JP2008227560A - Portable wireless apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a portable wireless apparatus which has no limitation as to the design and can avoid degradation in antenna characteristics, even if a human body approaches. <P>SOLUTION: In the portable wireless apparatus where a first case 3 and a second case 4 are coupled through a hinge 5 to open/close freely, a first circuit board 1 and a second circuit board 2 are connected electrically by a flexible cable 6, and a ground plane 9 in the vicinity of an antenna feeding point 7 provided on the first circuit board 1 is connected electrically to the ground plane 10 of the second circuit board 2 via a connection element 11. The connection element 11 may be connected directly with the ground plane 10, or connected via a capacitor 12. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a portable wireless device such as a mobile phone or a portable communication terminal, and more particularly to a portable wireless device having a structure in which two casings are movably connected.

  In recent years, portable wireless devices such as mobile phones have become mainstream due to the appearance design, etc., and the miniaturization of antennas has become an essential issue due to the increase in the number of components accompanying higher functionality. Yes. Generally speaking, miniaturization degrades antenna characteristics, leading to degradation of call quality.

  In addition, since the portable wireless device is used by a human hand or close to the ear, it is necessary to consider the influence on the antenna characteristics due to the proximity of the human body. In particular, since a mobile phone is in a state where the human body side head is in close contact during a call, a countermeasure that does not deteriorate the antenna characteristics in such a close state is necessary.

  Patent Document 1 discloses a portable wireless communication apparatus that attempts to improve antenna characteristics by making a part of a casing made of metal and using it as a radiating element. Specifically, a circuit board having an antenna feeding point is provided inside a housing formed of a metal front case and a resin rear case, and the ground surface near the antenna feeding point is brought into contact with the metal front case. Thus, the metal front case functions as a radiating element.

  In Patent Document 2, a battery pack is used as an antenna ground wire instead of a wireless board in a casing, thereby suppressing the radiation current of the antenna element flowing through the wireless board and reducing the deterioration of the antenna radiation gain when a human body approaches. An antenna device for a mobile communication terminal is disclosed.

Japanese Patent Laid-Open No. 11-340867 JP 2000-13118 A

  However, each of the above conventional portable wireless devices is provided with one circuit board in a single casing and connects the ground plane in the vicinity of the feeding point to a metal casing or a battery pack, and the two casings are movable. It does not teach an antenna device for a connected portable radio.

  Further, in the portable wireless communication device disclosed in Patent Document 1, it is necessary to form a part of the casing with a conductive material such as metal, which not only complicates the manufacturing process but also makes it difficult to reduce the weight of the portable device. It becomes. Furthermore, in Patent Document 1, in order to bring the ground surface near the antenna feeding point into contact with the metal case, it is necessary to form a metal contact on the ground surface in accordance with the position of the metal case, which increases the structural restrictions. The problem arises that the degree of freedom in design is reduced.

  Similarly, in the mobile communication terminal disclosed in Patent Document 2, since the ground terminal of the battery pack is used, configuration restrictions such as a positional relationship with the battery pack are generated, and the degree of freedom in antenna design is reduced.

  Furthermore, since these conventional wireless devices are configured with a single casing, it is impossible to avoid a state in which the spatial distance between the antenna device and the human head is extremely close during a call. Therefore, when the housing is downsized and the antenna device is to be accommodated therein, the antenna characteristics of the portable wireless device tend to be further deteriorated. In addition, as described above, the antenna characteristics are deteriorated even in the state of being close to the human body, and there is a problem that the gain is reduced.

  An object of the present invention is to provide a portable radio device that can improve antenna characteristics without any design restrictions.

  Another object of the present invention is to provide a portable wireless device capable of avoiding deterioration of antenna characteristics even when a human body is in close proximity.

  In the portable wireless device according to the present invention, the first circuit board of the first casing and the second circuit board of the second casing are electrically connected by a cable, and the first casing and the second casing are connected to each other. A mobile wireless device that is movably coupled by the antenna element, the antenna element connected to the antenna feeding point provided in the first circuit board built in the first housing, the ground plane in the vicinity of the antenna feeding point, and the second circuit board. Connecting means for electrically connecting the ground plane.

  According to an embodiment of the present invention, the connecting portion is a hinge that connects the first housing and the second housing so as to be openable and closable. Further, the connecting means needs to be connected to the ground plane of the second circuit board for the current in the frequency band to be used. In particular, the connecting means is connected to the ground plane of the second circuit board via a capacitor. Connectable. Alternatively, the connecting means may be connected to the ground plane of the second circuit board for direct current.

  According to one embodiment of the present invention, a foldable portable wireless device is provided with a first housing that houses a first circuit board on which a receiver (receiver) is provided, and a microphone unit (transmitter). And a second housing for accommodating the second circuit board, and an antenna element is provided near the hinge at the bottom of the first housing, and the vicinity of the antenna feeding point and the second circuit board are electrically connected by a connecting element. . The first circuit board and the second circuit board are usually connected by a flexible cable, but separately from this connection, the ground near the antenna feeding point and the ground of the second circuit board are electrically connected. Thus, a part of the current flowing in the first circuit board is passed to the second circuit board.

  As described above, by electrically connecting the ground plane near the antenna feeding point on the first circuit board and the ground plane of the second circuit board, the current flowing through the first circuit board can be reduced, and the human body Even in a state where the head is in close proximity (during a normal call), the portion where the current is concentrated can be changed, and deterioration of antenna characteristics due to the human body can be prevented. Therefore, it is possible to prevent deterioration of the antenna characteristics and maintain high call quality without impairing the appearance design.

1. First Embodiment FIG. 1A is a configuration diagram schematically showing the inside of a portable wireless device according to a first embodiment of the present invention. It should be noted that the ratios of shapes and dimensions on the drawings are merely schematically illustrated to explain the configuration of the present embodiment, and do not necessarily indicate the actual shapes and ratios of portable radio devices. .

  First, in the portable wireless device according to the present embodiment, the first circuit board 1 and the second circuit board 2 are provided inside the first casing 3 and the second casing 4, respectively. The first housing 3 and the second housing 4 are made of a non-conductive material such as plastic and are connected to each other by a hinge 5 so as to be opened and closed.

  The first circuit board 1 and the second circuit board 2 are electrically connected by a flexible cable 6. The flexible cable 6 is connected to one side (right side in the drawing) from the center line (one-dot chain line). A feeding point 7 is provided at the lower end of the first circuit board 1 and on the opposite side of the center line from the connecting portion of the flexible cable 6 to feed power to the antenna element 8. A wireless circuit (not shown) connected to the feeding point 7 is provided on either the first circuit board 1 or the second circuit board 2.

  The antenna element 8 is a built-in antenna having an L-shape that extends slightly in parallel (downward) with the center line from the feeding point 7 and then bends in a direction perpendicular to the center line, and is located on the back surface of the portable wireless device. As will be described later, when the first housing 3 and the second housing 4 are opened in the shape of a "<" (during a normal call), the antenna is located near the top of the "<" Transmission is possible in a state away from the human head. In addition to this, various types such as an inverted L type, an inverted F type, a monopole type, a meander type, a helical type, and a sheet metal mold can be used for the antenna element 8.

  Furthermore, according to the present embodiment, the ground plane 9 and the ground plane 10 provided respectively on the first circuit board 1 and the second circuit board 2 are electrically connected by the connecting element 11. The connection element 11 is connected to the ground plane 9 in the vicinity of the feeding point 7 in the first circuit board 1. Therefore, the connection element 11 is connected to a symmetrical position across the center line of the flexible cable 6. Since the connecting element 11 passes through the hinge 5, it is desirable to use a flexible wiring board like the flexible cable 6.

2. Second Embodiment FIG. 1B is a configuration diagram schematically showing the inside of a portable wireless device according to a second embodiment of the present invention. This figure is also schematically illustrated for explaining the configuration of the present embodiment, and does not necessarily indicate the actual shape and ratio of the portable wireless device. In addition, the same reference number is attached | subjected to the part same as the portable wireless apparatus of 1st Embodiment shown to Fig.1 (a), and description is abbreviate | omitted.

  In the second embodiment of the present invention, unlike the first embodiment, the connection element 11 is electrically connected to the second circuit board 2 ground plane 10 via a capacitor 12. The capacitor 12 is set so that the impedance becomes very small with respect to the current in the frequency band used in the portable wireless device. That is, in the frequency band, it can be considered that the connection element 11 is connected to the ground plane 10 in the same manner as in FIG. However, the connection element 11 is open to the ground plane 10 for direct current. Such a capacitor 12 can be formed, for example, by configuring the end of the connection element 11 and the ground plane 10 to face each other with an insulating layer interposed therebetween. Other configurations are the same as those of the first embodiment.

3. Embodiment FIG. 2 is a schematic side view showing an appearance of a foldable mobile phone according to an embodiment of the present invention. The same members as those in the portable wireless device shown in FIG. In the foldable mobile phone according to the present embodiment, a receiver 21 and a display unit 23 are provided on the front surface of the first housing 3, and a transmitter 22 and a key operation unit 24 are provided on the front surface of the second housing 4. .

  As shown in FIG. 2, the cross section of the first housing 3 has an L-shape having a bent portion 25 that is retracted behind the hinge 5, and the antenna element 8 described above is disposed on the back side of the bent portion 25. Has been. The first housing 3 and the second housing 4 can be opened and closed in the direction of the arrow by a hinge 5, and an open state (normal telephone conversation state) is illustrated here. Therefore, in a normal call state, the human body side head is close between the handset 21 and the handset 22, but the antenna element 8 is located far from the human body side head by a portion of the bent portion 25. The influence of the human body on the characteristics can be reduced.

  FIG. 3 is a schematic perspective view of the internal configuration of the foldable mobile phone according to the present embodiment as viewed from the back side. Here, a radio circuit unit 31 is provided on the second circuit board 2 and connected to the feeding point 7 through the coaxial cable 32. In the coaxial cable 32, the central conductor is connected to the radio circuit unit 31 and the antenna feeding point 7, and the outer conductor is connected to the ground planes 9 and 10 of the first circuit board 1 and the second circuit board 2. As described above, the ground plane 9 near the feeding point 7 of the first circuit board 1 and the ground plane 10 of the second circuit board 2 are electrically connected by the connection element 11.

  In this way, the ground plane 9 near the feeding point 7 of the first circuit board 1 and the ground plane 10 of the second circuit board 2 are electrically connected by the connection blocking 11, so that the current near the feeding point 7 where current concentrates. An electric current can be passed through the second circuit board 2 and the antenna characteristics when the head is approaching (during a call) can be improved. Hereinafter, the effect of the present invention will be specifically described using a comparative example in which the connection element 11 is not provided.

  FIG. 4 is a schematic perspective view of the internal configuration of a foldable mobile phone in which only the connection element 11 is removed as a comparative example, as viewed from the back side. Except for the absence of the connecting element 11, it is the same as the present embodiment shown in FIG. In such a configuration, the electric power from the radio circuit 31 passes through the coaxial cable 32 and is supplied to the antenna element 8. At this time, the maximum value of the feeding power is concentrated on the feeding point 7. Furthermore, since the antenna element 8 is built in the first housing 3, it is inevitable that the antenna characteristics deteriorate to some extent when the head is approaching (during a call).

  On the other hand, according to the present embodiment, the ground plane 9 close to the feeding point 7 of the first circuit board 1 and the ground plane 10 of the second circuit board 2 are electrically connected by the connection blocking 11, The portion where the current is concentrated can be passed to the second circuit board 2, and the characteristics when the head is close (during a call) are improved.

  FIG. 5 is a graph showing the difference in radiation efficiency between this example and the comparative example. Here, the calculation result by the FDTD (Finite Difference time Domain Method) method is shown. As is apparent from this calculation result, the radiation efficiency in the comparative example is −6.8 dB, whereas in the present example, it is −4.9 dB, which is an improvement of 1.9 dB.

  That is, the ground plane 9 close to the feeding point 7 of the first circuit board 1 and the ground plane 10 of the second circuit board 2 are electrically connected by the connection blocking 11 so that the human head is approaching (during a call) ) Antenna characteristics are improved and good call quality can be maintained.

  In this embodiment, the radio circuit unit 31 is arranged on the second circuit board 2 and the antenna element 8 and the radio circuit unit 31 are connected by the coaxial cable 32. However, the present invention is not limited to this. If the part 31 is arranged on the first circuit board 1, the coaxial cable 32 is not always necessary. Even in this case, it is obvious that the same effect can be obtained.

  The present invention is generally applicable to portable radio devices in which an antenna element is built in a housing and circuit boards are separately mounted in two housings.

(A) is a block diagram schematically showing the inside of the portable radio according to the first embodiment of the present invention, (b) is a block diagram schematically showing the inside of the portable radio according to the second embodiment of the present invention. is there. 1 is a schematic side view showing an appearance of a foldable mobile phone according to an embodiment of the present invention. It is the schematic perspective view which looked at the internal structure of the foldable mobile telephone by a present Example from the back side. It is the schematic perspective view which looked at the internal structure of the foldable mobile telephone which removed only the connection element 11 as a comparative example from the back side. It is a graph which shows the difference of the radiation efficiency of a present Example and a comparative example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 1st circuit board 2 2nd circuit board 3 1st housing | casing 4 2nd housing | casing 5 Hinge 6 Flexible cable 7 Feeding point 8 Antenna element 9 Grounding surface 10 Grounding surface 11 Connection element 12 Capacitance 21 Handset 22 Handset 23 Display Unit 24 operation unit 31 wireless circuit unit 32 coaxial cable

Claims (11)

The first circuit board of the first casing and the second circuit board of the second casing are electrically connected by a cable, and the first casing and the second casing are movably connected by a connecting portion. In the radio,
An antenna element built in the first housing and connected to an antenna feeding point provided on the first circuit board;
Connection means for electrically connecting a ground plane near the antenna feeding point and a ground plane of the second circuit board;
A portable wireless device comprising:   The portable wireless device according to claim 1, wherein the connecting portion is a hinge that connects the first housing and the second housing so as to be openable and closable.   The portable wireless device according to claim 1, wherein the connection means is connected to a ground plane of the second circuit board with respect to a current in a frequency band to be used.   The portable wireless device according to claim 3, wherein the connecting means is connected to a ground plane of the second circuit board via a capacitor.   The portable wireless device according to claim 3, wherein the connection means is connected to a ground plane of the second circuit board with respect to a direct current.   In the first circuit board, the antenna feeding point is connected to a position symmetrical to the connection position of the cable with respect to a center line in the opening / closing direction of the first casing and the second casing. The portable wireless device according to any one of claims 2 to 5, wherein   The connection means is connected to a position symmetrical to a connection position of the cable with respect to a center line in the opening / closing direction of the first casing and the second casing. The portable wireless device according to any one of the above.   The display unit and the handset are mounted on the front surface of the first housing, and the key operation unit and the transmitter are mounted on the front surface of the second housing. The portable wireless device according to item 1.   The portable wireless device according to any one of claims 1 to 8, wherein the antenna element is mounted on a back surface of the first housing in the vicinity of the connecting portion.   The portable wireless device according to claim 1, wherein the first housing and the second housing are formed of a non-conductive material.   The antenna feeding point is electrically connected through a coaxial cable to a radio circuit unit provided on the second circuit board, and a central conductor of the coaxial cable is connected to the radio circuit unit and the antenna feeding point, and an outer conductor The portable wireless device according to claim 1, wherein the portable wireless device is connected to a ground plane of the first circuit board and the second circuit board.

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