WO2015105117A1

WO2015105117A1 - Mobile terminal device

Info

Publication number: WO2015105117A1
Application number: PCT/JP2015/050220
Authority: WO
Inventors: 佐藤　直紀; 浩竹田; 聖治海道
Original assignee: シャープ株式会社
Priority date: 2014-01-10
Filing date: 2015-01-07
Publication date: 2015-07-16
Also published as: JP6257334B2; JP2015133578A

Abstract

An antenna switching device (40) of a mobile terminal device (100) is capable of switching each of multiple antennas (ANT1-ANT3) between a used state and unused state and switching a radiation pattern of each antenna in the used state. A control unit (30) controls an antenna switching device (40) so that when two or more antennas of the multiple antennas (ANT1-ANT3) are set in the used state to perform communication using two or more frequency bands, the radiation pattern of each antenna in the used state differs if there is a possibility of interfering waves to occur due to a combination of the frequency bands used in the communication, compared with a case where there is no possibility of the interfering waves to occur.

Description

Mobile terminal device

The present invention relates to a mobile terminal device having a plurality of antennas.

A technique for changing the radiation pattern of an antenna in order to improve the communication quality of a mobile terminal device is known. For example, a portable terminal device described in Japanese Patent Application Laid-Open No. 2010-199859 (Patent Document 1) includes a single or a plurality of antenna elements and a single or a plurality of ground conductors that are provided with the antenna elements and through which an image current flows With. The radiation pattern is switched by an image current flowing through a single ground conductor portion or an image current flowing through a ground conductor portion selected from a plurality of ground conductor portions.

JP 2010-199859 A JP 05-335855 A Japanese Patent Laid-Open No. 06-232771

In recent years, operation of a system that simultaneously uses a plurality of communication systems or a plurality of bands (frequency bands) such as SV-LTE (Simultaneous voice and LTE (registered trademark)) or carrier aggregation has been started. In this case, depending on the combination of bands, the harmonics of one transmission wave may become the interference wave of the other reception wave, or the intermodulation wave of multiple transmission waves may become the interference wave of one of the reception waves There can be.

However, the above-described patent document only discloses switching the radiation pattern of a single antenna to improve communication quality, and does not disclose a technique that can cope with the above-described problems related to a plurality of antennas.

An object of the present invention is to provide a mobile terminal device capable of suppressing quality degradation of a received signal that may occur due to a combination of bands when a plurality of communication methods / bands are used simultaneously.

A portable terminal device according to an embodiment includes a plurality of antennas, an antenna switching device, and a control unit. The antenna switching device can switch each of the plurality of antennas to the use state or the non-use state, and can switch the radiation pattern of each antenna in the use state. When the control unit performs communication using two or more frequency bands while using two or more antennas among a plurality of antennas, there is a possibility that an interference wave may be generated depending on a combination of frequency bands used for communication. Controls the antenna switching device so that the radiation pattern of the antenna in each use state is different from that in the case where there is no possibility of the occurrence of interference waves.

According to the above-described embodiment, when a plurality of communication methods / bands are used simultaneously, it is possible to suppress the quality degradation of the received signal that may occur due to the combination of bands.

1 is a block diagram schematically showing a configuration of a mobile terminal device 100 according to a first embodiment. It is a figure for demonstrating the jamming wave produced by SV-LTE. It is a figure for demonstrating the jamming wave which arises by a carrier aggregation. It is a figure which shows the structure of the radiation pattern switching part 41 typically. It is a figure for demonstrating the radiation pattern produced by the antenna ANT (when switch element SW2 is ON). It is a figure for demonstrating the radiation pattern produced by the antenna ANT (when switch element SW3 is ON). It is a figure which shows the equivalent circuit of the radiation pattern switching part 41 (when switch element SW2 is ON). It is a figure which shows the equivalent circuit of the radiation pattern switching part 41 (when switch element SW3 is ON). FIG. 2 is a diagram showing an example of radiation patterns of antennas ANT1 to ANT3 provided in the mobile terminal device of FIG. It is a figure for demonstrating the radiation pattern in the case of using antenna ANT1, ANT3 simultaneously in the antenna arrangement | positioning of FIG. It is a flowchart which shows the control procedure of the antenna radiation pattern by the control part 30 of FIG. It is a figure which shows an example of a radiation pattern switching table. FIG. 5 is a block diagram schematically showing a configuration of a mobile terminal device 101 according to a second embodiment. It is a flowchart which shows the switching procedure of a use antenna and a radiation pattern by the control part 30 of FIG. It is a figure which shows a specific example of an antenna and a radiation pattern switching table. It is a figure which shows the other specific example of an antenna and a radiation pattern switching table. FIG. 10 is a block diagram schematically showing a configuration of a mobile terminal device 102 according to a third embodiment. It is a flowchart which shows the switching procedure of the antenna radiation pattern by the control part 30 of FIG. FIG. 10 is a block diagram schematically showing a part of the configuration of a mobile terminal device according to a fourth embodiment. FIG. 20 is a circuit diagram showing an example of variable matching circuits 71 to 73 of FIG. It is a figure which shows an example of the antenna matching table 34 memorize | stored in the memory 31 of FIG. It is a flowchart which shows the switching procedure of a use antenna and a radiation pattern by the control part 30 of FIG. FIG. 10 is a block diagram schematically showing a configuration of a mobile terminal device 104 according to a fifth embodiment. It is a flowchart which shows the antenna switching operation | movement by the control part 30 of FIG.

Hereinafter, each embodiment will be described in detail with reference to the drawings. The same or corresponding parts are denoted by the same reference numerals, and the description thereof may not be repeated.

<Embodiment 1>
[Overall configuration of portable terminal device]
FIG. 1 is a block diagram schematically showing a configuration of a mobile terminal device 100 according to the first embodiment. Referring to FIG. 1, a mobile terminal device 100 includes

transceivers

11 and 21, power amplifiers (PAs) 12 and 22,

duplexers

13 and 23, an antenna switching device 40, antennas ANT1 to ANT3, A control unit 30 and a memory 31 are included.

The

transceivers

11 and 21 up-convert the transmission baseband signal received from the control unit 30 into a radio frequency band signal. The signals up-converted by the

transceivers

11 and 21 are amplified by the

power amplifiers

12 and 22, respectively, thereby generating transmission signals Tx (1) and Tx (2). The

transceivers

11 and 21 further generate received baseband signals by down-converting the received signals Rx (1) and Rx (2) received via the antennas ANT1 to ANT3, respectively. In this specification, the

transceivers

11 and 21 may be collectively referred to as a signal generation unit 10.

The

duplexers

13 and 23 are components used to share one antenna for the transmission signal Tx and the reception signal Rx. Each of the

duplexers

13 and 23 is provided with a filter that passes the transmission signal Tx and blocks the reception signal Rx, and a filter that passes the reception signal Rx and blocks the transmission signal Tx.

The antenna switching device 40 is a switch group that switches connections between the antenna-side nodes of the

duplexers

13 and 23 and the feeding points of the antennas ANT1 to ANT3 in accordance with instructions from the control unit 30. Each of the antennas ANT1 to ANT3 is put into use by being connected to one of the nodes on the antenna side of the

duplexers

13 and 23. Hereinafter, the antennas ANT1 to ANT3 are collectively referred to as antennas ANT when they are generically referred to or unspecified.

The antenna switching device 40 further includes a radiation pattern switching unit 41. As will be described with reference to FIGS. 4 to 8, the radiation pattern switching unit 41 includes a plurality of ground conductor portions. The direction in which the image current flows through the ground conductor changes by switching the connection between the feeding point of each antenna element and each ground conductor in accordance with a command from the control unit 30. As a result, the antenna radiation pattern is switched.

The control unit 30 includes a central processing unit (CPU) that controls the operation of the entire mobile terminal device 100 and a modem. The modem generates a transmission baseband signal by modulating the digital signal into a signal format used when communicating with the base station. The modem further demodulates the received baseband signal generated by the transceiver.

The CPU sets the frequency of the local oscillator of the

transceivers

11 and 21 so that it can operate in the communication method / band used for communication. Furthermore, the CPU sets each antenna to a use state or a non-use state according to a communication method / band used for communication by controlling the antenna switching device 40 with a control signal. Furthermore, the CPU switches the radiation pattern of the antenna used for communication by controlling the radiation pattern switching unit 41.

The mobile terminal device 100 communicates with the base station in the set frequency band (band), and a channel to be used in the frequency band is designated by the base station. After the channel to be used is specified by the base station, the CPU controls the

transceivers

11 and 21 to perform communication using the channel.

The memory 31 stores a program, transmission / reception data, application data, a radiation pattern switching table 32, and the like. The radiation pattern switching table 32 is referred to by the CPU of the control unit 30 when switching the radiation pattern of the antenna. Details of the radiation pattern switching table 32 will be described with reference to FIGS. 11 and 12.

[Generation of interference when using multiple antennas]
Hereinafter, generation of interference waves when a plurality of antennas are used simultaneously will be described.

FIG. 2 is a diagram for explaining an interference wave generated by SV-LTE. FIG. 2 illustrates an interference wave generated when the LTE (registered trademark) band 13 and the CDMA2000 (registered trademark) band class 0 subclass 1 are simultaneously used by SV-LTE.

Generally, LTE (Long Term Evolution) does not define a circuit switching mechanism for exchanging voice. Therefore, a method called SV-LTE is used as one method when a provider providing LTE (registered trademark) provides a voice service. SV-LTE provides LTE (registered trademark) data communication and CDMA (Code Division Multiple Access) voice communication simultaneously.

Referring to FIG. 2, the frequency of transmission signal Tx included in subclass 1 of CDMA2000 (registered trademark) band class 0 is f1, and the frequency of transmission signal Tx included in band 13 of LTE (registered trademark) is f2. . Then, the frequency of the third-order intermodulation distortion signal is represented by 2 × f1-f2 and 2 × f2-f1.

When specific numerical values are applied, 2 × f1 is determined by the transmission signal Tx (f1 = 824-849 MHz) included in the subclass 1 of the band class 0 and the transmission signal Tx (f2 = 776—786 MHz) included in the band 13. A third order intermodulation signal of −f2 = 862-922 MHz is generated. This third-order intermodulation signal can be an interference wave having a frequency that matches the reception signal Rx (869-894 MHz) included in subclass 1 of band class 0 of CDMA2000 (registered trademark). Similarly, a third-order intermodulation signal of 2 × f2-f1 = 703-748 MHz is also generated. This third-order intermodulation signal can be an interference wave having a frequency that matches the reception signal Rx (746-756 MHz) of the band 13 of LTE (registered trademark).

FIG. 3 is a diagram for explaining an interference wave generated by carrier aggregation. FIG. 3 illustrates an interference wave generated when LTE (registered trademark) band 4 and band 17 are simultaneously used by carrier aggregation. The transmission signal Tx is also referred to as an uplink (UL) signal, and the reception signal Rx is also referred to as a downlink (DL) signal.

Generally, carrier aggregation is a communication method defined by LTE-Advanced, and enables broadband communication exceeding 20 MHz by performing communication using a plurality of carriers simultaneously. By using carrier aggregation and multi-antenna transmission, a maximum downlink 1 Gbit / s and uplink 500 Mbit / s transmission rate are realized.

Referring to FIG. 3, when both band 4 and band 17 are used, the third harmonic of the transmission wave of band 17 can be an interference wave of the reception wave of band 4. Specifically, the frequency of the second harmonic (2H) of the transmission signal Tx (704-716 MHz) included in the band 17 is 1408-1432 MHz, and the frequency of the third harmonic (3H) is 211-12148 MHz. Since the frequency of the third harmonic wave overlaps with the frequency (2110-2155 MHz) of the reception signal Rx in band 4, it can be an interference wave.

As described above, when two bands are used at the same time, the harmonic wave of the transmission wave of one band becomes an interference wave of the reception wave of the other band, or the intermodulation wave of the transmission wave of both bands is In some cases, the received wave may be an interference wave in one or both bands. In the mobile terminal device 100 according to this embodiment, when there is a possibility that an interference wave is generated when a plurality of antennas are used at the same time, by switching the radiation pattern of each antenna used for communication, Increase isolation. This suppresses the quality degradation of the received signal due to the interference wave.

[How to change the antenna radiation pattern]
Next, a method for switching the antenna radiation pattern by the radiation pattern switching unit 41 in FIG. 1 will be described.

FIG. 4 is a diagram schematically showing the configuration of the radiation pattern switching unit 41. Referring to FIG. 4, the radiation pattern switching unit 41 includes a ground conductor portion GND1 as a main ground, ground conductor portions GND2 and GND3 as sub-grounds provided around the ground conductor portion GND, and switch elements SW2 and SW3. And choke coils 61 and 62. In FIG. 4, the antenna ANT is an example of an L-shaped monopole antenna connected to the power feeding unit 60, but is not limited to the form and shape of the antenna ANT.

The ground conductor portion GND2 is provided along the side 64 of the rectangular ground conductor portion GND1. The ground conductor portion GND3 is provided along the side 65 adjacent to the side 64 of the ground conductor portion GND1. The electrical length of the ground conductor portions GND2 and GND3 is set to one-fourth (λ / 4) of the wavelength corresponding to the frequency used by the antenna ANT or a value in the vicinity thereof.

One end of the ground conductor portion GND2 is connected to the power feeding portion 60 of the antenna ANT via the switch element SW2, and the other end of the ground conductor portion GND2 is connected to the antenna conductor portion GND1 via the choke coil 61. Similarly, one end of the ground conductor portion GND3 is connected to the power feeding portion 60 of the antenna ANT via the switch element SW3, and the other end of the ground conductor portion GND3 is connected to the antenna conductor portion GND1 via the choke coil 62. The choke coils 61 and 62 are used as impedance elements that block high-frequency currents.

FIG. 5 is a diagram for explaining a radiation pattern generated by the antenna ANT (when the switch element SW2 is on). Referring to FIG. 5, when switch element SW2 is on and switch element SW3 is off, image current Ii flows through ground conductor portion GND2 via switch element SW2. In FIG. 5, the portion where the image current Ii flows is hatched. The image current Ii flows in the Y direction in FIG. The

radiation patterns

66A and 66B are generated in a direction perpendicular to the image current Ii with the image current Ii as the center. Within the plane where the ground conductor portions GND1 to GND3 are provided, the

radiation patterns

66A and 66B are generated in the X direction.

FIG. 6 is a diagram for explaining a radiation pattern generated by the antenna ANT (when the switch element SW3 is on). Referring to FIG. 6, when switch element SW3 is on and switch element SW2 is off, image current Ii flows through ground conductor portion GND3 via switch element SW3. In FIG. 6, the portion where the image current Ii flows is hatched. The image current Ii flows in the X direction in FIG. The

radiation patterns

67A and 67B are generated in a direction orthogonal to the image current Ii with the image current Ii as the center. Within the plane where the ground conductor portions GND1 to GND3 are provided, the

radiation patterns

67A and 67B are generated in the Y direction.

FIG. 7 is a diagram showing an equivalent circuit of the radiation pattern switching unit 41 (when the switch element SW2 is on). In FIG. 7, a PIN diode is shown as an example of the switch elements SW2 and SW3. The anode of a PIN diode (hereinafter referred to as PIN diode SW2) as the switch element SW2 is connected to the ground conductor portion GND2, and the cathode of the PIN diode SW2 is connected to the power feeding portion 60. Similarly, the anode of the PIN diode SW3 is connected to the power feeding part 60, and the cathode of the PIN diode SW3 is connected to the ground conductor part GND3.

As shown in FIG. 7, the power supply unit 60 is further connected to a control terminal 63 that receives a control signal output from the control unit 30 of FIG. When a negative voltage with respect to the ground conductor portion GND1 is supplied from the control unit 30 to the control terminal 63 as a control signal, the PIN diode SW2 is turned on and the PIN diode SW3 is turned off. As a result, the image current Ii flows through the ground conductor portion GND2 (in FIG. 7, the portion through which the image current Ii flows is hatched).

Radiation patterns

66A and 66B are generated in a direction perpendicular to the image current Ii.

FIG. 8 is a diagram showing an equivalent circuit of the radiation pattern switching unit 41 (when the switch element SW3 is on). Referring to FIG. 8, when a positive voltage for ground conductor portion GND1 is supplied as a control signal from control portion 30 to control terminal 63, PIN diode SW3 is turned on and PIN diode SW2 is turned off. As a result, the image current Ii flows through the ground conductor portion GND3 (in FIG. 8, a portion through which the image current Ii flows is hatched).

Radiation patterns

67A and 67B are generated in the direction perpendicular to the image current Ii.

As described above, either one of the ground conductors GND2 and GND3 can be selected by switching on and off the switch elements SW2 and SW3 by the control signal from the control unit 30. As a result, the image current Ii flows through the selected ground conductor portion GND, and as a result, the radiation pattern of the antenna ANT is switched.

[Example of antenna radiation pattern in portable terminal device]
The radiation pattern switching unit 41 described with reference to FIGS. 4 to 8 is provided in each of the antennas ANT1, ANT2, and ANT3 in FIG. However, the ground conductor portion GND1 as the main ground can be shared by each antenna.

FIG. 9 is a diagram showing an example of the radiation pattern of the antennas ANT1 to ANT3 provided in the mobile terminal device of FIG.

FIG. 9 shows the arrangement of the antennas ANT1 to ANT3 taking the case where the mobile terminal device is a smartphone as an example. The longitudinal direction of the case 50 of the smartphone is the Y direction, the short direction is the X direction, and the thickness direction is the Z direction. A touch screen 51 is provided on the main surface of the casing 50, and operation keys 52 are provided below the touch screen 51 on the main surface. The touch screen 51 is formed by integrating a display and a touch panel. The operation key 52 functions as a home key for displaying a home screen, for example.

Antennas ANT1 to ANT3 are provided inside the housing 50. Specifically, the antenna ANT1 is provided in the vicinity of one end in the longitudinal direction (Y direction) of the housing 50 (that is, in the vicinity of the operation key 52). The antenna ANT3 is provided close to the other end in the longitudinal direction (Y direction) of the housing 50 (that is, on the opposite side of the operation key 52). The antenna ANT2 is provided close to one end of the casing 50 in the short direction (X direction).

FIG. 9 shows an example of a radiation pattern when each of the antennas ANT1 to ANT3 is used alone. In the case of the antenna ANT1, the radiation pattern 53A in the longitudinal direction (Y direction) of the housing 50 is controlled by controlling the radiation pattern switching unit 41 in FIG. 1 so that the image current flows in the short direction (X direction) of the housing 50. 53B is generated. Since the radiation pattern is generated perpendicular to the direction of the image current, the radiation pattern of the antenna ANT1 is also generated in the thickness direction (Z direction) of the housing 50. However, the radiation pattern in the short direction (X direction) of the casing 50 is not generated.

Similarly, in the case of the antenna ANT2, by controlling the radiation pattern switching unit 41 so that an image current flows in the longitudinal direction (Y direction) of the housing 50, the radiation pattern 54A in the short direction (X direction) of the housing 50 is obtained. 54B is generated (a radiation pattern is not generated in the longitudinal direction (Y direction) of the casing 50).

In the case of the antenna ANT3,

radiation patterns

55A and 55B in the longitudinal direction (Y direction) of the housing 50 are generated by controlling the radiation pattern switching unit 41 so that the image current flows in the short direction (X direction) of the housing 50. (A radiation pattern is not generated in the short direction (X direction) of the housing 50).

FIG. 10 is a diagram for explaining a radiation pattern when antennas ANT1 and ANT3 are simultaneously used in the antenna arrangement of FIG.

Referring to FIG. 10, when antennas ANT1 and ANT3 are used at the same time, when using a combination of bands in which interference waves are generated in one reception band, the isolation between antennas ANT1 and ANT3 is as large as possible. It is desirable to do. For this reason, the radiation pattern of the antennas ANT1 and ANT3 is changed from the case of FIG.

Specifically, in the case of the antenna ANT1, the radiation pattern 56A in the short direction (X direction) of the casing 50 is controlled by controlling the radiation pattern switching unit 41 so that the image current flows in the longitudinal direction (Y direction) of the casing 50. , 56B are generated. Also in the case of the antenna ANT3, the

radiation patterns

57A and 57B in the short direction (X direction) of the casing 50 are controlled by controlling the radiation pattern switching unit 41 so that the image current flows in the longitudinal direction (Y direction) of the casing 50. Is generated. In either case of the antennas ANT1 and ANT3, since a radiation pattern in the longitudinal direction (Y direction) of the housing 50, that is, in the direction of the other antenna is not generated, the isolation between the antennas ANT1 and ANT3 should be increased Can do.

[Control procedure at the start of communication]
Next, an antenna radiation pattern control procedure performed by the control unit 30 of FIG. 1 when communication is started by the mobile terminal device will be described. Hereinafter, a case where communication is performed using the LTE (registered trademark) band 4 and / or the band 17 will be described as a specific example.

FIG. 11 is a flowchart showing the control procedure of the antenna radiation pattern by the control unit 30 of FIG. Referring to FIGS. 1 and 11, when control unit 30 receives a processing request for starting communication from the user (YES in step S100), control unit 30 selects an antenna according to the communication method and band to be used (step S100). S110). In the case of the first embodiment, the antenna selection is uniquely determined according to the communication method and band to be used.

For example, the antenna ANT3 is selected when using LTE (registered trademark) band 4 (frequency band 1700/2100 MHz), and the antenna ANT1 is selected when using band 17 (frequency band 700). To do. The characteristics (for example, resonance frequency) of the antenna ANT3 and the antenna ANT1 are designed to be suitable for use in the band 4 and the band 17, respectively.

Next, the control unit 30 refers to the radiation pattern switching table 32 in FIG. 1 and selects the radiation pattern of the antenna selected in step S110 (steps S135 and S140). In this case, depending on whether or not a plurality of communication schemes or bands are used simultaneously (step S120), further, depending on whether or not an interference wave may occur in the reception band (step S125), The radiation pattern to be selected is different.

FIG. 12 is a diagram showing an example of a radiation pattern switching table. Referring to FIG. 12, when using LTE (registered trademark) band 4 alone (setting 1), as a radiation pattern of antenna ANT3, as shown in FIG. 9, the longitudinal direction (Y direction) of housing 50 is shown.

Radiation patterns

55A and 55B are selected. When the LTE (registered trademark) band 17 is used alone (setting 2), the

radiation pattern

53A, 53B in the longitudinal direction (Y direction) of the housing 50 is selected as the radiation pattern of the antenna ANT1, as shown in FIG. Is done.

When LTE (registered trademark) band 4 and band 17 are simultaneously used by carrier aggregation (setting 3), there is a possibility that an interference wave is generated in the reception band of band 4 as described in FIG. In this case, the control unit 30 selects the

radiation patterns

57A and 57B in the short direction (X direction) of the housing 50 as the radiation pattern of the antenna ANT3 for the band 4 as shown in FIG. As the radiation pattern of ANT1,

radiation patterns

56A and 56B in the short direction (X direction) of the casing 50 are selected. By selecting these radiation patterns, the isolation between the antennas ANT1 and ANT3 to be used can be further increased.

Referring to FIGS. 1 and 11 again, next, control unit 30 outputs a control signal to antenna switching device 40 and radiation pattern switching unit 41 so that the selected antenna and radiation pattern are obtained (step S150). Thereby, the antenna to be used and its radiation pattern are switched.

The above steps S110 to S150 are repeated until a communication end request is received from the user (that is, until YES in step S160).

[effect]
As described above, in the mobile terminal device according to the first embodiment, when communicating using a plurality of bands at the same time, harmonics of the transmission wave or intermodulation waves of the transmission wave become interference waves of the reception wave. A solution is shown when the reception sensitivity is significantly degraded. Specifically, in the case of a combination of bands in which reception characteristics can be deteriorated, the antenna radiation pattern is switched so that isolation between antennas to be used is as good as possible. As a result, it is possible to suppress deterioration in the quality of the received signal due to the interference wave.

Furthermore, the portable terminal device of the first embodiment has an advantage that the mounting area of the radio circuit can be reduced as compared with the conventional case. Specifically, in the conventional radio circuit, in order to suppress the influence of interference waves such as harmonics and intermodulation waves, for example, a notch filter is provided between each of the

duplexers

13 and 23 of FIG. In addition, a low-pass filter is provided, and an isolator is provided between each of the

duplexers

13 and 23 and the

corresponding power amplifiers

12 and 22. In the case of the mobile terminal device according to the present embodiment, it is not necessary to provide components such as the low-pass filter, the notch filter, and the isolator. For this reason, the mounting area of the wireless circuit can be reduced as compared with the conventional case, and the component cost can be further reduced.

<Embodiment 2>
In general, the isolation between antennas deteriorates as the distance between the antennas becomes shorter. For example, in the examples of FIGS. 9 and 10, the antenna ANT3 is provided at a position away from the antennas ANT1 and ANT2. For this reason, the isolation of the antenna ANT3 with respect to each of the antennas ANT1 and ANT2 is better than the isolation between the antennas ANT1 and ANT2.

When communicating using two bands, any two of the antennas ANT1 to ANT3 are selected according to the band to be used. Here, when two bands are used, the harmonic wave of the transmission wave of one band becomes an interference wave of the reception wave of the other band, or the intermodulation wave of the transmission wave of both bands is one or both. It should be noted that the received signal may be an interference wave of the received signal in the other band. Therefore, even if it is better to use the antennas ANT1 and ANT2 considering only the antenna characteristics, there are cases where it is better to use the antenna ANT3 instead of one of the antennas ANT1 and ANT2 when considering the interference wave.

In the mobile terminal device according to the second embodiment, it is used depending on whether or not a plurality of communication methods or bands are used at the same time, and further depending on whether or not an interference wave may be generated in the reception band. Both the antenna to be switched and its radiation pattern are switched. Hereinafter, a specific description will be given with reference to FIGS.

[Configuration and operation of portable terminal device]
FIG. 13 is a block diagram schematically showing the configuration of the mobile terminal device 101 according to the second embodiment. Referring to FIG. 13, mobile terminal apparatus 101 is different from mobile terminal apparatus 100 of FIG. 1 in that antenna / radiation pattern switching table 33 is stored in memory 31 instead of radiation pattern switching table 32. In the antenna / radiation pattern switching table 33, the antenna and the radiation pattern to be used are associated with the communication method and the band to be used. When using multiple antennas at the same time, if there is a possibility that interference will occur, use it compared to using a single antenna or if there is no possibility that interference will occur. Antenna combinations and radiation patterns are changed.

The CPU of the control unit 30 refers to the antenna / radiation pattern switching table 33 and outputs a control signal for selecting an antenna to be used and a radiation pattern to the antenna switching device 40 and the radiation pattern switching unit 41. In response to this control signal, the antenna switching device 40 switches the antenna to be used, and the radiation pattern switching unit 41 switches the radiation pattern of the antenna used.

The other points in FIG. 13 are the same as those in FIG. 1, and therefore, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

In the following description, it is assumed that the antenna ANT1 in FIG. 13 is designed to obtain optimum characteristics (characteristics with high radiation efficiency and small return loss) in the 700 and 800 MHz frequency bands. It is assumed that the antenna ANT2 is designed to obtain optimum characteristics in the frequency band of 1700/2100 MHz. It is assumed that the antenna ANT3 can be used in any frequency band of 700/800/1700/2100 MHz, that is, has a plurality of resonance frequencies and / or is designed in a wide band. However, for this reason, the characteristics of the antenna ANT3 in each frequency band are inferior to those of the antennas ANT1 and ANT2.

FIG. 14 is a flowchart showing the switching procedure of the antenna used and the radiation pattern by the control unit 30 of FIG. The flowchart of FIG. 14 differs from the flowchart of FIG. 11 in that step S110 is not provided and that steps S135A and 140A are provided instead of steps S135 and S140.

The control unit 30 refers to the antenna / radiation pattern switching table 33 in FIG. 13 and selects both the antenna used for communication and its radiation pattern (steps S135A and S140A). In this case, depending on whether or not a plurality of communication schemes or bands are used simultaneously (step S120), further, depending on whether or not an interference wave may occur in the reception band (step S125), Different antennas and radiation patterns are selected.

The other points in FIG. 14 are the same as those in FIG. 11, and the same or corresponding steps are denoted by the same reference numerals and description thereof will not be repeated. Hereinafter, a specific example of the antenna / radiation pattern switching table 33 will be described.

[Specific examples of antenna control]
FIG. 15 is a diagram illustrating a specific example of an antenna / radiation pattern switching table. In the example shown in FIG. 15, when the LTE (registered trademark) band 13 is used alone (setting 1), when the subclass 1 of the band class 0 of CDMA2000 (registered trademark) is used alone (setting 2), and The case where these are used simultaneously as SV-LTE (setting 3) is shown.

Specifically, when the LTE (registered trademark) band 13 is used alone (setting 1), the antenna ANT1 is selected as the antenna to be used for communication, and the radiation pattern of the antenna ANT1 is shown in FIG. The

radial patterns

53A and 53B in the longitudinal direction (Y direction) are selected. When subclass 1 of band class 0 of CDMA2000 (registered trademark) is used alone (setting 2), antenna ANT1 is selected as the antenna to be used for communication, and the enclosure as shown in FIG. 9 shows the radiation pattern of antenna ANT1. 50

radial patterns

53A and 53B in the longitudinal direction (Y direction) are selected.

When the LTE (registered trademark) band 13 and the CDMA2000 (registered trademark) band class 0 subclass 1 are simultaneously used by SV-LTE (setting 3), as described with reference to FIG. ) Band 13 and subclass 1 of CDMA2000 (registered trademark) band class 0 may cause interference waves. In this case, the control unit 30 selects the antenna ANT1 for the LTE (registered trademark) band 13 and selects the antenna ANT3 for the subclass 1 of the band class 0 of CDMA2000 (registered trademark). That is, in order to improve isolation, antennas that are as far as possible from each other are selected. Further, as shown in FIG. 10, the control unit 30 selects the

radiation patterns

56A and 56B in the short direction (X direction) of the housing 50 as the radiation pattern of the antenna ANT1, and the short of the housing 50 as the radiation pattern of the antenna ANT3.

Radiation patterns

57A and 57B in the direction (X direction) are selected. By selecting these radiation patterns, the isolation between the antennas ANT1 and ANT3 to be used can be further increased.

FIG. 16 is a diagram showing another specific example of the antenna / radiation pattern switching table. In the example shown in FIG. 16, when the LTE (registered trademark) band 4 is used alone (setting 1), the LTE (registered trademark) band 17 is used alone (setting 2), and these are simultaneously used as carrier aggregation. The case of setting (setting 3) is shown.

Specifically, when the band 4 of LTE (registered trademark) is used alone (setting 1), the antenna ANT2 is selected as the antenna used for communication, and the housing 50 is shown as the radiation pattern of the antenna ANT2 as shown in FIG. The

radiation patterns

54A and 54B in the short direction (X direction) are selected. When the LTE (registered trademark) band 17 is used alone (setting 2), the antenna ANT1 is selected as the antenna to be used for communication, and the radiation pattern of the antenna ANT1 is shown in FIG. (Y direction)

radiation patterns

53A and 53B are selected.

When LTE (registered trademark) band 4 and band 17 are used simultaneously as carrier aggregation (setting 3), as described with reference to FIG. Can be a disturbing wave. In this case, the control unit 30 selects the antenna ANT3 for the LTE (registered trademark) band 4 and selects the antenna ANT1 for the LTE (registered trademark) band 17. That is, in order to improve isolation, antennas that are as far as possible from each other are selected. Further, as shown in FIG. 10, the control unit 30 selects the

radiation patterns

Radiation patterns

[Effect of Embodiment 2]
As described above, in the mobile terminal device according to the second embodiment, when communicating using a plurality of bands simultaneously, harmonics of the transmission wave or intermodulation waves of the transmission wave become interference waves of the reception wave. Shows a solution when the reception sensitivity is significantly deteriorated. Specifically, in the case of a combination of bands that can deteriorate the reception characteristics, the antenna is selected so that the distance between the antennas to be used is as large as possible, and the antenna radiation pattern to be used is switched. As a result, the isolation between the plurality of antennas to be used becomes better, and as a result, it is possible to suppress the deterioration of the quality of the received signal due to the interference wave.

In the above description, the total number of antennas provided in the mobile terminal device 101 is three. However, by changing the setting contents of the antenna / radiation pattern switching table 33, the number of antennas is two or four or more. Also, the above technique can be easily applied.

<Embodiment 3>
FIG. 17 is a block diagram schematically showing a configuration of mobile terminal apparatus 102 according to the third embodiment. Referring to FIG. 17, mobile terminal apparatus 102 is different from mobile terminal apparatus 100 of FIG. 1 in that it further includes an interference detection circuit 90 that detects whether or not the received signal is actually deteriorated due to the presence of an interference wave. Different.

In the mobile terminal device 100 according to the first embodiment, when a plurality of bands are used at the same time in SV-LTE or carrier aggregation, a combination of bands that may cause an interference wave in the reception band is used. The antenna radiation pattern was changed to suppress the effect. However, even in a combination of bands in which interference waves occur, interference waves may not actually occur depending on the channel used.

Therefore, in the mobile terminal device 102 according to the third embodiment, the interference detection circuit 90 detects whether or not an interference wave actually exists. The CPU of the control unit 30 may generate a jamming wave if the jamming detection circuit 90 does not detect the occurrence of the jamming wave, even if the combination of bands may cause the jamming wave in the reception band. Control is made so that the antenna radiation pattern is not changed from the case where there is no characteristic.

Various methods have been proposed as a method for detecting whether or not an interfering wave exists. For example, in the technique described in Japanese Patent Application Laid-Open No. 05-335855 (Patent Document 2), it is determined whether or not there is intermodulation interference by examining the change in the output of the S meter when the attenuation of the received signal is changed. Is determined. In the technique described in Japanese Patent Laid-Open No. 06-232771 (Patent Document 3), in order to detect intermodulation interference, a received signal is amplitude-modulated with an auxiliary signal, and at this time, a side wave located outside the effective frequency range A band is generated and the amplitude of at least one sideband produced by amplitude modulation is compared with the amplitude of the received carrier in the intermediate frequency signal. The presence of intermodulation interference is detected depending on whether or not a deviation has occurred from the value of the ratio determined by the degree of modulation during amplitude modulation by the auxiliary signal.

Since the other points in FIG. 17 are the same as those in FIG. 1, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

FIG. 18 is a flowchart showing a procedure for switching the antenna radiation pattern by the control unit 30 of FIG. The flowchart of FIG. 18 differs from the flowchart of FIG. 11 in that step S130 is further included between step S125 and step S140.

Referring to FIGS. 17 and 18, the CPU of control unit 30 uses a plurality of communication methods or bands simultaneously (YES in step S120), and there is a possibility that an interference wave is generated in the reception band (step). In the case of YES in S125), the interference detection circuit 90 detects whether or not an interference wave actually exists. As a result, when the presence of the interference wave is not detected (NO in step S130), the CPU of the control unit 30 uses the antenna in the radiation pattern switching table 32 or the occurrence of the interference wave. Select the radiation pattern with reference to the case where there is no possibility. On the other hand, when the presence of an interference wave is detected (YES in step S130), the CPU selects a radiation pattern with reference to a case where an interference wave may be generated in the radiation pattern switching table 32. To do.

The interference detection circuit 90 can also be provided in the mobile terminal device 101 of the second embodiment. The CPU of the control unit 30 changes the antenna to be used and changes the antenna radiation pattern when the interference wave actually exists when simultaneously using a combination of bands that may cause the interference wave in the reception band. change.

<Embodiment 4>
[Overall configuration of portable terminal device]
FIG. 19 is a block diagram schematically showing a part of the configuration of the mobile terminal device according to the fourth embodiment. Referring to FIG. 19, the mobile terminal device is different from mobile terminal device 101 in FIG. 13 in that it further includes an antenna matching adjustment unit 70 connected between antennas ANT1-ANT3 and antenna switching device 40.

When the frequency characteristics of the antennas ANT1 to ANT3 are designed in a wide band, it is necessary to compensate for the frequency characteristics of the antenna used for communication according to the communication standard and / or band used for communication. The antenna matching adjustment unit 70 adjusts the matching state and frequency band of the antenna used for communication under the control of the control unit 30.

Specifically, in the case of FIG. 19, the antenna matching adjustment unit 70 includes

variable matching circuits

71, 72, and 73 corresponding to the antennas ANT1, ANT2, and ANT3, respectively. Each of the variable matching circuits 71 to 73 includes a variable capacitance element. By changing the capacitance value of the variable capacitance element, impedance matching of the corresponding antenna can be performed, and the resonance frequency of the corresponding antenna can be changed.

The CPU of the control unit 30 outputs antenna tuning information (that is, information regarding the set values of the variable capacitance elements of the variable matching circuits 71 to 73) to the antenna matching adjustment unit 70 according to the communication standard / band used for communication. . The antenna matching adjustment unit 70 changes the setting values of the variable capacitance elements of the variable matching circuits 71 to 73 according to the antenna tuning information received from the CPU.

The correspondence relationship between the frequency band (band) / communication standard of signals to be transmitted and received and the setting values of the variable capacitance elements of the variable matching circuits 71 to 73 is stored in the memory 31 as the antenna matching table 34. The control unit 30 determines the setting values (antenna tuning information) of the variable capacitance elements included in the variable matching circuits 71 to 73 by referring to the antenna matching table 34.

Since other points in FIG. 19 are the same as those in FIG. 1, the same reference numerals are given to the same or corresponding parts, and the description will not be repeated.

[Configuration example of variable matching circuit]
FIG. 20 is a circuit diagram showing an example of the variable matching circuits 71 to 73 in FIG. Referring to FIG. 20, each of variable matching circuits 71-73 includes inductor elements 84 and 45 and variable capacitance element 86. The inductance values of the inductor elements 84 and 45 are L1 (nH) and L2 (nH), respectively, and the capacitance value of the variable capacitance element 86 is C1 (pF).

In the example shown in FIG. 20, inductor element 84 is connected between input /

output nodes

82 and 83, inductor element 85 is connected between input / output node 82 and ground node GND, and variable capacitance element 86 is input / output. Connected between node 83 and ground node GND. One of the input /

output nodes

82 and 83 is connected to the antenna ANT. The other of the input /

output nodes

82 and 83 is connected to the antenna switching device 40, and is connected to the

duplexers

13 and 23 via the antenna switching device 40.

As the variable capacitance element 86, for example, a variable capacitance diode (also referred to as a varicap or a varactor) can be used. Alternatively, a variable capacitance element of a type that changes the capacitance value by switching the number of capacitors connected in parallel by a switch can be used. Alternatively, a variable capacitance element of a type that changes the distance between the electrodes of the capacitor using MEMS (Micro Electro Mechanical System) can be used.

Unlike the configuration of FIG. 20, the capacitive element may have a constant capacitance value and the inductance of the inductor element may be variable, or both the capacitance value of the capacitive element and the inductance of the inductor element may be variable. Also good.

[Example of antenna matching table]
FIG. 21 is a diagram showing an example of the antenna matching table 34 stored in the memory 31 of FIG. As shown in FIG. 21, the set value of the capacitance value C1 (pF) of the variable capacitance element 86 in FIG. 20 is determined according to the communication standard / band used in the antenna ANT. The inductance values L1 and L2 (nH) of the inductor elements 84 and 45 are fixed values.

[Specific example of antenna switching operation]
FIG. 22 is a flowchart showing the switching procedure of the antenna used and the radiation pattern by the control unit 30 of FIG. Referring to FIGS. 19 and 22, the flowchart of FIG. 22 differs from the flowchart of FIG. 14 in that it further includes step S145 executed after step S135A or S140A.

In the case of the fourth embodiment, when the antenna used for communication is selected in step S135A or S140A, the control unit 30 matches the antenna matching state used for communication according to the antenna matching table 34 stored in the memory 31. Is adjusted (step S145). Specifically, the control unit 30 outputs a control signal to the antenna matching adjustment unit 70, and the set value of the corresponding variable matching circuit is changed according to the control signal.

For example, when the LTE (registered trademark) band 13 and the CDMA2000 (registered trademark) band class 0 subclass 1 are simultaneously used by SV-LTE, the control unit 30 performs antenna / radiation pattern switching shown in FIG. According to the table, antenna ANT3 is selected for communication of CDMA2000 (registered trademark), and antenna ANT1 is selected for communication of band 13 of LTE (registered trademark). Furthermore, the control unit 30 sets the capacitance value C1 of the variable capacitance element of the variable matching circuit 73 corresponding to the antenna ANT3 to A3 (pF) according to the antenna matching table shown in FIG. 21, and the variable matching circuit corresponding to the antenna ANT1. The capacitance value C1 of the variable quantity element 71 is set to A2 (pF).

When LTE (R) band 4 and band 17 are used simultaneously by carrier aggregation, the control unit 30 selects the antenna ANT3 for communication of band 4 according to the antenna / radiation pattern switching table shown in FIG. The antenna ANT1 is selected for band 17 communication. Furthermore, the control unit 30 sets the capacitance value C1 of the variable capacitance element of the variable matching circuit 73 corresponding to the antenna ANT3 to A1 (pF) according to the antenna matching table 34 shown in FIG. 21, and the variable matching corresponding to the antenna ANT1. The capacitance value C1 of the variable element of the circuit 71 is set to A2 (pF).

[Summary and effect]
As described above, the mobile terminal device according to the fourth embodiment further includes the antenna matching adjustment unit 70 in addition to the configuration of the mobile terminal device 101 of the second embodiment. Therefore, the mobile terminal device can achieve the effects described in Embodiment 2 and improve the characteristics of each antenna. The antenna matching adjustment unit 70 described above can also be provided in the mobile terminal device 100 according to the first embodiment.

<Embodiment 5>
FIG. 23 is a block diagram schematically showing a configuration of the mobile terminal device 104 according to the fifth embodiment. The portable terminal device 104 in FIG. 23 is provided with

attenuators

14 and 24 between the

duplexers

13 and 23 and the corresponding power amplifiers (PA) 12 and 22, respectively. And different. Since the other points are the same as those of the mobile terminal device 101 of FIG. 13, the same or corresponding parts are denoted by the same reference numerals and the description thereof may not be repeated.

Referring to FIG. 23,

attenuators

14 and 24 use the standards to set the strengths of transmission signals Tx (1) and Tx (2) output from corresponding

power amplifiers

12 and 22 according to the control of CPU of control unit 30. Attenuate within the allowable lower limit. As a result, when two bands are used at the same time, even when a harmonic wave or intermodulation wave of the transmission wave can become an interference wave of the reception wave, the quality deterioration of the reception signal due to the interference wave can be further reduced. .

FIG. 24 is a flowchart showing the antenna switching operation by the control unit 30 of FIG. The flowchart of FIG. 24 differs from the flowchart of FIG. 14 in that step S155 is added after step S150. In step S155, as already described, the

attenuators

14 and 24 perform the intensity of the transmission signals Tx (1) and Tx (2) output from the

corresponding power amplifiers

12 and 22 according to the control of the CPU of the control unit 30. Is attenuated to the lower limit allowed by the standard. The

attenuators

14 and 24 can also be provided in the mobile terminal device 100 of the first embodiment shown in FIG.

The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. For example, the features of the third to fifth embodiments can be combined with each other, and the combined configuration is applied to both the form terminal apparatus 100 of the first embodiment and the form terminal apparatus 101 of the second embodiment. can do. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

10 signal generation unit, 11, 21 transceiver, 12, 22 power amplifier, 13, 23 duplexer, 14, 24 attenuator, 30 control unit, 31 memory, 32 radiation pattern switching table, 33 antenna / radiation pattern switching table, 34 antenna Matching table, 40 antenna switching device, 41 radiation pattern switching unit, 50 housing, 51 touch screen, 52 operation keys, 60 power feeding unit, 61, 62 choke coil, 63 control terminal, 70 antenna matching adjustment unit, 71-73 variable matching Circuit, 86 variable capacitance element, 90 interference detection circuit, 100, 101, 102, 104 mobile terminal device, ANT1 to ANT3 antenna.

Claims

Multiple antennas,
An antenna switching device capable of switching each of the plurality of antennas to a use state or a non-use state, and capable of switching a radiation pattern of each antenna in the use state;
When communication is performed using two or more frequency bands with two or more of the plurality of antennas being used, interference may occur if there is a possibility that interference waves may be generated depending on the combination of frequency bands used for communication. A portable terminal device comprising: a control unit that controls the antenna switching device so that a radiation pattern of an antenna in each use state differs from that in a case where there is no possibility of generation of waves.
In the case where there is a possibility that an interference wave is generated when communication is performed using two or more frequency bands, the control unit is a combination of antennas to be used in comparison with a case where there is no possibility that the interference wave is generated. The mobile terminal device according to claim 1, wherein the antenna switching device is controlled such that the antenna switching devices are different from each other.
The mobile terminal device detects whether or not an interference wave is generated in the reception band of each frequency band when there is a possibility that the interference wave is generated when communication is performed using two or more frequency bands. A detection circuit;
The control unit is configured so that when the occurrence of an interference wave is not detected by the interference detection circuit, the radiation pattern of the antenna in each use state is not different from the case where there is no possibility that the interference wave is generated. The portable terminal device according to claim 1, which controls an antenna switching device.
An antenna matching adjustment unit connected to the plurality of antennas and capable of changing a matching state of the plurality of antennas according to control of the control unit;
The control unit according to any one of claims 1 to 3, wherein the control unit adjusts a matching state of the antenna in use by the antenna matching adjustment unit according to a frequency band of a signal transmitted and received from the antenna in use. Mobile terminal device.
A signal generator for generating a transmission signal to be supplied to the antenna in use;
An attenuator that further attenuates the transmission signal generated by the signal generation unit within an allowable range according to the control of the control unit and supplies the attenuated transmission signal to the antenna in use. The mobile terminal device according to any one of the above.