JP6773587B2 - Antenna device and communication terminal device - Google Patents

Description

The present invention relates to an antenna device and a communication terminal device.

In recent years, various ring-shaped communication terminal devices such as rings, bracelets, and wristwatches that can be directly worn and carried have been devised. Such a communication terminal device is a so-called wearable terminal, and is an information terminal in a form of being worn on a body and used instead of being carried like a smartphone or a notebook computer.

For example, Patent Document 1 describes a communication terminal device provided with an integrated circuit, a wireless tag side antenna, and a reader / writer side antenna on the pedestal portion of the ring. Patent Document 2 describes a bracelet-type communication terminal device that is connected to a control circuit in a main body and performs non-contact data communication by two sheet-shaped coils embedded in a belt. Patent Document 3 describes a ring-type communication terminal device in which a linear conductor continuous in the circumferential direction is built in an arm and functions as an antenna.

Japanese Unexamined Patent Publication No. 2008-187653 Japanese Unexamined Patent Publication No. 3-202997 Japanese Unexamined Patent Publication No. 2003-933668

However, the communication terminal devices of Patent Documents 1 to 3 still have a problem of low communication characteristics.

An object of the present invention is to provide a ring-shaped antenna device having good communication characteristics and a communication terminal device including the antenna device.

The antenna device of the present invention includes a feeding coil and a ring-shaped conductor arranged around an axis and having a first end face and a second end face in the axial direction, and the feeding coil is provided from the radial direction of the ring-shaped conductor. As seen, the feeding line is wound, and the ring-shaped conductor has an opening extending around the axis and opening outward at a position separated from the first end surface and the second end surface. The portion is characterized in that at least a part thereof overlaps with the coil opening of the feeding coil when viewed from the radial direction.

Further, the antenna device of the present invention includes a feeding coil, a ring-shaped conductor arranged around an axis and having a first end face and a second end face in the axial direction, and an inner ring-shaped member inserted in the ring-shaped conductor. The feeding coil is configured by winding a feeding wire around the outer surface of the inner ring-shaped member, and the ring-shaped conductor is located at a position separated from the first end surface and the second end surface. It is characterized by having an opening extending around an axis and opening outward, and a part of the feeding coil is located in the opening when viewed from the radial direction of the ring-shaped conductor.

The communication terminal device of the present invention includes the above-mentioned antenna device and a feeding circuit connected to the feeding coil or coupled with an electric field, a magnetic field, or an electromagnetic field.

According to the present invention, it is possible to realize a ring-shaped antenna device having good communication characteristics and a communication terminal device including the antenna device.

The antenna device according to the first embodiment is shown, where (a) is a plan view, (b) is a sectional view taken along line 1b-1b of (a), and (c) is 1c-1c of (a). It is sectional drawing along the line. A modification of the antenna device according to the first embodiment is shown, where (a) is a plan view, (b) is a cross-sectional view taken along line 2b-2b of (a), and (c) is (a). A cross-sectional view taken along the line 2c-2c, (d) is a plan view showing a state in which only the side surfaces of the opening on both sides around the axis extend outward. A modified example of the antenna device according to the first embodiment is shown, in which (a) is a cross-sectional view showing a state in which both side surfaces around an axis at the opening are spread outward, and (b) is (a). ), (C) is a cross-sectional view showing a state in which one side surface around the axis of the opening extends outward, and (d) is a plan view of (c). The antenna device according to the second embodiment is shown, (a) is a plan view, (b) is a sectional view taken along line 4b-4b of (a), and (c) is 4c-4c of (a). It is sectional drawing along the line. The antenna device according to the third embodiment is shown, (a) is a plan view, (b) is a cross-sectional view taken along line 5b-5b of (a), and (c) is 5c-5c of (a). It is sectional drawing along the line. A modification of the antenna device according to the third embodiment is shown, where (a) is a plan view and (b) is a cross-sectional view taken along line 6b-6b of (a). Other modifications of the antenna device according to the third embodiment are shown, where (a) is a plan view, (b) is a cross-sectional view taken along line 7b-7b of (a), and (c) is (a). ) Is a cross-sectional view taken along the line 7c-7c. The antenna device according to the 4th Embodiment is shown, (a) is a plan view, (b) is a sectional view along line 8b-8b of (a). It is explanatory drawing which shows the simulation model of the antenna device of FIG. It is explanatory drawing which shows the simulation model of the antenna device of FIG.

Hereinafter, a plurality of embodiments for carrying out the present invention will be shown with reference to the drawings with reference to some specific examples. The same reference numerals are given to the same parts in each figure. Each embodiment is exemplary and allows partial replacement or combination of the configurations shown in different embodiments.

In each of the embodiments shown below, the "antenna device" is an antenna that radiates magnetic flux. The antenna device is an antenna used for near-field communication using magnetic field coupling with the antenna on the communication partner side, and is used for communication such as NFC (Near Field Communication). In the antenna device, the communication frequency band is used, for example, in the HF band, and particularly in a frequency near 13.56 MHz.

FIG. 1 shows an antenna device according to the first embodiment, and the antenna device includes a ring-shaped conductor 1 and a feeding coil 5.

The ring-shaped conductor 1 is a ring-shaped conductor arranged around the axis A, and has a first end surface 11 and a second end surface 12 perpendicular to the axis A direction (vertical direction in FIG. 1A). The ring-shaped conductor 1 has an opening 3 extending around the axis A and opening outward at a portion separated from the first end surface 11 and the second end surface 12 by a predetermined distance. The side surface of the opening 3 on the side around the axis A is composed of a through hole having a side surface along the radial direction (indicated by an arrow) of the ring-shaped conductor 1.

In other words, the first end surface 11 and the second end surface 12 of the ring-shaped conductor 1 are continuous in the circumferential direction, and the opening 3 is not connected to the first end surface 11 and the second end surface 12.

The opening 3 has a rectangular shape in a plan view (viewed from the radial direction), and the feeding coil 5 is housed in the opening 3. The feeding coil 5 is a spiral-shaped conductor pattern in which a feeding wire is wound when viewed from the radial direction of the ring-shaped conductor 1, and both ends thereof are connected to a feeding circuit (not shown). The feeding coil 5 in the present embodiment is, for example, a Cu foil, and is formed on the main surface of a resin sheet such as polyimide (PI) or liquid crystal polymer (LCP).

Since the feeding coil 5 is housed in the opening 3, the entire coil opening of the feeding coil 5 overlaps the opening 3 when viewed from the radial direction of the ring-shaped conductor 1.

The opening 3 is filled with a dielectric material 7 such as resin or glass, and a power feeding coil 5 is embedded in the dielectric material 7. As shown in FIG. 1C, the power feeding coil 5 is arranged at the central portion of the dielectric material 7 in the radial direction, in other words, at the central portion in the thickness direction. Such an antenna device can be manufactured, for example, by fitting a dielectric material 7 containing a feeding coil 5 into an opening 3 of a ring-shaped conductor 1.

Further, in the present embodiment, the ring-shaped conductor 1 is curved around the axis A, which is an example of the ring-shaped conductor "arranged around the axis" in the present invention. The magnetic fields are shown by broken lines in FIGS. 1 (b) and 1 (c).

In such an antenna device, the conductors above and below the feeding coil 5 are eliminated to eliminate the reverse current and improve the antenna characteristics. In this embodiment, the cost can be reduced without the need for a magnetic material. By arranging the entire power feeding coil 5 in the opening 3, the spread of the magnetic field can be increased and the antenna can function as an antenna.

In such an antenna device, it is preferable that the ring-shaped conductor 1 is provided in a mounting portion through which a part of the human body (for example, a finger) is inserted. With this configuration, as a so-called wearable terminal, a communication terminal device including an antenna device used in an HF band or UHF band communication system can be realized.

In the above example, the operation when the antenna device is the transmitting side antenna has been described, but the reversible theorem (reciprocity theorem) of the antenna holds even if the transmission and reception are reversed. That is, the same operation is performed when the antenna device is a receiving side antenna.

Further, the antenna device according to the present embodiment shows an example in which the shape of the feeding coil is a rectangular spiral-shaped conductor pattern when viewed from the radial direction, but the present invention is not limited to this configuration. The shape of the feeding coil can be appropriately changed to be circular, elliptical, polygonal, etc. when viewed from the radial direction. Further, as described above, it is desirable that the opening 3 is sealed with a low-loss dielectric material 7 such as resin or glass. At this time, a part of the dielectric material 7 may have a decoration made of a dielectric such as sapphire or ruby.

The communication terminal device includes, for example, the antenna device, RFIC elements connected to both ends of the feeding coil 5, and a capacitor connected in parallel to the feeding coil 5.

FIG. 2 shows a modification of the antenna device according to the first embodiment of FIG. 1 described above. In this antenna device, all the side surfaces of the opening 3 of the ring-shaped conductor 1 expand outward. ing.

That is, as shown in FIG. 2C, the opening 3 is composed of an annular inner side surface 31 along the radial direction and an annular outer side surface 32 extending outward from the inner side surface 31. The power feeding coil 5 is located on the outer side surface 32. The outer side surface 32 is formed on the entire circumference of the opening 3. The outer side surface 32 is a portion of the alternate long and short dash line in FIG. 2 (c) so that the outer surface of the ring-shaped conductor 1 of FIG. 1 is flush with the outer surface 32 formed on the entire circumference of the opening 3. It can be formed by removing it by polishing or the like.

In such an antenna device, the magnetic field spreads from the feeding coil 5 in the direction around the axis A and in the direction of the axis A, and the magnetic field spreads more outward than the antenna device of FIG. 1, so that it is easier to couple with the antenna coil on the communication partner side. Therefore, it is possible to provide an antenna device having good communication characteristics. It is desirable that at least a part of the feeding coil 5 is above the flat surface of the outer side surface 32. If only a part of the feeding coil 5 is above the flat surface of the outer side surface 32, the effect of improving the antenna characteristics can be obtained. The reason for this is that the magnetic field can be spread in the plane direction from the feeding coil 5 by eliminating the conductor on the side surface of the feeding coil 5 even if only a part of the magnetic field is removed.

In FIG. 2, the outer side surface 32 forming the opening 3 is polished so as to be in the same plane, but the outer side surface 32 may be extended outward, and a part of the outer side surface 32 may be inclined at a different angle. You may have a face.

Further, as shown in FIG. 2D, the outer surfaces of the ring-shaped conductor 1 near the first end surface 11 side and the second end surface 12 side are not polished, but are polished in the direction around the axis A of the ring-shaped conductor 1. Is also good. In this case, the outer side surface 32 is formed only on both sides of the opening 3 in the direction around the axis A.

Even in such an antenna device, since the magnetic field spreads outward in the direction around the axis A as compared with the antenna device of FIG. 1, it becomes easier to couple with the antenna coil on the communication partner side, and an antenna device having good communication characteristics can be provided.

FIG. 3 shows another form of the antenna device in which the side surface of the opening 3 is widened, whereas in FIG. 2, a part (outer part) of the side surface of the opening 3 is widened toward the outside. In FIGS. 3 (a) and 3 (b), the entire side surfaces 33 on both sides of the ring-shaped conductor 1 in the direction around the axis A are widened outward. That is, in this antenna device, the side surfaces of the opening 3 on the first end surface 11 side and the second end surface 12 side are side surfaces along the radial direction, but the side surfaces 33 on both sides of the ring-shaped conductor 1 in the direction around the axis A. However, it is inclined outward from the radial side surface.

In such an antenna device, since the magnetic field spreads to the outside in the direction around the axis A, it becomes easy to couple with the antenna coil on the communication partner side, and an antenna device having good communication characteristics can be provided.

Further, in FIGS. 3C and 3D, one side surface of the opening 3 around the axis A is widened outward to form a side surface 34, and the other side surface is a side surface 35 along the radial direction. Even in such an antenna device, since the magnetic field spreads to the outside, it becomes easy to couple with the antenna coil on the communication partner side. The magnetic field can be expanded outward as the distance between the side surface of the opening 3 and the feeding coil 5 increases. In FIG. 3C, the distance between the side surface 35 along the radial direction and the feeding coil 5 is larger than the distance between the side surface 34 extending outward and the feeding coil 5.

FIG. 4 shows an antenna device in which the opening 3 of the ring-shaped conductor 1 is formed by a recess that opens outward. Since the bottom surface of the opening 3 formed of the recess is the ring-shaped conductor 1, power is supplied. Although not shown, a magnetic material layer is arranged between the coil 5 and the bottom surface of the opening 3.

Even with such an antenna device, the same effect as that of the antenna device of FIG. 1 can be obtained. Further, even in this form of the antenna device, the side surface on the axial side constituting the opening 3 of the ring-shaped conductor 1 as shown in FIG. 2 can be widened outward.

FIG. 5 shows an antenna device according to the second embodiment, and the antenna device includes a ring-shaped conductor 1 and a feeding coil 5.

In this antenna device, an inner ring-shaped member 15 made of, for example, an insulating material such as resin is arranged inside the ring-shaped conductor 1, and the bottom of the opening 3 is closed by the inner ring-shaped member 15 to supply power. A part of the coil 5 is arranged between the ring-shaped conductor 1 and the inner ring-shaped member 15.

The side surface of the opening 3 is formed by the side surface of the ring-shaped conductor 1 along the radial direction. Similar to the first embodiment, the opening 3 is filled with a dielectric material 7 such as resin or glass, and when viewed from the radial direction of the ring-shaped conductor 1, the opening 3 is a feeding coil. It overlaps a part of the coil opening of 5. Although not shown, a magnetic material layer is arranged between the power feeding coil 5 and the ring-shaped conductor 1.

Such an antenna device can be manufactured by inserting an inner ring-shaped member 15 in which the feeding coil 5 is arranged into the ring-shaped conductor 1 having the opening 3 formed therein.

Even with such an antenna device, the same effect as that of the antenna device of FIG. 1 can be obtained.

FIG. 6 shows a modification of the antenna device of FIG. 5 according to the second embodiment. In this antenna device, openings 3 are arranged on both sides of the feeding coil 5 around the axis A. That is, two openings 3 are formed around the axis A of the ring-shaped conductor 1 at intervals, and coil openings at both ends around the axis A of the power feeding coil 5 overlap each other in these openings. ..

In such an antenna device, the magnetic field can be spread more outward from the two openings 3, and it becomes easier to couple with the antenna coil on the communication partner side, so that an antenna device having good communication characteristics can be provided.

FIG. 7 shows a modified example of the antenna device according to the second embodiment. In this antenna device, the side surface forming the opening 3 of the ring-shaped conductor 1 extends outward. In such an antenna device, as shown in FIG. 7 (c), the opening 3 has an inner side surface (not shown) extending in the radial direction and an outer side surface extending outward from the inner side surface. It is composed of 36, and the feeding coil 5 is located outside the outer side surface 36. The outer side surface 36 is formed on the entire circumference of the opening 3. The outer side surface 36 can be formed by polishing the outer surface of the ring-shaped conductor 1 so that the outer side surfaces 36 formed on the entire circumference of the opening 3 are flush with each other (FIG. 2 and the details). See the relevant part of the book).

In such an antenna device, for example, the inner ring-shaped member 15 in which the feeding coil 5 is arranged is inserted into the ring-shaped conductor 1 having the opening 3, and the insulating material 7 is arranged in the opening 3. Can be made.

In such an antenna device, the magnetic field spreads from the feeding coil 5 in the direction around the axis A and in the axis A direction, in other words, the magnetic field spreads from the feeding coil 5 in all directions, and it becomes easier to couple with the antenna coil on the communication partner side. , An antenna device having good communication characteristics can be provided.

In the embodiments shown in FIGS. 5 to 7, the inner ring-shaped member 15 made of an insulating material such as resin is used, but a conductive inner ring-shaped member can also be used. When a conductive inner ring-shaped member is used, it is necessary to arrange a magnetic material layer between the feeding coil 5 and the inner ring-shaped member.

Further, in FIG. 7, the outer side surface 36 formed on the entire circumference of the opening is polished so as to be in the same plane, but the outer side surface 36 may extend outward, and a part thereof may be at a different angle. It may have an inclined surface.

Further, the outer surfaces of the ring-shaped conductor 1 on the first end surface 11 side and the second end surface 12 side may be polished in the direction around the axis A of the ring-shaped conductor 1. In this case, the outer side surface 32 is formed only on both sides of the opening 3 in the direction around the axis A (see FIG. 2D).

FIG. 8 shows an antenna device according to a third embodiment. In this antenna device, an inner ring-shaped member 15 is inserted in the ring-shaped conductor 1, and the feeding coil 5 is an inner ring-shaped member 15. It is configured by winding a power supply wire around the outer surface of the antenna.

The power feeding coil 5 is configured by winding a feeding wire around the outer surface of the inner ring-shaped member 15, and a part of the feeding coil 5 is located in the opening 3 when viewed from the radial direction of the ring-shaped conductor 1. ing.

Even with such an antenna device, it becomes easy to combine with the antenna coil on the communication partner side, and an antenna device having good communication characteristics can be provided.

Even in the antenna device of FIG. 8, by widening the side surface forming the opening toward the outside, it becomes easy to connect with the antenna coil on the communication partner side, and an antenna device having good communication characteristics can be provided.

The antenna device of the present invention can be used, for example, for rings, bangles, wristbands, wristwatches, bracelets, earrings, piercings and the like. When considered as jewelry, the conductor may be a precious metal such as gold, silver or platinum, or a cemented carbide such as cermet. Since it is desirable that the size can be adjusted as a function when used as a ring, the inner ring-shaped member as shown in FIG. 8 is preferably a member whose dimensions can be easily changed. For example, a metal such as silver may be stretched or polished.

In the above embodiment, when the ring-shaped conductor 1 has an opening 3 extending around the axis A at a position separated from the first end surface 11 and the second end surface 12, the opening 3 of the ring-shaped conductor 1 is formed. The case where the side surface on the side around the axis A is widened outward has been described, but the structure in which the opening extends to the first end surface and / or the second end surface, in other words, the first end surface and / or Even if the structure is such that a slit extending inward from the second end surface of the ring-shaped conductor is connected to the opening 3, the magnetic field is expanded in the direction around the axis A by expanding the side surface on the side around the axis A toward the outside. It is possible to improve the communication characteristics.

The transmission characteristics of the antenna device of the embodiment shown in FIG. 5 were calculated by simulation. The analysis model is shown in FIG. In the simulation, the magnetic material and conductor were set to be lossless in order to investigate the effect of communication jamming due to the aperture. The ring-shaped conductor has a width of 12 mm, an inner diameter of 8.5 mm, and an outer diameter of 14 mm, and is a conductor including the side surface except for the opening.

The ring consists of inner to inner conductor, inner magnetic material, air, coil, air, outer magnetic material,
It is an outer conductor, and the thickness is 0.5 mm, 1 mm, 1 mm, and 0.01 mm, respectively.
It is 1 mm, 1 mm, and 1 mm. However, since the coil is included in the air layer, it is not included in the total thickness. The opening has a length of 13 mm and a width of 3 mm as an arc with respect to the outer magnetic material and the outer conductor.

The coil has a width of 0.1 mm, an interval of 0.1 mm, and 13 turns, is curved along the ring, and sets the port 1. When the start of 13 turns is the outside, the outer dimensions of the coil are 20.1 mm in length and 10.1 mm in width, and when the end of 13 turns is the inside, the inner dimensions are 15.3 mm in length and 5. It is 1 mm.

Further, a coil different from the ring coil is prepared and the port 2 is set. The coil of the port 2 has a width of 0.1 mm, an interval of 0.1 mm, and a planar structure of 13 turns. When the start of 13 turns is the outside, the outer dimensions of the coil are 80.1 mm in length and 40.1 mm in width, and when the end of 13 turns is the inside, the inner dimensions are 75.1 mm in length and 35. It is 3 mm. In the antenna device of FIG. 5, the amount of attenuation between the coils at the analysis frequency of 13.56 MHz was −9.4 dB, which was within an acceptable range.

On the other hand, in the antenna device of FIG. 5, the attenuation amount is -0.2 dB in the antenna device of FIG. 7 in which both side surfaces on the axial side forming the opening are widened outward, which can be dramatically improved. It was. The analysis model at this time is shown in FIG.

From these simulations, it can be seen that the antenna device of the present invention can be easily coupled with the antenna coil on the communication partner side, and an antenna device having good communication characteristics can be provided.

A ... Shaft 1 ... Ring-shaped conductor 3 ... Opening 5 ... Feed coil 11 ... First end face 12 ... Second end face 15 ... Inner ring-shaped member 31, 35. .. Inner side 32, 33, 34, 36 ... Outer side

Claims (9)

With the power supply coil
A ring-shaped conductor arranged around an axis and having a first end face and a second end face in the axial direction,
With
The feeder is wound around the feeder when viewed from the radial direction of the ring-shaped conductor.
The ring-shaped conductor has an opening extending around the axis and opening outward at a position separated from the first end surface and the second end surface.
The antenna device is characterized in that at least a part of the opening overlaps the coil opening of the feeding coil when viewed from the radial direction. The antenna device according to claim 1, wherein the openings are arranged on both sides of the feeding coil around the axis. The antenna device according to claim 1 or 2, wherein the opening is formed of a through hole or a recess formed in the ring-shaped conductor. An inner ring-shaped member is inserted inside the ring-shaped conductor, the bottom of the opening is closed by the inner ring-shaped member, and at least a part of the feeding coil is the ring-shaped conductor and the said. The antenna device according to any one of claims 1 to 3, which is arranged between the inner ring-shaped member and the antenna device. With the power supply coil
A ring-shaped conductor arranged around an axis and having a first end face and a second end face in the axial direction,
An inner ring-shaped member inserted into the ring-shaped conductor and
With
The feeding coil is configured by winding a feeding wire around the outer surface of the inner ring-shaped member.
The ring-shaped conductor has an opening extending around the axis and opening outward at a position separated from the first end surface and the second end surface.
An antenna device characterized in that a part of the feeding coil is located in the opening when viewed from the radial direction of the ring-shaped conductor. The antenna device according to any one of claims 1 to 5, wherein the side surface on the axial side constituting the opening of the ring-shaped conductor extends outward. The antenna device according to any one of claims 1 to 6, wherein resin or glass is arranged in the opening. The antenna device according to any one of claims 1 to 7.
A communication terminal device including a feeding circuit connected to the feeding coil or coupled with an electric field, a magnetic field, or an electromagnetic field. The communication terminal device according to claim 8, wherein the ring-shaped conductor is provided in a mounting portion through which a part of a human body is inserted.