through a small number of paired short feed pins located with a high degree of freedom. 
     A third embodiment of the present invention will be described with reference to  FIGS. 10-13 . A radio apparatus of the third embodiment is a same as the radio apparatus  1  given the same reference numeral of the first embodiment for convenience of explanation, having a conductive pattern formed on a casing material configured to be fed by an antenna feed circuit provided on a printed board through an antenna feed material and feed pins, as described with respect to the first embodiment. Each of portions of the radio apparatus  1  of the third embodiment is given the same reference numeral as shown in  FIG. 2   
     The conductive pattern  11   c  of the third embodiment, however, is formed by a pair of conductive patterns of a signal side and a ground side.  FIG. 10  is a diagram showing an antenna feed connection of the radio apparatus  1  of the third embodiment. 
     As shown in  FIG. 10 , the first feed pin  17  is formed by the signal side and the ground side paired with each other, and so are the feed conductor  16   a  and the second feed pin  18  (each of the pairs is shown as surrounded by a dashed ellipse in  FIG. 10 ). The conductive pattern  11   c  is formed as a pair of conductive patterns of the signal side and of the ground side. The signal side of the conductive pattern  11   c  is connected to a signal side of the antenna feed circuit through the signal sides of the second feed pin  18 , the feed conductor  16   a  and the first feed pin  17 . The ground side of the conductive pattern  11   c  is connected to a ground side of the antenna feed circuit through the ground sides of the second feed pin  18 , the feed conductor  16   a  and the first feed pin  17 . 
     As described above, each of the first feed pin  17 , the feed conductor  16   a,  the second feed pin  18  and the conductive pattern  11   c  may be formed as a pair of the signal side and the ground side so as to form an antenna having a ground region on a face of the upper piece  11   a.  Although using an unbalanced current excited and distributed on the ground region as a main radiation source, an antenna may not have a sufficient size of a ground region on the printed board  15 . Even in such a case, the ground region may be enlarged on the upper piece  11   a  so that the antenna gain may be improved. The antenna may be fed through paired short feed pins as similarly described with respect to the second embodiment. 
     A modification of the third embodiment will be described with reference to  FIG. 11 , showing a modification of the antenna feed connection of the third embodiment shown in  FIG. 10  that the first feed pin  17  is replaced by the connector  19  (a pair of connectors joined to each other as described with respect to the modification of the first embodiment) as similarly shown in  FIG. 3 . Each of portions of the modification shown in  FIG. 11  is given a same reference numeral as shown in  FIG. 3  for convenience of explanation. 
     As shown in  FIG. 11 , the connector  19  is formed by a signal side and a ground side paired with each other, and so are the feed conductor  16   n,  the second feed pin  18  and the conductive pattern  11   c  (each of the pairs is shown as surrounded by a dashed ellipse in  FIG. 11 ). The signal side of the conductive pattern  11   c  is connected to a signal side of the antenna feed circuit through the signal sides of the second feed pin  18 , the feed conductor  16   n  and the connector  19 . The ground side of the conductive pattern  11   c  is connected to a ground side of the antenna feed circuit through the ground sides of the second feed pin  18 , the feed conductor  16   n  and the connector  19 . 
     As described above, each of the connector  19 , the feed conductor  16   n,  the second feed pin  18  and the conductive pattern  11   c  may be formed as a pair of the signal side and the ground side so as to form an antenna having a ground region on the face of the upper piece  11   a.  The antenna feed connection shown in  FIG. 11  may lack the first feed pin  17  included in the antenna feed connection of the third embodiment shown in  FIG. 10 , and thus may further improve third embodiment shown in  FIG. 10 , and thus may further improve the assembly work efficiency. 
     Another modification of the third embodiment will be described with reference to  FIG. 12 . The modification shown in  FIG. 12  is a same as the modification of the second embodiment shown in  FIG. 8  except that the conductive pattern  11   c  is formed by a pair of conductive patterns of the signal side and of the ground side. Thus, an additional effect may be obtained that the additional system may lack a feed pin of the ground side, as similarly described with reference to  FIG. 8 . 
     According to the third embodiment of the present invention described above, an additional effect may be obtained that an antenna that may not have a sufficient size of a ground region in a printed board inside a casing material may certainly have a ground region on a face of the casing material. 
     A fourth embodiment of the present invention will be described with reference to  FIGS. 13-14 . A radio apparatus of the fourth embodiment has a first section  21   m,  a second section (not shown) and a connection (not shown) movably connecting the first section  21   m  and the second section, in such a way as to open or close the two sections to each other, similarly as the radio apparatus  1  shown in  FIG. 1 .  FIG. 13  is a partial cross sectional view of the first section  21   m  as similarly shown in  FIG. 1 . 
     The first section  21   m  is formed by an upper piece  21   a  and a lower piece  21   b  both made of dielectric material and mechanically joined in a vertical direction. The first section  21   m  contains a printed board  25  on which a radio circuit is provided but is not shown. The radio circuit and a feed line  24  that will be mentioned later are called an antenna feed circuit together. 
     The upper piece  21   a  has an inner face facing the printed board  25 , and conductive patterns  21   s  and  21   g  are formed on the inner face of the upper piece  21   a.  The conductive patterns  21   s  and  21   g  are formed by using a same method as the conductive pattern  11   c  is as described with reference to  FIG. 2 . 
     An antenna feed material  26   m  made of nonconductive and heat-resistant material (e.g., liquid crystal polymer) is arranged between the inner face of the upper piece  21   a  and the printed board  25 . The antenna feed material  26   m  may be provided on the face of the printed board  25  facing the inner face of the upper piece  21   a  as the antenna feed material  16   m  is as shown in  FIG. 3 . 
     Feed pins  28   s  and  28   g  are provided on a face of the antenna feed material  26   m  facing the inner face of the upper piece  21   a.  Each of the feed pins  28   s  and  28   g  is a same as the second feed pin  18  described with reference to  FIG. 2 . The feed pin  28   s  is connected to a signal side of the above radio circuit that is provided on the printed board  25  but is not shown through a signal side of a feed line  24 . The feed pin  28   g  is connected to a ground side of the above radio circuit that is provided on the printed board  25  but is not shown through a ground side of the feed line  24 . 
     As the antenna feed material  26   m  is made of heat-resistant material, tips of the signal side and the ground side of the feed line  24  may be soldered to the feed pin  28   s  and the feed pin  28   g,  respectively. Another end of the feed line  24  may be connected to the above radio circuit that is not shown through a conductive pattern formed in the printed board  25 . The feed line  24  may be connected to the feed pins  28   s  and  28   g  through a conductive pattern formed on a face, or as a via hole, of the antenna feed material  26   m  by being soldered to the conductive pattern. 
     Tips of plungers of the feed pins  28   s  and  28   g  are pressed against and thus connected to the conductive patterns  21   s  and  21   g,  respectively. The feed pins  28   s  and  28   g  may be arranged on the upper piece  21   a  and connected to the conductive patterns  21   s  and  21   g  respectively, and the tips of the plungers may be pressed against the conductive patterns formed on the antenna feed material  26   m  to which tips of signal and ground sides of the feed line  24  are soldered. 
     According to the above configuration of the fourth embodiment, the conductive patterns  21   s  and  21   g  may be fed by being connected to the signal side and the ground side of the antenna feed circuit of the printed board  25 . The conductive patterns  21   s  and  21   g  may be coupled to each other as a pair of the signal side and the ground side, and so may be the feed pins  28   s  and  28   g,  so as to form an antenna having a ground region on the face of the upper piece  21   a  as similarly described with respect to the third embodiment. Meanwhile, the number of necessary feed pins may be reduced in comparison with the third embodiment. 
     According to the above configuration of the fourth embodiment, an antenna that uses an unbalanced current excited and distributed in the ground region as a main radiation source may expand the ground region so as to improve the antenna gain, even if having an insufficient size of the ground region in the printed board  25 . The antenna may be fed through the pair of the short feed pins  28   s  and  28   g,  as similarly described with respect to the previous embodiments.  FIG. 14  is a diagram showing an antenna feed connection of the antenna configured as described above. Reference numerals given to the portions shown in  FIG. 14  and connections among the portions are same as described with reference to  FIG. 13 , and their explanations are omitted. 
     If the conductive patterns  21   s  and  21   g  that are separate to each other are replaced by one consecutive conductive pattern  21   c,  a portion of the conductive pattern  21   c  is connected to the signal side of the antenna feed circuit, and another portion of the conductive pattern  21   c  is grounded. Thus, an antenna of a type fed at one portion and grounded at another portion may be formed, as similarly described with respect to the second embodiment, by including a reduced number of the feed pins in comparison with the second embodiment. 
     In  FIG. 13 , the conductive pattern  21   g  may be connected to the ground side through a conductive tape or a conductive gasket instead of the feed pin  28   g,  so as to further reduce the number of necessary feed pins. 
     According to the fourth embodiment of the present invention described above, an antenna feed material made of heat-resistant material may be used so that the number of feed pins required for the configuration of the second or the third embodiment may be reduced. 
     A fifth embodiment of the present invention will be described with reference to  FIG. 15 . The embodiments described above may be modified in such a way that an additional conductive pattern is formed on or inside the antenna feed material  16  or  26  and connected to a separate feed system, so as to form a radio apparatus of the fifth embodiment. 
     The above additional conductive pattern may be used for an application other than an application of the antenna formed by the conductive pattern formed on the casing material. That is, e.g., the former is applied to a mobile phone use and the latter is applied to a wireless local area network (WLAN) use.  FIG. 15  is an exemplary diagram showing an antenna configuration and an antenna feed connection of the fifth embodiment. 
     The connection shown in  FIG. 15  is based on a modification of the configuration of the fourth embodiment shown in  FIG. 13 , in such a way that the conductive patterns  21   s  and  21   g  are short-circuited by a pattern provided on the surface of the upper piece  21   a.  Thus, some of reference numerals shown in  FIG. 15  are same as shown in  FIG. 13 . Location of each portion shown in  FIG. 8  may be divided into three areas, i.e., on the printed board  25 , on the antenna feed material  26   m  and on the upper piece  21   a  as divided by vertical dashed lines. The antenna feed material  26   m  is made of heat-resistant material as described with respect to the fourth embodiment. 
     As shown on a left side of  FIG. 15 , the printed circuit  25  includes two kinds of radio circuits. One is a “radio circuit- 1 ” to which the feed line  24 , i.e., a same as shown in  FIG. 13 , is connected. Another one is a “radio circuit- 2 ” to which a feed line  34  of a same kind as the feed line  24  is connected. 
     As shown in a middle portion of  FIG. 15 , an additional conductive pattern  35  and a ground pattern  36  are formed on the antenna feed material  26   m.  Each of tips of ground sides of the feed lines  24  and  34  (e.g., an outer conductor of a coaxial cable) are soldered to the ground pattern  36 . A tip of a signal side of the feed line  34  is connected to the additional conductive pattern  35 , that is short-circuited nearby with the ground pattern  36  so as to form an inverted F antenna. 
     A tip of a signal side of the feed line  24  is soldered to the feed pin  28   s  as described with respect to the fourth embodiment, and is connected to the conductive pattern  21   s  through the feed pin  28   s.  The ground pattern  36  is connected to the conductive pattern  21   g  through the feed pin  28   g,  so as to form on the ground side a connection being almost equivalent to the connection shown in  FIG. 13 . 
     As shown on a right side of  FIG. 15 , the conductive pattern  21   s  is formed, e.g., by a combination of a folded monopole antenna element, an open-ended monopole antenna and a short circuit configured to adjust impedance of the open-ended monopole antenna, as disclosed in Japanese Granted Patent Publication (Toroku), No. 3775795. The conductive pattern  21   g  is an antenna ground region formed on the face of the upper piece  21   a  as described with respect to the fourth embodiment. As shown in  FIG. 15 , a tip of the folded monopole antenna included in the conductive pattern  21   s  is short-circuited to the conductive pattern  21   g.    
     According to the above configuration of the fifth embodiment, only two feed pins are enough to feed the antenna formed on the antenna feed material  26   m  and the antenna formed on the upper piece  21   a  separately. Given a three-dimensional shape, the antenna feed material  26   m  may usually have an advantage over the upper piece  21   a  of an effective surface area on which antenna element patterns are formed. Thus, it seems appropriate in lots of cases, although not in every case, that antennas of systems using a relatively low frequency and a relatively high frequency are provided on the antenna feed material  26   m  and on the upper piece  21   a,  respectively. 
     As described above with respect to the fifth embodiment, the additional antenna element is added to the antenna feed material  26   m  on the basis of the configuration shown in  FIG. 13  of the fourth embodiment. The additional antenna element is not limited to the above, and may be added to the antenna feed material of any of the embodiments described above. 
     According to the fifth embodiment of the present invention described above, an additional antenna element may be provided on the antenna feed material so that the radio apparatus may have multiple functions. 
     The particular hardware or software implementation of the present invention may be varied while still remaining within the scope of the present invention. It is therefore to be understood that within the scope of the appended claims and their equivalents, the invention may be practiced otherwise than as specifically described herein.