Wireless communication device

Abstract

To provide a radio communication device with improved non-directivity.SOLUTION: The wireless communication device includes an RFIC chip, a matching circuit part connected to the RFIC chip, and an antenna magnetically coupled to the matching circuit part. The antenna includes a first coil magnetically coupled to the matching circuit unit, and a first electrode and a second electrode respectively connected to both ends of the first coil. The first electrode and the second electrode face each other.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a wireless communication device equipped with an antenna, and more particularly to a wireless communication device that utilizes RFID (Radio-Frequency Identification) technology. [Background technology]

[0002] Conventionally, "RFID tags," which are wireless communication devices, have been attached to articles. RFID tags may include an RFID inlay therein, which is an antenna wiring disposed on a film substrate. As shown in FIG. 10, the IC tag in Patent Document 1 includes a radiating element portion 101 that functions as a dipole antenna, and an RFIC (Radio-Frequency Integrated Circuit) 105 is mounted on a matching loop circuit 103 that can be magnetically coupled to this radiating element portion 101. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2010-268023 Summary of the Invention [Problem to be solved by the invention]

[0004] However, for example, when an IC tag 100 with a dipole antenna is wrapped around a cylindrical article 110 as shown in FIG. 11, a null point occurs in the horizontal direction where the communication distance is significantly reduced.

[0005] The present invention aims to provide a wireless communication device with improved omnidirectionality. [Means for solving the problem]

[0006] A wireless communication device according to one embodiment of the present invention includes an RFIC chip, a matching circuit connected to the RFIC chip, and an antenna magnetically coupled to the matching circuit. The antenna has a first coil magnetically coupled to the matching circuit, and a first electrode and a second electrode connected to both ends of the first coil, respectively. The first electrode and the second electrode face each other. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a wireless communication device with improved omnidirectionality. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a perspective plan view showing a schematic configuration of an RFID inlay according to a first embodiment. [Figure 2] Illustrative diagram showing the electric and magnetic field distribution of an RFID inlay [Figure 3] Illustrative diagram showing voltage and current distribution in RFID inlay [Figure 4] FIG. 4 is an explanatory diagram showing the portion of the RFID inlay corresponding to the voltage and current distribution in FIG. 3. [Figure 5] Enlarged view of the matching circuit area in Figure 1 [Figure 6] FIG. 1 shows the antenna gain of the RFID inlay of the first embodiment. [Figure 7] FIG. 1 shows the antenna gain of an RFID inlay in a comparative example. [Figure 8] FIG. 10 is a partial perspective plan view showing a schematic configuration of a modified example of the RFID inlay of the first embodiment. [Figure 9] FIG. 10 is a perspective plan view showing a schematic configuration of an RFID inlay according to a second embodiment. [Figure 10] FIG. 1 is a plan view showing a schematic configuration of an RFID inlay in a comparative example. [Figure 11] An explanatory diagram showing how an RFID inlay is used in a comparative example. DETAILED DESCRIPTION OF THE INVENTION

[0009] Each of the embodiments described below shows a specific example of the present invention, and the present invention is not limited to this configuration. Furthermore, the numerical values, shapes, configurations, steps, and step orders specifically shown in the following embodiments are examples and do not limit the present invention. Among the components in the following embodiments, components that are not described in the independent claims that represent the highest concepts are described as optional components. Furthermore, in all embodiments, the configurations in each modification are the same, and the configurations described in each modification may be combined with each other.

[0010] (Embodiment 1) Next, a schematic configuration of an RFID inlay 1, which is a wireless communication device according to a first embodiment of the present invention, will be described with reference to Fig. 1. Fig. 1 is a perspective plan view showing a schematic configuration of the RFID inlay 1 according to the first embodiment. Note that the longitudinal direction of the RFID inlay 1 is defined as the X-axis direction, the width direction of the RFID inlay 1 is defined as the Z-axis direction, and the direction perpendicular to the XZ plane is defined as the Y-axis direction.

[0011] In the first embodiment, the RFID inlay 1 includes a substrate 3, an antenna 5, a matching circuit section 21, and an RFIC chip .

[0012] The substrate 3 is a flexible substrate having insulating properties and flexibility, and is made of a resin such as PET (polyethylene terephthalate) or PEN (polyethylene naphthalate). The substrate 3 has a first main surface 31 and a second main surface 33, which face each other in the Y-axis direction. The matching circuit section 21 and the RFIC chip 23 are arranged on the first main surface 31 side, and most of the antenna 5 is arranged on the second main surface 33 side.

[0013] The antenna 5 includes a first electrode 7, a second electrode 9, and a first coil 11. The first electrode 7, the second electrode 9, and the first coil 11 are each disposed on the second main surface 33 of the substrate 3. The first coil 11 is a spiral coil-shaped wiring wound in the same direction, and is magnetically coupled to the matching circuit section 21. The first coil 11 has at least one turn of wiring. One end 35 of the first coil 11 is connected to one end of the first electrode 7.

[0014] The antenna 5 further includes interlayer connection conductors 13 and 15, such as through-hole conductors, and a wiring electrode 17. The interlayer connection conductors 13 and 15 each pass through the substrate 3. The other end of the first coil 11 is connected to one end of the interlayer connection conductor 13, and the other end of the interlayer connection conductor 13 is connected to one end of the wiring electrode 17 arranged on the first main surface 31. The wiring electrode 17 extends from the inside to the outside of the first coil, and the other end of the wiring electrode 17 is connected to one end of the interlayer connection conductor 15. The other end of the interlayer connection conductor 15 is connected to one end of the second electrode 9.

[0015] The first electrode 7 and the second electrode 9 are disposed opposite each other in the width direction (Z-axis direction) of the substrate 3. The first electrode 7 and the second electrode 9 each extend in the longitudinal direction of the substrate 3, and therefore extend in the same direction. The first electrode 7 and the second electrode 9 each function as a radiating element. The other end of the first electrode 7 and the other end of the second electrode 9 are each open ends.

[0016] The matching circuit section 21 matches the impedance between the antenna 5 and the RFIC chip 23. The matching circuit section 21 includes a second coil 25 and a third coil 27. The second coil 25 and the third coil 27 are each a spiral coil-shaped wire.

[0017] The second coil 25 is wound in the same direction as the second coil 25 and has an outer peripheral end 41 and an inner peripheral end 43. The third coil 27 is wound in the same direction as the second coil 25 and has an outer peripheral end 45 and an inner peripheral end 47. Therefore, when the second coil 25 is wound counterclockwise, the third coil 27 is also wound counterclockwise, and when the second coil 25 is wound clockwise, the third coil 27 is also wound clockwise. The outer peripheral end 41 of the second coil 25 and the outer peripheral end 45 of the third coil 27 are connected via the RFIC chip 23. The inner peripheral end 43 of the second coil 25 is connected to one end of a wiring electrode 49 disposed on the second main surface 33 of the substrate 3 via an interlayer connection conductor. The other end of the wiring electrode 49 is connected to the inner peripheral end 47 of the third coil 27 via an interlayer connection conductor. Therefore, the matching circuit section 21 of the first embodiment is an eight-shaped spiral coil.

[0018] The outer peripheral end 41 of the second coil 25 and the outer peripheral end 45 of the third coil 27 may be connected via wiring. Alternatively, by arranging the RFIC chip 23 on the second main surface 33 side of the substrate 3, the inner peripheral end 43 of the second coil 25 may be connected to one end of the RFIC chip 23 via an interlayer connection conductor, and the inner peripheral end 47 of the third coil 27 may be connected to the other end of the RFIC chip 23 via an interlayer connection conductor.

[0019] In Fig. 1, the winding axis of the third coil 27 is the Y-axis. Fig. 1 is a plan view of the RFID inlay 1 as viewed from the Y-axis direction, and the matching circuit unit 21 is disposed at a position where all or part of the coil opening 28 of the third coil 27 overlaps with the coil opening 12 of the first coil 11. This allows for appropriate magnetic field coupling between the first coil 11 of the antenna 5 and the third coil 27 of the matching circuit unit 21. This allows for current to flow in the RFIC chip 23 using the current flowing in the antenna 5 due to a wireless signal at a communication frequency as an energy source.

[0020] The matching circuit section 21 is disposed between the first electrode 7 and the second electrode 9. This allows the space on the substrate 3 to be used effectively, and the RFID inlay 1 to be made smaller.

[0021] The first electrode 7, second electrode 9, and first coil 11 of the antenna 5, the wiring electrode 17, the second coil 25 and third coil 27 of the matching circuit section 21, and the wiring electrode 49 are composed of conductor patterns made of a conductive material such as aluminum foil or copper foil.

[0022] The magnetic field generated from the antenna 5 will be described with reference to Figures 2 to 4. Figure 2 is an explanatory diagram showing the electric and magnetic field distribution of the RFID inlay 1. Figure 3 is an explanatory diagram showing the voltage and current distribution of the RFID inlay 1. Figure 4 is an explanatory diagram showing the part of the RFID inlay 1 corresponding to the voltage and current distribution of Figure 3.

[0023] Since the dipole antenna 5 has the first coil 11 at the center of its electrical length, the current of the antenna 5 is concentrated in the first coil 11. This reduces the current flowing through the first electrode 7 and the second electrode 9, reducing the bias of the electric field distribution at the first electrode 7 and the second electrode 9. Since the first electrode 7 and the second electrode 9 are arranged opposite each other, one of them is positive and the other is negative, an electric field of approximately uniform strength is generated perpendicular to the first electrode 7 and the second electrode 9. In this way, the electric field distribution generated between the first electrode 7 and the second electrode 9 arranged opposite each other is approximately uniform along the extension direction of the first electrode 7 and the second electrode 9, i.e., along the longitudinal direction of the substrate 3.

[0024] A magnetic field is generated perpendicular to the direction of the electric field generated by the antenna 5. Because the electric field distribution is uniform, a nearly uniform magnetic field is generated horizontally and uniformly along the direction in which the first electrode 7 and the second electrode 9 extend. Therefore, the radiation characteristics of the antenna 5 are omnidirectional in the horizontal plane.

[0025] 3 and 4, if the electrical length of antenna 5 is λ / 2 with respect to the resonant frequency (communication frequency) of antenna 5, the electrical length of first coil 11 is λ / 4 or more with respect to the resonant frequency. That is, the electrical length of each of first electrode 7 and second electrode 9 is λ / 8 or less with respect to the resonant frequency.

[0026] By making the electrical length of the first coil 11 λ / 4 or more, the current flowing through the antenna 5 is concentrated in the first coil 11, and the gradient of the voltage distribution in the opposing first electrode 7 and second electrode 9 becomes almost constant. This makes the electric field strength between the first electrode 7 and the second electrode 9 uniform.

[0027] The first electrode 7 and the second electrode 9 are arranged parallel to each other. Here, "parallel" does not only mean that the first electrode 7 and the second electrode 9 are completely parallel to each other, but also means that the angle between the first electrode 7 and the X-axis is between -15 degrees and 15 degrees, and the angle between the second electrode 9 and the X-axis is between -15 degrees and 15 degrees. By arranging the first electrode 7 and the second electrode 9 in parallel to each other in this way, the direction of the electric field generated between the first electrode 7 and the second electrode 9 can be made uniform.

[0028] Next, reference is made to Figure 5. Figure 5 is a partially enlarged view of the area around matching circuit unit 21 in Figure 1. By employing a so-called figure-8 spiral coil as matching circuit unit 21, the magnetic field generated by second coil 25 and third coil 27 becomes a closed magnetic field, making it possible to suppress radiation of a magnetic field from matching circuit unit 21. Therefore, it is possible to suppress the magnetic field generated by matching circuit unit 21 from affecting the magnetic fields radiated from first electrode 7 and second electrode 9 of antenna 5.

[0029] Furthermore, the first electrode 7 has a thick wire portion 51 and a thin wire portion 52, and the second electrode has a thick wire portion 53 and a thin wire portion 54. The thin wire portion 52 extends from the connection point with one end 35 of the first coil 11 in a direction away from the first coil 11 in the longitudinal direction of the substrate 3, and is connected to the thick wire portion 51 near the end of the matching circuit section 21 opposite the first coil 11. The thick wire portion 51 extends from near the end of the matching circuit section 21 in a direction away from the matching circuit section 21 in the longitudinal direction of the substrate 3.

[0030] The line width Wk of the thick line portions 51 and 53 is larger than the line width Wn of the thin line portions 52 and 54. Furthermore, the line width Wk of the thick line portions 51 and 53 and the line width Wn of the thin line portions 52 and 54 are larger than the line width of the first coil 11. Since the line width Wk of the thick line portions 51 and 53 is larger than the line width of the first coil 11, the charge density in the thick line portions 51 and 53 can be more uniform, and a more uniform electric field can be generated. In the first embodiment, the line widths Wk of the thick line portions 51 and 53 may be the same but different. Similarly, the line widths Wn of the thin line portions 52 and 54 may be the same but different. Furthermore, the thick line portions 51 and 53 are each linear, but may also be curved. The distance Lb between the thick line portions 51 and 53 is, for example, 1 mm or more and 40 mm or less.

[0031] By forming the portions of the first electrode 7 and the second electrode 9 facing the matching circuit section 21 as the thin wire sections 52 and 54, respectively, it is possible to increase the distance La between the first electrode 7 and the second electrode 9 and the matching circuit section 21, and to suppress magnetic field coupling between the first electrode 7 and the second electrode 9 and the matching circuit section 21. This makes it possible to suppress the magnetic field generated in the matching circuit section 21 from affecting the magnetic fields radiated from the first electrode 7 and the second electrode 9 of the antenna 5.

[0032] Please refer to Fig. 6. Fig. 6 is a diagram showing the antenna gain of the RFID inlay 1 in embodiment 1. As shown in Fig. 6, the RFID inlay 1 can obtain omnidirectional antenna gain in the XY plane. That is, omnidirectional antenna gain can be obtained on a plane perpendicular to the main surface of the substrate 3. Therefore, when the XZ plane of the RFID inlay 1 is wrapped around a cylindrical article, omnidirectional antenna gain can be obtained in the horizontal direction from the cylindrical surface, allowing wireless communication without the occurrence of null points.

[0033] In contrast, the antenna gain of an RFID inlay having a conventional dipole antenna will be described with reference to Fig. 7. Fig. 7 is a diagram showing the antenna gain of an RFID inlay in a comparative example. As shown in Fig. 7, with a conventional dipole antenna, a null point occurs in the X-axis direction. Therefore, when the XZ plane of the RFID inlay is wrapped around a cylindrical object, a direction in which wireless communication is not possible occurs horizontally from the cylindrical surface, which may prevent smooth wireless communication and may lead the user to mistakenly believe that the RFID inlay is damaged.

[0034] As described above, the RFID inlay 1 of the first embodiment includes the RFIC chip 23, the matching circuit section 21 connected to the RFIC chip 23, and the antenna 5 magnetically coupled to the matching circuit section 21. The antenna 5 includes the first coil 11 magnetically coupled to the matching circuit section 21, and the first electrode 7 and the second electrode 9 connected to both ends of the first coil 11, respectively. The first electrode 7 and the second electrode 9 face each other.

[0035] With the RFID inlay 1 having this configuration, the current flowing through the antenna 5 can be concentrated in the first coil 11, so the strength of the electric field generated between the opposing first electrode 7 and second electrode 9 can be made uniform. Therefore, the strength of the magnetic field generated in a direction perpendicular to the electric field can also be made uniform, improving the omnidirectionality of the antenna 5. The RFID inlay 1 is not limited to being used on cylindrical objects, and may be attached across multiple surfaces of a rectangular object.

[0036] The matching circuit section 21 also has a second coil 25 and a third coil 27. The second coil 25 is wound in the same direction and has an outer peripheral end 41 and an inner peripheral end 43. The third coil 27 is wound in the same direction and has an outer peripheral end 45 and an inner peripheral end 47. The outer peripheral end 41 of the second coil 25 and the outer peripheral end 45 of the third coil 27 are connected via the RFIC chip 23, and the inner peripheral end 43 of the second coil 25 and the inner peripheral end 47 of the third coil 27 are connected via a wiring electrode 49. Alternatively, the outer peripheral end 41 of the second coil 25 and the outer peripheral end 45 of the third coil 27 are connected via a wiring, and the inner peripheral end 43 of the second coil 25 and the inner peripheral end 47 of the third coil 27 are connected via the RFIC chip 23.

[0037] Since the matching circuit section 21 on which the RFIC chip 23 is mounted is a so-called figure-8 coil, the magnetic field generated by the matching circuit section 21 is closed, and the influence on the magnetic field generated by the antenna 5 can be reduced.

[0038] Furthermore, the matching circuit section 21 is arranged at a position where, when viewed from the winding axis of the second coil 25 or the third coil 27, all or part of the coil opening 28 of the second coil 25 or the third coil 27 overlaps with the coil opening 12 of the first coil 11.

[0039] This allows for appropriate magnetic field coupling between the second coil 25 or the third coil 27 of the matching circuit section 21 and the first coil 11 of the antenna 5.

[0040] Next, an RFID inlay 1A according to a modification of the first embodiment will be described with reference to Fig. 8. Although the coil opening 12 of the first coil 11 of the antenna 5 of the RFID inlay 1 described above overlaps with the coil opening 28 of the third coil 27 of the matching circuit unit 21 in a plan view, this is not limitative. As shown in Fig. 8, in the RFID inlay 1A according to the modification, the coil opening 12 of the first coil 11 of the antenna 5A overlaps with the coil opening 26 of the second coil 25 of the matching circuit unit 21 in a plan view.

[0041] Therefore, in a plan view, matching circuit section 21 is disposed on the opposite side of first coil 11 from first electrode 7A and second electrode 9A of antenna 5A. In this case, first electrode 7A and second electrode 9A may have thick line portions 51 and 53 throughout their entirety, without being provided with thin line portions 52 and 54, respectively, as in embodiment 1. The line widths of first electrode 7A and second electrode 9A of antenna 5A in this modification are the same as the line width Wk of thick line portions 51 and 53 of first electrode 7 and second electrode 9 of antenna 5 in embodiment 1.

[0042] (Embodiment 2) Next, an RFID inlay 1B of embodiment 2 will be described with reference to Fig. 9. Fig. 9 is a perspective plan view showing a schematic configuration of the RFID inlay 1B of embodiment 2. The RFID inlay 1B of embodiment 2 will be described mainly focusing on the differences from the RFID inlay 1 of embodiment 1. In the description of embodiment 2, elements having the same configuration, action, and function as those of embodiment 1 will be given the same reference numerals, and descriptions will be omitted to avoid duplication.

[0043] The matching circuit section 21 in the RFID inlay 1 of the first embodiment is an eight-shaped spiral coil, whereas the matching circuit section 21B in the RFID inlay 1B of the second embodiment is a single spiral coil.

[0044] 9, an outer peripheral end 61 of the matching circuit section 21B is connected to one end of the RFIC chip 23 via a wiring electrode. An inner peripheral end 63 of the matching circuit section 21B is connected to one end of a wiring electrode 65 disposed on the second main surface 33 of the substrate 3 via an interlayer connection conductor such as a through-hole conductor. The other end of the wiring electrode 65 is connected to the other end of the RFIC chip via the interlayer connection conductor and the wiring electrode.

[0045] A part of the coil opening 67 of the matching circuit unit 21B overlaps with a part of the coil opening 12 of the first coil 11 of the antenna 5 and a part of the first coil 11 in a plan view, so that the matching circuit unit 21B and the first coil 11 can be magnetically coupled. This allows a current to flow in the RFIC chip 23 using the current flowing in the antenna 5 by a wireless signal of a communication frequency as an energy source.

[0046] According to the RFID inlay 1B of the second embodiment, the magnetic field generated by the matching circuit section 21B has only a small effect on the magnetic field generated by the antenna 5, so that an antenna gain with improved omnidirectionality can be obtained compared to conventional methods.

[0047] The present invention is not limited to the above-described embodiments, but can be modified as follows.

[0048] (1) In the above embodiment, the RFID inlay 1 is used as an example of a wireless communication module, but this is not limiting. The above-described antenna configuration may be configured such that the substrate 3 is made of a rigid, inflexible material. Furthermore, the wireless communication module may be configured as an RFID tag using the RFID inlay 1.

[0049] Although the present invention has been described in various embodiments with a certain degree of detail, the disclosure of these embodiments may vary in structural details, and variations in the combination and order of elements in the various embodiments may be realized without departing from the scope and spirit of the invention as claimed.

[0050] A wireless communication device according to a first aspect of the present invention includes an RFIC chip, a matching circuit connected to the RFIC chip, and an antenna magnetically coupled to the matching circuit. The antenna has a first coil magnetically coupled to the matching circuit, and a first electrode and a second electrode connected to both ends of the first coil, respectively. The first electrode and the second electrode face each other.

[0051] According to the wireless communication device of this aspect, the current flowing through the antenna can be concentrated in the first coil, so the strength of the electric field generated between the opposing first and second electrodes can be made uniform, and therefore the strength of the magnetic field generated in a direction perpendicular to the electric field can also be made uniform, improving the omnidirectionality of the antenna.

[0052] According to a second aspect, in the wireless communication device of the first aspect, the matching circuit unit includes a second coil and a third coil. The second coil is wound in the same direction and has a first outer circumferential end and a first inner circumferential end. The third coil is wound in the same direction as the second coil and has a second outer circumferential end and a second inner circumferential end. The first outer circumferential end of the second coil and the first outer circumferential end of the third coil are connected via an RFIC chip, and the first inner circumferential end of the second coil and the second inner circumferential end of the third coil are connected via wiring, or the first outer circumferential end of the second coil and the first outer circumferential end of the third coil are connected via wiring, and the first inner circumferential end of the second coil and the second inner circumferential end of the third coil are connected via the RFIC chip.

[0053] According to a third aspect, in the wireless communication device of the first or second aspect, the matching circuit unit has a second coil and a third coil, and is arranged at a position where, when viewed from the winding axis of the second coil or the third coil, all or part of the coil opening of the second coil or the third coil overlaps with the coil opening of the first coil.

[0054] According to a fourth aspect, in the wireless communication device of the second or third aspect, the second coil is disposed between the first electrode and the second electrode.

[0055] According to a fifth aspect, in the wireless communication device of any one of the first to fourth aspects, the first electrode and the second electrode are arranged in parallel.

[0056] According to a sixth aspect, in the wireless communication device of any one of the first to fifth aspects, the length of each of the first electrode and the second electrode is λ / 8 or less, where λ is a wavelength corresponding to the resonant frequency of the antenna.

[0057] According to a seventh aspect, the wireless communication device of any one of the first to sixth aspects further comprises a flexible substrate on which the matching circuit section and the antenna are arranged.

[0058] According to an eighth aspect, in the wireless communication device of any one of the first to seventh aspects, the line width of the first electrode and the line width of the second electrode are larger than the line width of the first coil. [Explanation of symbols]

[0059] 1 RFID inlay 3. Circuit Board 5 Antennas 7 1st electrode 9 Second electrode 11 First coil 12 Coil opening 13, 15 Interlayer connecting conductor 17 Wiring electrode 21 Matching circuit section 23 RFIC chip 25 Second coil 26 Coil opening 27 Third coil 28 Coil opening 31 First main surface 33 Second main surface 35 one end 41 Outer edge 43 Inner edge 45 Outer edge 47 Inner edge 49 Wiring electrode 51 Bold line section 52 Thin line part 53 Thick line section 54 Thin line part 61 Outer edge 63 Inner edge 65 Wiring electrode 67 Coil opening

Claims

1. An RFIC chip; a matching circuit unit connected to the RFIC chip; an antenna that is magnetically coupled with the matching circuit section, the antenna includes a first coil that is magnetically coupled with the matching circuit unit, and a first electrode and a second electrode that are connected to both ends of the first coil, The first electrode and the second electrode face each other. Wireless communication devices.

2. the matching circuit section has a second coil and a third coil, the second coil is wound in the same direction and has a first outer circumferential end and a first inner circumferential end; the third coil is wound in the same direction as the second coil and has a second outer circumferential end and a second inner circumferential end; the first outer peripheral end of the second coil and the first outer peripheral end of the third coil are connected via the RFIC chip, and the first inner peripheral end of the second coil and the second inner peripheral end of the third coil are connected via wiring, or the first outer peripheral end of the second coil and the first outer peripheral end of the third coil are connected via wiring, and the first inner peripheral end of the second coil and the second inner peripheral end of the third coil are connected via the RFIC chip. The wireless communication device of claim 1 .

3. the matching circuit section has a second coil and a third coil, the matching circuit unit is disposed at a position where, when viewed from a winding axis of the second coil or the third coil, all or part of a coil opening of the second coil or the third coil overlaps with a coil opening of the first coil. The wireless communication device of claim 1 .

4. The second coil is disposed between the first electrode and the second electrode.

4. A wireless communication device according to claim 2 or 3.

5. The first electrode and the second electrode are arranged in parallel. The wireless communication device of claim 1 .

6. The length of each of the first electrode and the second electrode is λ / 8 or less, where λ is a wavelength corresponding to a resonant frequency of the antenna. The wireless communication device of claim 1 .

7. a flexible substrate on which the matching circuit section and the antenna are disposed, The wireless communication device of claim 1 .

8. The line width of the first electrode and the line width of the second electrode are larger than the line width of the first coil. The wireless communication device of claim 1 .

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