Collapsible mobile radio device

The invention is to improve antenna performance in an internal antenna in a closed state without deteriorating the antenna performance in a state where a foldable portable radio apparatus is opened. A foldable portable radio apparatus includes a foldable mechanism in which an upper casing 101 and a lower casing 104 are rotatably connected, a first conductor plate 102 and a second conductor plate 103 that are provided in the upper casing 101, and a feeding system that is provided in the lower casing 104, and connects an antenna element 107, a circuit board 105, the first conductor plate 102, and the circuit board, a detecting unit 109 that detects opened and closed states between the upper casing 101 and the lower casing 104, and a first switching unit 110 that switches between an electrically opened state and an electrically short-circuited state between the first conductor plate and the second conductor plate according to the detected result by the detecting unit 109.

TECHNICAL FIELD

The present invention relates to a portable radio apparatus that includes a foldable mechanism, and more particularly, to an antenna that is incorporated into a casing and a ground structure in upper and lower casings.

BACKGROUND ART

In recent times, an antenna that is incorporated into a foldable cellular phone is mainly disposed like a case where the antenna is disposed on a lower end of a lower casing and a case where the antenna is disposed in an upper casing. However, in all of the cases, it has been known that antenna performance is much affected by a ground structure near the antenna and an adjacent metal conductor.

Further, as a size of a cellular phone is decreased, a length of a casing is decreased, and thus an antenna bandwidth is reduced. According to this trend, a structure has been suggested in which a ground wiring line is disposed near a feeding point of the antenna. However, even in this case, it has been known that a positional relationship between the ground wiring line and a proximity object affects the performance of the antenna.

As an internal antenna for a foldable portable radio apparatus according to the related art, for example, as disclosed in Patent Document 1, a structure has been suggested in which an internal antenna is disposed at a location most spaced apart from a flexible antenna attached to the outside of the casing, and a diversity gain as an antenna system is improved.

Further, as an internal antenna for another foldable portable radio apparatus, as disclosed in Patent Document 2, a plurality of non-feeding elements are disposed near the internal antenna so as to achieve a width bandwidth in the antenna.

DISCLOSURE OF THE INVENTION

Problem that the Invention is to Solve

However, in a structure that has the internal antenna disposed at the location most spaced apart from the flexible antenna attached to the outside of the casing, a spatial diversity effect with the antenna attached to the outside of the casing is obtained. However, according to this structure, there is a problem in that the performance as the internal antenna is lowered.

Further, in the structure in which a plurality of parasitic elements are disposed in the internal antenna so as to achieve a width bandwidth in the antenna, there are problems in that it is difficult to set the plurality of parasitic elements at the same time, and it is likely for the antenna to be affected by the proximity objects, and the performance of the antenna is deteriorated.

In addition to theses problems, according to the structure in the related art, there is a problem in that the performance of the antenna is deteriorated by a case in which a high frequency current flowing into the casing operating as the ground of the antenna is affected by a high frequency current flowing into the other casing and the high frequency current is cancelled.

The invention has been made in order to solve the above problems, and it is an object of the invention to improve performance of an internal antenna.

Means for Solving the Problem

According to a first aspect of the invention, a foldable portable radio apparatus includes a foldable mechanism in which an upper casing and a lower casing are rotatably connected; a first conductor plate and a second conductor plate that are provided in the upper casing; an antenna element, a circuit board, and a feeding unit which connects the first conductor plate to the circuit board that are provided in the lower casing; a detecting unit that detects opened and closed states of the upper casing and the lower casing; and a switching unit that switches between an electrically opened state and an electrically short-circuited state of the first conductor plate and the second conductor plate in accordance with the detected result by the detecting unit. In this case, it is possible to achieve an effect of improving antenna performance in a closed state without deteriorating the antenna performance in an opened state.

According to a second aspect of the invention, in the foldable portable radio apparatus according to the first aspect of the invention, the antenna element, the circuit board, and a second circuit board are provided in the lower casing. The foldable portable radio apparatus further includes a second switching unit that switches between an electrically opened state and an electrically short-circuited state of the first circuit board and the second circuit board in accordance with the detected result by the detecting unit. In this case, it is possible to achieve an effect of improving antenna performance in a closed state without deteriorating the antenna performance in an opened state.

According to a third aspect of the invention, in the foldable portable radio apparatus according to the first or second aspect of the invention, the switching unit is connected through a predetermined reactance element. In this case, it is possible to achieve an effect of improving antenna performance in a closed state without deteriorating the antenna performance in an opened state.

According to a fourth aspect of the invention, in the foldable portable radio apparatus according to any one of the first to third aspects of the invention, a conductor having a predetermined length is electrically short circuited at a location that is opposite to the antenna element through the circuit board. In this case, it is possible to achieve an effect of improving antenna performance in a closed state without deteriorating the antenna performance in an opened state.

According to a fifth aspect of the invention, in the foldable portable radio apparatus according to any one of the first to fourth aspects of the invention, further includes a connecting unit that electrically connects the first conductor plate and the circuit board in a closed state. In this case, it is possible to achieve an effect of improving antenna performance in a closed state without deteriorating the antenna performance in an opened state.

According to the invention, it is possible to It is possible to improve the antenna performance in a closed state without deteriorating the antenna performance in a state where the foldable portable radio apparatus is opened.

DESCRIPTION OF REFERENCE NUMERALS AND SIGNS

110FIRST SWITCHING UNIT

111WIRELESS CIRCUIT UNIT

112FIRST MATCHING CIRCUIT

113SECOND MATCHING CIRCUIT

115ANTENNA SWITCHING UNIT

116SOLID LINE INDICATING VSWR FREQUENCY CHARACTERISTIC IN FIRST STATE

117BROKEN LINE INDICATING VSWR FREQUENCY CHARACTERISTIC IN SECOND STATE

118SOLID LINE INDICATING X-Z SURFACE DIRECTIVITY IN FIRST STATE

119BROKEN LINE INDICATING X-Z SURFACE DIRECTIVITY IN SECOND STATE

120SOLID LINE INDICATING VSWR FREQUENCY CHARACTERISTIC IN THIRD STATE

121BROKEN LINE INDICATING VSWR FREQUENCY CHARACTERISTIC IN FOURTH STATE

122SOLID LINE INDICATING X-Z SURFACE DIRECTIVITY IN THIRD STATE

123BROKEN LINE INDICATING X-Z SURFACE DIRECTIVITY IN FOURTH STATE

201SECOND SWITCHING UNIT

202SECOND CIRCUIT BOARD

203INTERVAL BETWEEN ANTENNA ELEMENT AND GROUND CONDUCTOR

204DISTANCE BETWEEN ANTENNA ELEMENT107AND GROUND CONDUCTOR THAT HAS EXPANDED BY ALLOWING CIRCUIT BOARD105AND SECOND CIRCUIT BOARD202TO ENTER ELECTRICALLY OPENED STATE

205INTERVAL BETWEEN ANTENNA ELEMENT107AND GROUND CONDUCTOR WHEN CIRCUIT BOARD105AND SECOND CIRCUIT BOARD202ARE ELECTRICALLY OPENED

301FIRST REACTANCE UNIT IN THIRD EMBODIMENT

302SECOND REACTANCE UNIT IN THIRD EMBODIMENT

303SOLID LINE INDICATING VSWR FREQUENCY CHARACTERISTIC IN FIFTH STATE

304BROKEN LINE INDICATING VSWR FREQUENCY CHARACTERISTIC IN SIXTH EMBODIMENT

401CONNECTING GROUND WIRING LINE

402INTERVAL OF GROUND CONDUCTOR INCREASED BY CONNECTING GROUND WIRING LINE

403SOLID LINE INDICATING VSWR FREQUENCY CHARACTERISTIC IN SEVENTH STATE

404BROKEN LINE INDICATING VSWR FREQUENCY CHARACTERISTIC IN EIGHTH STATE

405SOLID LINE INDICATING X-Z SURFACE DIRECTIVITY IN SEVENTH STATE

406BROKEN LINE INDICATING X-Z SURFACE DIRECTIVITY IN EIGHTH STATE

501FIRST CONTACT UNIT

502: SECOND CONTACT UNIT

503SOLID LINE INDICATING X-Z SURFACE DIRECTIVITY IN NINTH STATE

504BROKEN LINE INDICATING X-Z SURFACE DIRECTIVITY IN TENTH STATE

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the invention will be described with reference toFIGS. 1 to 17.

First Embodiment

A foldable portable radio apparatus according to a first embodiment will be described with reference toFIGS. 1 to 7.

FIG. 1is a perspective view illustrating a closed state of a foldable portable radio apparatus according to first embodiment. InFIG. 1, an upper casing101of the foldable portable radio apparatus is formed of a resin that has, for example a thickness of approximately 1 mm. This size is set to the longitudinal 100 mm and the horizontal 50 mm. The upper casing101of the foldable portable radio apparatus includes a first conductor plate102and a second conductor plate103that are provided therein. The first conductor plate102is composed of a printed circuit board that has, for example, a thickness of 1 mm, and the size is set to the longitudinal 70 mm and the horizontal 40 mm. A ground pattern is formed on the first conductor plate102.

The second conductor plate103is composed of a printed circuit board that has, for example, a thickness of 1 mm, and the size is set to the longitudinal 20 mm and the horizontal 40 mm. Similar to the second conductor plate102, a ground pattern is formed on the second conductor plate103.

A lower casing104of the foldable portable radio apparatus is formed of a resin that has, for example a thickness of approximately 1 mm. This size is set to the longitudinal 100 mm and the horizontal 50 mm.

The lower casing104of the foldable portable radio apparatus includes a circuit board105and an antenna element107that are provided therein. The circuit board105is composed of a printed circuit board that has, for example, a thickness of 1 mm, and the size is set to the longitudinal 80 mm and the horizontal 40 mm. A ground pattern is formed on the circuit board105, and the ground pattern functions as a ground conductor with respect to the antenna.

The upper casing101and the lower casing104have a structure that are connected to each other by means of a foldable mechanism106. The upper casing101and the lower casing104rotate about the foldable mechanism106, such that two states of an opened state and a closed state are taken.

The antenna element107is composed of a conductor line that has, for example, a diameter of 1 mm, and is disposed on a lower end of the circuit board105. Further, the antenna element107is composed of a conductor having a length that becomes an about ¼ wavelength in a band of 800 MHz used in a territorial cellular system, and the length of the antenna element is set to have a total length of about 90 mm.

The connecting conductor108is composed of a conductor plate that has, for example, a thickness of 0.1 mm, and connects a left lower end of the first conductor plate102and left upper end of the circuit board105. The size is set to the longitudinal 40 mm and the horizontal 5 mm.

The detecting unit109(sensing unit) is formed on the first conductor plate102, and detects whether the foldable portable radio apparatus according to this embodiment is in any state of either an opened state or a closed state and transmits the detected result to a first switching unit110that is disposed on the first conductor plate102. The detecting unit109is composed of a hall element that has, for example, a size of about 3×3 mm.

The first switching unit110selects either an electrical opened state or an electrical short circuit state between the first conductor plate102and the second conductor plate103according to the detected result by the detecting unit109. The first switching unit110is composed of, for example, a PIN diode.

The wireless circuit unit111is deposed on the circuit board105, and is connected to the antenna element107by the first matching circuit112. Further, the wireless circuit unit11is connected to the right lower end of the first conductor plate102through the power line114via the second matching circuit113.

The first conductor plate102is used as the antenna element in the foldable portable radio apparatus according to this embodiment. In this case, with respect to the circuit board105, an antenna that supplies power to the antenna element107is set to a first antenna and an antenna that supplies power to the first conductor plate102is set to a second antenna.

The first antenna is mainly used when the foldable portable wireless antenna according to this embodiment is used in a closed state. Meanwhile, the second antenna is mainly used when the foldable portable radio apparatus according to this embodiment is opened.

FIGS. 2 and 3show a side view of a state where the foldable portable radio apparatus according to this embodiment is closed and a front view where the foldable portable radio apparatus according to this embodiment is opened, respectively. InFIGS. 2 and 3, the same reference numerals as those ofFIG. 1perform the same operations, and the description thereof will be omitted.

InFIG. 3, the antenna switching unit115is connected to the first and second antennas through the matching circuits112and113, respectively. The antenna switching unit115sets an antenna connected to the wireless circuit unit111according to the detected result from the detecting unit109. For example, in a state where the foldable portable radio apparatus according to this embodiment is opened, the antenna switching unit115sets the second antenna by the signal from the detecting unit109. Further, in this case, the first switching unit110operates such that the first conductor plate102and the second conductor plate103become an electrical short circuit state therebetween. Meanwhile, in a state where the foldable portable radio apparatus according to this embodiment is closed, the antenna switching unit115selects the first antenna according to the signal from the detecting unit109. In this case, the first switching unit110operates such that the first conductor plate102and the second conductor plate103becomes an electrically opened state therebetween.

FIG. 4shows a VSWR frequency characteristic of the first antenna in the closed state. In this case, a state where the first antenna is selected and the first conductor plate and the second conductor plate are electrically short-circuited is set to ‘a first state’, and a state where the first antenna is selected and the first conductor plate and the second conductor plate are electrically opened is set to ‘a second state’.

A curved line116(graph) indicates a first state, and a curved line117(graph) indicates a VSWR frequency characteristic in a second state. As such, a wide frequency bandwidth is obtained in the second state rather than the first state. The bandwidths where the VSWR becomes 4 become about 150 MHz and 200 MHz, respectively, and the bandwidth in the second state is wider than that in the first state by about 50 MHz.

FIG. 5shows X-Z surface directivity in a free space of a first antenna in closed state. In this case, an X direction of the curved line118(graph) is set to a front direction of the foldable portable radio apparatus in this embodiment, and a Z direction is set to a top direction.

In this case, directivity of only a longitudinal direction component of the foldable portable radio apparatus in this embodiment is shown. This is because antenna performance in the free space is almost determined by the performance of the longitudinal direction component of the radio apparatus.

A curved line118(graph) indicates a first state, and a curved line119(graph) indicates X-Z surface directivity in a second state. As such, high antenna performance is obtained in the second state rather than the first state. In this case, PAGs (Paftern Average Gain) of the first state and the second state become −9 dB and −8 dB, respectively, and the PAG in the second state is higher than that in the first state by about 1 dB.

The PAG indicates an average value of power directivity of one plane (in this case, X-Z surface). Generally, the PAG of a half-wave dipole antenna is defined as 0 dB, and is used as an evaluation index.

FIG. 6shows a VSWR frequency characteristic of the second antenna in the closed state. In this case, a state where the second antenna is selected and the first conductor plate and the second conductor plate are electrically opened is set to ‘a third state’, and a state where the second antenna is selected and the first conductor plate and the second conductor plate are electrically short circuited is set to ‘a fourth state’.

A curved line120(graph) indicates a third state, and a curved line121(graph) indicates a VSWR frequency characteristic in a fourth state. As such, a wide frequency bandwidth is obtained in the fourth state rather than the third state. The bandwidths where the VSWR becomes 4 become about 400 MHz and 700 MHz, respectively, and the bandwidth in the fourth state is wider than that in the third state by about 300 MHz.

FIG. 7shows X-Z surface directivity in a free space of a second antenna in an opened state. In this case, an X direction of the curved line122(graph) is set to a front direction of the foldable portable radio apparatus in this embodiment, and a Z direction is set to a top direction.

In this case, a curved line122(graph) indicates a third state, and a curved line123(graph) indicates X-Z surface directivity in a fourth state. As such, high antenna performance is obtained in the fourth state rather than the third state. In this case, PAGs (Pattern Average Gain) of the third state and the fourth state become −6 dB and −5 dB, respectively, and the PAG in the fourth state is higher than that in the third state by about 1 dB.

As described above, according to the portable radio apparatus in this embodiment, the portion of the conductor plate of the upper casing is opened or closed to be switched between the electrically short circuited state and the electrically opened state, so that the antenna performance of the closed state can be improved without lowering an antenna gain in the opened state.

Further, the shape or structure of the antenna element107is not limited to that of this embodiment, and the antenna element107can be accommodated in the portable radio apparatus as a helical structure, and may be incorporated into the dielectric. Further, if the first switching unit110can ensure high isolation between the first conductor plate102and the second conductor plate103, the same effect can be obtained without depending on the structure of the first switching unit110.

Further, the selection of the first and second antennas is not limited to this embodiment. That is, the same effects as the above can be obtained even in a structure that performs control such that the levels received by the respective antennas are detected and compared with each other, and the antenna having a high reception level is selected.

Second Embodiment

The foldable portable radio apparatus according to the second embodiment will be described with reference toFIGS. 8,9, and10.FIG. 8shows a perspective view of a foldable portable radio apparatus according to a second embodiment. InFIG. 8, the same reference numerals as those ofFIG. 1perform the same operations, and the description thereof will be omitted.

The foldable portable radio apparatus according to the second embodiment shown inFIG. 8has a structure in which in addition to the structure of the first embodiment shown inFIG. 1, a second circuit board202, and a second switching unit201that electrically opens or short circuits the circuit board105and the second circuit board202according to the detected result of the detecting unit109are additionally provided.

FIG. 9shows a side view of a foldable portable radio apparatus according to a second embodiment. InFIG. 9, the same reference numerals as those ofFIG. 1perform the same operations, and the description thereof will be omitted.

FIG. 10shows an enlarged front view of peripheral portions of the circuit board105, the second circuit board202, the second switching unit201, and the antenna element107.

Similar to the first switching unit110, the second switching unit201allows the circuit board105and the second circuit board202to be eclectically opened when the foldable portable radio apparatus is closed. Meanwhile, when the foldable portable radio apparatus according to this embodiment is opened, the first switching unit110allows the circuit board105and the second circuit board202to be electrically short circuited.

When the circuit board105and the second circuit board202are electrically short circuited, the distance between the antenna element107and the ground conductor is represented by the interval203. In contrast, when the circuit board105and the second circuit board202are electrically opened, the distance between the antenna element107and the ground conductor is represented by the interval205.

In a state where the foldable portable radio apparatus is closed, the circuit board105and the second circuit board202are electrically opened, so that the distance between the antenna element107and the ground conductor can be increased by the interval204.

As described above, according to the portable radio apparatus in this embodiment, the portion of the circuit board of the lower casing is switched between the electrically short circuited state and the electrically opened state by the opened and closed states of the foldable portable radio apparatus, so that the antenna performance of the closed state can be improved without lowering an antenna gain in the opened state. In this case, for example, an antenna gain with respect to the gain of the first embodiment can be increased by approximately 1 dB.

Further, if the second switching unit107can ensure high isolation between the circuit board105and the second circuit board202, the same effect can be obtained without depending on the structure of the second switching unit107.

Third Embodiment

The foldable portable radio apparatus according to the third embodiment will be described with reference toFIGS. 11 and 12.FIG. 11shows a perspective view of a foldable portable radio apparatus according to the third embodiment. InFIG. 11, the same reference numerals as those ofFIG. 8perform the same operations, and the description thereof will be omitted.

The foldable portable radio apparatus according to the third embodiment shown inFIG. 11has a structure in which in addition to the structure of the second embodiment shown inFIG. 8, a first reactance unit301and a second reactance unit302are additionally provided.

In the foldable portable radio apparatus according to the third embodiment, the first switching unit110and the second switching unit201operate through the first reactance unit301and the second reactance unit302, respectively.

In this case, a state where the first antenna is selected and the first reactance unit301and the second reactance unit302are electrically opened is set to ‘a fifth state’, and a state where the first reactance unit301and the second reactance unit302are set to have 100 nH and 100 nH, respectively is set to ‘a sixth state’.

FIG. 12shows the VSWR frequency characteristic of the first antenna in the closed state.

A curved line303(graph) indicates the VSWR frequency characteristic in the fifth state. The curved line304(graph) indicates the VSWR frequency characteristic in the sixth state.

As shown inFIG. 12, the excellent frequency characteristic is obtained in the sixth state rather than the fifth state. At this time, the bandwidths where the VSWR becomes 4 become about 200 MHz and 300 MHz, respectively.

The first and second conductor plates102and103that are connected through the reactance elements become the non-feeding elements. As a result, electromagnetic interaction is generated between the antenna element107, and the first and second conductor plates, and thus it is possible to increase the bandwidth of the first antenna.

As described above, according to the portable radio apparatus in this embodiment, the portion of the circuit boards of the lower and upper casings is switched between the electrically short circuited state and the electrically opened state through the reactance elements by the opened and closed states of the foldable portable radio apparatus, and the portion of the circuit board is used as the element whether the power is not supplied with respect to the antenna element107, so that the antenna performance of the closed state can be improved without lowering an antenna gain in the opened state. In this case, for example, an antenna bandwidth with respect to the gain of the second embodiment can be increased by approximately 100 MHz.

Further, if the reactance unit operates as the non-feeding element by the antenna element107, the same effect can be obtained even in any combination of the reactance positive number set to the reactance unit.

Fourth Embodiment

The foldable portable radio apparatus according to the fourth embodiment will be described with reference toFIGS. 13,14, and15.FIG. 13shows a side view of a foldable portable radio apparatus according to the fourth embodiment. InFIG. 13, the same reference numerals as those ofFIG. 1perform the same operations, and the description thereof will be omitted.

The foldable portable radio apparatus according to the second embodiment shown inFIG. 13has a structure in which in addition to the structure of the first embodiment shown inFIG. 11, a connecting ground wiring line is additionally provided.

The connecting conductor401is composed of a conductor that has, for example of a thickness of 0.1 mm, and is disposed along the connecting conductor108from the peripheral portion of the upper left end of the circuit board105to the lower left end of the first conductor plate102. For example, the size is set to the longitudinal 30 mm and the horizontal 5 mm, and the connecting conductor401is not connected to the first conductor102. At this time, the circuit board105that serves as the grounding conductor of the first antenna operates in a state where the circuit board105expands by the interval402by means of the connecting ground wiring line401.

FIG. 14shows the VSWR frequency characteristic of the first antenna in the closed state. In this case, a state where the first antenna is selected and the connecting ground wiring line401is not provided is set to ‘a seventh state’, and a state where the first antenna is selected and the connecting ground wiring line401is provided is set to ‘an eighth state’.

A curved line403(graph) indicates a VSWR frequency characteristic in a seventh state, and a curved line404(graph) indicates a VSWR frequency characteristic in the eighth state. As such, a wide frequency bandwidth is obtained in the eighth state rather than the seventh state. The bandwidths where the VSWR becomes 4 become about 300 MHz and 350 MHz, respectively, and the bandwidth in the eighth state is wider than that in the seventh state by about 50 MHz. In particular, the bandwidth in the low frequency band is increased.

FIG. 15shows X-Z directivity in a free space in the eighth state.

In this case, a curved line405(graph) indicates X-Z surface directivity in the eighth state, and a curved line406(graph) indicates X-Z surface directivity in the eighth state. As such, high antenna performance is obtained in the eighth state rather than the seventh state. In this case, PAGs (Pattern Average Gain) of the seventh and eighth states become −7 dB and −6.5 dB, respectively, and the PAG in the eighth state is higher than that in the seventh state by about 0.5 dB.

As described above, according to the portable radio apparatus in this embodiment, the connecting ground wiring line is connected to the circuit board that operates as the ground conductor of the antenna so as to increase an electric field of the ground conductor, and the antenna performance of the closed state can be improved without lowering an antenna gain in the opened state. In this case, the antenna gain can be improved by about 0.5 dB.

Further, if the connecting ground wiring line401can have a structure that it can increase a length in a +Z direction with respect to the circuit board105, the same effect can be obtained even in any combination.

Fifth Embodiment

The foldable portable radio apparatus according to the fifth embodiment will be described with reference toFIGS. 16 and 17.FIG. 16shows a side view of a foldable portable radio apparatus according to the fifth embodiment. InFIG. 16, the same reference numerals as those ofFIG. 13perform the same operations, and the description thereof will be omitted.

The foldable portable radio apparatus according to the fifth embodiment shown inFIG. 16has a structure in which in addition to the structure of the fourth embodiment shown inFIG. 13, a first contact unit501and a second contact unit502are additionally provided.

The first contact unit501is disposed near the first switching unit110of a surface opposite to the second conductor plate103above the first conductor plate102. The first contact unit501is composed of a metallic pin that has flexibility and a length of 3 mm, and metal plating with high conductivity is performed on the surface of the first contact unit501.

The second contact unit502is disposed at a neighboring portion of the second switching unit201of the side opposite to the antenna element107above the circuit unit105and the location that contacts the first contact unit501, in a state where the foldable portable radio apparatus according to this embodiment is closed.

The second contact unit502is formed of a metallic spring that stably contacts the first contact unit501, and the metal plating with high conductivity is performed on the surface of the second contact unit502.

In this case, a state where the first antenna is selected and the first contact unit501and the second contact unit502are not provided is set to ‘a ninth state’, and a state where the first antenna is selected and the first contact unit501and the second contact unit502are provided is set to ‘a tenth state’.

FIG. 17shows X-Z surface directivity in a free space in the ninth and tenth states.

In this case, a curved line503(graph) indicates X-Z surface directivity in the ninth state, and a curved line504(graph) indicates X-Z surface directivity in the tenth state. As such, high antenna performance is obtained in the tenth state rather than the ninth state. In this case, PAGs (Pattern Average Gain) of the ninth and tenth seventh and eighth states become −6.5 dB and −6.0 dB, respectively, and the PAG in the tenth state is higher than that in the ninth by about 0.5 dB.

As described above, according to the portable radio apparatus in this embodiment, the conductor plate and the circuit board are connected to each other in a closed state, a reversed-phase current component that flows in the ground conductor of the antenna is reduced, and the antenna performance of the closed state can be improved without lowering an antenna gain in the opened state. In this case, the antenna gain can be improved by about 0.5 dB, as compared with the fourth embodiment.

Further, if the contact unit has a structure that can stably contact in a closed state, the same effect can be obtained even in any combination. Further, if the conductivity can be ensured, even when the shock absorbing conductive rubber and the conductive cushion are used, the same effect can be obtained.

The invention has been described with reference to the preferred embodiments, but it can be apparent to those skilled in the art that various changes and modifications can be made without the spirit and scope of the invention.

This application claims priority from Japanese Patent Application (Application No. 2004-190928), filed on Jun. 29, 2004, the contents of which are incorporated herein for reference.

INDUSTRIAL APPLICABILITY

As described above, according to the foldable portable radio apparatus of the invention, the antenna performance in the closed state can be improved without the antenna gain in the opened state, and it is advantages in improving a characteristic in a standby mode in a cellular phone.