CN219203496U

CN219203496U - Antenna device, antenna system, and communication terminal device

Info

Publication number: CN219203496U
Application number: CN202190000411.4U
Authority: CN
Inventors: 立花真也
Original assignee: Murata Manufacturing Co Ltd
Current assignee: Murata Manufacturing Co Ltd
Priority date: 2020-07-20
Filing date: 2021-04-28
Publication date: 2023-06-16
Anticipated expiration: 2031-04-28
Also published as: JPWO2022018925A1; WO2022018925A1; JP7176667B2

Abstract

The utility model provides an antenna device, an antenna system and a communication terminal device. The 1 st antenna device includes a1 st radiating element, a1 st connection portion of a power supply circuit, a matching circuit for performing impedance matching, and a1 st switching circuit for switching characteristics of the matching circuit. The matching circuit has: a1 st coil connected between the 1 st radiating element and the connection part of the 1 st power supply circuit; and a2 nd coil connected between the 1 st radiating element and the ground and performing magnetic field coupling with respect to the 1 st coil, the 1 st switching circuit having a1 st capacitor and a1 st switch. The 1 st switching circuit switches between a1 st state in which the 1 st capacitor is not connected to the 1 st coil and a2 nd state in which the 1 st capacitor is connected in parallel to the 1 st coil.

Description

Antenna device, antenna system, and communication terminal device

Technical Field

The present utility model relates to an antenna device having an impedance matching circuit, an antenna system having a plurality of antenna devices, and a communication terminal device having the antenna system.

Background

Patent document 1 discloses a transformer type matching circuit for matching the impedance of a power supply circuit and a radiation element. If such a transformer type matching circuit is used, impedance matching of the power supply circuit and the radiating element can be obtained across a wide band.

Prior art literature

Patent literature

Patent document 1: japanese patent No. 6048593

Disclosure of Invention

Problems to be solved by the utility model

Recently, a system with a wide bandwidth for the fifth generation mobile communication system is adopted for communication of the portable telephone terminal. Among them, a band of 3GHz to 6GHz band is also paid attention to, and an antenna device applied to the band is added to a terminal.

Meanwhile, the Wi-Fi antenna of the wireless LAN standard is also used in a wideband of the 5GHz band.

In addition, in a mobile phone terminal, there are increasing situations in which a number of antennas requiring antenna isolation are provided due to expansion of communication bandwidth, introduction of MIMO (multiple-input and multiple-output), and the like.

However, in a case where the 1 st antenna device and the 2 nd antenna device are adjacent to each other, when the 1 st antenna device is an antenna device including a transformer-type matching circuit as disclosed in patent document 1, energy is extracted from the 2 nd radiating element of the 2 nd antenna device by the 1 st radiating element of the 1 st antenna device due to the influence of the broadband matching characteristic caused by the matching circuit, and there is a problem that the 2 nd radiating element of the 2 nd antenna device cannot obtain sufficient radiation efficiency.

Fig. 22A and 22B are diagrams showing an example of a decrease in radiation efficiency of the radiation element caused by wasteful coupling of the 1 st antenna device and the 2 nd antenna device. In fig. 22A, characteristic EA1 shows the radiation efficiency of the 2 nd radiation element when the 1 st antenna device including the transformer type matching circuit is not present, and characteristic EA2 shows the radiation efficiency of the 2 nd radiation element in a state where the 1 st radiation element and the 2 nd radiation element are uselessly coupled. The broken line in the figure is the center frequency of the use band C of the 2 nd antenna device.

In fig. 22B, characteristic EB1 shows the radiation efficiency of the 3 rd radiation element when the 1 st antenna device is not present, and characteristic EB3 shows the radiation efficiency of the 3 rd radiation element in a state where the 3 rd radiation element is uselessly coupled with the 1 st radiation element. The broken line in the figure is the center frequency of the use band D of the 1 st antenna device.

In this way, in the case where two radiating elements are adjacent, the radiation efficiency of the radiating element is lowered due to interference thereof.

Accordingly, an object of the present utility model is to provide an antenna device capable of suppressing interference between adjacent radiating elements, an antenna system in which a decrease in radiation efficiency due to interference between adjacent radiating elements is suppressed, and a communication terminal device provided with the antenna system.

Technical scheme for solving problems

(A) An antenna device as an example of the present disclosure includes:

a1 st radiating element;

a matching circuit for impedance matching a1 st power supply circuit connected to the 1 st radiation element and the 1 st radiation element; and

a1 st switching circuit connected to the matching circuit and switching the matching circuit to a1 st state and a2 nd state,

the matching circuit has:

a1 st coil connected between the 1 st power supply circuit and the 1 st radiating element; and

a2 nd coil connected between the 1 st radiating element and the ground and magnetically coupled with respect to the 1 st coil,

the 2 nd state of the 1 st switching circuit has a larger capacitance in parallel of the 1 st coil than the 1 st state of the 1 st switching circuit.

(B) An antenna device as an example of the present disclosure includes:

a1 st radiating element;

a2 nd switching circuit connected to the matching circuit and switching the matching circuit to a 3 rd state and a 4 th state,

the matching circuit has:

the 4 th state of the 2 nd switching circuit is larger in capacitance between the 2 nd coil and the ground than the 3 rd state of the 2 nd switching circuit.

(C) An antenna system as an example of the present disclosure includes:

a1 st antenna device including a1 st radiating element for communicating signals in a1 st communication band; and

a2 nd antenna device including a2 nd radiating element for communicating signals of a2 nd communication band,

the 1 st antenna device includes:

the matching circuit has:

(D) An antenna system as an example of the present disclosure includes:

a 3 rd antenna device including a 3 rd radiating element for communicating signals of a 3 rd communication band,

the 1 st antenna device includes:

the matching circuit has:

(E) The communication terminal device as an example of the present disclosure includes the antenna system described in (C), a1 st power supply circuit, and a2 nd power supply circuit connected to a2 nd radiating element.

(F) The communication terminal device as an example of the present disclosure includes the antenna system described in (D), a1 st power supply circuit, and a 3 rd power supply circuit connected to a 3 rd radiating element.

Effects of the utility model

According to the present utility model, an antenna device capable of suppressing interference with an adjacent antenna device, an antenna system in which a decrease in radiation efficiency due to interference with antenna devices adjacent to each other is suppressed, and a communication terminal device including the antenna system can be obtained.

Drawings

Fig. 1A and 1B are circuit diagrams showing the configuration of an antenna system 501 according to embodiment 1.

Fig. 2A is a smith chart showing frequency characteristics of the reflection coefficient in the 1 st radiation element 11 direction as viewed from the connection portion P1 of the 1 st power supply circuit 10 in the 1 st state shown in fig. 1A. Fig. 2B is a smith chart showing frequency characteristics of the reflection coefficient in the direction of the matching circuit 12 viewed from the connection portion P0 of the 1 st radiation element 11 in the 2 nd state shown in fig. 1B.

Fig. 3 is a block diagram of a communication terminal apparatus 601 including the 1 st antenna apparatus 101 and the 2 nd antenna apparatus 201.

Fig. 4 is a diagram showing a relationship between the state of the 1 st antenna device 101 and the frequency bands used by the 1 st antenna device 101 and the 2 nd antenna device 201.

Fig. 5 is a circuit diagram showing the structure of another 1 st antenna device 101 according to embodiment 1.

Fig. 6 is a circuit diagram showing the structure of still another 1 st antenna device 101 according to embodiment 1.

Fig. 7 is a perspective view of matching circuit 12 according to embodiment 1.

Fig. 8 is an exploded top view of the matching circuit 12.

Fig. 9A and 9B are circuit diagrams of the matching circuit 12.

Fig. 10A and 10B are circuit diagrams showing the configuration of an antenna system 502 according to embodiment 2.

Fig. 11A is a smith chart showing frequency characteristics of the reflection coefficient in the 1 st radiation element 11 direction as viewed from the connection portion P1 of the 1 st power supply circuit 10 in the 3 rd state shown in fig. 10A. Fig. 11B is a smith chart showing frequency characteristics of the reflection coefficient in the direction of the matching circuit 12 viewed from the connection portion P0 of the 1 st radiation element 11 in the 4 th state shown in fig. 10B.

Fig. 12 is a diagram showing a relationship between the state of the 1 st antenna device 102 and the frequency bands used by the 1 st antenna device 102 and the 3 rd antenna device 302.

Fig. 13 is a circuit diagram showing the structure of another 1 st antenna device 102 according to embodiment 2.

Fig. 14 is a circuit diagram showing the structure of the 1 st antenna device 102 according to embodiment 2.

Fig. 15 is a circuit diagram showing the structure of an antenna system 503 according to embodiment 3.

Fig. 16 is a diagram showing a relationship between the state of the 1 st antenna device 103 and the frequency bands used by the 1 st antenna device 103 and the 4 th antenna device 403.

Fig. 17 is a circuit diagram of another 1 st antenna device 103 according to embodiment 3.

Fig. 18 is a circuit diagram of still another 1 st antenna device 103 according to embodiment 3.

Fig. 19 is a plan view of a communication terminal apparatus 601 according to embodiment 4.

Fig. 20 is a cross-sectional view at an X-X portion of the communication terminal apparatus 601 shown in fig. 19.

Fig. 21A and 21B are diagrams showing the structures of the 1 st radiation element 11 and the 2 nd radiation element 21 configured by a part of the housing 50.

Fig. 22A and 22B are diagrams showing an example of a decrease in radiation efficiency of the radiation element caused by useless coupling of the 1 st antenna device and the 2 nd antenna device.

Detailed Description

In the following, several specific examples are illustrated with reference to the drawings to illustrate various embodiments for carrying out the present utility model. In the drawings, the same reference numerals are given to the same parts. In view of the ease of explanation or understanding of the gist, the embodiments are shown as being divided into a plurality of embodiments for convenience of explanation, but partial substitutions or combinations of structures shown in different embodiments can be made. Description of matters common to embodiment 1 will be omitted after embodiment 2, and only the differences will be described. In particular, regarding the same operational effects based on the same structure, it will not be mentioned successively in each embodiment.

Embodiment 1

Fig. 1A and 1B are circuit diagrams showing the configuration of an antenna system 501 according to embodiment 1. The antenna system 501 includes the 1 st antenna device 101 and the 2 nd antenna device 201.

The 1 st antenna device 101 includes a connection portion P1 of the 1 st power supply circuit 10 for the 1 st radiation element 11, a matching circuit 12 for impedance matching the 1 st radiation element 11 and the 1 st power supply circuit 10, a1 st switching circuit 13 connected to the matching circuit 12 and switching characteristics of the matching circuit 12, and a control circuit for controlling the 1 st switching circuit 13. As for this control circuit, it will be shown later.

The 2 nd antenna device 201 includes a connection portion P2 of the 2 nd power supply circuit 20 with respect to the 2 nd radiating element 21, and a matching circuit 22 for impedance matching the 2 nd radiating element 21 and the 2 nd power supply circuit 20.

The 1 st antenna device 101 is, for example, an antenna device for cellular use, and the 2 nd antenna device 201 is, for example, an antenna device for wireless LAN using the 1.5GHz band. The communication band using the 1 st antenna device 101 and the communication band using the 2 nd antenna device 201 are different but adjacent.

The matching circuit 12 of the 1 st antenna device 101 includes a1 st coil L1 connected between the connection portion P1 of the 1 st power supply circuit 10 and the 1 st radiating element 11, and a2 nd coil L2 connected between the 1 st radiating element 11 and the ground and magnetically coupled to the 1 st coil L1. The 1 st coil L1 and the 2 nd coil L2 constitute an autotransformer circuit.

The 1 st switching circuit 13 has, for example, a1 st capacitor C1 and a1 st switch SW1. The off state of the 1 st switch SW1 corresponds to the 1 st state in which the 1 st capacitor C1 is not connected to the 1 st coil L1. Further, the on state of the 1 st switch SW1 corresponds to the 2 nd state in which the 1 st capacitor C1 is connected in parallel with the 1 st coil L1. That is, fig. 1A shows the "1 st state", and fig. 1B shows the "2 nd state". Further, it can be said that the 2 nd state of the 1 st switching circuit 13 is larger in capacitance connected in parallel with the 1 st coil L1 than the 1 st state of the 1 st switching circuit 13. Here, the 1 st switching circuit 13 has been shown as having the 1 st capacitor C1 and the 1 st switch SW1, but the present utility model is not limited to this, and a variable reactance element, a pin diode, or the like may be used.

Fig. 2A is a smith chart showing frequency characteristics of the reflection coefficient in the 1 st radiation element 11 direction as viewed from the connection portion P1 of the 1 st power supply circuit 10 in the 1 st state shown in fig. 1A. Fig. 2B is a smith chart showing frequency characteristics of the reflection coefficient in the direction of the matching circuit 12, as viewed from the connection portion P0 of the 1 st radiation element 11 in the 2 nd state shown in fig. 1B.

In the 1 st state, as shown in fig. 2A, the 1 st radiating element 11 matches 50Ω, which is the impedance of the 1 st power supply circuit 10, across a given frequency band centering on the frequency shown by a mark M01.

In the 2 nd state, as shown in fig. 2B, the impedance indicated by a reference symbol M02 is set at a frequency of 1.54 GHz. In this example, the impedance in the direction of the matching circuit 12 is 394.0-j63.8[ Ω ] as viewed from the connection portion P0 of the 1 st radiation element 11, and the real part thereof is 5 times or more the impedance (50Ω) of the 1 st power supply circuit 10. The frequency is the parallel resonance frequency of the 1 st coil L1 and the 1 st capacitor C1. That is, the impedance in the direction of the matching circuit 12 becomes substantially open when viewed from the connection portion P0 of the 1 st radiating element 11, and only the 2 nd coil L2 becomes visible when viewed from the connection portion P0 of the 1 st radiating element 11. In the present utility model, a state of 5 times or more of the impedance of the 1 st power supply circuit 10 is expressed as "substantially open circuit".

As described above, in the 2 nd state, the 1 st radiating element 11 of the 1 st antenna device 101 appears to be substantially open as viewed from the 2 nd radiating element 21 of the 2 nd antenna device 201, and therefore the 2 nd radiating element 21 of the 2 nd antenna device 201 is hardly interfered by the 1 st radiating element 11 of the 1 st antenna device 101.

Fig. 3 is a block diagram of a communication terminal apparatus 601 including the 1 st antenna apparatus 101 and the 2 nd antenna apparatus 201. The communication terminal apparatus 601 is, for example, a smart phone or a mobile phone terminal, and includes a1 st antenna apparatus 101, a2 nd antenna apparatus 201,

RF modules

71 and 72,

transmission circuits

61 and 62,

reception circuits

81 and 82, and a baseband circuit 70. The antenna device 101 includes the matching circuit 12 and the 1 st radiation element 11. The RF module 71 is a circuit for performing mutual communication between a transmission signal and a reception signal of a cellular signal. The transmission circuit 61 is a transmission circuit for cellular use, and the reception circuit 81 is a reception circuit for cellular use. The RF module 72 is a circuit for performing mutual communication between a transmission signal and a reception signal of a wireless LAN signal. The transmission circuit 62 is a transmission circuit for wireless LAN, and the reception circuit 82 is a reception circuit for wireless LAN.

In fig. 3, the baseband circuit 70 outputs a transmission signal to the

transmission circuits

61 and 62, and receives an electric signal from the

reception circuits

81 and 82. The baseband circuit 70 controls the 1 st antenna device 101 and the 2 nd antenna device 201. In particular, on/off control of the 1 st switch SW1 in the 1 st switching circuit 13 in the 1 st antenna device 101 is performed. That is, the 1 st switch SW1 is turned off in the case of cellular communication, and the 1 st switch SW1 is turned on in the case of wireless LAN communication. The "control circuit" is a part of the baseband circuit 70.

As shown in fig. 4, the frequency band in which the 1 st antenna device 101 communicates is the frequency band a, and the frequency band in which the 2 nd antenna device 201 communicates is the frequency band C. The height relationship of each frequency band is that the frequency band C is less than the frequency band A.

When communication is performed in the frequency band a using the 1 st antenna device 101, the 1 st switch SW1 is set to the 1 st state in which it is turned off. When communication is performed in the frequency band C using the 2 nd antenna device 201, the 1 st switch SW1 is set to the 2 nd state in which it is on. Thus, the 2 nd antenna device 201 is hardly interfered by the 1 st antenna device 101, and the radiation efficiency of the 2 nd radiation element 21 can be maintained high, so that communication of the wireless LAN using the frequency band C can be performed.

Fig. 5 is a circuit diagram showing the structure of another 1 st antenna device 101 according to embodiment 1. The 1 st antenna device 101 includes a connection portion P1 of the 1 st power supply circuit 10 for the 1 st radiation element 11, a matching circuit 12 for impedance matching the 1 st radiation element 11 and the 1 st power supply circuit 10, a1 st switching circuit 13 connected to the matching circuit 12 and switching characteristics of the matching circuit 12, and a control circuit for controlling the matching circuit 12. The 1 st switching circuit 13 has a structure different from that of the antenna device 101 shown in fig. 1A and 1B. The 1 st switching circuit 13 has a1 st capacitor C1 and a1 st switch SW1, but in the example shown in fig. 5, the 1 st capacitor C1 is constituted by the parasitic capacitance of the 1 st switch SW1.

In fig. 5, when the 1 st switch SW1 is in the off state, the 1 st capacitor C1 is connected between the two ends of the 1 st switch SW1, and when the 1 st switch SW1 is in the on state, the 1 st switching circuit 13 is in the on state, and the 1 st capacitor C1 does not appear.

As shown in fig. 5, the 1 st capacitor C1 may be constituted by a parasitic capacitance of the 1 st switch SW1. The 1 st capacitor C1 may be constituted by a parallel connection circuit of a capacitor as a physical element shown in fig. 1A and 1B and a parasitic capacitance shown in fig. 5. That is, the 1 st capacitor C1 may also include the parasitic capacitance of the 1 st switch SW1.

Fig. 6 is a circuit diagram showing the structure of still another 1 st antenna device 101 according to embodiment 1. The 1 st switching circuit 13 has a structure different from that of the antenna device 101 shown in fig. 1A and 1B. The 1 st switching circuit 13 includes a1 st capacitor C1 and a1 st switch SW1 connected in series with the 1 st capacitor C1, but in the example shown in fig. 6, the 1 st switch SW1 is provided on the connection portion P1 side of the 1 st power supply circuit 10, and the 1 st capacitor C1 is provided on the 1 st radiating element 11 side. As such, the connection order of the 1 st switch SW1 and the 1 st capacitor C1 may be arbitrary.

Next, the configuration of the matching circuit 12 is exemplified. Fig. 7 is a perspective view of matching circuit 12 according to embodiment 1. The matching circuit 12 is an element formed in a rectangular parallelepiped laminated body, which is a laminated body of base material layers S1 to S14 shown later, and includes a1 st input/output terminal T1, a2 nd input/output terminal T2, and a ground terminal GND. Terminal NC in fig. 1 is a blank terminal.

Fig. 8 is an exploded top view of the matching circuit 12. The matching circuit 12 includes a first 1 st coil L11, a second 1 st coil L21, a first 2 nd coil L12, and a second 2 nd coil L22.

The first 1 st coil L11 includes conductor patterns P11 and P12 formed on the substrate layers S2 and S3 and connected in series. The first 2 nd coil L12 includes conductor patterns P13, P14, P15, and P16 formed on the substrate layers S4, S5, S6, and S7 and connected in series. Similarly, the second 1 st coil L21 includes conductor patterns P21 and P22 formed on the base material layers S13 and S12 and connected in series. The second 2 nd coil L22 includes conductor patterns P23, P24, P25, P26 formed on the substrate layers S11, S10, S9, S8 and connected in series.

The 1 st coil L21 including the conductor patterns P21 and P22 has the same structure as the 1 st coil L11 including the conductor patterns P11 and P12. The structure of the 2 nd coil L22 including the conductor patterns P23, P24, P25, and P26 is the same as the structure of the 2 nd coil L12 including the conductor patterns P13, P14, P15, and P16.

The 1 st end E11 of the 1 st coil L11 is connected to the 1 st input/output terminal T1, and the 2 nd end E12 is connected to the 2 nd input/output terminal T2. The 3 rd end E13 of the 2 nd coil L12 is connected to the ground terminal GND, and the 4 th end E14 of the 2 nd coil L12 is connected to the 2 nd input/output terminal T2. Similarly, the 1 st end E21 of the 1 st coil L21 is connected to the 1 st input/output terminal T1, and the 2 nd end E22 is connected to the 2 nd input/output terminal T2. The 3 rd end E23 of the 2 nd coil L22 is connected to the ground terminal GND, and the 4 th end E24 of the 2 nd coil L22 is connected to the 2 nd input/output terminal T2. The broken line in fig. 8 shows the connection relationship using the interlayer connection conductor.

Fig. 9A and 9B are circuit diagrams of the matching circuit 12. Fig. 9B is an equivalent circuit diagram of the matching circuit 12. As shown in fig. 9A, the first 1 st coil L11 and the second 1 st coil L21 are connected in parallel, and the first 2 nd coil L12 and the second 2 nd coil L22 are connected in parallel. Accordingly, the matching circuit 12 can be represented as in fig. 9B. As described above, the matching circuit 12 is constituted by an autotransformer circuit including the 1 st coil L1 and the 2 nd coil L2. The self-inductance of the 1 st coil L1 is the self-inductance of the 1 st coils L11 and L21, and the self-inductance of the 2 nd coil L2 is the self-inductance of the 2 nd coils L12 and L22.

Embodiment 2

In embodiment 2, an antenna device including a2 nd switch and a2 nd capacitor is shown.

Fig. 10A and 10B are circuit diagrams showing the configuration of an antenna system 502 according to embodiment 2. The antenna system 502 includes the 1 st antenna device 102 and the 3 rd antenna device 302.

The 1 st antenna device 102 includes a connection portion P1 of the 1 st power supply circuit 10 for the 1 st radiation element 11, a matching circuit 12 for impedance matching the 1 st radiation element 11 and the 1 st power supply circuit 10, a2 nd switching circuit 14 connected to the matching circuit 12 and switching characteristics of the matching circuit 12, and a control circuit for controlling the 2 nd switching circuit 14.

The 3 rd antenna device 302 includes a connection portion P3 of the 3 rd power supply circuit 30 for the 3 rd radiating element 31 and a matching circuit 32 for impedance matching the 3 rd radiating element 31 and the 3 rd power supply circuit 30.

The 1 st antenna device 102 is, for example, an antenna device for a cellular phone, and the 3 rd antenna device 302 is, for example, an antenna device for a cellular phone using a 4GHz band. The communication band using the 1 st antenna device 102 and the communication band using the 3 rd antenna device 302 are different but adjacent.

The matching circuit 12 of the 1 st antenna device 102 includes a1 st coil L1 connected between the connection portion P1 of the 1 st power supply circuit 10 and the 1 st radiating element 11, and a2 nd coil L2 connected between the 1 st radiating element 11 and the ground and magnetically coupled to the 1 st coil L1. The 1 st coil L1 and the 2 nd coil L2 constitute an autotransformer circuit.

The 2 nd switching circuit 14 has, for example, a2 nd capacitor C2 and a2 nd switch SW2 selectively connected to the 2 nd capacitor C2. The 2 nd switch SW2 switches between a state (3 rd state) in which the 2 nd coil L2 is connected to the ground without the 2 nd capacitor C2 and a state (4 th state) in which the 2 nd coil L2 is connected to the ground with the 2 nd capacitor C2. Further, it can be said that the 4 th state of the 2 nd switching circuit 14 is larger in capacitance between the 2 nd coil L2 and the ground than the 3 rd state of the 2 nd switching circuit 14. Here, the example in which the 2 nd switching circuit 14 has the 2 nd capacitor C2 and the 2 nd switch SW2 is shown, but the present utility model is not limited to this, and a variable reactance element, a pin diode, or the like may be used.

As shown in fig. 10A, the state in which the 2 nd switch SW2 selects the ground corresponds to the "3 rd state", and as shown in fig. 10B, the state in which the 2 nd switch SW2 selects the 2 nd capacitor C2 corresponds to the "4 th state".

Fig. 11A is a smith chart showing frequency characteristics of the reflection coefficient in the 1 st radiation element 11 direction as viewed from the connection portion P1 of the 1 st power supply circuit 10 in the 3 rd state shown in fig. 10A. Fig. 11B is a smith chart showing frequency characteristics of the reflection coefficient in the direction of the matching circuit 12, as viewed from the connection portion P0 of the 1 st radiation element 11 in the 4 th state shown in fig. 10B.

In the 3 rd state, as shown in fig. 11A, the 1 st radiating element 11 matches 50Ω, which is the impedance of the 1 st power supply circuit 10, across a given frequency band centering on the frequency shown by a mark M03.

In the 4 th state, as shown in fig. 11B, the impedance indicated by a symbol M04 is set at a frequency of 4.06 GHz. In this example, the impedance in the direction of the matching circuit 12 is 3.99 to j51.8[ Ω ] as viewed from the connection portion P0 of the 1 st radiation element 11, and the real part thereof is 1/5 times or less the impedance (50Ω) of the 1 st power supply circuit 10. The frequency is the series resonance frequency of the 2 nd coil L2 and the 2 nd capacitor C2. That is, the impedance in the direction of the matching circuit 12 becomes a substantial short circuit when viewed from the connection portion P0 of the 1 st radiation element 11. In the present utility model, a state of 1/5 times or less of the impedance of the 1 st power supply circuit 10 is expressed as "substantially short-circuited".

As described above, in the 4 th state, the 1 st radiating element 11 of the 1 st antenna device 102 appears to be substantially short-circuited as viewed from the 3 rd radiating element 31 of the 3 rd antenna device 302, and therefore the 3 rd radiating element 31 of the 3 rd antenna device 302 is hardly interfered by the 1 st radiating element 11 of the 1 st antenna device 102.

As shown in fig. 12, the frequency band in which the 1 st antenna device 102 performs communication is the frequency band B, and the frequency band in which the 3 rd antenna device 302 performs communication is the frequency band D. The height relationship of each frequency band is that the frequency band B < the frequency band D.

When communication is performed in the frequency band B using the 1 st antenna device 102, the 3 rd state is set in which the 2 nd switch SW2 is selectively grounded. When communication is performed in the frequency band D using the 3 rd antenna device 302, the 4 th state of the 2 nd capacitor C2 is selected by the 2 nd switch SW2. Thus, the 3 rd antenna device 302 is hardly interfered by the 1 st antenna device 102, and the radiation efficiency of the 3 rd radiation element 31 can be maintained high, so that communication using the frequency band D can be performed.

Fig. 13 is a circuit diagram showing the structure of another 1 st antenna device 102 according to embodiment 2. The 1 st antenna device 102 includes a connection portion P1 of the 1 st power supply circuit 10 for the 1 st radiation element 11, a matching circuit 12 for impedance matching the 1 st radiation element 11 and the 1 st power supply circuit 10, a2 nd switching circuit 14 connected to the matching circuit 12 and switching characteristics of the matching circuit 12, and a control circuit for controlling the matching circuit 12. The configuration of the 2 nd switching circuit 14 is different from the antenna device 102 shown in fig. 10A and 10B. The 2 nd switching circuit 14 has a2 nd capacitor C2 and a2 nd switch SW2, but in the example shown in fig. 13, the 2 nd capacitor C2 is constituted by the parasitic capacitance of the 2 nd switch SW2.

In fig. 13, when the 2 nd switch SW2 is in the off state, the 2 nd coil L2 is connected to the ground via the 2 nd capacitor C2 configured by the parasitic capacitance of the 2 nd switch SW2, and when the 2 nd switch SW2 is in the on state, the 2 nd coil L2 is directly connected to the ground, and the 2 nd capacitor C2 does not appear.

As shown in fig. 13, the 2 nd capacitor C2 may be constituted by a parasitic capacitance of the 2 nd switch SW2. The 2 nd capacitor C2 may be constituted by a parallel connection circuit of a capacitor as a physical element shown in fig. 10A and 10B and a parasitic capacitance shown in fig. 13. That is, the 2 nd capacitor C2 may also include the parasitic capacitance of the 2 nd switch SW2.

Fig. 14 is a circuit diagram showing the structure of the 1 st antenna device 102 according to embodiment 2. The configuration of the 2 nd switching circuit 14 is different from the antenna device 102 shown in fig. 10A and 10B. The 2 nd switching circuit 14 has a2 nd capacitor C2 and a2 nd switch SW2, but in the example shown in fig. 14, the 2 nd switch SW2 is provided on the ground side. As such, the connection order of the 2 nd switch SW2 and the 2 nd capacitor C2 may be arbitrary.

Embodiment 3

In embodiment 3, an antenna device including a1 st switch, a1 st capacitor, a2 nd switch, and a2 nd capacitor is shown.

Fig. 15 is a circuit diagram showing the structure of an antenna system 503 according to embodiment 3. The antenna system 503 includes a1 st antenna device 103 and a 4 th antenna device 403. In the present embodiment, the 4 th antenna device 403 includes the structures of the "2 nd antenna device" and the "3 rd antenna device" according to the present utility model.

The 1 st antenna device 103 includes a connection portion P1 of the 1 st power supply circuit 10 for the 1 st radiating element 11, a matching circuit 12 for impedance matching the 1 st radiating element 11 and the 1 st power supply circuit 10, a1 st switching circuit 13 and a2 nd switching circuit 14 connected to the matching circuit 12 and switching characteristics of the matching circuit 12, and a control circuit for controlling the 1 st switching circuit 13 and the 2 nd switching circuit 14.

The 4 th antenna device 403 includes a connection portion P4 of the 4 th power supply circuit 40 with respect to the 4 th radiating element 41, and a matching circuit 42 for impedance matching the 4 th radiating element 41 and the 4 th power supply circuit 40.

The 1 st antenna device 103 is, for example, an antenna device for cellular use, and the 4 th antenna device 403 is, for example, an antenna device for wireless LAN. The communication band using the 1 st antenna device 103 and the communication band using the 4 th antenna device 403 are different but adjacent.

The 1 st switching circuit 13 is structured as shown in embodiment 1. Further, the structure of the 2 nd switching circuit 14 is as shown in embodiment 2. Other structures are shown in embodiment 1 and embodiment 2.

The 1 st antenna device 103 can obtain 4 states by a combination of the state of the 1 st switch SW1 and the state of the 2 nd switch SW2.

As shown in fig. 16, the frequency band in which the 1 st antenna device 103 is used for communication is the frequency band a or the frequency band B, and the frequency band in which the 4 th antenna device 403 is used for communication is the frequency band C or the frequency band D. The height relationship of each frequency band is that the frequency band C is less than the frequency band A is less than the frequency band D is less than the frequency band B.

The parallel resonance frequency of the 1 st coil L1 and the 1 st capacitor C1 is within the frequency band C, and the series resonance frequency of the 2 nd coil L2 and the 2 nd capacitor C2 is within the frequency band D.

When the 1 st antenna device 103 is used to perform communication in the frequency band a or the frequency band B, the 1 st switch SW1 is set to the 1 st state of being turned off, and the 2 nd switch SW2 is set to the 3 rd state of being selectively grounded. When communication is performed in the frequency band C using the 4 th antenna device 403, the 1 st switch SW1 is set to the 2 nd state in which it is on. Thus, the 4 th antenna device 403 is hardly interfered by the 1 st antenna device 103, and the radiation efficiency of the 4 th radiation element 41 can be maintained high, so that communication of the wireless LAN using the frequency band C can be performed. When communication is performed in the frequency band D using the 4 th antenna device 403, the 4 th state of the 2 nd capacitor C2 is selected for the 2 nd switch SW2. Thus, the 4 th antenna device 403 is hardly interfered by the 1 st antenna device 103, and the radiation efficiency of the 4 th radiation element 41 can be maintained high, so that communication of the wireless LAN using the frequency band D can be performed.

When the 1 st switch SW1 is in the on 2 nd state, the 2 nd switch SW2 may be in the 4 th state where the 2 nd capacitor C2 is selected, and when the 2 nd switch SW2 is in the 4 th state where the 2 nd capacitor C2 is selected, the 1 st switch SW1 may be turned on to be in the 2 nd state.

Fig. 17 is a circuit diagram of another 1 st antenna device 103 according to embodiment 3. In this example, a matching circuit 15 is provided between the connection portion P1 of the 1 st power supply circuit 10 and the matching circuit 12. Further, a matching circuit 16 is provided between the connection portion P0 of the 1 st radiation element 11 and the matching circuit 12. The configuration of the matching circuit 12, the 1 st switching circuit 13, and the 2 nd switching circuit 14 is as described so far.

In this way, the matching

circuits

15 and 16 may be provided in addition to the transformer type matching circuit 12.

Fig. 18 is a circuit diagram of still another 1 st antenna device 103 according to embodiment 3. In this example, additional circuits are provided in the 1 st switching circuit 13 and the 2 nd switching circuit 14. A switching circuit 13 including a1 st capacitor C1, an inductor L3, and a1 st switch SW1 is connected between the 1 st input/output terminal T1 and the 2 nd input/output terminal T2 of the matching circuit 12. A circuit including a2 nd switch SW2, a2 nd capacitor C2, and an inductor L4 is connected between the ground terminal GND of the matching circuit 12 and ground. Accordingly, various frequency dependencies can be imparted to the matching characteristics of the matching circuit 12 by selection of the 1 st switch SW1 or the 2 nd switch SW2.

Embodiment 4

In embodiment 4, a configuration example of a communication terminal device is illustrated.

Fig. 19 is a plan view of a communication terminal apparatus 601 according to embodiment 4. In this case, the upper half of the case 600 is detached. The communication terminal apparatus 601 includes a circuit board 60 and a case 600 containing the circuit board 60 therein. The case 600 has a conductive frame 50. The antenna device 101 includes a part of the housing 50 and a part of the circuit board 60. The circuit board 60 constitutes a power supply circuit shown later.

Fig. 20 is a cross-sectional view at an X-X portion of the communication terminal apparatus 601 shown in fig. 19. A ground conductor 60G is formed on the upper surface of the circuit board 60. The ground conductor 60G is electrically connected to the conductor portion of the case 600. The circuit board 60 is a multilayer board, but illustration of the internal layers is omitted in fig. 20.

Fig. 21A and 21B are diagrams showing the structures of the 1 st radiation element 11 and the 2 nd radiation element 21 configured by a part of the housing 50. In the example shown in fig. 21A, the 1 st radiating element 11 constitutes a loop antenna, and the 2 nd radiating element 21 constitutes a T-branched antenna. The 1 st radiation element 11 and the ground conductor 60G of the circuit board 60 together form a loop. The ground conductor 60G of the circuit board 60 adjacent to the 2 nd radiating element 21 functions as a mirror image forming conductor.

In the example shown in fig. 21B, the 1 st radiating element 11 constitutes an inverted-F antenna, and the 2 nd radiating element 21 constitutes an inverted-L antenna. The ground conductor 60G of the circuit board 60 adjacent to the 1 st radiation element 11 functions as a mirror image forming conductor. Similarly, the ground conductor 60G of the circuit board 60 adjacent to the 2 nd radiating element 21 functions as a mirror image forming conductor.

According to the present embodiment, an antenna system in which interference between the 1 st antenna device having the 1 st radiating element 11 and the 2 nd antenna device having the 2 nd radiating element 21 is suppressed, and a communication terminal device including the antenna system can be obtained.

Finally, the present utility model is not limited to the above-described embodiments. Modifications and variations can be made as appropriate by those skilled in the art. The scope of the utility model is not shown by the embodiments described above but by the claims. Further, the scope of the present utility model includes modifications and variations from the embodiments within the scope equivalent to the claims.

For example, in the embodiment shown above, the 1 st antenna device 101 is used for cellular communication and the 2 nd antenna device 201 is used for wireless LAN, but the present utility model can also be applied to a case where the 1 st antenna device and the 2 nd antenna device other than the 1 st antenna device are used for the same communication system (for example, cellular communication).

In the above-described embodiment, the loop antenna, the T-branch antenna, the inverted L antenna, the inverted F antenna, and the like are exemplified as examples of the 1 st radiation element 11 or the 2 nd radiation element 21, but monopole antennas, dipole antennas, and the like can be used in addition to these.

In the above-described embodiment, the 1 st antenna device 101 and the like have been shown as having a lower impedance than the 1 st power supply circuit 10, but the present utility model can be applied even if the relationship between the impedance and the impedance is reversed.

Description of the reference numerals

C1: a1 st capacitor;

c2: a2 nd capacitor;

e11: end 1;

e12: end 2;

e13: end 3;

e14: a 4 th end;

e21: end 1;

e22: end 2;

e23: end 3;

e24: a 4 th end;

GND: a ground terminal;

l1, L11, L21: a1 st coil;

l2, L12, L22: a2 nd coil;

l3, L4: an inductor;

NC: an empty terminal;

p0: a connection portion of the 1 st radiation element 11;

p1: a1 st connection part of the power supply circuit;

p2: a connection part of the 2 nd power supply circuit 20;

p3: a 3 rd power supply circuit 30;

p4: a connection portion of the 4 th power supply circuit 40;

p11, P12, P13, P14, P15, P16: a conductor pattern;

p21, P22, P23, P24, P25, P26: a conductor pattern;

S1-S14: a substrate layer;

SW1: a1 st switch;

SW2: a2 nd switch;

t1: 1 st input/output terminal;

t2: a2 nd input/output terminal;

10: a1 st power supply circuit;

11: a1 st radiating element;

12: a matching circuit;

13: a1 st switching circuit;

14: a2 nd switching circuit;

15. 16: a matching circuit;

20: a2 nd power supply circuit;

21: a2 nd radiation element;

22: a matching circuit;

30: a 3 rd power supply circuit;

31: a 3 rd radiating element;

32: a matching circuit;

40: a 4 th power supply circuit;

41: a 4 th radiating element;

42: a matching circuit;

50: a frame;

60: a circuit substrate;

60G: a ground conductor;

61. 62: a transmitting circuit;

70: a baseband circuit;

71. 72: an RF module;

81. 82: a receiving circuit;

101-103: 1 st antenna device;

201: a2 nd antenna device;

302: 3 rd antenna device;

403: a 4 th antenna device;

501 to 503: an antenna system;

600: a housing;

601: a communication terminal device.

Claims

1. An antenna device, characterized by comprising:

a1 st radiating element;

the matching circuit has:

2. The antenna device according to claim 1, wherein,

the 1 st switching circuit has a1 st capacitor and a1 st switch, the 1 st state is the 1 st state in which the 1 st capacitor is not connected in parallel with the 1 st coil, and the 2 nd state is the 1 st state in which the 1 st capacitor is connected in parallel with the 1 st coil.

3. An antenna arrangement according to claim 2, characterized in that,

the 1 st capacitor includes a parasitic capacitance of the 1 st switch.

4. An antenna device according to any one of claims 1-3, characterized in that,

the device is provided with: a2 nd switching circuit connected to the matching circuit and switching the matching circuit to a 3 rd state and a 4 th state,

5. An antenna device, characterized by comprising:

a1 st radiating element;

the matching circuit has:

6. The antenna device according to claim 5, wherein,

the 2 nd switching circuit has a2 nd capacitor and a2 nd switch selectively connected to the 2 nd capacitor, the 2 nd coil is not connected to the ground via the 2 nd capacitor and is in the 3 rd state, and the 2 nd coil is connected to the ground via the 2 nd capacitor and is in the 4 th state.

7. The antenna device according to claim 6, wherein,

the 2 nd capacitor includes a parasitic capacitance of the 2 nd switch.

8. An antenna system, comprising:

the 1 st antenna device includes:

the matching circuit has:

9. The antenna system according to claim 8, comprising:

a 3 rd antenna device including a 3 rd radiating element for communicating signals in a 3 rd communication band; and

10. An antenna system according to claim 8 or 9, characterized in that,

the 1 st switching circuit has a1 st capacitor and a1 st switch, the 1 st capacitor is not connected in parallel with the 1 st coil in the 1 st state, the 1 st capacitor is connected in parallel with the 1 st coil in the 2 nd state,

the parallel resonant frequency of the 1 st coil and the 1 st capacitor is in the 2 nd communication band.

11. An antenna system according to claim 8 or 9, characterized in that,

in the 2 nd communication band, when the 1 st switching circuit is in the 1 st state, the impedance of the matching circuit as viewed from the connection portion of the 1 st radiating element is substantially open.

12. The antenna system of claim 9, wherein the antenna system comprises a plurality of antenna elements,

when the 2 nd switching circuit is in the 4 th state, a series resonance frequency of the capacitor between the 2 nd coil and the ground and the 2 nd coil is in the 3 rd communication band.

13. The antenna system of claim 9, wherein the antenna system comprises a plurality of antenna elements,

in the 3 rd communication band, when the 2 nd switching circuit is in the 4 th state, the impedance of the matching circuit as viewed from the connection portion of the 1 st radiating element is substantially short-circuited.

14. An antenna system, comprising:

the 1 st antenna device includes:

the matching circuit has:

15. The antenna system of claim 14, wherein the antenna system comprises a plurality of antenna elements,

16. The antenna system of claim 14, wherein the antenna system comprises a plurality of antenna elements,

17. A communication terminal device, comprising:

the antenna system of claim 8;

the 1 st power supply circuit of claim 8; and

a2 nd feeding circuit connected to the 2 nd radiating element included in the 2 nd antenna device in the antenna system according to claim 8.

18. A communication terminal device, comprising:

the antenna system of claim 14;

the 1 st power supply circuit of claim 14; and

a 3 rd power supply circuit connected to a 3 rd radiating element comprised by a 3 rd antenna device in the antenna system according to claim 14.