CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application is based upon and claims the benefit of priority from prior Japanese Patent Application No. 2003-427846, filed Dec. 24, 2003, the entire contents of which are incorporated herein by reference.  
       BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The invention relates to a foldable mobile terminal, more particularly to a mobile terminal of a diversity transceiving system.  
         [0004]     2. Description of the Related Art  
         [0005]     A conventional foldable mobile terminal of a diversity transceiving system monitors a receive level of a antenna and a channel quality to change a diversity transceiving system (refer to, for example, Japanese Patent Laid-Open No. 2000-183793).  
         [0006]     In the above conventional foldable mobile terminal of a diversity transceiving system, correlation between antennas is not considered when the diversity transceiving system is changed. Therefore, there is a problem such as incrementation of power consumption or incrementation of a circuitry scale because a receiving level and a channel quality have to be always monitored. In addition, in an antenna configuration, a antenna whose certain face become nondirectional, such as a monopole antenna is not considered. For this reason, there is a problem that an electrical performance of each antenna may be deteriorated. This results mainly from circumstance that only communication performance in the state that a majority number of conventional foldable mobile terminals are opened is considered.  
         [0007]     It is an object of this invention to provide a foldable mobile terminal changing a diversity transceiving system according to folding-in/folding-out of the foldable mobile terminal.  
       BRIEF SUMMARY OF THE INVENTION  
       [0008]     An aspect of the present invention provides a foldable mobile terminal comprising: a pair of housings which are coupled through a hinge to make the terminal foldable; at least one antenna arranged on each of the housings; a switch connected to the antenna; at least one radio unit mounted on one of the housing and connected selectively to the antenna through the switch; and a selector to select a diversity transceiving system according to folding-out or folding-in of the terminal. 
     
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING  
       [0009]      FIGS. 1A  to  1 D show schematic configurations of a mobile terminal according to first to fourth embodiments of the present invention.  
         [0010]      FIGS. 2A and 2B  show a block circuit of a mobile terminal and a schematic configuration thereof according to the first embodiment of the present invention.  
         [0011]      FIGS. 3A and 3B  show a block circuit of a mobile terminal and a schematic configuration thereof according to the second embodiment of the present invention.  
         [0012]      FIGS. 4A and 4B  show a block circuit of a mobile terminal and a schematic configuration thereof according to the third embodiment of the present invention.  
         [0013]      FIGS. 5A and 5B  show a block circuit of a mobile terminal and a schematic configuration thereof according to the fourth embodiment of the present invention.  
         [0014]      FIGS. 6A and 6B  show a block circuit of a mobile terminal and a schematic configuration thereof according to the fifth embodiment of the present invention.  
         [0015]      FIGS. 7A  to  7 C shows block circuits to explain a high frequency switch control in the mobile terminal of the fifth embodiment.  
         [0016]      FIGS. 8A and 8B  show perspective views of a mobile terminal using an inverse F antenna and of a hinge thereof in the fifth embodiment.  
         [0017]      FIGS. 9A and 9B  show perspective views of a mobile terminal using an inverse F antenna and a whip antenna and of a hinge thereof in the fifth embodiment.  
         [0018]      FIGS. 10A and 10B  show perspective views of a mobile terminal using an inverse F antenna and a helical antenna and of a hinge thereof in the fifth embodiment.  
         [0019]      FIGS. 11A and 11B  show perspective views of a mobile terminal using an inverse F antenna and of a hinge thereof in the fifth embodiment. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0020]     The embodiments will be described in detail in conjunction with the accompanying drawings.  
       FIRST EMBODIMENT  
       [0021]     The first embodiment of the present invention is described using  FIGS. 1A  to  2 B.  FIGS. 1A and 1B  shows an example of an antenna layout of a foldable mobile terminal.  FIGS. 1A and 1B  show a side view of the terminal and a perspective view thereof in the state that the terminal is folded out, respectively.  FIGS. 1C and 1D  show a side view of the terminal and a perspective view thereof in the state that the terminal is folded in, respectively.  
         [0022]     The mobile terminal is freely foldable with a first housing  103  and a second housing  104  being coupled to each other by a hinge  105  to be foldable the terminal. In  FIG. 1C , assuming that the surface that the first housing  103  and the second housing  104  face with each other is an inner face, and the face that they do not face with each other is an outer face. When antennas  101  and  102  are mounted on the first and second housings  104  and  103 , respectively, the antennas  101  and  102  are arranged on the outside faces of the first and second housings  104  and  103  at the upper corner of the first housing  103  and the lower corner of the second housing  104 , respectively, which are displaced in a width direction of the housing. By this configuration, when the terminal is folded in, that is, the housings  103  and  104  are closed, the antennas  101  and  102  do not overlap. Also, when the terminal is folded in or folded out, that is, the housings  103  and  104  are closed or opened, the antenna  101  does not contact the housing or the antenna  102 . Consequently, degradation of an electrical performance due to contact between the antennas is avoided. Also, the first housing  103  is equipped with a display, a speaker, a camera (not shown), etc. The second housing  104  is equipped with a microphone, a key panel (not shown), etc.  
         [0023]     An example of a selective diversity receiving mode to switch the antennas with a switch in this embodiment is described in conjunction with  FIGS. 2A and 2B .  FIG. 2A  shows a block circuit of a selective diversity transceiving system.  FIG. 2B  shows a mobile terminal of an example of a selective diversity transceiving system.  
         [0024]     The first antenna  201  is arranged on, for example, a right upper corner on the outside face of a first housing  205 . The second antenna  202  is arranged on a left lower corner of the outside face of the second housing  206 . These antennas  201  and  202  are connected to the high frequency switch  203 . The antenna to be connected to the radio unit  204  is selected with this high-frequency switch  203 . Then, it is desirable for acquiring an electrical performance not less than that of a single antenna by the selective diversity transceiving system that the first and second antennas  201  and  202  function without degradation of an electrical performance.  
         [0025]     According to the embodiment, since the first and second antennas  201  and  202  are arranged so that they do not come in contact with each other, the electrical performance of each antenna does not deteriorate regardless of the folding-in/folding-out of the terminal. Consequently, the selective diversity receiving condition of the present embodiment can obtain an electrical performance not less than a receiving mode using a single antenna. The first embodiment describes an example of a mobile terminal wherein antennas are mounted on the first and second housing, respectively. However, even if two or more antennas are arranged without contacting with each other, the effect not less than the above effect can be expected.  
       SECOND EMBODIMENT  
       [0026]     The second embodiment of the present invention is described in conjunction with  FIGS. 1A  to  1 D and  FIGS. 3A and 3B .  
         [0027]     In the present embodiment, there will be described a case of performing a synthesis diversity receiving mode synthesizing the received signals of a plurality of antennas with a synthesizer referring to  FIGS. 3A and 3B .  FIG. 3A  shows a block circuit of a synthesis diversity transceiving system.  FIG. 3B  shows a mobile terminal with the synthesis diversity transceiving system.  
         [0028]     The first antenna  301  is arranged on, for example, a right upper corner of the outside face of a first housing  306 . The second antenna  302  is arranged on a left lower corner of the outside face of a second housing  307 . In other words, the first and second antennas  301  and  302  are arranged so that they do not overlap, when the terminal are folded in. The first and second antennas  301  and  302  are connected to the first and second radio units  303  and  304 , respectively.  
         [0029]     The first and second radio units  303  and  304  are connected to the synthesis unit  305 . The synthesis unit  305  synthesizes detection signals from the first and second radio units  303  and  304  with the phases thereof being matched. Then, it is desirable for acquiring an electrical performance more than that of a single antenna by the synthesis diversity transceiving system that the first and second antennas  301  and  302  function without degradation of an electrical performance.  
         [0030]     According to the second embodiment, since the first and second antennas  301  and  302  are arranged so that they do not come in contact with each other, the electrical performance of each antenna does not deteriorate regardless of the folding-in/folding-out of the terminal. Consequently, the synthesis diversity receiving mode of the present embodiment can obtain an electrical performance higher than a receiving mode using a single antenna. The second embodiment describes an example of a mobile terminal wherein antennas are mounted on the first and second housing, respectively. However, even if two or more antennas are arranged without contacting with each other, the effect more than the above effect can be expected.  
       THIRD EMBODIMENT  
       [0031]     The third embodiment of the present invention will be described in conjunction with  FIGS. 1A  to  1 D and  FIGS. 4A and 4B .  
         [0032]     In the present embodiment, an example of a selective diversity receiving mode to switch the antennas with a switch and a synthesis diversity receiving mode to synthesize the received signals of a plurality of antennas by a synthesizer is described in conjunction with  FIGS. 4A and 4B .  
         [0033]      FIG. 4A  shows a block circuit of a mobile terminal performing at least one of the selective diversity transceiving system and the synthesis diversity transceiving system.  FIG. 4 B  shows an example of the radio terminal.  
         [0034]     A first antenna  401  is arranged on, for example, a right upper corner of the outside face of a first housing  407 . A second antenna  401  is arranged on a left lower corner of the outside face of a second housing  408 . In other words, the first and second antennas  401  and  402  are arranged so that they do not overlap when the housings are folded. These antennas  401  and  402  are connected to a high-frequency switch  403 . The antenna to be connected to the first and second radio units  404  and  405  is selected with this high-frequency switch  403 . The first and second radio units  404  and  405  are connected to a synthesis unit  406 . The synthesis unit  406  synthesizes detection signals from the first and second radio units  404  and  405  with the phases thereof being matched.  
         [0035]     The synthesis diversity transceiving system is compared with the selective diversity transceiving system in the synthesis unit  406 . The diversity transceiving system to be used is determined by evaluating a communication performance or a power consumption. Then, in order to acquire an electrical performance not less than that obtained by a single antenna by executing at least either the selective diversity transceiving system or the synthesis diversity transceiving system, it is desirable that the first and second antennas  401  and  402  function without degradation of an electrical performance.  
         [0036]     Since the first and second antennas  401  and  402  are arranged so that they do not come in contact with each other in the third embodiment, degradation of an electrical performance of each antenna does not occur regardless of the folding-in/folding-out of the terminal. Therefore, the selective execution of the selective diversity transceiving system and synthesis diversity transceiving system allows providing an electrical performance not less than that obtained by a single antenna. The third embodiment describes an example of a mobile terminal wherein antennas are mounted on the first and second housing, respectively. However, even if two or more antennas are arranged without contacting with each other, the effect not less than the above effect can be expected.  
       FOURTH EMBODIMENT  
       [0037]      FIGS. 5A and 5B  show an embodiment of a mobile terminal in which three antennas are installed.  FIG. 5A  shows a block circuit of a mobile terminal doing at least either a selection diversity transceiving system or a synthesis diversity transceiving system.  FIG. 5B  shows an example of configuration of the mobile terminal.  
         [0038]     The fourth embodiment of  FIGS. 5A and 5B  differs from the third embodiment of  FIGS. 4A and 4B  in the point that a third antenna  507  installed in a first housing  508  is connected to a high-frequency switch  503 . In other words, the first antenna  501  is installed in, for example, the right upper corner of the outside face of the first housing  508 . The second antenna  502  is installed in a left lower corner of the outside face of the second housing  509 . The third antenna  507  is arranged on the left side corner of the outside face of the first housing  508  so that it is not in contact with the second antenna  502 . That is to say, the first and third antennas  501  and  507  are arranged so that they do not overlap the second antenna  502  when the terminal is folded in.  
         [0039]     Two antennas of the first, second, third antennas  501 ,  502  and  507  are selected to allow the synthesis diversity transceiving system. In this embodiment, too, since the first, second and third antennas  501 ,  502  and  507  are arranged so that they are not in contact with one another, degradation of an electrical performance of each antenna does not occur regardless of the folding-in/folding-out of the terminal. Therefore, this embodiment can obtain an electrical performance not less than that obtained by a single antenna.  
       FIFTH EMBODIMENT  
       [0040]     The fifth embodiment of the present invention is described referring to  FIGS. 1A  to  1 D,  6 A,  6 B, and  7 A to  7 C.  
         [0041]     At first, a method of changing the diversity systems is described referring to  FIGS. 6A and 6B .  FIG. 6A  shows a block circuit of a mobile terminal changing a selective diversity receiving mode and a synthesis diversity receiving mode according to the folding-in/folding-out of the terminal.  FIG. 6B  shows an example of configuration of the mobile terminal.  
         [0042]     The first antenna  601  is installed in, for example, a right upper corner of the outside face of the first housing  611 . The second antenna  602  is installed in a left lower corner of the outside face of the second housing  612 . In other words, the first and second antennas  601  and  602  are arranged so that they do not overlap when the terminal are folded in. These antennas  601  and  602  are connected to a high-frequency switch  603 . This high-frequency switch  603  selects an antenna to be connected to the first and second radio units  604  and  605 . The first and second radio units  604  and  605  are connected to a synthesizer  606 .  
         [0043]     The synthesizer  606  synthesizes detection signals from the first and second radio units  604  and  605  with the phases thereof being matched. A folding-in/folding-out detector  607  notifies a feeding controller  608  and a switch controller  609  of the opening/closing state of the housings  611  and  612 , that is, the folding-in/folding-out of the terminal. The folding-in/folding-out detector  607  may comprise a Hall sensor using change of a magnetic field, a reed switch or a changeover switch that is physically pushed by a projection provided inside the housing  611  when the terminal is folded in.  
         [0044]     The feeding controller  608  controls a power supply to the first radio unit  604  according to the opening/closing state of the housings. The switch controller  609  controls switching of the high-frequency switch  603  according to the opening/closing state of the housings and a receiving level of the second radio unit  605  notified by a receiving level detector  610 .  
         [0045]     The control of power supply to the radio unit  604  according to the opening/closing state of the housings and the control of the high-frequency switch  603  are described in conjunction with  FIG. 7 .  FIG. 7  shows only a first antenna  701 , a second antenna  702 , a high-frequency switch  703 , a first radio unit  704 , a second radio unit  705 , a feeding controller  706 , a switch controller  707  in correspondence with the first antenna  601 , second antenna  602 , high-frequency switch  603 , first radio unit  604 , second radio  605 , feeding controller  606 , switch controller  607  of  FIG. 6 . Other elements shown in  FIG. 6  are omitted in  FIG. 7 .  
         [0046]     The state that the housings are opened is shown in  FIG. 7A . In this state, the feeding controller  706  admits power-supplying to the first radio unit  704 . The switch controller  707  controls the high-frequency switch  703  so that the first antenna  701  is connected to the radio unit  704  and the second antenna  701  is connected to the second radio unit  705 . The detection signals from the first and second radio units  704  and  705  are synthesized by a synthesizer (not shown) with their phases being matched. As a result, the effect of synthesis diversity transceiving system can be expected.  
         [0047]     The state that the terminal is folded in is shown in  FIG. 7B  and  FIG. 7C . In this state, the feeding controller  706  stops power-supplying to the first radio unit  704 , and the switch controller  707  controls the high-frequency switch  703  to connect the second radio unit  705  to the first antenna  701  or the second antenna  702 . In the radio unit  705 , a receiving level obtained when the first antenna  701  is connected to the second radio  705  as shown in  FIG. 7B  is compared with a receiving level obtained when the second antenna  702  is connected to the second radio unit  705  as shown in  FIG. 7C . If the radio unit  705  selects the connection indicating the higher receiving level, the effect of the selective diversity transceiving system can be expected.  
         [0048]     As discussed above, the synthesis diversity transceiving system is selected when the terminal is folded out. The selective diversity transceiving system is selected when the terminal is folded in. In this case, it is desirable that the first and second antennas  601  and  602  function without degradation of an electrical performance in order to acquire an electrical performance not less than an electrical performance obtained by a single antenna.  
         [0049]     According to the configuration of the present embodiment, since an electrical performance of each antenna is not deteriorated regardless of the folding-in/folding-out of the terminal, it is possible to obtain an electrical performance not less than that obtained by a single antenna by performing at least either the selective diversity transceiving system or the synthesis diversity transceiving system.  
         [0050]     The folding-out of the terminal lowers the correlation between the antennas to be appropriate for the synthesis diversity transceiving system, because a distance between the first antenna  601  of the first housing  611  and the second antenna  602  of the second housing  612  increases. The folding-in of the terminal enhances the correlation between the antennas due to a pattern diversity effect to be appropriate for the selective diversity transceiving system, because the distance between the first antenna  601  of the first housing  611  and the second antenna  602  of the second housing  612  decreases.  
         [0051]     As the installation positions of the first and second antennas  601  and  602  approach the housing end positioned far from the hinge  613 , the distance between the antennas when the terminal is folded out increases. For this reason, the correlation between the antennas lowers resulting in increasing the effect of the synthesis diversity transceiving system. Therefore, it is effective to change the diversity system according to the folding-in/folding-out of the terminal.  
         [0052]     The concrete antenna elements applied to the embodiment of  FIGS. 6A and 6B  are explained referring to  FIGS. 8A  to  11 B.  FIGS. 8A and 8B  show an example adopting inverse F antennas  801  and  802  to first and second housings  811  and  812 .  FIG. 8A  shows the folding-out of the terminal, and  FIG. 8B  shows the folding-out thereof. The inverse F antennas  801  and  802  are connected to first and second feeding points  816  and  817  provided on the first and second housing substrates  814  and  815 , respectively.  
         [0053]     Since the inverse F antennas  801  and  802  both are located on the housing end outside the housing and far from the hinge  813  as shown in  FIG. 8B , a distance between the antennas is large in the state that the terminal is folded out, and it is small in the state that the terminal is folded in. As described below, when the distance between the antennas is large, correlation between the antennas becomes small due to a space diversity effect. Therefore, the synthesis diversity transceiving system is preferable. When the distance between the antennas is small, the correlation between the antennas becomes small due to a pattern diversity effect. Thus, the selection diversity transceiving system is preferable.  
         [0054]     There will be explained a mechanism that the pattern diversity occurs. In the case of the antenna selection diversity transceiving system, the unselected antenna becomes an open end as shown in  FIGS. 8B and 8C . In this case, the antenna element can act as a parasitic element. This parasitic element changes a radiation pattern of the selected antenna element. An electromagnetic field coupling occurs between a feed antenna and a parasitic element adjacent thereto, so that a current distribution occurs on the parasitic element. An antenna pattern changes due to radiation from this current. This change makes it possible to lower a correlation coefficient because of a diversity effect to call a radiation pattern diversity. As described above, even if the antennas are adjacent to each other, it becomes possible to suppress a correlation between the antennas by applying a pattern diversity effect. As a result, an improved diversity performance can be realized.  
         [0055]     However, this pattern diversity is not suitable for the synthesis diversity transceiving system showing an effect when the antenna element is nondirectional, because it causes a comparatively large distortion on the radiation pattern of the antenna.  
         [0056]     On the other hand, in the case of the synthesis diversity transceiving system, too, when viewing from the antenna the other antenna, the other antenna acts like the parasitic element. However, in this case, because both antennas are connected to a radio circuit, an apparent parasitic element is connected to a reflectionless terminal. Since the reflectionless terminal absorbs an induced current generated in the parasitic element due to an electromagnetic field coupling, the change of the radiation pattern of the antenna becomes small in comparison with the selection diversity transceiving system. In other words, when the antennas are adjacent to each other, if the synthesis diversity is done, the space diversity effect and the pattern diversity effect do not act effectively, resulting in the diversity performance is not enough brought out. Accordingly, in this case, it is desirable to use the space diversity which provides a diversity effect by increasing the antenna-to-antenna distance with the terminal being folded out. In this case, two antennas provide inherent radiation characteristics, that is, non-directionalities, because they separate from each other to weaken a coupling. As thus described, when the terminal is folded out, the synthesis diversity transceiving system is preferable, because the radiation patterns of two antennas are substantially nondirectional and the correlation between the patterns is low.  
         [0057]     As described above, in this configuration, when two antennas assume as a diversity antenna, it is obvious that the diversity effect varies according to the folding-in/folding-out of the terminal. Further, a diversity reception system suitable for the folded-out terminal or the folded-in terminal is obvious according to the folding-in/folding-out of the terminal. Thus, it is possible to determine an optimum diversity transceiving system according to the folding-in/folding-out of the terminal. As a result, it is unnecessary to monitor a receiving level and a channel quality, and it is possible to suppress incrementation of power consumption and incrementation of a circuit scale.  
         [0058]     In  FIG. 8 , the high-frequency switch  803 , the first and second radio units  804  and  805 , the synthesizer  806 , the folding-in/folding-out detector  807 , the feeding controller  808 , the switch controller  809 , the receiving level detector  810  correspond respectively to the high-frequency switch  603 , the first and second radio units  604  and  605 , the synthesizer  606 , the folding-in/folding-out detector  607 , the feeding controller  608 , the switch controller  609 , the receiving level detector  610  shown in  FIG. 6 .  
         [0059]      FIG. 9  shows an example adopting a whip antenna  901  to a first housing  911 , and an inverse F antenna  902  to a second housing  912 .  FIG. 9A  shows a state that the housings open, and  FIG. 9B  shows a state that the housings close. The whip antenna  901  and inverse F antenna  902  are connected to antenna feeding points  916  and  917  provided on first and second housing substrates  914  and  915 , respectively.  
         [0060]     As shown in  FIG. 9B , the whip antenna  901  and inverse F antenna  902  are arranged outside the housings and the inverse F antenna  902  is located far from the hinge  913 . Thus, when the housings open, the antenna- to-antenna distance is large, and when they close, it is small. When the antenna-to-antenna distance is large, the synthesis diversity transceiving system is suitable, because the antenna-to-antenna correlation becomes small due to a space diversity. When the antenna-to-antenna distance is small, the selection diversity transceiving system is suitable, because the antenna-to-antenna correlation becomes small due to a pattern diversity. As described before, since an optimum diversity transceiving system can be selected according to the folding-in/folding-out of the terminal, it is unnecessary to monitor a receiving level or a channel quality, and it is possible to suppress incrementation of a power consumption and a circuit scale.  
         [0061]     In addition, since the antennas are arranged so that they do not overlap when the housings close, an electrical performance of each antenna does not deteriorate even when the housings close. Further, the diversity transceiving system can provide an electrical performance more than that obtained by a single antenna.  
         [0062]     In  FIG. 9 , the high-frequency switch  903 , the first and second radio units  904  and  905 , the synthesizer  906 , the folding-in/folding-out detector  907 , the feeding controller  908 , the switch controller  909 , the receiving level detector  910  correspond to the high-frequency switch  603 , the first and second radio units  604  and  605 , the synthesizer  606 , the folding-in/folding-out detector  607 , the feeding controller  608 , the switch controller  609 , the receiving level detector  610  shown in  FIG. 6 , respectively.  
         [0063]      FIGS. 10A and 10B  show an example adopting a helical antenna  1001  to a first housing  1011  and an inverse F antenna  1002  to a second housing  1012 .  FIG. 10A  shows a state that the terminal is folded out, and  FIG. 10B  illustrates a state that it is folded in.  
         [0064]     The helical antenna  1001  and inverse F antenna  1002  are connected to antenna feeding points  1016  and  1017  of the housing substrates  1014  and  1015 . As shown in  FIG. 10B , the helical antenna  1001  and inverse F antenna  1002  are disposed outside the housings, and the inverse F antenna  1002  is arranged far from hinge  1013 . Therefore, the antenna-to-antenna distance is large when the terminal is folded out, and it is small when it is folded in.  
         [0065]     The synthesis diversity transceiving system is preferable when the antenna-to-antenna distance is large, because the antenna-to-antenna correlation is low due to a space diversity. The selective diversity transceiving system is preferable when the antenna-to-antenna distance is small, because the antenna-to-antenna correlation is low due to a pattern diversity.  
         [0066]     As described before, since an optimum diversity transceiving system can be selected according to the folding-in/folding-out of the terminal, it is unnecessary to monitor a receiving level or a channel quality, and it is possible to suppress incrementation of a power consumption and a circuit scale. In addition, since the antennas are arranged so that they do not overlap when the terminal is folded in, an electrical performance of each antenna does not deteriorate even when the terminal is folded in. Further, the diversity transceiving system can provide an electrical performance not less than that obtained by a single antenna.  
         [0067]     In  FIG. 10A , the high-frequency switch  1003 , the first and second radio units  1004  and  1005 , the synthesizer  1006 , the folding-in/folding-out detector  1007 , the feeding controller  1008 , the switch controller  1009 , the receiving level detector  1010  correspond to the high-frequency switch  603 , the first and second radio units  604  and  605 , the synthesizer  606 , the folding-in/folding-out detector  607 , the feeding controller  608 , the switch controller  609 , the receiving level detector  610  shown in  FIG. 6 , respectively.  
         [0068]      FIG. 11  shows an example adopting inverse F antennas  1101  and  1102  to first and second housings  1111  and  1112 , respectively.  FIG. 11A  shows a state that the terminal is folded out, and  FIG. 11B  shows a state that it is folded in.  
         [0069]     The inverse F antennas  1101  and  1102  are connected to first and second antenna feeding points  1116  and  1117  provided on first and second housing substrates  1114  and  1115 , respectively. As shown in  FIG. 11B , the helical antenna  1001  and inverse F antenna  1002  are disposed outside the housings, and the inverse F antenna  1002  is arranged far from hinge  1013 . Therefore, the antenna-to-antenna distance is large when the terminal is folded out, and it is small when it is folded in.  
         [0070]     The synthesis diversity transceiving system is suitable when the antenna-to-antenna distance is large, because the antenna-to-antenna correlation is low due to a space diversity. The selective diversity transceiving system is preferable when the antenna-to-antenna distance is small, because the antenna-to-antenna correlation is low due to a pattern diversity.  
         [0071]     As described before, since an optimum diversity transceiving system can be selected according to the folding-in/folding-out of the terminal, it is unnecessary to monitor a receiving level or a channel quality, and it is possible to suppress incrementation of a power consumption and a circuit scale. In addition, since the antennas are arranged so that they do not overlap when the terminal is folded in, an electrical performance of each antenna does not deteriorate even when the terminal is folded in. Further, the diversity transceiving system can provide an electrical performance not less than that obtained by a single antenna.  
         [0072]     In  FIG. 11A , the high-frequency switch  1103 , the first and second radio unit  1104  and  1105 , the synthesizer  1106 , the folding-in/folding-out detector  1107 , the feeding controller  1108 , the switch controller  1109 , the receiving level detector  1110  correspond to the high-frequency switch  603 , the first and second radio units  604  and  605 , the synthesizer  606 , the folding-in/folding-out detector  607 , the feeding controller  608 , the switch controller  609 , the receiving level detector  610  shown in  FIG. 6 , respectively.  
         [0073]     The above embodiment describes an example of a mobile terminal wherein antennas are mounted on the first and second housing, respectively. However, even if two or more antennas are arranged without contacting with each other, the effect not less than the previous effect can be expected.  
         [0074]     Additional advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described herein. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.
A foldable mobile terminal comprises a pair of housings which are coupled through a hinge to make the terminal foldable, at least one antenna arranged on each of the housings, a switch connected to the antenna, at least one radio unit mounted on one of the housing and connected selectively to the antenna through the switch, and a selector to select a diversity transceiving system according to folding-out or folding-in of the terminal.