Abstract:
Provided is a portable wireless device ( 100 ) including: a circuit board ( 130 ); an input unit wiring pattern ( 140 ) comprising a flexible substrate that is separate from the circuit board ( 130 ); and an antenna element ( 160 ) of which a power feed unit ( 162 ) is connected to the substrate edge ( 130   a ) of the circuit board ( 130 ). A vertical wiring unit ( 142 ) is wired perpendicularly to the antenna element ( 160 ). A first cutoff circuit ( 171 ) is installed between the vertical wiring unit ( 142 ) and a horizontal wiring unit ( 143 ), and cuts off the wiring at a high frequency. The horizontal wiring unit ( 143 ) is connected to the circuit board ( 130 ) with a connector ( 150 ) disposed in the vicinity of the power feed unit ( 162 ) therebetween.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to a mobile radio apparatus, such as a mobile telephone, and particularly, to a mobile radio apparatus having a bar structure. 
       BACKGROUND ART 
       [0002]    Mobile radio apparatuses such as mobile telephones have been reduced in size and increasing in functionality. In addition, mobile radio apparatuses including built-in antennas have been developed for improving the designability of the apparatuses. 
         [0003]    Moreover, a mobile radio apparatus such as a mobile telephone prevents deterioration of the sensitivity of an antenna by increasing the distance between the antenna and a human body. An SAR (Specific Absorption Rate) value is used for an index indicating electromagnetic wave energy absorbed by human body. 
         [0004]    Patent Literature (hereinafter, abbreviated as “PTL”) 1 describes a mobile radio configured to selectively use first and second antenna sections placed in a housing, according to a communication mode being used, and thereby to increase the distance between the antenna and the human body to secure favorable communication. 
         [0005]    In a mobile radio apparatus having a bar structure, such as a smart phone, a cellular antenna is usually placed at the bottom portion of the apparatus for reducing SAR or ensuring the implementation volume. 
         [0006]    PTL 2 describes a receiver including an antenna that is placed near a wiring pattern and that receives an electric wave. In the apparatus described in PTL 2, an antenna element (loop antenna) is orthogonal to the wiring pattern in order to prevent a magnetic field component from crossing over the aperture plane of the antenna. Reception sensitivity performance is improved by reducing the reception of a noise component emitted from the wiring pattern. 
       CITATION LIST 
     Patent Literature 
       [0000]    
       
         PTL 1 
         Japanese Patent Application Laid-Open No. 2003-163956 
         PTL 2 
         Japanese Patent Application Laid-Open No. HEI 7-203514 
       
     
       SUMMARY OF INVENTION 
     Technical Problem 
       [0011]    In such a mobile radio apparatus according to the prior art, a cellular antenna is usually placed at a lower end housing portion for reducing SAR or ensuring the implementation volume. Moreover, a configuration using a large screen LCD requires an input part to be placed at the bottom portion. Furthermore, a larger screen display section leads to a reduction in the implementation volume. 
         [0012]    As described above, the input part is placed in the vicinity of the antenna element at the lower end of the housing. The signal lines of the input part placed near the antenna element leads to a problem of deteriorating the antenna performance due to the closely placed conductors. 
         [0013]    It is an object of the present invention to provide a mobile radio apparatus including an antenna element at a lower end housing portion and being capable of reducing the influence of an closely placed input part on the antenna performance and also capable of achieving an increase in the implementation volume of the mobile radio apparatus. 
       Solution to Problem 
       [0014]    A mobile radio apparatus according to an aspect of the present invention includes: a circuit board; an input part wiring pattern that includes a flexible board different from the circuit hoard; and an antenna element that includes an electric supply section connected to an end of the circuit hoard, in which the input part wiring pattern includes: a key surface portion that includes one or more key portions; an orthogonal wiring portion that includes a wiring pattern wired orthogonally with respect to the antenna element from the key surface portion; a horizontal wiring portion that is connected to the orthogonal wiring portion and that is wired horizontally with respect to the antenna element; and a connector that is placed at the horizontal wiring portion near the electric supply section and that connects the horizontal wiring portion and the circuit board. 
       Advantageous Effects of Invention 
       [0015]    According to the present invention, it is possible to provide a mobile radio apparatus including an antenna element at a lower end housing portion and being capable of reducing the influence of an closely placed input part on the antenna performance and also capable of achieving an increase in the implementation volume of the mobile radio apparatus. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0016]      FIG. 1  is a perspective view illustrating an outline configuration of a mobile radio apparatus according to Embodiment 1 of the present invention; 
           [0017]      FIG. 2  is a front view illustrating a main portion of configuration elements of the mobile radio apparatus in  FIG. 1 ; 
           [0018]      FIG. 3  is a rear view illustrating a main portion of configuration elements of the mobile radio apparatus in  FIG. 1 ; 
           [0019]      FIG. 4  is a side view illustrating a main portion of configuration elements of the mobile radio apparatus in  FIG. 1 ; 
           [0020]      FIG. 5  is a developed view illustrating a wiring pattern of an input part in the mobile radio apparatus according to Embodiment 1; 
           [0021]      FIG. 6  is a block diagram illustrating a configuration of the wiring pattern of the input part in the mobile radio apparatus according to Embodiment 1; 
           [0022]      FIG. 7  is a block diagram illustrating a configuration of a key surface portion in the mobile radio apparatus according to Embodiment 1; 
           [0023]      FIG. 8  is a perspective view illustrating the relationship of an orthogonal wiring portion and an antenna element in the mobile radio apparatus according to Embodiment 1; 
           [0024]      FIG. 9  is a perspective view explaining how an input part in the mobile radio apparatus according to Embodiment 1 is incorporated; 
           [0025]      FIG. 10  is a perspective view explaining how a connector is placed in a horizontal wiring portion in the mobile radio apparatus according to Embodiment 1; 
           [0026]      FIG. 11  illustrates, as a comparative example, a case where a connector is placed on a side opposite to a side where an electric supply section is placed in the mobile radio apparatus according to Embodiment 1; 
           [0027]      FIG. 12  is a perspective view illustrating a configuration of a first isolation circuit and the GND of a circuit board in the mobile radio apparatus according to Embodiment 1; 
           [0028]      FIG. 13  is a top view illustrating a key surface portion of a wiring pattern of an input part in a mobile radio apparatus according to Embodiment 2 of the present invention; and 
           [0029]      FIG. 14  is a block diagram illustrating a configuration of the key surface portion in the mobile radio apparatus according to Embodiment 2. 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
       [0030]    Hereinafter, embodiments of the present invention will be explained in detail with reference to the accompanying drawings. 
       Embodiment 1 
       [0031]      FIG. 1  is a perspective view illustrating an outline configuration of mobile radio apparatus  100  according to Embodiment 1 of the present invention.  FIGS. 2 ,  3 , and  4  are front, rear, and side views of a main portion of configuration elements of mobile radio apparatus  100 , respectively. 
         [0032]    Hereinafter, mobile radio apparatus  100  according to the present invention is embodied with a mobile information terminal such as a PDA (Personal Digital Assistant). Alternatively, application to a camera equipped mobile telephone or a PHS (Personal Handy-Phone System) is also possible. 
         [0033]    As illustrated in  FIGS. 1 to 4 , mobile radio apparatus  100  includes input part  101 , housing  110 , display section  120 , circuit board  130 , microphone signal line  140 , microphone  150 , antenna element  160 , shielding pattern  170 , and isolation circuit  180 . 
         [0034]    Input part  101  is mounted at lower end housing portion (bottom portion)  110   a  of housing  110  below display section  120  and includes functional buttons. Input part  101  is placed at lower end housing portion  110   a  and is connected to input part wiring pattern  140  to be described below. Display section  120  also has a function of input means, and therefore input part  101  serves as an auxiliary function for input operations and has only few functional buttons and a reduced implementation volume. 
         [0035]    Housing  110  has a bar type structure. In the case of folding type mobile radio apparatus  100 , housing  110  is a main body side housing 
         [0036]    Display section  120  is a large display substantially covering the whole surface of housing  110 . Display section  120  includes, for example, an LCD display or an organic electro-luminescence (EL) display and displays, for example, received information and content. A touch panel (not illustrated) is mounted on display section  120 . Therefore, display section  120  also has a function of input means. The implementation volume of housing  110  is reduced by the large screen of display section  120 . 
         [0037]    Circuit board  130  is a printed circuit board on which circuit components realizing various functions of mobile radio apparatus  100  are installed. Board end  130   a  connected to antenna element  160  and circuit board GND portion  130   b , are formed at the lower edge of circuit board  130 . 
         [0038]    Input part wiring pattern  140  is formed on a flexible board different from circuit board  130 . Input part wiring pattern  140  is mounted at lower end housing portion  110   a . Input part wiring pattern  140  connects input part  101  (functional buttons) with circuit board  130 . Input part wiring pattern  140  is mounted so as to be orthogonal to antenna element  160  described below. A configuration of input part wiring pattern  140  will be described in detail below. 
         [0039]    Connector  150  is installed near electric supply section  162 . Connector  150  is a board connection section connecting input part wiring pattern  140  with circuit board  130 . 
         [0040]    Antenna element  160  is mounted at lower end housing portion  110   a  in the width direction of housing  110 . Antenna element  160  is placed orthogonally to horizontal wiring portion  143  of input part wiring pattern  140 . Antenna element  160  is connected to board end portion  130   a  of circuit board  130  through electric supply section  162 . Antenna element  160  has electric supply section  162 , and conductor portion  161  formed of a metal frame. Electric supply section  162  is connected to board end portion  130   a  of circuit board  130 . The metal frame forming antenna element  160  is formed by using a metal which has high conductivity, a light weight, and high strength such as a magnesium alloy. Conductor portion  161  extends in the width direction of housing  110  in lower end housing portion  110   a  from electric supply section  162  connected to board end portion  130   a . Antenna element  160  is placed near input part wiring pattern  140 . 
         [0041]    Mobile radio apparatus  100  described above includes: conductor portion  161  of antenna element  160 ; key surface portion  141 ; orthogonal wiring portion  142 ; horizontal wiring portion  143 ; and connector  150  in this order from lower end housing portion  110   a  in the upward longitudinal direction of housing  110 . In this configuration, key surface portion  141 , orthogonal wiring portion  142 , and horizontal wiring portion  143  are bent along board end portion  130   a . Connector  150  is placed near electric supply section  162  on horizontal wiring portion  143 . 
         [0042]      FIG. 5  is a developed view illustrating input part wiring pattern  140 . 
         [0043]    As illustrated in  FIG. 5 , input part wiring pattern  140  includes: key surface portion  141  where key portions  101   a  to  101   c , which are depression switches in input part  101  (functional buttons), are installed; orthogonal wiring portion  142  where is wired from key surface portion  141  is made orthogonally to antenna element  160 ; and horizontal wiring portion  143  where wiring is made to connector  150  from orthogonal wiring portion  142  in parallel to antenna element  160  and circuit board  130 . 
         [0044]    Key surface portion  141  includes key portions  101   a  to  101   c , LEDs  102 , second isolation circuits  172  installed between signal lines having the same potential among key portions  101   a  to  101   c , and third isolation circuits  173  each installed between LED  102  and orthogonal wiring portion  142 . 
         [0045]    First isolation circuit  171  is installed between orthogonal wiring portion  142  and horizontal wiring portion  143 . 
         [0046]    Connector  150  connecting input part wiring pattern  140  with circuit board  130  is attached near electric supply section  162  of horizontal wiring portion  143 . 
         [0047]      FIG. 6  is a block diagram illustrating a configuration of input part wiring pattern  140 . 
         [0048]    As illustrated in  FIG. 6 , input part wiring pattern  140  includes key surface portion  141 , orthogonal wiring portion  142 , first isolation circuit  171 , and horizontal wiring portion  143 . Horizontal wiring portion  143  is connected to connector  150  placed near electric supply section  162 . 
         [0049]    Key surface portion  141  is bent along board end portion  130   a  ( FIG. 3 ). 
         [0050]    Orthogonal wiring portion  142  is wired orthogonally with respect to antenna element  160 . 
         [0051]    First isolation circuit  171  is installed between orthogonal wiring portion  142  and horizontal wiring portion  143  and isolates the wiring in a high frequency manner. 
         [0052]    Horizontal wiring portion  143  is connected to circuit board  130  through connector  150  placed near electric supply section  162 . 
         [0053]    Hereinafter, a configuration of each part of input part wiring pattern  140  will be explained. 
         [0054]    [Key Surface Portion  141 ] 
         [0055]      FIG. 7  is a block diagram illustrating a configuration of key surface portion  141 .  FIG. 7  illustrates an example case where three key portions that are depression switches and two LEDs are provided. Components other than an LED may be mounted on key surface portion  141 , and any number of the components may be mounted thereon. 
         [0056]    As illustrated in  FIG. 7 , key surface portion  141  includes key portions  101   a  to  101   c , LEDs  102 , second isolation circuits  172  installed between signal lines having the same potential among key portions  101   a  to  101   c , and third isolation circuits  173  each installed between LED  102  and orthogonal wiring portion  142 . 
         [0057]    On key surface portion  141 , the signal lines having the same potential in key portions  101   a  to  101   c  on key surface portion  141  are connected through second isolation circuits  172 . 
         [0058]    LED  102  serving as an example of a component of key surface portion  141  is connected to orthogonal wiring portion  142  through third isolation circuit  173 . 
         [0059]    In this way, the signal lines having the same potential in key portions  101   a  to  101   c  can be connected on key surface portion  141 , and mobile radio apparatus  100  can thereby reduce the number of wiring lines in orthogonal wiring portion  142  and reduce the physical width of orthogonal wiring portion  142 . As a result, it is made possible to further reduce the influence on the antenna performance and the size of the apparatus. 
         [0060]    Moreover, mobile radio apparatus  100  isolates the signal lines from one another in the horizontal direction on key surface portion  141  in a high frequency manner by placing second isolation circuits  172  among key portions  101   a  to  101   c  to make the wiring on key surface portion  141  look as if the wiring is not connected in the horizontal direction. This can reduce the wiring while maintaining the configuration of the orthogonal wiring design. 
         [0061]    Moreover, the components placed on key surface portion  141  are configured as floating conductors by being separated via second isolation circuits  172  and third isolation circuits  173  in a high frequency manner. This can reduce the influence on the antenna performance due to the closely placed conductors. 
         [0062]    Mobile radio apparatus  100  connects LEDs  102  to orthogonal wiring portion  142  through third isolation circuits  173  and can thereby prevent static electricity from damaging LEDs  102 . 
         [0063]      FIGS. 5 and 6  are only examples of the key surface configuration, and the present invention is not limited to this configuration. 
         [0064]    [Orthogonal Wiring Portion  142 ] 
         [0065]      FIG. 8  is a perspective view illustrating the relationship of orthogonal wiring portion  142  and antenna element  160 .  FIG. 9  is a perspective view explaining how input part  101  is incorporated. 
         [0066]    As illustrated in  FIG. 8 , horizontal wiring portion  143  in input part wiring pattern  140  is connected to circuit board  130  through connector  150  placed near electric supply section  162 . 
         [0067]    Orthogonal wiring portion  142  in input part wiring pattern  140  is bent at the bottom surface of circuit board  130 . 
         [0068]    Orthogonal wiring portion  142  adopts a basic configuration in which the orthogonal wiring portion is wired orthogonally with respect to antenna element  160 . 
         [0069]    Furthermore, as illustrated in  FIG. 9 , orthogonal wiring portion  142  is configured in such a way that different wiring lines of orthogonal wiring portion  142  do not overlap each other when input part wiring pattern  140 , which is formed on a flexible board, is bent. In other words, orthogonal wiring portion  142  is bent in such a way that the bent portions of orthogonal wiring portion  142  face each other. In this configuration, the same wiring lines of orthogonal wiring portion  142  overlap each other while different wiring lines thereof do not overlap each other. 
         [0070]    In this way, mobile radio apparatus  100  causes an antenna current (refer to a solid line arrow in  FIG. 8 ) flowing through antenna element  160  to be orthogonal to a flexible board current (refer to dashed line arrows in  FIG. 8 ) flowing through input part wiring pattern  140 , and can thereby reduce the influence on the antenna performance. 
         [0071]    Moreover, the occurrence of capacitive coupling between wiring lines of orthogonal wiring portion  142  close to antenna element  160  can reduce an increase in the influence on the antenna performance due to orthogonal wiring portion  142 . 
         [0072]    [Horizontal Wiring Portion  143 ] 
         [0073]      FIGS. 10 and 11  are perspective views explaining how connector  150  is placed in horizontal wiring portion  143 .  FIG. 10  illustrates a case where conductor  150  is placed on a side where the electric supply section is placed in the present embodiment.  FIG. 11  illustrates, as a comparative example, a case where a connector is placed on a side opposite to the side where the electric supply section is placed. 
         [0074]    As illustrated in  FIG. 10 , horizontal wiring portion  143  in input part wiring pattern  140  in the present embodiment is wired horizontally with respect to antenna element  160  and circuit board  130 , and is connected to circuit board  130  through connector  150  placed near electric supply section  162 . 
         [0075]    In this way, mobile radio apparatus  100  causes a hoard (GND) current (refer to a solid line arrow in  FIG. 10 ) flowing through circuit board  130  to have the same phase as a wiring pattern current (refer to a dashed line arrow in  FIG. 10 ) flowing through the wiring pattern of horizontal wiring portion  143  ( 140 ), and can thereby reduce the influence on the antenna performance. 
         [0076]    As illustrated in the comparative example of  FIG. 11 , when horizontal wiring portion  143  is connected to a portion of circuit board  130  on a side opposite to a side where the electric supply section is placed, through connector  150   a  placed on the side opposite to the electric supply section, a board (GND) current (refer to a solid line arrow in  FIG. 11 ) flowing through circuit hoard  130  has an opposite phase to a wiring pattern current (refer to a dashed line arrow in  FIG. 11 ) flowing through the wiring pattern of horizontal wiring portion  143  ( 140 ). The influence on the antenna performance cannot be reduced in this case. 
         [0077]    In the present embodiment, horizontal wiring portion  143  is wired horizontally with respect to antenna element  160  and circuit board  130  and is connected to circuit board  130  through connector  150  placed on the side where the electric supply section is placed. This configuration causes a board (GND) current flowing through circuit board  130  to have the same phase as a wiring pattern current flowing through the wiring pattern of horizontal wiring portion  143  ( 140 ) and thus can reduce the influence on the antenna performance. 
         [0078]    In addition to the effect achieved by placing connector  150  on the side the electric supply section is placed, the wiring lines of horizontal wiring portion  143  are bundled by connector  150  in the width direction of circuit board  130 , which in turn achieves the following effect. 
         [0079]    The wiring of horizontal wiring portion  143  is bundled at the end in the width direction of circuit board  130  and is then connected to circuit board  130  through connector  150 , which makes it possible to increase the implementation space of circuit board  130 . 
         [0080]    [First Isolation Circuit  171 ] 
         [0081]      FIG. 12  is a perspective view illustrating a configuration of first isolation circuit  171  and the GND of circuit board  130 . 
         [0082]    As illustrated in  FIG. 12 , input part wiring pattern  140 , which is formed on a flexible board, is bent along the lower end of circuit board  130 . In this case, orthogonal wiring portion  142  is placed so as not to overlap with circuit board GND portion  130   b.    
         [0083]    On the other hand, first isolation circuit  171  is placed between orthogonal wiring portion  142  and horizontal wiring portion  143  and isolates the wiring in a high frequency manner. 
         [0084]    First isolation circuit  171  is configured to be placed at a position in such a way orthogonal wiring portion  142  and orthogonal horizontal wiring portion  143  do not overlap each other when input part wiring pattern  140  is bent and incorporated. That is, first isolation circuit  171  is placed so as to not to overlap with bent orthogonal wiring portion  142 . 
         [0085]    In this way, mobile radio apparatus  100  includes first isolation circuit  171  installed between orthogonal wiring portion  142  and horizontal wiring portion  143  and does not cause overlapping between orthogonal wiring portion  142  and circuit board GND portion  130   b . Therefore, the influence on the antenna performance can further be reduced by separating a high frequency current between orthogonal wiring portions  142  and horizontal wiring portions  143 . 
         [0086]    Moreover, coupling between orthogonal wiring portion  142  and horizontal wiring portion  143  in a high frequency manner can be reduced. This can improve a high frequency isolation effect achieved by first isolation circuit  171 . 
         [0087]    Moreover, coupling between orthogonal wiring portion  142  and circuit board  130  in a high frequency manner can be reduced. This can improve a high frequency isolation effect achieved by first isolation circuit  171 . 
         [0088]    As explained in detail above, mobile radio apparatus  100  according to the present embodiment includes circuit board  130 , input part wiring pattern  140  formed on a flexible board which is different from circuit board  130 , and antenna element  160  including electric supply section  162  connected to board end  130   a  of circuit board  130 . 
         [0089]    Conductor portion  161  of antenna element  160 , key surface portion  141  bent along board end portion  130   a , orthogonal wiring portion  142 , horizontal wiring portion  143 , connector  150  placed near electric supply section  162  on horizontal wiring portion  143  are placed in this order from lower end housing portion  110   a  in the upward longitudinal direction of housing  110 . 
         [0090]    Orthogonal wiring portion  142  is wired orthogonally with respect to antenna element  160 . First isolation circuit  171  is installed between orthogonal wiring portion  142  and horizontal wiring portion  143 , and isolates orthogonal wiring portion  142  and orthogonal horizontal wiring portion  143  from each other in a high frequency manner. Horizontal wiring portion  143  is connected to circuit board  130  through connector  150  placed near electric supply section  162 . 
         [0091]    The following effects can be achieved by the above configuration. 
         [0092]    (1) The wiring of input part wiring pattern  140  close to antenna element  160  is placed orthogonally with respect to antenna element  160  (orthogonal placement of orthogonal wiring portion  142  and antenna element  160 ). This configuration can reduce the influence of input part wiring pattern  140  placed closely to antenna element  160 . 
         [0093]    Moreover, horizontal wiring portion  143  is wired in the horizontal direction at a position of overlapping with circuit board GND portion  130   b , and the wiring lines are brought together at the end of horizontal wiring portion  143 . Then, horizontal wiring portion  143  is connected to circuit board  130  through connector  150 . This configuration can increase the implementation space of circuit board  130 . 
         [0094]    In particular, connector  150  is placed near electric supply section  162 , which makes it possible to cause a current flowing through horizontal wiring portion  143  to have the same phase as a current through circuit board GND portion  130   b  and thus to achieve a high antenna performance. 
         [0095]    (2) First isolation circuit  170  is installed between orthogonal wiring portion  142  and horizontal wiring portion  143 , and isolates orthogonal wiring portion  142  and orthogonal horizontal wiring portion  143  from each other in a high frequency manner. Moreover, circuit board GND portion  130   b  is placed on circuit board  130  except for a portion overlapping with orthogonal wiring portion  142  in planar view. Alternatively, circuit board  130  is placed so as not to overlap with orthogonal wiring portion  142 . 
         [0096]    The effects in (1) can further be improved by separating a high frequency current between orthogonal wiring portion  142  and horizontal wiring portion  143 . 
         [0097]    Moreover, orthogonal wiring portion  142  is prevented from overlapping with circuit board GND portion  130   b , which in turn prevents coupling between orthogonal wiring portion  142  and circuit board GND portion  130   b  through the hoard. The high frequency isolation effect achieved by first isolation circuit  171  can be thereby further improved. 
         [0098]    (3) In the case of providing the plurality of key portions  101   a  to  101   e , signal lines having the same potential, such as GND lines on diaphragms on key surface portion  141 , are connected on key surface portion  141  through second isolation circuits  172  placed between the plurality of key portions  101   a  to  101   c.    
         [0099]    The signal lines having the same potential can be connected on key surface portion  141 , which in turn makes it possible to reduce the number of wiring lines of orthogonal wiring portion  142  and reduce the physical width of orthogonal wiring portion  142 . As a result, it is made possible to further reduce the influence on the antenna performance and also to reduce the size of the apparatus. 
         [0100]    In addition, placing second isolation circuits  172  among key portions  101   a  to  101   c  makes the wiring on key surface portion  141  look as if the wiring is not connected in the horizontal direction. Accordingly, the wiring lines can be reduced while the effects described in (1) are maintained with the orthogonal wiring design. 
         [0101]    (4) Orthogonal wiring portion  142  is bent in such a way that wiring lines do not overlap each other. Moreover, components (for example, LED  102 ) of key surface portion  141  are connected to orthogonal wiring portion  142  through third isolation circuit  173 . 
         [0102]    Accordingly, it is possible to avoid increases in the influence on the performance due to closely positioned antenna element  160 , which otherwise occur due to capacitive coupling of overlapping wiring lines causing a reduction in the isolation effect achieved by second isolation circuit  172 . 
         [0103]    Moreover, the components placed on key surface portion  141  are separated from orthogonal wiring portion  142  in a high frequency manner by third isolation circuit  173  and are thereby configured as floating conductors. Accordingly, the influence on the antenna performance due to the conductors closely placed to antenna element  160  can be reduced. 
       Embodiment 2 
       [0104]      FIG. 13  is a top view illustrating key surface portion  241  of an input part wiring pattern of a mobile radio apparatus according to Embodiment 2 of the present invention.  FIG. 14  is a block diagram illustrating a configuration of key surface portion  241 . In the explanation of the present embodiment, the same reference numerals are given to the same components as those illustrated in  FIGS. 5 and 7 , and any duplicate explanation of the components will be omitted. 
         [0105]    As illustrated in  FIGS. 13 and 14 , key surface portion  241  includes key portions  101   a  to  101   c , LEDs  102 , second isolation circuits  172  installed between the signal lines having the same potential among key portions  101   a  to  101   c , third isolation circuit  173  installed between LEDs  102  and orthogonal wiring portion  142 , GND patterns  242 , and varistors  243  each connected between LED  102  and GND pattern  242  and configured to protect LED  102  from a high voltage. 
         [0106]    Key surface portion  141  connects the signal lines having the same potential among key portions  101   a  to  101   c  on key surface portion  141  through second isolation circuits  172 . 
         [0107]    LEDs  102  each serving as an example of a component of key surface portion  141  is connected to orthogonal wiring portion  142  through third isolation circuit  173 . 
         [0108]    LEDs  102  are connected to GND patterns  242  through varistors  243 , respectively. 
         [0109]    In this embodiment, the signal lines having the same potential can be connected together on key surface portion  241 , which in turn reduces the number of wiring lines of orthogonal wiring portion  142  as described above. Thus, the physical width of orthogonal wiring portion  142  can be reduced, which makes it possible to further reduce the influence on the antenna performance and also the size of the apparatus. 
         [0110]    Moreover, according to the present embodiment, placing second isolation circuits  172  among key portions  101   a  to  101   c  makes the wiring on key surface portion  241  look as if the wiring is not connected in the horizontal direction. Accordingly, the wiring lines can be reduced while the configuration of the orthogonal wiring design is maintained. 
         [0111]    Moreover, the components placed on key surface portion  241  (in this case, LEDs  102 ) are separated in a high frequency manner by third isolation circuit  173  and are thereby configured as floating conductors. Thus, the influence on the antenna performance due to the conductors placed closely to antenna element  160  can be reduced. 
         [0112]    Moreover, connecting LEDs  102  to GND patterns  242  through varistors  243 , respectively, can prevent static electricity from damaging LEDs  102 . 
         [0113]    The above explanation is provided as an example of preferred embodiments of the present invention and the scope of the invention is by no means limited to this explanation. 
         [0114]    The present invention can be applied to any mobile radio apparatus including an antenna element connected to a circuit board and a microphone placed near the antenna element. The present invention is obviously applicable to a mobile radio apparatus having a bar structure, and is also applicable to, for example, a mobile telephone, a PHS (Personal Handy-Phone System), a mobile information terminal such as a PDA (Personal Digital Assistant), and an information processing apparatus such as a notebook size personal computer. 
         [0115]    Moreover, the electric supply section of each of the above-described embodiments is schematically illustrated on the drawings. In reality, the circuit board and the antenna element are connected by, for example, an elastic metal or a pin. 
         [0116]    In the above-described embodiments, the term “mobile radio apparatus” is used for convenience of the explanation. However, terms such as “mobile radio” and “radio apparatus” may obviously be used. 
         [0117]    Moreover, the housing, antenna element, flexible board the connector included in each of the above-described mobile radio apparatuses are by no means limited to the type, quantity, and connection method described in the above-described embodiments. 
         [0118]    The disclosure of Japanese Patent Application No. 2011-108203, filed on May 13, 2011, including the specification, drawings and abstract, is incorporated herein by reference in its entirety. 
       INDUSTRIAL APPLICABILITY 
       [0119]    The present invention can provide a mobile radio apparatus including an antenna element at a lower end housing portion and being capable of reducing the influence of a closely placed input part on the antenna performance and also capable of achieving an increase in the implementation volume of the mobile radio apparatus. The present invention is suitable for use in mobile radio apparatuses such as mobile telephones having a bar structure. 
       REFERENCE SIGNS LIST 
       [0000]    
       
           100  Mobile radio apparatus 
           101  Input part 
           101   a  to  101   c  Key portions 
           102  LED 
           110  Housing 
           110   a  Lower end housing portion 
           130  Circuit board 
           130   a  Board end portion 
           140  Input part wiring pattern 
           141 ,  241  Key surface portion 
           142  Orthogonal wiring portion 
           143  Horizontal wiring portion 
           150  Connector 
           160  Antenna element 
           161  Conductor portion 
           162  Electric supply section 
           171  First isolation circuit 
           172  Second isolation circuit 
           173  Third isolation circuit 
           242  GND pattern 
           243  Varistor