WO2014017352A1

WO2014017352A1 - Antenna device and communication device

Info

Publication number: WO2014017352A1
Application number: PCT/JP2013/069404
Authority: WO
Inventors: 久村　達雄; 佑介久保; 弘幸良尊
Original assignee: デクセリアルズ株式会社
Priority date: 2012-07-26
Filing date: 2013-07-17
Publication date: 2014-01-30
Also published as: JP6005430B2; TW201414085A; JP2014027464A

Abstract

Provided is an antenna device wherein mutual interference between antennas is minimized while a plurality of antennas is efficiently positioned in a space saving manner. The antenna device (10) is provided with a loop antenna (3) having a spiral coil-shaped loop antenna element (2), a magnetic sheet (4b) on which the loop antenna element (2) is mounted, and a magnetic resin layer (4a). Moreover, an antenna section (13), which is positioned in an inner diameter (7) of the loop antenna (3), comprises a spiral coil-shaped antenna element (12), a magnetic sheet (14b) on which the antenna element (12) is mounted, and a magnetic resin layer (14a). The magnetic sheet (4b) of the loop antenna (3) is annularly formed with an empty inner diameter (7), and the magnetic sheet (4b) of the loop antenna (3) and the magnetic sheet (14b) of the antenna section (13) are physically isolated. The magnetic resin layers (4a, 14a) of the loop antenna (3) and the antenna section (13) are also physically isolated.

Description

Antenna device and communication device

The present invention relates to an antenna device having a plurality of antennas, and more particularly to an antenna device in which another antenna is arranged on the inner diameter of a loop antenna and a communication device using the antenna device. This application claims priority on the basis of Japanese Patent Application No. 2012-165993 filed on July 26, 2012 in Japan, and is incorporated herein by reference. Is done.

Recent wireless communication devices are equipped with a plurality of RF antennas such as a telephone communication antenna, a GPS antenna, a wireless LAN / BLUETOOTH (registered trademark) antenna, and an RFID (Radio Frequency Identification). In addition to these, with the introduction of non-contact charging, antenna coils for power transmission have also been mounted. Examples of the power transmission method used in the non-contact charging method include an electromagnetic induction method, a radio wave reception method, and a magnetic resonance method. These all use electromagnetic induction and magnetic resonance between the primary side coil and the secondary side coil, and the above-described RFID also uses electromagnetic induction.

Even if these antennas are designed so that the maximum characteristics can be obtained at the target frequency with the antenna itself, it is difficult to obtain the target characteristics when actually mounted on an electronic device. This is because the magnetic field component around the antenna interferes (couples) with the surrounding metal and the like, and the inductance of the antenna coil is substantially reduced, so that the resonance frequency is shifted. In addition, the reception sensitivity is lowered due to a substantial decrease in inductance. As countermeasures against these problems, by inserting a magnetic shield material between the antenna coil and the metal existing around it, the magnetic flux generated from the antenna coil is collected on the magnetic shield material, thereby reducing the interference caused by the metal. it can.

With the trend toward downsizing and higher functionality of electronic devices, the space allocated for mounting a plurality of antennas as described above on electronic devices such as portable terminal devices is extremely small. As shown in FIG. 10, a general antenna has a configuration in which a magnetic flux concentrating magnetic shielding sheet 42 is attached to a spiral coil-shaped loop antenna element 2 with an adhesive layer 41 coated with an adhesive. However, in such a loop antenna, each antenna occupies a mounting space in an electronic device in which the antenna is mounted, so that the mounting area increases with an increase in the type and quantity of antennas to be mounted. For this reason, there is an increasing demand for downsizing and thinning of these antennas, as well as integration and integration.

Further, the magnetic shield sheet 42 of the loop antenna using the spiral coil shown in FIG. 10 prevents interference with the periphery of the loop antenna, particularly interference with the metal portion, and further increases the transmission efficiency by the magnetic flux focusing action. Have a purpose. However, when a plurality of antennas are installed close to each other in order to save space, there is a problem that interference between antennas increases when the performance of each antenna is improved by increasing the magnetic permeability of the magnetic shielding sheet or the like. .

Therefore, an object of the present invention is to provide an antenna device that suppresses mutual interference between antennas while efficiently arranging a plurality of antennas in a space-saving manner.

As a means for solving the above-described problems, an antenna device according to the present invention includes a loop antenna and one or more antennas arranged on the inner diameter of the loop antenna. The loop antenna has a magnetic shield layer, and the one or more antennas have another magnetic shield layer. At least one of the magnetic shield layer or the other magnetic shield layer has a magnetic resin layer made of a resin containing magnetic particles, and each of the magnetic shield layer and the other magnetic shield layer is physically It is separated. The communication device according to the present invention includes an antenna device having a loop antenna and one or more other antennas arranged on the inner diameter of the loop antenna, and each power receiving input of the loop antenna and the one or more other antennas. The loop antenna has a magnetic shield layer containing a magnetic material, and the other antenna has another magnetic shield layer containing a magnetic material, and the magnetic shield layer or other magnetic At least one of the shield layers has a magnetic resin layer made of a resin containing magnetic particles, and each of the magnetic shield layer and the other magnetic shield layer is physically separated.

According to the antenna device and the communication device according to the present invention, since one or more other antennas are arranged on the inner diameter of the loop antenna, the mounting area of the antenna device becomes the occupied area of the loop antenna, and the mounting space can be reduced. become. In addition, since the loop antenna and the other antennas have magnetic shield layers that are physically separated from each other, it is possible to realize an antenna having high electrical characteristics with little interference between the antennas.

FIG. 1A is a plan view of an antenna device to which the present invention is applied. FIG. 1B is a cross-sectional view taken along the line AA ′ of FIG. FIG. 2A is a plan view of an antenna device to which the present invention is applied. FIG. 2B is a cross-sectional view taken along the line AA ′ of FIG. FIG. 3A is a plan view of an antenna device to which the present invention is applied. FIG. 3B is a cross-sectional view taken along line AA ′ of FIG. FIG. 4A is a plan view of an antenna device according to a modification of the present invention. FIG. 4B is a cross-sectional view taken along line AA ′ of FIG. FIG. 5A is a plan view of an antenna device according to a modification of the present invention. FIG. 5B is a cross-sectional view taken along line AA ′ of FIG. FIG. 6A is a plan view of an antenna device according to a modification of the present invention. FIG. 6B is a cross-sectional view taken along the line AA ′ in FIG. FIG. 7A is a plan view of an antenna device according to a modification of the present invention. FIG. 7B is a cross-sectional view taken along the line AA ′ of FIG. FIG. 8A is a plan view of an antenna device according to a modification of the present invention. FIG. 8B is a cross-sectional view taken along the line AA ′ of FIG. FIG. 9A is a plan view of an antenna device for comparing characteristics of the antenna device of the present invention. FIG. 9B is a cross-sectional view taken along the line AA ′ of FIG. FIG. 10A is a plan view of a conventional single antenna device. FIG. 10B is a cross-sectional view taken along line AA ′ of FIG.

Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings. In addition, this invention is not limited only to the following embodiment, Of course, a various change is possible in the range which does not deviate from the summary of this invention.

[Configuration of antenna device]
As shown in FIGS. 1A and 1B, an antenna device 10 according to the present invention includes a spiral coil-shaped loop antenna element 2 formed by winding a conducting wire 1 in a spiral shape, and a loop antenna element. 2 is provided with a loop antenna portion 3 having a magnetic sheet 4b for mounting 2 and a magnetic resin layer 4a formed so as to embed the entire loop antenna element 2. The antenna unit 13 is disposed on the inner diameter 7 of the loop antenna unit 3. The antenna portion 13 is formed so as to embed the entire antenna element 12, a spiral coil-shaped antenna element 12 formed by winding the conducting wire 11 in a spiral shape, a magnetic sheet 14 b on which the antenna element 12 is placed, and the antenna element 12. And a magnetic resin layer 14a. The magnetic sheet 4b of the loop antenna unit 3 is formed in an annular shape having an inner diameter 7 and the magnetic sheet 4b of the loop antenna unit 3 and the magnetic sheet 14b of the antenna unit 13 are physically separated. The

magnetic resin layers

4a and 14a of the loop antenna part 3 and the antenna part 13 are also physically separated. Therefore, since the loop antenna unit 3 and the antenna unit 13 are arranged via air having a low magnetic permeability (high magnetic resistance), the magnetic coupling is weakened. The loop antenna unit 3 and the antenna unit 13 are preferably placed on the same plane, but may be on different planes depending on the mounting location of the electronic device to be mounted. When mounting on the same plane, the loop antenna unit 3 and the antenna unit 13 may be fixed to an insulating material having a high magnetic resistance, for example, a sub-substrate such as epoxy or phenol, or a flexible substrate such as polyimide. Good.

The antenna element 12 is not limited to the loop antenna as shown in FIG. 1, but may be another antenna element. The power feeding to the antenna and the output from the antenna are connected to an external circuit by the

lead portions

5 and 15 formed at the ends of the

lead wires

1 and 11 of the loop antenna element 2 and the antenna element 12.

The

magnetic resin layers

4a and 14a contain magnetic particles made of soft magnetic powder and a resin as a binder. The magnetic particles are oxide magnetic materials such as ferrite, Fe-based, Co-based, Ni-based, Fe-Ni-based, Fe-Co-based, Fe-Al-based, Fe-Si-based, Fe-Si-Al-based, Fe- Ni-Si-Al-based crystal system, microcrystalline metal magnetic material, or Fe-Si-B system, Fe-Si-BC system, Co-Si-B system, Co-Zr system, Co-Nb Or amorphous metal magnetic particles such as Co—Ta. As the magnetic particles, spherical or flat powder having a particle size of several μm to several tens of μm is used, but crushed powder may be mixed. In the case of the above-described metal magnetic material, the complex permeability has frequency characteristics, and loss occurs due to the skin effect when the operating frequency becomes high, so the particle size and shape are adjusted according to the frequency band to be used. . Further, the inductance value of the antenna device 10 is determined by the real part magnetic permeability (hereinafter simply referred to as magnetic permeability) of the magnetic material, but the magnetic permeability can be adjusted by the mixing ratio of the magnetic particles and the resin. . Since the relationship between the average magnetic permeability of the

magnetic resin layers

4a and 14a and the magnetic permeability of the magnetic particles to be blended generally follows the logarithmic mixing rule with respect to the blending amount, the volume filling factor 40 vol at which the interaction between the particles increases. % Or more is preferable. Note that the heat conduction characteristics of the

magnetic resin layers

4a and 14a also improve as the filling rate of the magnetic particles increases.

The

magnetic resin layers

4a and 14a are not limited to being composed of a single magnetic material. Two or more kinds of magnetic materials may be mixed and used, and a magnetic resin layer may be formed by laminating in multiple layers. Moreover, even if it is the same magnetic material, the particle size and / or shape of magnetic particles may be selected and mixed, or may be laminated in multiple layers. Further, the magnetic material or composition may be changed for each antenna. Since these variations are possible, desired magnetic characteristics can be realized.

As the binder, a resin that is cured by heat, ultraviolet irradiation, or the like is used. As the binder, for example, a known material such as a resin such as an epoxy resin, a phenol resin, a melamine resin, a urea resin, or an unsaturated polyester, or a rubber such as silicone rubber, urethane rubber, acrylic rubber, butyl rubber, or ethylene propylene rubber is used. However, the material is not limited to these, and a known material can be used. An appropriate amount of a surface treatment agent such as a flame retardant, a reaction modifier, a crosslinking agent, or a silane coupling agent may be added to the above-described resin or rubber.

The

magnetic sheets

4b and 14b are generally made of ferrite having a high electrical resistivity. However, a magnetic material similar to the magnetic particles, for example, an amorphous metal magnetic material such as Fe-based or Co-based material may be used. Of course, Fe-based crystalline metal magnetic materials such as permalloy, microcrystalline magnetic materials, and the like can be used. Further, the

magnetic sheets

4b and 14b may be sheets prepared by mixing one or more materials selected from the above magnetic bodies and a resin, such as the

magnetic resin layers

4a and 14a. Needless to say, as with the

magnetic resin layers

4a and 14a, the magnetic material or composition may be changed for each antenna.

The conductive wire 1 forming the loop antenna element 2 is used when the loop antenna unit 3 is used as a secondary charging coil for non-contact charging having a charging output capacity of about 5 W, and when used at a frequency of about 120 kHz. It is preferable to use a single wire made of Cu having a diameter of 0.20 mm to 0.45 mm or an alloy containing Cu as a main component. Alternatively, in order to reduce the skin effect of the conducting wire 1, a parallel line obtained by bundling a plurality of fine wires thinner than the above-described single wire, a knitted wire may be used, one layer using a thin rectangular wire or a flat wire, Or it is good also as alpha winding of 2 layers. The antenna unit 13 can also be arbitrarily determined in consideration of the frequency and current capacity used. Note that a Cu foil or the like patterned on a predetermined substrate may be used according to the current capacity.

In the antenna device 10 of the present invention configured as described above, since the antenna portion 13 is disposed on the inner diameter 7 of the loop antenna portion 3, the inner diameter 7 of the loop antenna portion 3 does not become a dead space, and space saving. An integrated antenna device can be realized. Even if the loop antenna portion 3 and the antenna portion 13 are arranged close to each other in this manner, the

magnetic resin layers

4a and 14a and the

magnetic sheets

4b and 14b are physically separated from each other. Mutual interference between the respective antennas is reduced.

Furthermore, since the antenna device 10 of the present invention has the loop antenna element 2 and the antenna element 12 embedded in the

magnetic resin layers

4a and 14a, respectively, the magnetic flux density near the coil can be increased and the number of turns is small. However, a desired inductance value can be obtained. Since the number of turns can be reduced in order to obtain a desired inductance value, the direct current resistance of the conducting

wires

1 and 11 can be reduced, and the loss can be reduced. Further, the high heat conduction characteristics of the

magnetic resin layers

4a and 14a allow heat to be radiated more efficiently, and it is also possible to reduce the heat radiation space in the electronic device due to a decrease in heat generation.

[Manufacturing method of antenna device]
Next, an example of a method for manufacturing the antenna device 10 will be described. First,

magnetic sheets

4b and 14b are prepared. Here, an example in which ferrite is used as the

magnetic sheets

4b and 14b will be described.

¡A mixture of ferrite raw materials is pressed into a mold and molded, fired to form bulk ferrite, and then molded into a sheet by slicing.

The

magnetic sheets

4b and 14b thus molded are further arranged in a mold, and after placing the loop antenna element 2 and the antenna element 12 on the

magnetic sheets

4b and 14b, respectively, the

magnetic resin layer

4a , 14a are injected into the mold. Then, the magnetic resin is cured by heating or ultraviolet irradiation, and the antenna device 10 is removed from the mold. Further, the loop antenna element 2 and the antenna element 12 may be embedded after the magnetic resin is injected. Alternatively, when the magnetic resin is injected into the mold, the loop antenna element 2 and the antenna element 12 are embedded, and the

magnetic resin layers

4a and 14a are covered with the sintered

magnetic sheets

4b and 14b. Thereafter, the magnetic resin may be cured.

When forming the

magnetic sheets

4b and 14b, other methods can be used regardless of slicing. For example, a ferrite slurry prepared by mixing ferrite raw material powder and a binder is molded into a thin sheet by a doctor blade method (green sheet), and then the green sheet molded into a predetermined shape by a punching die is sintered. Alternatively, a ferrite sheet method may be used. The antenna device 10 of the present invention can be formed by applying the same processing as described above to the sintered ferrite

magnetic sheets

4b and 14b.

In addition, you may form the notch part for accommodating the drawer | drawing-out

parts

5 and 15 of the conducting

wires

1 and 11 in the

magnetic sheets

4b and 14b. In this case, the notched portion may be formed in a bulk state after the bulk ferrite is sintered, or the notched portion may be formed by grooving after slicing the

magnetic sheets

4b and 14b. Further, when the

magnetic sheets

4b and 14b are formed from green sheets, it is possible to form the

magnetic sheets

4b and 14b in which the notches are formed by preparing a cutting die that takes into account the notches in advance. .

The amount of resin or the like may be an amount for completely embedding the loop antenna element 2 and the antenna element 12 as shown in FIG. 1 or an amount for exposing a part of the loop antenna element 2 and the antenna element 12. Good. Further, as will be described later, the position of the resin or the like may be a position embedded so as to fill all or part of the outer diameter portion or the inner diameter portion of the loop antenna element 2 and / or the antenna element 12.

The antenna device 10 is configured by arranging the formed antenna portion 13 on the inner diameter 7 of the formed loop antenna portion 3. When mounted in an electronic device, they may be arranged separately. The loop antenna portion 3 and the antenna portion 13 are arranged on the inner diameter 7 on a sub-substrate such as a phenol substrate or a flexible substrate such as polyimide. May be.

When the loop antenna element 2 and the antenna element 12 and the

magnetic resin layers

4a and 14a are fixed by the manufacturing method as described above, it is not necessary to use an adhesive. Accordingly, the number of steps for applying the adhesive is reduced, and the antenna device 10 can be made thinner by the amount of the adhesive layer formed by applying the adhesive.

Although it is preferable to connect the high permeability

magnetic sheets

4b and 14b in terms of the characteristics of the antenna, the antenna device 10 may be configured without connecting the high permeability

magnetic sheets

4b and 14b. In that case, the

magnetic resin layers

4a and 14a are kneaded with the resin as described above, and therefore do not cause breakage such as cracking against external impacts. There is no need to affix. Therefore, the protective sheet sticking process can be reduced, and an increase in the thickness of the antenna device over the protective sheet can be suppressed.

[Modification 1]
As shown in FIGS. 2A and 2B, an antenna device 10 according to the present invention includes a spiral coil loop antenna element 2 formed by winding a conducting wire 1 in a spiral shape, and a loop antenna element. 2 is provided with a loop antenna portion 3 having a magnetic sheet 4b on which 2 is placed and an adhesive layer 41 for fixing the loop antenna element 2 on the magnetic sheet 4b. The antenna unit 13 is disposed on the inner diameter 7 of the loop antenna unit 3. The antenna portion 13 is formed so as to embed the entire antenna element 12, a spiral coil-shaped antenna element 12 formed by winding the conducting wire 11 in a spiral shape, a magnetic sheet 14 b on which the antenna element 12 is placed, and the antenna element 12. And a magnetic resin layer 14a. The magnetic sheet 4b of the loop antenna unit 3 and the magnetic sheet 14b of the antenna unit 13 are physically separated. Therefore, the loop antenna unit 3 and the antenna unit 13 are weakly magnetically coupled via air having a higher magnetic resistance than a magnetic circuit. The loop antenna unit 3 and the antenna unit 13 are placed on the same plane. For mounting on the same plane, it may be fixed to an insulating material having a high magnetic resistance, for example, a sub-board such as epoxy or phenol.

In this modification, the magnetic resin layer 14a is formed so as to embed the entire antenna element 12 only for the antenna portion 13 disposed on the inner diameter side of the loop antenna portion 3. In the loop antenna unit 3, an adhesive is applied on the magnetic sheet 4 b and the loop antenna element 2 is fixed via the adhesive layer 41.

In this modification, the magnetic resin layer 14a of only the antenna portion 13 is formed so as to embed the entire antenna element 12. Compared to the case of FIG. 1, since the entire loop antenna element 2 and antenna element 12 are not embedded in the magnetic resin layer 14 a, the amount of magnetic resin can be reduced, and the antenna device 10 can be reduced in weight and cost. Contribute to Furthermore, since the magnetic resin layer 14a is formed on the magnetic circuit without embedding the entire loop antenna element 2 and antenna element 12, it is possible to improve electrical characteristics such as an improvement in inductance. In addition, due to the high thermal conductivity characteristics of the magnetic resin, Joule heat (copper loss) generated in the conductive wire 11 can be efficiently radiated, which contributes to reduction of the heat radiation space in the electronic device.

As shown in FIGS. 3A and 3B, an antenna device 10 according to the present invention includes a spiral coil loop antenna element 2 formed by winding a conducting wire 1 in a spiral shape, and a loop antenna element. 2 is provided with a loop antenna portion 3 having a magnetic sheet 4b for mounting 2 and a magnetic resin layer 4a formed so as to embed the entire loop antenna element 2. The antenna unit 13 is disposed on the inner diameter 7 of the loop antenna unit 3. The antenna unit 13 is used for fixing the antenna element 12 on the magnetic sheet 14b, a spiral coil-shaped antenna element 12 formed by winding the conducting wire 11 in a spiral shape, a magnetic sheet 14b on which the antenna element 12 is placed, and the antenna element 12. Adhesive layer 41. The magnetic sheet 4b of the loop antenna unit 3 and the magnetic sheet 14b of the antenna unit 13 are physically separated. Therefore, the loop antenna unit 3 and the antenna unit 13 are weakly magnetically coupled via air having a higher magnetic resistance than a magnetic circuit. The loop antenna unit 3 and the antenna unit 13 are preferably placed on the same plane, but may be placed on different planes depending on the mounting location of the electronic device to be mounted. For mounting on the same plane, it may be fixed to an insulating material having a high magnetic resistance, for example, a sub-board such as epoxy or phenol.

In this modification, the magnetic resin layer 4a is formed so as to embed the entire loop antenna element 2 only for the loop antenna element 2. The antenna unit 13 is configured by applying an adhesive on the magnetic sheet 14 b and fixing the antenna element 12 via the adhesive layer 41.

In this modification, as in the case of FIG. 2, the entire loop antenna element 2 and antenna element 12 are not embedded in the magnetic resin layer 4a, so the amount of magnetic resin is reduced and the weight of the antenna device 10 is reduced. Contributes to cost reduction. Furthermore, since the magnetic resin layer 4a is formed on the magnetic circuit without embedding the entire loop antenna element 2 and antenna element 12, it is possible to improve electrical characteristics such as an improvement in inductance. In addition, the high heat conduction characteristics of the magnetic resin enable efficient heat dissipation, contributing to the reduction of the heat dissipation space in the electronic device.

[Modification 2]
As shown in FIGS. 4A and 4B, an antenna device 10 according to the present invention includes a spiral coil-shaped loop antenna element 2 formed by winding a conducting wire 1 in a spiral shape, and a loop antenna element. 2 is provided with a loop antenna portion 3 having a magnetic sheet 4b on which 2 is placed and an adhesive layer 41 for fixing the loop antenna element 2 on the magnetic sheet 4b. The antenna unit 13 is disposed on the inner diameter 7 of the loop antenna unit 3. The antenna unit 13 is embedded so as to fill a spiral coil-shaped antenna element 12 formed by winding the conducting wire 11 in a spiral shape, a magnetic sheet 14 b on which the antenna element 12 is placed, and an inner diameter portion of the antenna element 12. And a magnetic resin layer 14a formed as described above. The magnetic sheet 4b of the loop antenna unit 3 and the magnetic sheet 14b of the antenna unit 13 are physically separated. Therefore, the loop antenna unit 3 and the antenna unit 13 are weakly magnetically coupled via air having a higher magnetic resistance than a magnetic circuit.

In this modification, the magnetic resin layer 14a is formed so as to fill a part of the antenna part 13 arranged on the inner diameter 7 of the loop antenna part 3, that is, the inner diameter part of the antenna part 13.

As shown in FIGS. 5A and 5B, instead of filling the inner diameter portion of the antenna portion 13 of FIG. 4 with magnetic resin, the antenna element 12 is embedded at a portion excluding the inner diameter portion. Thus, the magnetic resin layer 14a may be formed.

4 and 5, the presence of the magnetic resin layer 14a can improve the electrical characteristics such as the inductance value, and the amount of the magnetic resin can reduce the weight and cost of the antenna device. It becomes.

As shown in FIG. 6, the magnetic resin layer 4a and the magnetic resin layer 14a in which the loop antenna element 2 and the antenna element 12 are respectively embedded are attached to the magnetic sheet 4b and the magnetic sheet 14b by the adhesive layer 41, respectively. Good. As described above, the

magnetic resin layers

4a and 14a are formed in a sheet shape in advance, and the loop antenna element 2 and the antenna element 12 are placed on the sheet and subjected to pressure or pressure heat treatment, whereby the loop antenna element 2 In addition, the loop antenna portion 3 and the antenna portion 13 can also be formed by forming a sheet in which the antenna element 12 is embedded and attaching the sheet to the

magnetic sheets

4b and 14b with the adhesive layer 41.

[Modification 3]
In the antenna device 10 of the present invention, three antennas can be combined. As shown in FIG. 7A and FIG. 7B, the antenna device 10 of the present invention includes a loop antenna unit 3, a first antenna unit 13 disposed on the inner diameter 7 of the loop antenna unit 3, and And a second antenna portion 23 disposed on the inner diameter 7 of the first antenna portion 13. The loop antenna unit 3, the first antenna unit 13, and the second antenna unit 23 (hereinafter referred to as the loop antenna unit 3 etc.) are all formed in a spiral coil shape formed by winding the

conductive wires

1, 11 and 21 in a spiral shape. Loop antenna element 2, first antenna element 12 and second antenna element 22 (hereinafter referred to as loop antenna element 2 etc.),

magnetic sheets

4b, 14b, 24b on which loop antenna element 2 etc. are placed, It has

magnetic resin layers

4a, 14a, 24a formed so as to embed the entire loop antenna element 2 and the like. Each of the

magnetic sheets

4b, 14b, 24b such as the loop antenna portion 3 is physically separated, and the

magnetic resin layers

4a, 14a, 24a are also physically separated. Therefore, since the loop antenna unit 3 and the like are coupled with air having high magnetic resistance in terms of a magnetic circuit, interference between antennas is reduced. Needless to say, a part of the loop antenna element 2 or the like may be embedded without being embedded as shown in FIGS.

Thus, in the antenna device 10 of the present invention, by arranging the loop antennas in a nested manner, even three antennas can be arranged in a smaller space. Since the

magnetic sheets

4b, 14b, and 24b and the

magnetic resin layers

4a, 14a, and 24a are physically separated from each other, mutual interference between the antennas can be reduced.

Further, by embedding at least a part of the loop antenna element 2 or the like in the

magnetic resin layers

4a, 14a, and 24a, it is possible to improve electrical characteristics such as inductance and increase heat dissipation characteristics. Can be realized.

The shape and size of the antenna are limited to some extent by the frequency of radio waves to be transmitted and received. For this reason, as shown in FIG. 7 described above, there are cases where all the antennas cannot be arranged in a nested state.

As shown in FIGS. 8 (A) and 8 (B), in the antenna device 10 of the present invention, the first and second antenna sections 13 are not nested and the first and

second antenna sections

13 and 23 are not nested. , 23 may be arranged side by side on the inner diameter 7 of the loop antenna portion 3 so that they do not overlap each other.

Various variations can be taken for the arrangement of the antenna portion in the inner diameter of the loop antenna portion 3. The number of antennas that can be combined by arranging the antenna parts arranged on the inner diameter of the loop antenna part 3 without overlapping each other, or arranging them on the inner diameters of other antennas, and further combining them is 2 as described above. The number is not limited to three and may be four or more.

[Characteristic comparison with conventional antenna devices]
The characteristics of the antenna device 10 according to the present invention were evaluated by using a simulation program.

Hereinafter, Example 1, Example 2, and Comparative Example to be described are all antenna device models having the same antenna shape and size except for the presence or absence of a magnetic resin layer and an adhesive layer.

<Example 1>
In the first embodiment, the configuration of FIG. 2 is used as the antenna device 10. That is, in the antenna device 10, only the antenna element 12 on the inner diameter 7 side of the loop antenna portion 3 is embedded in the magnetic resin layer 14a.

The coil of the loop antenna unit 3 was a 1T flat coil having an outer diameter of 44.8 mm made of a flat rectangular wire having a line width of 2.4 mm and a wire thickness of 0.25 mm. The magnetic sheet 4b was an annular Ni—Zn ferrite (permeability = 100) having an outer diameter of 48 mm, an inner diameter of 36 mm, and a thickness of 0.4 mm. An adhesive layer 41 having a thickness of 0.1 mm is inserted between the loop antenna element 2 and the magnetic sheet 4b.

The coil of the antenna unit 13 arranged on the inner diameter 7 of the loop antenna unit 3 is a 1T flat coil having a flat width of 5.6 mm and a thickness of 0.25 mm and an outer diameter of 29.2 mm. The magnetic sheet 14b was 34 mm × 34 mm × 0.4 mm Ni—Zn ferrite (permeability = 100), and the magnetic resin layer 14a was set to have permeability = 15.

The magnetic resin layer 14a is formed so that the entire antenna element 12 is buried.

<Example 2>
In Example 2, the structure of FIG. 1 was used as the configuration of the antenna device. That is, in the antenna device, both the loop antenna element 2 and the antenna element 12 are embedded in the

magnetic resin layers

4a and 14a.

The coil of the loop antenna unit 3 was a 1T flat coil having an outer diameter of 44.8 mm made of a flat rectangular wire having a line width of 2.4 mm and a wire thickness of 0.25 mm. The magnetic sheet 4b was an annular Ni—Zn ferrite (permeability = 100) having an outer diameter of 48 mm, an inner diameter of 36 mm, and a thickness of 0.4 mm, and the magnetic resin layer 4a was set to have permeability = 15.

<Comparative example>
In the comparative example, the structure of FIG. 9 was used as the configuration of the antenna device. That is, in the antenna device 10, the loop antenna element 2 and the antenna element 12 are bonded to the

magnetic sheets

4 b and 14 b by the adhesive layer 41 without using the magnetic resin layer.

The coil of the loop antenna unit 3 was a 1T flat coil having an outer diameter of 44.8 mm made of a flat rectangular wire having a line width of 2.4 mm and a wire thickness of 0.25 mm. The magnetic sheet 4b was an annular Ni—Zn ferrite (permeability = 100) having an outer diameter of 48 mm, an inner diameter of 36 mm, and a thickness of 0.4 mm. An adhesive layer 41 having a thickness of 0.1 mm was inserted between the loop antenna element 2 and the magnetic sheet 4b.

The coil of the antenna unit 13 arranged on the inner diameter 7 of the loop antenna unit 3 is a 1T flat coil having a flat width of 5.6 mm and a thickness of 0.25 mm and an outer diameter of 29.2 mm. The magnetic sheet 14b was 34 mm × 34 mm × 0.4 mm Ni—Zn ferrite (permeability = 100). An adhesive layer 41 having a thickness of 0.1 mm was inserted between the loop antenna element 2 and the magnetic sheet 4b.

<Result>
The results are shown in Table 1. The results for the inductance and the Q value are shown as normalized values based on the comparative example.

Regarding the electrical characteristics of the antenna part 13 arranged on the inner diameter 7 of the loop antenna part 3, the inductances of Examples 1 and 2 showed a value about 10% larger than that of the comparative example. This is because the entire antenna element 12 is embedded in the magnetic resin layer 14a in the antenna section 13, so that the volume of the magnetic material increases and the magnetic flux density around the antenna element 12 increases. Q was significantly increased to 40% or more in Examples 1 and 2 than in the comparative example.

Regarding the electrical characteristics of the loop antenna part 3, the inductance of Example 2 was about 20% larger than that of the comparative example. This is because the entire loop antenna element 2 is embedded in the loop antenna unit 3 to increase the volume of the magnetic material and increase the magnetic flux density around the antenna element 12. On the other hand, in Example 1, since the magnetic resin layer was not added to the loop antenna element 2, the value equivalent to the comparative example was shown. Q was significantly increased in Example 2 by 40% compared to the comparative example.

A coupling coefficient k is used as an index representing the degree of electromagnetic coupling between the coils. Regarding the coupling coefficient k, in Example 2, the inductance value and the Q value are compared with the comparative example in both the loop antenna unit 3 and the antenna unit 13. On the other hand, the numerical value is equal to or lower than that of the comparative example. Therefore, by adopting the configuration of the antenna device of the present invention, it is possible to improve the electrical characteristics such as inductance and Q value without deteriorating the mutual interference between the antennas.

In the antenna device of the present invention, the inductance and Q value can be increased without deteriorating interference between antennas, and the performance of each antenna can be improved. In addition, this increase in inductance can reduce the number of turns of the antenna element when adjusting to a desired inductance value, so that the DC resistance value of the antenna element can be reduced, resulting in a reduction in power consumption. can do. Along with the reduction in power consumption, the heat generated from the antenna device is reduced, and the heat radiation space in the electronic device on which the antenna device is mounted can be reduced, contributing to the substantial downsizing and thinning of the device. it can.

1,11,21 conducting wire, 2 loop antenna element, 12, 22 antenna element, 3 loop antenna part, 13, 23 antenna part, 4a, 14a, 24a magnetic resin layer, 4b, 14b, 24b magnetic sheet, 5,15 drawer Part, 7, 17 inner diameter, 10 antenna device, 41 adhesive layer, 42 magnetic shielding sheet

Claims

A loop antenna,
One or more other antennas arranged on the inner diameter of the loop antenna,
The loop antenna has a magnetic shield layer containing a magnetic material,
Each of the other antennas has another magnetic shield layer containing a magnetic material,
At least one of the magnetic shield layer or the other magnetic shield layer has a magnetic resin layer made of a resin containing magnetic particles, and each of the magnetic shield layer and the other magnetic shield layer includes: An antenna device characterized by being physically separated.
The antenna device according to claim 1, wherein at least a part of at least one of the loop antenna or the one or more other antennas is embedded in the magnetic resin layer.
The antenna device according to claim 1, wherein at least one of the loop antenna or the one or more other antennas is entirely embedded in the magnetic resin layer.
The magnetic shield layer of the loop antenna includes a magnetic sheet,
The antenna device according to any one of claims 1 to 3, wherein the magnetic shield layer of the one or more other antennas includes a magnetic sheet.
The antenna device according to claim 1, wherein the other antennas are two or more antennas.
The antenna device according to claim 5, wherein the two or more antennas are arranged on the inner diameter of the loop antenna without overlapping each other.
Two or more of the antennas are both loop-shaped,
6. The antenna device according to claim 5, wherein one of the two or more antennas is disposed on an inner diameter of the remaining antenna.
The antenna device according to claim 7, wherein the two or more antennas are concentrically arranged on an inner diameter of the remaining antenna.
An antenna device having a loop antenna and one or more other antennas disposed on an inner diameter of the loop antenna;
A rectifier circuit for rectifying each power receiving input of the loop antenna and the one or more other antennas,
The loop antenna has a magnetic shield layer containing a magnetic material,
Each of the other antennas has another magnetic shield layer containing a magnetic material,
At least one of the magnetic shield layer or the other magnetic shield layer has a magnetic resin layer made of a resin containing magnetic particles, and each of the magnetic shield layer and the other magnetic shield layer includes: A communication device that is physically separated.