Patent Application
20120086609
The present invention relates to a wireless communication terminal such as a cellular phone or a PHS (personal handy-phone system).
The wireless communication terminals such as the cellular phone or the PHS are required to accept a plurality of wireless systems different in operating frequency whereas an antenna element is mainly incorporated into the wireless communication terminal for thinning and downsizing. From the above viewpoints, an antenna element responding to a plurality of operating frequencies needs to be disposed within a limited space. Hence, when a plurality of antenna elements is arranged, the respective antenna elements are spatially electromagnetically coupled with each other to deteriorate the antenna performance.
In order to avoid the deterioration caused by the electromagnetic coupling, for example, Patent Document 1 discloses a technique in which “a distance between the antenna elements are made long to improve an isolation performance between the antenna elements. As illustrated in
Also, in addition to the above example, for example, Patent Document 2 discloses a technique “that accepts the plurality of wireless systems different in the operating frequency, and forms a slit between antenna feeders for avoiding the electromagnetic coupling between the antenna elements to improve the isolation performance”. As illustrated in
Also, in order to avoid the deterioration of coupling, when one antenna element accepts the plurality of wireless systems different in the operating frequency, there is a need to provide a broadband antenna element.
In order to provide the broadband antenna, for example, Patent Document 3 discloses a technique in which “a power is fed from each end of one antenna element to switch a matching circuit”. As illustrated in
Patent Document 1: JP-A 2005-277703
Patent Document 2: JP-A-2004-244317
Patent Document 3: JP-A-2006-310995
However, when the plurality of wireless systems different in the operating frequency operates at the same time, there arises such a problem that an excellent antenna performance cannot be obtained. For example, when the respective antenna elements are provided for a first wireless system and a second wireless system, a space in which the antenna elements can be arranged is limited because the wireless communication terminal is more downsized and thinned, and the higher density is caused by higher function. Therefore, those antenna elements cannot be arranged sufficiently at a distance from each other to deteriorate the isolation performance, resulting in the deterioration of the antenna performance due to the electromagnetic coupling effect between the antenna elements. Also, when the antenna elements are close to each other, the slit is formed between the feeder parts to prevent a current from flowing in therebetween, as a result of which the isolation performance can be improved. However, pattern lines and implemented parts are concentrated on an actual board, thereby making it difficult to ideally form the slit. This leads to a reduction in the implemented area, an increase in the costs, and an increase in the board size, thus affecting the terminal size.
In order to solve the above problem, if one antenna element accepts the first wireless system and the second wireless system, the electromagnetic couple effect can be removed. However, in order that the one antenna element accepts a plurality of frequencies, there is a need to provide a wideband antenna element. Under the circumstances, in order to accept the operating frequencies of the respective wireless systems, a matching circuit having a resonance frequency of the antenna element as the respective wireless operating frequencies is disposed at each end of the antenna element, and the connection of a wireless part can be switched. However, the operation of those wireless systems cannot be conducted at the same time.
An object of the present invention is to provide a wireless communication terminal in which one antenna element is connected with a plurality of wireless systems different in the operating frequency, the plurality of wireless systems can operate at the same time, and the antenna performance is excellent.
To achieve the above objection, there is provided a wireless communication terminal having a plurality of wireless systems different in operating frequencies, and having a hinge part which rotatably couples a first housing with a second housing, the wireless communication terminal comprising: a first wireless circuit having a first frequency band as the operating frequency; a second wireless circuit having a second frequency band different from the first frequency band as the operating frequency; a first circuit board disposed in the first housing and having the first wireless circuit mounted therein; a second circuit board disposed in the second housing and having the second wireless circuit mounted therein; an inter-board connection line that connects the first circuit board and the second circuit board for control the first circuit board and the second circuit board; an antenna element disposed at a given distance from the first circuit board; a first connection part electrically connected to the antenna element; a second connection part electrically connected to the antenna element at a position different from that of the first connection part; a first conductive element electrically connected to the first connection part; a first blocking part electrically connected to the first conductive element and the first wireless circuit, disposed on the first circuit board, and blocks the second frequency band; a second conductive element electrically connected to the second connection part; and a second blocking part electrically connected to the second conductive element and the second wireless circuit, disposed on the second circuit board, and blocks the second frequency band.
According to the above configuration, the electromagnetic coupling deterioration caused by disposing the plurality of antenna elements close to each other is reduced, a power is fed to one antenna element from the plurality of wireless systems different in the operating frequency mounted on the first circuit board and the second circuit board configuring the wireless communication terminal to prevent a current from flowing in between the feeder parts through the GND pattern on the same board, thereby enabling the isolation performance between the wireless systems to be improved. In the above configuration, because the GND patterns of the two circuit boards are connected by an inter-board connection line (a GND line for a thin control line in a DC manner), the potential is the same. However, in a high frequency manner, because of only the connection with the thin GND line, the potential is not the same, and the GND patterns can be dealt with as the boards different in the potential.
In the above configuration, the first connection part and the second connection part which are electrically connected to the antenna element are formed at both ends of the antenna element in a longitudinal direction of the antenna element.
According to the above configuration, the feed current is prevented from flowing through the GND patterns arranged on the same board. In addition, the high frequency current is allowed to flow in the antenna element in only a desired frequency band used by the respective wireless systems, and in other frequency bands, a current can be prevented from flowing into the respective wireless systems through the antenna element.
In the above configuration, a GND pattern provided on the first circuit board and a GND pattern provided on the second circuit board are configured at positions that do not overlap with each other when the housings are closed.
According to the above configuration, the current is prevented from flowing through the GND patterns arranged on the same board. In addition, when the housing is closed, the GND pattern on the first circuit board and the GND pattern on the second circuit board come close to each other, and are connected to each other in a high frequency manner with a capacitance provided therebetween. This enables the deterioration of the isolation performance caused by the electromagnetic coupling to be suppressed. Accordingly, even when the housing is closed, the isolation performance can be improved.
In the above configuration, the first blocking part provided in the first circuit board and the second blocking part provided in the second circuit board are configured on surfaces that do not overlap with each other when the housings are closed.
According to the above configuration, the respective blocking parts on which the current flowing from the antenna element is concentrated come close to each other on a plane. As a result, like the GND pattern, the respective blocking parts are connected to each other in a high frequency manner with a capacitance provided therebetween, and the deterioration of the isolation performance caused by the electromagnetic coupling is suppressed, thereby enabling the isolation performance to be improved.
In the above configuration, the hinge part is configured by the antenna element.
According to the above configuration, the existing hinge part can be used as the antenna element, and there is no need to newly provide the antenna element, and the terminal can be further downsized and thinned.
According to the present invention, the wireless communication terminal can accept the plurality of wireless systems different in the operating frequency by one antenna element, and those wireless systems can operate at the same time. Therefore, the wireless communication terminal that accepts the plurality of wireless systems can be downsized and thinned.
a) and 1(b) are diagrams for illustrating an outline configuration of a wireless communication terminal according to an embodiment of the present invention.
a) and 4(b) are diagrams for illustrating a first conductive element of the wireless communication terminal according to the embodiment of the present invention.
a) and 4(b) are diagrams for illustrating a second conductive element of the wireless communication terminal according to the embodiment of the present invention.
a) and 8(b) are schematic diagrams of operating states of a first frequency band and a second frequency band in the wireless communication terminal according to the embodiment of the present invention.
a) and 9(b) are schematic diagrams of a configuration in which the wireless communication terminal is closed according to the embodiment of the present invention.
a) to 13(c) are diagrams illustrating an overview of a conventional wireless communication terminal providing wideband by one element.
Hereinafter, a preferred embodiment for implementing the present invention will be described in detail with reference to the drawings.
a) and 1(b) are configuration diagrams of a wireless communication terminal 200 according to an embodiment of the present invention.
Referring to
The antenna element 1 is disposed at a given distance from the first circuit board 20. Also, a first connection part 11 is electrically connected to one end of the antenna element 1, and a second connection part 12 is connected to the other end of the antenna element 1 at a side different from that of the first connection part 11. In the example, the given distance is directed to 2 mm or larger, and if the distance is larger, a radiation resistance is more increased to improve an antenna performance.
A first wireless circuit 21 having a first frequency band as an operating frequency, and a first blocking part 22 that is electrically connected to the first wireless circuit 21 are disposed on the first circuit board 20.
A second wireless circuit 31 having a second frequency band as the operating frequency, and a second blocking part 32 that is electrically connected to the second wireless circuit 31 are disposed on the second circuit board 30.
The first circuit board 20 and the second circuit board 30 are electrically connected to each other through an inter-board connection line 40.
The first connection part 11 is electrically connected to the first blocking part 22 on the first circuit board 20 through a first conductive element 23. Also, the second connection part 12 is electrically connected to the second blocking part 32 on the second circuit board 30 through a second conductive element 33.
In the above configuration, a description will be given in detail of a case in which, for example, the first wireless circuit 21 corresponds to Bluetooth (registered trademark) using 2.4 GHz band which is the first frequency band, and the second wireless circuit 31 corresponds to a GPS using 1.5 GHz band which is the second frequency band.
First, the configurations of the respective components will be described in detail.
With the above configuration, the respective wireless systems are connected to both ends of the antenna element 1 to enable communication.
In this embodiment, the first connection part 11 and the second connection part 12 are disposed at both ends of the antenna element 1. However, the present invention is not limited to this configuration. As the first connection part 11 and the second connection part 12 are wider, the antenna performances of those connection parts can be more increased. A sufficient advantage is obtained if the frequency band is 1/10 or more of the lower frequency band of the first frequency band and the second.
a) and 4(b) are diagrams illustrating an example of a specific configuration of the first conductive element 23 in the wireless communication terminal 200 according to this embodiment.
With the above configuration, the first connection part 11 and the first circuit board 20 are connected to each other through the first conductive element 23 whereby the antenna element 1 and the first circuit board 20 are connected to each other in a high frequency manner.
The first blocking circuit 50 blocks 1.5 GHz band that is the second frequency band, and allows the passing of 2.4 GHz band which is the first frequency band. For example, the first blocking circuit 50 is configured by a band-pass circuit that allows the passing of 2.4 GHz (blocks 1.5 GHz band), or a bandwidth blocking circuit that blocks 1.5 GHz band (allows the passing of 2.4 GHz band).
With the above configuration, the first blocking part 22 can block 1.5 GHz band which is the second frequency band among flow-in high frequency currents, and can allow the passing of 2.4 GHz band which is the first frequency band.
a) and 6(b) are diagrams illustrating an example of a specific configuration of the second conductive element 33 in the wireless communication terminal 200 according to this embodiment.
With the above configuration, regardless of the open or close operation of the housing, the second connection part 12 is connected to the second blocking part 32 through the second conductive element 33 with the result that the antenna element 1 and the second circuit board 30 can be stably connected to each other in a high frequency manner.
The second blocking circuit 60 blocks 2.4 GHz band that is the first frequency band, and allows the passing of 1.5 GHz band which is the second frequency band. For example, the second blocking circuit 60 is configured by a band-pass circuit that allows the passing of the 1.5 GHz (blocks the 2.4 GHz band), or a bandwidth blocking circuit that blocks the 2.4 GHz band (allows the passing of the 1.5 GHz band).
With the above configuration, the second blocking part 32 can block the 2.4 GHz band which is the first frequency band among flow-in high frequency currents, and can allow the passing of the 1.5 GHz band which is the second frequency band.
Subsequently, the antenna operation of the respective wireless systems with the above configuration will be described.
In the 2.4 GHz band that is the first frequency band used by the first wireless circuit 21, a power (high frequency current) supplied from the first wireless circuit 21 flows in the first blocking part 22, the first conductive element 23, and the first connection part 11 without any loss, and is supplied to the antenna element 1. Also, because the second blocking part 32 blocks the 2.4 GHz band that is the first frequency band, no high frequency current flows from the antenna element 1 to the second blocking part 32.
When the antenna element 1 and the second wireless circuit 31 are connected to each other through the second conductive element 33 in a state where there is no second blocking part 32, the power (high frequency current) supplied from the first wireless circuit 21 flows into the second wireless circuit 31 side, and is consumed. Therefore, the antenna performance and the isolation performance are deteriorated. On the contrary, as in this embodiment, the first wireless circuit 21 and the second wireless circuit 31 are disposed on boards different in potential, and the second blocking part 32 that blocks the first frequency band is provided. As a result, because the power (high frequency current) supplied from the first wireless circuit 21 flows in only the antenna element 1, it is possible to prevent the high frequency current from flowing into the second wireless circuit 31 through the antenna element 1. As described above, the antenna performance and the isolation performance which are excellent for the respective wireless systems can be ensured while feeding a power to one antenna element from the plurality of wireless systems.
Likewise, in the 1.5 GHz band that is the second frequency band used by the second wireless circuit 31, a power (high frequency current) supplied from the first wireless circuit 31 flows in the second blocking part 32, the second conductive element 33, and the second connection part 12 without any loss, and is supplied to the antenna element 1. Also, because the first blocking part 22 blocks the 1.5 GHz band that is the second frequency band, no high frequency current flows from the antenna element 1 to the first blocking part 22.
When the antenna element 1 and the first wireless circuit 21 are connected to each other through the first conductive element 23 in a state where there is no first blocking part 22, the power (high frequency current) supplied from the second wireless circuit 31 flows into the first wireless circuit 21 side, and is consumed. Therefore, the antenna performance and the isolation performance are deteriorated. On the contrary, as in this embodiment, the first wireless circuit 21 and the second wireless circuit 31 are disposed on the boards different in potential, and the first blocking part 22 that blocks the second frequency band is provided. As a result, because the power (high frequency current) supplied from the second wireless circuit 31 flows in only the antenna element 1, it is possible to prevent the high frequency current from flowing into the first wireless circuit 21 through the antenna element 1. As described above, the antenna performance and the isolation performance which are excellent for the respective wireless systems can be ensured while feeding a power to one antenna element from the plurality of wireless systems.
As described above, according to the wireless communication terminal 200 of this embodiment, one antenna element can accept the plurality of wireless systems different in the operating frequency, and the antenna performance excellent for the respective wireless systems can be obtained. Also, the wireless systems can operate at the same time, and the wireless communication terminal 200 that accepts the plurality of wireless systems can be downsized and thinned. In the above configuration, the GND patterns of the two circuit boards are connected by the inter-board connection line 40 (thin GND line for control line in the DC manner), the GND patterns have the same potential. However, in the high frequency manner, because of only the connection with the thin GND line, the potential is not the same, and it is assumed that the GND patterns are dealt with as the boards different in the potential.
Also, the antenna element 1 according to this embodiment assumes a folding structure, and in order to obtain the excellent isolation performance even if the housing is closed, the following configuration is assumed.
When the housing of the wireless communication terminal 200 illustrated in
As described above, because the powers supplied from the wireless systems of the different boards flows in the respective boards, the antenna performance and the isolation performance are deteriorated. In order to solve the above problem, the wireless communication terminal 200 according to this embodiment is configured so that the respective circuit boards (GND patterns) are not overlapped with each other even if the housing is closed.
Also, as illustrated in
According to the wireless communication terminal 200 of this embodiment, one antenna element is used to accept the plurality of wireless systems different in the operating frequency, and the antenna performance excellent for the respective wireless systems can be obtained regardless of the open or close state of the housing. Also, because those wireless systems can operate at the same time, the wireless communication terminal 200 that accepts the plurality of wireless systems can be downsized and thinned.
Also, as illustrated in
In this embodiment, the first frequency band is higher than the second frequency band, and an interval between the lowest frequency of the first frequency band and the highest frequency of the second frequency band is a fractional bandwidth 5% or higher to the center frequency of the first frequency band. With the above configuration, the first blocking part 22 can allow the passing of the first frequency band, and block the second frequency band. Likewise, the second blocking part 32 can allow the passing of the second frequency band, and block the first frequency band. Accordingly, the connection of the respective wireless systems to the antenna element 1 can be conducted in the frequency bands used by the wireless systems without any loss.
Also, in this embodiment, an example in which the first frequency band is the 2.4 GHz band, and the second frequency band is 1.5 GHz band is described. However, the present invention is not limited to those frequency bands, but it is assumed that the frequency bands accept various wireless systems.
Also, the respective drawings in this embodiment represent a coordinate system, and the positional relationship in each drawing is arranged on the basis of the coordinate system.
The present invention has been described in detail and with reference to a specific embodiment. However, it would be obvious to an ordinary skilled person that the present invention can be variously changed or corrected without departing from the spirit and scope of the present invention.
The present invention is based on Japanese Patent Application No. 2009-276293 filed on Dec. 4, 2009, and the contents of which are incorporated herein by reference.
The wireless communication terminal according to the present invention has such advantages that one antenna element is used to accept the plurality of wireless systems different in the operating frequency, and the antenna performance excellent for the respective wireless systems can be obtained. The present invention can be applied to the thinned and downsized wireless communication terminal in which the plurality, of wireless systems is mounted.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2009-276293 | Dec 2009 | JP | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/JP2010/007069 | 12/3/2010 | WO | 00 | 9/22/2011 |
