CN203674401U - Antenna device and communication terminal device - Google Patents

Abstract

The object of the utility model is to provide an antenna device and a communication terminal device. The antenna device comprises a printed wiring board (71), the printed wiring board (71) comprises a grounding conductor (111) arranged on the surface layer or the inner layer of an insulating base material and a power supply coil (112), the power supply coil (112) is formed on the surface layer or the inner layer of a printed wiring substrate in a coil-shaped pattern manner, one portion of the grounding conductor (111) comprises an annular coupling portion, the annular coupling portion comprises a first end part and a second end part, and the power supply coil (112) is coupled to the annular coupling portion of the grounding conductor (111) via an electromagnetic field. In this way, the small-scale antenna device advantaged by stable communication characteristic and capable of being stored in a limited space and the communication terminal device comprising the small-scale antenna device are provided.

Description

Antenna device and communication terminal device

technical field

The utility model relates to an antenna device and a communication terminal device used in HF frequency band and UHF frequency band communication systems.

Background technique

RFID (Radio Frequency Identification: Radio Frequency Identification) systems are spreading as systems for managing expenses and items. In the RFID system, the reader-writer and the RFID tag communicate wirelessly in a non-contact manner, and high-frequency signals are sent and received between the above-mentioned devices. The reader/writer and the RFID tag respectively include: a wireless IC chip for processing high-frequency signals; and an antenna element for transmitting and receiving high-frequency signals. As an antenna element, for example, in an HF band RFID system using a 13.56 MHz band, a coil-shaped antenna is used, and the antenna coil on the reader/writer side and the antenna coil on the tag side are coupled by an induced magnetic field.

In this HF band RFID system, an antenna coil is built into a portable communication terminal, such as the FeliCa (registered trademark) compatible terminal disclosed in Patent Document 1, and the communication terminal itself is used as a reader/writer or an RFID tag. FIG. 6 is a vertical cross-sectional view showing a non-contact IC card reader/writer 1 described in Patent Document 1. As shown in FIG.

Non-contact IC card reader 1 comprises: the antenna substrate that is provided with loop antenna, capacitor on the upper surface; The control substrate 6 that is provided with sending and receiving circuit, chip type coil 5 on the upper surface; The magnetic sheet 10 between the substrates 6 ; and the insulating case 15 . In order to form the opening 11 above the chip coil 5 provided on the control board 6 , the magnetic sheet 10 is arranged so as to avoid above the chip coil 5 . The chip-type coil (feeding coil) 5 is coupled to the loop antenna of the antenna substrate 4 by an induced magnetic field as indicated by the magnetic flux φ1 . The antenna substrate 4 is magnetically coupled to the IC card 20 as indicated by the magnetic flux φ2. By adopting this structure, it is possible to substantially connect the IC chip for RFID and the antenna coil without using pins or flexible cables.

Existing patent documents

patent documents

Patent Document 1: Japanese Patent No. 4325621

Utility model content

Technical problems to be solved by the utility model

However, in the above structure, since the chip coil and the loop antenna are provided on different substrates, if the distance between the two changes, the strength of the magnetic field coupling will also change accordingly. As a result, It will cause deviation in the communication characteristics. In addition, since a space for arranging the patch coil and the loop antenna is required, there may be a problem that a sufficient space cannot be secured in the terminal case.

The object of the present invention is to provide a small antenna device and a communication terminal device having the small antenna device. The above small antenna device can obtain stable communication characteristics and can be accommodated in a limited space.

Technical solutions adopted to solve technical problems

(1) The antenna device of the present invention is characterized in that it includes:

A printed wiring board having an insulating base material as a body and having a ground conductor provided on a surface layer or an inner layer of the insulating base material; and

a power supply coil formed in a coil-like pattern on the surface or inner layer of the printed wiring board,

A portion of the ground conductor has a ring-shaped coupling portion therein, the ring-shaped coupling portion having a first end and a second end,

The feeding coil is coupled to the annular coupling portion of the ground conductor through an electromagnetic field.

According to this structure, since the ground conductor of the printed wiring board is used as the emitter for transmitting and receiving wireless signals, and the feeding coil is arranged on the printed wiring board, there is no large distance between the feeding coil and the emitter. Deviation, the deviation of electromagnetic field coupling between the power supply coil and the launch board will also be reduced.

(2) Preferably, a capacitive element is provided between the first end portion and the second end portion. With this structure, a resonant circuit is formed with the inductance component of the ring-shaped coupling part of the ground conductor and the capacitance component of the chip capacitor, and the ring-shaped coupling part functions as a resonator, and the resonant frequency is made close to the frequency band used (e.g. HF band), which can improve efficiency and increase the maximum read distance.

(3) Preferably, the ring-shaped coupling portion is formed by a slit provided in the ground conductor. With this configuration, it is not necessary to separately provide a ring-shaped coupling portion with a special conductor pattern, and miniaturization can be easily achieved.

(4) Preferably, the coil opening of the power supply coil overlaps with the opening of the annular coupling portion. With this structure, the degree of coupling between the power supply circuit and the ground conductor, and the degree of coupling between the power supply coil and the annular coupling portion can be increased.

(5) It is preferable that the power supply coil is a laminated coil formed by laminating a plurality of annular patterns, and the first end face and the second end face of the laminated coil are located on the first main surface side and the second end face of the ground conductor. main side. With this configuration, the planar size of the feed coil can be reduced, and the necessary degree of electromagnetic field coupling between the feed coil and the ring-shaped coupling portion can be maintained.

(6) The communication terminal device of the present invention is characterized in that it includes:

A printed wiring board, which uses an insulating base material as a body, and has a ground conductor provided on the surface or inner layer of the insulating base material;

a power supply coil formed in a coil-like pattern on the surface or inner layer of the printed wiring board;

a power supply element mounted on the printed wiring board and connected to the power supply coil; and

a housing in which the printed wiring board is housed,

A portion of the ground conductor has a ring-shaped coupling portion therein, the ring-shaped coupling portion having a first end and a second end,

The feeding coil is coupled to the annular coupling portion of the ground conductor through an electromagnetic field.

According to the above structure, the variation in the electromagnetic field coupling degree between the feeding coil and the radiation plate is reduced, thereby constituting a small-sized communication terminal device having stable communication characteristics.

According to the utility model, since the ground conductor of the printed wiring board is used as the emitter for sending and receiving wireless signals, and the power supply coil is arranged on the printed wiring board, the distance between the power supply coil and the emitter is not too large. The deviation of the electromagnetic field coupling between the power supply coil and the emitter will also be reduced. Therefore, it is possible to realize a downsized antenna device and a communication terminal device having stable communication characteristics.

Description of drawings

FIG. 1(A) is a plan view of the antenna device and the communication terminal device according to the first embodiment.

FIG. 1(B) is a cross-sectional view of the antenna device and the communication terminal device according to the first embodiment.

FIG. 2 is a schematic perspective view of the antenna device according to Embodiment 1. FIG.

FIG. 3 is a schematic plan view of the antenna device according to Embodiment 1. FIG.

FIG. 4 is a diagram showing the form of current flowing through the feeding coil 112 and the ground conductor 111 due to the coupling between the feeding coil 112 and the annular coupling portion of the opening AP of the ground conductor 111 .

FIG. 5(A) is a plan view of the antenna device according to Embodiment 2, and FIG. 5(B) is a cross-sectional view of the antenna device.

FIG. 6 is a vertical cross-sectional view showing a non-contact IC card reader/writer 1 described in Patent Document 1. As shown in FIG.

Detailed ways

"Implementation Mode 1"

The communication terminal device according to Embodiment 1 is a mobile communication terminal equipped with an NFC (Near Field Communication) system which is an HF band RFID system.

FIG. 1(A) is a plan view of the antenna device 206 and the communication terminal device 306 according to Embodiment 1, and FIG. 1(B) is a cross-sectional view thereof. FIG. 2 is a schematic perspective view of the antenna device 206 according to the first embodiment. FIG. 3 is a schematic plan view of the antenna device 206 .

A first printed wiring board 71 , a second printed wiring board 81 , a battery pack 83 , and the like are mounted in a case (outer package) of the communication terminal device according to the first embodiment. On the first printed wiring board 71 and the second printed wiring board 81, various functional elements and functional circuits such as the cellular antenna 72, the drive circuit of the liquid crystal display element, and the power supply control circuit are mounted. The above-mentioned functional components and functional circuits are constituted as surface mount components. Wiring patterns for connecting the functional elements and functional circuits described above are formed three-dimensionally on the printed wiring boards 71 and 81 .

The first printed wiring board 71 and the second printed wiring board 81 use a flame retardant insulating base material such as epoxy resin as a body. The printed wiring boards 71 and 81 have a multilayer structure, and a ground conductor is provided on the inner layer so as to cover almost the entire area of the printed wiring boards 71 and 81 . The ground conductor is used as the ground conductor of the above-mentioned various functional elements and functional circuits.

An opening is provided near the end of the ground conductor 111 of the first printed wiring board 71 , and a slit SL for connecting the opening AP and the end of the ground conductor is formed. The slit SL connects the opening AP in the ground conductor 111 with adjacent sides of the opening AP. The opening AP and the slit SL provided in the ground conductor 111 are defined by the cutout CP formed in the planar ground conductor 111 . The opposing portions of the cutout CP of the ground conductor 111 with the CP slit SL therebetween are used as the first end and the second end, and the inner periphery of the opening AP is used as the ring-shaped coupling portion.

The inner layer of the first printed wiring board 71 is provided with a power feeding coil 112 . The feeding coil 112 is patterned simultaneously with other various wirings formed on the first printed wiring board 71 , and is patterned into a multi-turn single-layer coil shape. The first end and the second end of the feeding coil 112 are respectively connected to two input and output terminals of the NFC IC chip 73 which is a feeding element. The coil opening of the feeding coil 112 has the same shape and the same size as the opening AP of the ground conductor 111 . That is, the coil pattern of the feeding coil 112 overlaps with the periphery of the opening of the ground conductor 111 . In addition, the IC chip 73 for NFC may be a bare chip or a packaged IC. A chip capacitor 74 is connected between the NFC IC chip 73 and the feeding coil 112 in parallel with the feeding coil 112 , thereby obtaining a resonant circuit composed of the feeding coil 112 and the chip capacitor 74 . The resonance frequency of this resonance circuit is set to be substantially equal to the frequency of transmission and reception signals. Between the IC chip 73 for NFC and the feeding coil 112, a filter element and a matching element may be further provided.

FIG. 4 is a diagram showing the form of current flowing through the feeding coil 112 and the ground conductor 111 due to the coupling between the feeding coil 112 and the annular coupling portion of the opening AP of the ground conductor 111 .

As shown in FIG. 4 , when a signal current flows through the feeding coil 112 , an induced current flows around the edge of the ground conductor 111 via the opening AP and the slit SL of the ground conductor 111 . That is, in the transmission mode, when a high-frequency signal is transmitted from the IC chip 73 for NFC to the power supply coil 112, the induced current of the current flowing through the power supply coil 112 flows through the ring-shaped coupling portion of the ground conductor, and flows through the loop-shaped coupling portion of the ground conductor. The current will be guided to the whole ground conductor 111 (or part of the ground conductor 111 ), so that the ground conductor 111 acts as a high-frequency signal emitter. In addition, in the receiving mode, when the ground conductor 111 receives a high-frequency signal, a current will flow through the ring-shaped coupling part of the ground conductor 111, so the power supply coil 112 will receive the induced current of the above current and transmit the induced current to the IC chip 73 for NFC.

The ring-shaped coupling portion of the ground conductor is connected to the chip capacitor 74 . The first end of the slit SL of the ground conductor 111 is connected to the first terminal of the chip capacitor, and the second end of the slit SL is connected to the second terminal of the chip capacitor. Thus, a resonant circuit is formed with the inductance component of the ring-shaped coupling part of the ground conductor and the capacitance component of the chip capacitor 74, the ground conductor functions as a part of the resonator, and the resonant frequency is made close to the frequency used, that is, HF. frequency band, which can increase the maximum read distance.

Although not shown in the figure, display elements such as a liquid crystal display panel electrostatically shielded by a metal plate are provided on the front surface S2 side of the housing 91, and therefore, the directing direction of the antenna device for NFC is the rear surface S1 side of the housing 91. . Therefore, especially the communication distance toward the side where the feeding coil 112 and the slit SL are provided increases. Therefore, it is preferable to arrange the feeding coil 112 in the vicinity of the end portion of the case 91 on the side having directivity, and it is preferable to extend the slit SL toward the end portion of the case 91 .

As described above, according to the antenna device and communication terminal device of this embodiment, since the ground conductor 111 of the first printed wiring board 71 is used as a radiator for transmitting and receiving high-frequency signals, and the feeding coil 112 is provided on the same first printed wiring board 71 On the wiring board 71, therefore, when the first printed wiring board 71 is produced, the distance between the power supply coil 112 and the ground conductor (emitter) 111 can be determined substantially, so that the accuracy that occurs when assembling the communication terminal device decreases, The warping and deformation of the shell can hardly cause the distance between the power supply coil and the ground conductor (emitter) to deviate. Therefore, the degree of electromagnetic field coupling between the feeding coil 112 and the ring-shaped coupling portion is less likely to vary, so that stable communication characteristics can be obtained.

In addition, since both the power supply coil 112 and the ground conductor (emitter) 111 are provided on the first printed wiring board 71, in other words, it is not a structure in which the power supply coil is provided on another printed wiring board, nor is it placed on another printed wiring board. The configuration of the radiator eliminates the need to ensure a large space for installing the antenna device in the casing, and thus greatly contributes to reducing the size of the antenna device, thereby reducing the size of the communication terminal device.

In addition, since there is no undesired substance such as solder or machining waste that flows out between the feeding coil and the annular coupling portion of the ground conductor, the stability of communication characteristics can be further improved.

In addition, since the power supply coil 112 and the ground conductor 111 are not directly connected, even if surge noise such as ESD is applied to the ground conductor 111, the surge noise is not easy to enter the IC chip 73 for NFC. The surge resistance of the IC chip 73 is improved. Also, even if noise from various functional circuits enters the ground conductor 111 , the noise does not significantly affect the characteristics of the NFC IC chip 73 .

In the present embodiment, when viewed from the ground conductor 111, the feeding coil 112 is provided on the surface S2 side of the case 91, and when viewed from the ground conductor 111, the NFC IC chip 73 is mounted on the back surface of the case 91. S1 side. Therefore, the IC chip 73 for NFC and the feeding coil 112 can be connected without passing through the layer where the ground conductor 111 is located.

"Implementation Mode 2"

FIG. 5(A) is a plan view of an antenna device according to Embodiment 2, and FIG. 5(B) is a cross-sectional view of the antenna device.

In Embodiment 2, the feeding coil 112 is a laminated coil formed by laminating a plurality of loop patterns. The first end surface of the multilayer coil is located on the first main surface side of the ground conductor 111 , and the second end surface of the multilayer coil is located on the second main surface side of the ground conductor 111 . By adopting the above configuration, the planar size of the feeding coil 112 can be reduced, and the required degree of electromagnetic field coupling between the feeding coil 112 and the annular coupling portion of the ground conductor 111 can be maintained.

"Other Implementation Modes"

As mentioned above, although this invention was demonstrated based on concrete embodiment, this invention is not limited to said embodiment.

For example, as the communication terminal device, various devices having a wireless communication function such as a tablet terminal and a notebook computer may be used in addition to a mobile communication terminal. Not only printed wiring boards and battery packs, but also various components such as liquid crystal display elements can be mounted on the terminal case.

The ground conductor can be provided not only on the inner layer of the printed wiring board, but also on the surface layer of the printed wiring board. In addition, when the ground conductor is formed on a plurality of layers, each ground conductor layer may be used as a radiator, or only the ground conductor of the outermost layer or the lowermost layer may be used as a radiator.

The external shape of the ground conductor is not limited to a rectangle, and may be provided in various shapes according to the shape of the printed wiring board, various functional elements, and wiring patterns of the functional circuits.

The power supply coil can be arranged not only on the inner layer of the printed wiring board, but also on the surface layer of the printed wiring board. The number of layers and turns of the power supply coil can be appropriately designed according to the required inductance value.

The annular coupling portion provided on the ground conductor is not limited to the opening and the slit. For example, a recess may be provided at the edge of the ground conductor, and the outer peripheral surface of the recess may be used as the annular coupling portion. In addition, a loop conductor may be added to the edge of the ground conductor and used as the loop coupling portion. The width of the opening and the slit may be the same.

Preferably, in a plan view, the coil opening of the power supply coil 112 overlaps with at least a part of the opening AP of the ground conductor 111, but it is not necessary to make the coil opening of the power supply coil 112 have the same shape and size as the shape and size of the opening AP of the ground conductor 111. . For example, the coil opening of the power supply coil 112 may be larger than the opening AP of the ground conductor 111 , and the coil opening of the power supply coil 112 may also be smaller than the opening AP of the ground conductor 111 . When the outer dimensions of the feed coil 112 are smaller than the opening AP of the ground conductor 111 , the feed coil 112 and the ground conductor 111 may be formed on the same layer (inside the opening AP).

Regarding the arrangement position of the feeding coil 112 with respect to the ground conductor 111 , the feeding coil 112 may be arranged on the rear surface S1 side of the housing 91 when viewed from the ground conductor 111 . In this case, it is preferable to also mount the IC chip 73 for NFC on the rear surface S1 side of the housing.

reference sign

AP opening

CP incision

S1 back

S2 surface

SL slit

71 The first printed wiring board

72 cellular antenna

73 IC chip for NFC

74 chip capacitors

81 Second printed wiring board

83 battery pack

91 shell

110 printed wiring board

111 Ground conductor

112 power supply coil

206 Antenna device

306 Communication terminal device

Claims (7)

1. An antenna device, characterized in that, comprising: A printed wiring board, which uses an insulating base material as a body, and has a ground conductor provided on the surface layer or inner layer of the insulating base material; and a power supply coil, the power supply coil is formed in a coil-like pattern on the surface or inner layer of the printed wiring board, A portion of the ground conductor has an annular coupling portion therein, the annular coupling portion having a first end and a second end, The feeding coil is coupled to the annular coupling portion of the ground conductor through an electromagnetic field. the 2. Antenna device as claimed in claim 1, characterized in that, A capacitive element is provided between the first end and the second end. the 3. Antenna device as claimed in claim 1, characterized in that, The ring-shaped coupling portion is formed by a cutout provided in the ground conductor. the 4. The antenna device according to any one of claims 1 to 3, characterized in that, The coil opening of the power supply coil coincides with the opening of the annular coupling part. the 5. The antenna device according to any one of claims 1 to 3, characterized in that, The power supply coil is a laminated coil formed by stacking a plurality of annular patterns, and the first end surface and the second end surface of the laminated coil are located on the first main surface side and the second main surface side of the ground conductor. the 6. Antenna device as claimed in claim 4, characterized in that, The power supply coil is a laminated coil formed by stacking a plurality of annular patterns, and the first end surface and the second end surface of the laminated coil are located on the first main surface side and the second main surface side of the ground conductor. the 7. A communication terminal device, characterized in that it comprises: A printed wiring board, which uses an insulating base material as a green body, and has a ground conductor provided on the surface or inner layer of the insulating base material; A power supply coil, the power supply coil is formed in a coil-like pattern on the surface or inner layer of the printed wiring board; a power supply element mounted on the printed wiring board and connected to the power supply coil; and a casing, the printed wiring board is accommodated in the casing, A portion of the ground conductor has an annular coupling portion therein, the annular coupling portion having a first end and a second end, The feeding coil is coupled to the annular coupling portion of the ground conductor through an electromagnetic field. the

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