Antenna device and antenna module including same

Abstract

To provide an antenna device that requires less space and less number of components.SOLUTION: An antenna device 1 comprises a substrate 2, and a coil pattern CP1, a coil pattern CP2 and a capacitor C2 provided on a surface 2a of the substrate 2. The coil pattern CP2 has an aperture area smaller than the coil pattern CP1, and is placed at a position overlapping the aperture area of the coil pattern CP1. The coil pattern CP2 is connected to the capacitor C2 to form a closed circuit. Therefore, an antenna device that requires less space and less number of components can be provided.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to an antenna device and an antenna module including the same. [Background technology]

[0002] Near Field Communication (NFC) is one of the short-range wireless communication standards, and a method of wirelessly communicating via an antenna coil is known. In order to extend the communication distance in wireless communication, Patent Document 1 proposes placing a booster antenna between an RFIC tag and an RFIC reader / writer. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 4358242 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the booster antenna disclosed in Patent Document 1 has a problem in that it requires a large space because it is located about 6 mm away from the RFIC reader / writer. Also, the booster antenna disclosed in Patent Document 1 has a problem in that the number of parts increases because a capacitor is connected to the coil pattern.

[0005] Therefore, an object of the present disclosure is to provide an antenna device that requires a small space and has a small number of parts, and an antenna module including the same. [Means for solving the problem]

[0006] An antenna device according to one embodiment of the present disclosure comprises a substrate, a first coil pattern, a second coil pattern, and a first capacitor provided on a surface of the substrate, wherein the first coil pattern has an opening area smaller than that of the second coil pattern and is positioned so as to overlap with the opening area of ​​the second coil pattern, and one of the first and second coil patterns is connected to the first capacitor to form a closed circuit. Effect of the Invention

[0007] According to the present disclosure, it is possible to provide an antenna device that requires a small space and has a small number of parts, and an antenna module including the same. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic cross-sectional view for explaining the structure of an antenna device 1 according to an embodiment. [Diagram 2] FIG. 2 is a schematic plan view showing the shape of the conductor pattern formed on the front surface 2a of the base material 2. As shown in FIG. [Diagram 3] FIG. 3 is a schematic plan view showing the shape of the conductor pattern formed on the front surface 2b of the base material 2. As shown in FIG. [Figure 4] FIG. 4 is a graph showing the relationship between the coupling coefficient k of the coil patterns CP1 and CP2 and the communication distance. [Diagram 5] FIG. 5 is a graph showing the relationship between the resonance frequency f1 and the communication distance. [Figure 6] FIG. 6 is a graph showing the relationship between the resonance frequency f2 and the communication distance. [Figure 7] FIG. 7 is a schematic plan view showing the shape of a conductor pattern formed on a front surface 2a of a substrate 2 in an antenna device according to a first modified example. [Figure 8] FIG. 8 is a schematic plan view showing the shape of a conductor pattern formed on the front surface 2b of the substrate 2 in an antenna device according to a first modified example. [Figure 9] FIG. 9 is a schematic plan view showing the shape of a conductor pattern formed on a front surface 2a of a substrate 2 in an antenna device according to a second modified example. [Figure 10] FIG. 10 is a schematic plan view showing the shape of a conductor pattern formed on the front surface 2b of the substrate 2 in an antenna device according to the second modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

[0010] FIG. 1 is a schematic cross-sectional view for explaining the structure of an antenna device 1 according to an embodiment.

[0011] As shown in Fig. 1, an antenna device 1 according to an embodiment includes a base material 2 made of a PET film or the like, coil patterns CP1 and CP2 provided on a surface 2a of the base material 2, a metal member 3 overlapping the base material 2, and a magnetic body 4 disposed between the base material 2 and the metal member 3. The coil pattern CP1 is an antenna coil connected to an IC module. The coil pattern CP2 is a booster antenna for extending the communication distance by coupling with the antenna coil.

[0012] Fig. 2 is a schematic plan view showing the shape of the conductor pattern formed on the surface 2a of the substrate 2. Fig. 3 is a schematic plan view showing the shape of the conductor pattern formed on the surface 2b of the substrate 2, as viewed from the surface 2a side of the substrate 2, that is, as viewed through the substrate 2.

[0013] As shown in FIG. 2, the surface 2a of the substrate 2 is formed with a conductor pattern 10 wound in a spiral shape with three turns and a conductor pattern 20 wound in a spiral shape with five turns. The conductor pattern 10 constitutes a coil pattern CP1, and the conductor pattern 20 constitutes a coil pattern CP2. That is, in the example shown in FIG. 2 and FIG. 3, the coil pattern CP2 has a larger number of turns than the coil pattern CP1. The conductor patterns 10 and 20 are both substantially rectangular when viewed from the z-axis direction, which is the coil axis, and the conductor pattern 20 is disposed in the opening region (inner diameter region) of the conductor pattern 10. That is, the conductor pattern 20 has a smaller opening area than the conductor pattern 10, and is disposed at a position overlapping the opening region of the conductor pattern 10. In this way, the conductor pattern 10 is configured to go around the outside of the conductor pattern 20 when viewed from the z-axis direction, which is the coil axis, and the conductor pattern 20 is contained within the opening region of the conductor pattern 10. In the example shown in FIG. 2 and FIG. 3, the coil pattern CP1 is an example of a second coil pattern, and the coil pattern CP2 is an example of a first coil pattern.

[0014] The outer peripheral end 11 of the conductor pattern 10 is connected to the terminal electrode E1. The inner peripheral end 12 of the conductor pattern 10 is connected to a through-hole conductor 13 penetrating the substrate 2. The through-hole conductor 13 is connected to a through-hole conductor 15 penetrating the substrate 2 via a connection pattern 14 formed on the surface 2b of the substrate 2. The through-hole conductor 15 is connected to a terminal electrode E2 formed on the surface 2a of the substrate 2. As a result, one end and the other end of the spiral conductor pattern 10 are connected to the terminal electrodes E1 and E2, respectively. The terminal electrodes E1 and E2 are connected to a capacitor C1 for adjusting a resonance frequency and to an IC module 5. As a result, an antenna module is formed by the antenna device 1 according to this embodiment and the IC module 5, and a signal transmitted and received from the IC module 5 is supplied to the coil pattern CP1. The coil pattern CP1 and the capacitor C1 form a resonance circuit. In FIG. 2, the capacitor C1 is connected in parallel to the coil pattern CP1, but instead of or in addition to this, the capacitor C1 may be connected in series to the coil pattern CP1.

[0015] The outer peripheral end 21 of the conductor pattern 20 is connected to a through-hole conductor 23 that penetrates the substrate 2. The inner peripheral end 22 of the conductor pattern 20 is connected to a capacitor electrode pattern 24. The through-hole conductor 23 is connected to a capacitor electrode pattern 25 formed on the surface 2b of the substrate 2. The capacitor electrode patterns 24, 25 face each other via the substrate 2 to form a capacitor C2. The coil pattern CP2 and the capacitor C2 form another resonant circuit. Unlike the coil pattern CP1, the coil pattern CP2 does not have a terminal electrode for connecting to the outside, and is connected only to the capacitor C2. In other words, the coil pattern CP2 is completed by the conductor patterns formed on the surfaces 2a, 2b of the substrate 2, and forms a closed circuit that is completely closed in terms of direct current. The coil pattern CP2 functions as a booster antenna for expanding the communication distance by being coupled with the coil pattern CP1. In the example shown in FIG. 2 and FIG. 3, the capacitor C2 is an example of a first capacitor.

[0016] The coil pattern CP2 is coupled to the coil pattern CP1 because it has the same coil axis direction as the coil pattern CP1 and is arranged in the opening region of the coil pattern CP1. The coupling coefficient between the coil pattern CP1 and the coil pattern CP2 can be adjusted mainly by the layout of the conductor patterns 10 and 20. In the example shown in FIG. 2, the sections of the conductor patterns 10 and 20 extending in the y direction are close to each other and are designed to minimize the distance between them in the x direction, so that the degree of coupling between them is high in this section. In contrast, the sections of the conductor patterns 10 and 20 extending in the x direction are separated from each other and the distance between them in the y direction is sufficiently secured, so that the degree of coupling between them in this section is low. In other words, the conductor pattern 10 is arranged so that there is a section (extending in the y direction) where the distance between the conductor pattern 10 and the conductor pattern 20 is relatively large and a section (extending in the x direction) where the distance is small when viewed from the z-axis direction, which is the coil axis. In this way, by bringing some sections of the conductor patterns 10 and 20 close to each other and separating other sections, it is possible to adjust the coupling coefficient between the coil patterns CP1 and CP2.

[0017] Moreover, the capacitor C2 is arranged so that the distance between the capacitor electrode patterns 24, 25 and the conductor pattern 20 is greater than the interval between adjacent patterns of the conductor pattern 20. This makes it possible to suppress the magnetic field generated by the coil pattern CP2 from being affected by the capacitor C2.

[0018] FIG. 4 is a graph showing the relationship between the coupling coefficient k of the coil patterns CP1 and CP2 and the communication distance, and shows the case where the wireless communication frequency by NFC is 13.56 MHz.

[0019] As shown in Fig. 4, the communication distance is maximum when the coupling coefficient k between the coil patterns CP1 and CP2 is about 0.18. Considering this, it is preferable to design the coupling coefficient k between the coil patterns CP1 and CP2 to be 0.15 or more and 0.22 or less, and more preferably to design it to be 0.17 or more and 0.19 or less. If the coupling coefficient k is 0.15 or more and 0.22 or less, a long communication distance can be ensured, and if the coupling coefficient k is 0.17 or more and 0.19 or less, an even longer communication distance can be ensured.

[0020] 2, corner 19 of conductor pattern 10 located on the outside and constituting coil pattern CP1 is gently curved, while corner 29 of conductor pattern 20 located on the inside and constituting coil pattern CP2 is bent at a nearly right angle. In other words, corner 29 of conductor pattern 20 has a smaller radius of curvature than corner 19 of conductor pattern 10. This reduces electric field concentration at corner 19 of conductor pattern 10 located on the outside. Also, by making corner 29 nearly right-angled for conductor pattern 20 located on the inside, it is possible to maximize the area of ​​the opening region.

[0021] Furthermore, since the coil pattern CP1 is connected to the IC module 5, it is desirable that the resistance value be as low as possible. In contrast, since the coil pattern CP2 forms a closed circuit that is not connected to an external circuit, a certain degree of resistance value is allowed compared to the coil pattern CP1. Taking this into consideration, in this embodiment, the pattern width W1 of the coil pattern CP1 is designed to be wider than the pattern width W2 of the coil pattern CP2.

[0022] In addition, when the resonant frequency of the resonant circuit formed by the coil pattern CP1 and the capacitor C1 is f1, and the resonant frequency of the resonant circuit formed by the coil pattern CP2 and the capacitor C2 is f2, the resonant frequency f1 and the resonant frequency f2 are designed to be different from each other. Specifically, the resonant frequency f1 and the resonant frequency f2 are designed to be different from the wireless communication frequency so as to sandwich the wireless communication frequency by NFC. In other words, if the wireless communication frequency by NFC is 13.56 MHz, one of the resonant frequencies f1 and f2 is set to be less than 13.56 MHz, and the other of the resonant frequencies f1 and f2 is set to be more than 13.56 MHz. Here, when the wireless communication frequency by NFC is 13.56 MHz, it is preferable that the difference between the resonant frequencies f1 and f2 is 3 MHz or more. Here, the resonant frequencies f1 and f2 refer to the resonant frequencies when the metal member 3 and the magnetic body 4 are present directly below.

[0023] Fig. 5 is a graph showing the relationship between resonance frequency f1 and communication distance, and Fig. 6 is a graph showing the relationship between resonance frequency f2 and communication distance, both of which show the case where the NFC wireless communication frequency is 13.56 MHz.

[0024] As shown in FIG. 5, the resonant frequency f1 of the resonant circuit consisting of the coil pattern CP1 and the capacitor C1 is designed to be slightly lower than the wireless communication frequency of 13.56 MHz, thereby increasing the communication distance, and the resonant frequency f1 is set to 13.43 MHz, thereby maximizing the communication distance. As shown in FIG. 6, the resonant frequency f2 of the resonant circuit consisting of the coil pattern CP2 and the capacitor C2 is designed to be 3 MHz or higher than the wireless communication frequency of 13.56 MHz, thereby increasing the communication distance. In the example shown in FIG. 5 and FIG. 6, when the difference between the resonant frequencies f1 and f2 is smaller than 3 MHz, the resonant frequencies f1 and f2 are switched. In this case, the resonant circuit consisting of the coil pattern CP1 and the capacitor C1 does not match the resonant circuit consisting of the coil pattern CP2 and the capacitor C2, and the communication distance is significantly reduced.

[0025] As described above, in the antenna device 1 according to this embodiment, since both the coil pattern CP1 and the coil pattern CP2 are provided on the front surface 2a of the substrate 2, the thickness in the z direction can be reduced, and since the coil patterns CP1 and CP2 do not overlap in the z direction, it is possible to suppress the stray capacitance between them. Moreover, since the capacitor electrode patterns 24 and 25 constituting the capacitor C2 are also formed on the front and back surfaces of the substrate 2, it is also possible to reduce the number of parts.

[0026] <First Modification> Figures 7 and 8 are schematic plan views for explaining the configuration of an antenna device according to a first modified example, with Figure 7 showing the shape of the conductor pattern formed on the surface 2a of the substrate 2 and Figure 8 showing the shape of the conductor pattern formed on the surface 2b of the substrate 2. Figure 8 shows the state as viewed from the surface 2a side of the substrate 2, that is, the state as viewed through the substrate 2.

[0027] As shown in FIG. 7, the surface 2a of the substrate 2 is provided with a conductor pattern 30 wound in a spiral shape for three turns and a conductor pattern 40 wound in a spiral shape for three turns. The conductor pattern 30 constitutes a coil pattern CP1, and the conductor pattern 40 constitutes a coil pattern CP2. The conductor patterns 30 and 40 are both substantially rectangular when viewed from the z-axis direction, which is the coil axis, and the conductor pattern 30 is disposed in the opening region (inner diameter region) of the conductor pattern 40. That is, the conductor pattern 30 has a smaller opening area than the conductor pattern 40, and is disposed at a position overlapping the opening region of the conductor pattern 40. In this way, the conductor pattern 40 is configured to go around the outside of the conductor pattern 30 when viewed from the z-axis direction, which is the coil axis, and the conductor pattern 30 is contained within the opening region of the conductor pattern 40. In the examples shown in FIG. 7 and FIG. 8, the coil pattern CP1 is an example of a first coil pattern, and the coil pattern CP2 is an example of a second coil pattern.

[0028] An outer peripheral end 31 of the conductor pattern 30 is connected to a through-hole conductor 33 penetrating the substrate 2. An inner peripheral end 32 of the conductor pattern 30 is connected to a through-hole conductor 34 penetrating the substrate 2. The through-hole conductor 33 is connected to a through-hole conductor 36 penetrating the substrate 2 via a connection pattern 35 formed on the surface 2b of the substrate 2. The through-hole conductor 36 is connected to a terminal electrode E3 formed on the surface 2a of the substrate 2. The through-hole conductor 34 is connected to a through-hole conductor 38 penetrating the substrate 2 via a connection pattern 37 formed on the surface 2b of the substrate 2. The through-hole conductor 38 is connected to a terminal electrode E4 formed on the surface 2a of the substrate 2. As a result, one end and the other end of the spiral conductor pattern 30 are connected to the terminal electrodes E3 and E4, respectively. The terminal electrodes E3 and E4 are connected to a capacitor C1 for adjusting a resonant frequency and to an IC module 5. As a result, an antenna module is formed by the antenna device according to the first modified example and the IC module 5.

[0029] An outer peripheral end 41 of the conductor pattern 40 is connected to a through-hole conductor 43 that penetrates the substrate 2. An inner peripheral end 42 of the conductor pattern 40 is connected to a capacitor electrode pattern 44. The through-hole conductor 43 is connected to a capacitor electrode pattern 45 formed on the surface 2b of the substrate 2. The capacitor electrode patterns 44, 45 face each other via the substrate 2 to form a capacitor C2. The coil pattern CP2 and the capacitor C2 form a closed circuit and function as a booster antenna for expanding the communication distance. In the example shown in FIGS. 7 and 8, the capacitor C2 is an example of a first capacitor.

[0030] As exemplified in the first modified example, the coil pattern CP2 functioning as a booster antenna may be disposed on the outside, and the coil pattern CP1 connected to the IC module 5 and functioning as an antenna coil may be disposed in the opening area. In the first modified example, the pattern width of the coil pattern CP1 and the pattern width of the coil pattern CP2 are the same, but it is preferable to make the pattern width of the coil pattern CP1 connected to the IC module 5 wider than the pattern width of the coil pattern CP2 that constitutes a closed circuit that is not connected to an external circuit. This makes it possible to keep the resistance value of the coil pattern CP1 connected to the IC module 5 low.

[0031] <Second Modification> Figures 9 and 10 are schematic plan views for explaining the configuration of an antenna device according to a second modified example, with Figure 9 showing the shape of the conductor pattern formed on the surface 2a of the substrate 2 and Figure 10 showing the shape of the conductor pattern formed on the surface 2b of the substrate 2. Figure 10 shows the state as viewed from the surface 2a side of the substrate 2, that is, the state as viewed through the substrate 2.

[0032] As shown in FIG. 9, the surface 2a of the substrate 2 is formed with a conductor pattern 50 wound in a spiral shape with five turns and a conductor pattern 60 wound in a spiral shape with seven turns. The conductor pattern 50 constitutes a coil pattern CP1, and the conductor pattern 60 constitutes a coil pattern CP2. That is, in the example shown in FIG. 9 and FIG. 10, the coil pattern CP2 has a larger number of turns than the coil pattern CP1. The conductor patterns 50 and 60 are both substantially rectangular when viewed from the z-axis direction, which is the coil axis, and the conductor pattern 60 is disposed in the opening region (inner diameter region) of the conductor pattern 50. That is, the conductor pattern 60 has a smaller opening area than the conductor pattern 50, and is disposed at a position overlapping the opening region of the conductor pattern 50. In this way, the conductor pattern 50 is configured to go around the outside of the conductor pattern 60 when viewed from the z-axis direction, which is the coil axis, and the conductor pattern 60 is contained within the opening region of the conductor pattern 50. In the example shown in FIG. 9 and FIG. 10, the coil pattern CP1 is an example of a second coil pattern, and the coil pattern CP2 is an example of a first coil pattern.

[0033] An outer peripheral end 51 of the conductor pattern 50 is connected to a through-hole conductor 53 that penetrates the substrate 2. An inner peripheral end 52 of the conductor pattern 50 is connected to a capacitor electrode pattern 54. The through-hole conductor 53 is connected to a capacitor electrode pattern 55 formed on the front surface 2b of the substrate 2. The capacitor electrode patterns 54 and 55 face each other via the substrate 2 to form a capacitor C3.

[0034] An outer peripheral end 61 of the conductor pattern 60 is connected to a capacitor electrode pattern 63. An inner peripheral end 62 of the conductor pattern 60 is connected to a through-hole conductor 64 penetrating the substrate 2. The through-hole conductor 64 is connected to a capacitor electrode pattern 65 formed on the surface 2b of the substrate 2. The capacitor electrode patterns 63, 65 face each other via the substrate 2 to form a capacitor C2. The coil pattern CP2 and the capacitor C2 form a closed circuit and function as a booster antenna for expanding the communication distance. In the example shown in FIGS. 9 and 10, the capacitor C2 is an example of a first capacitor.

[0035] Furthermore, on the front surface 2b of the substrate 2, a coil pattern CP3 is provided at a position within the opening region of the conductor pattern 50 but outside the opening region of the conductor pattern 60. The coil pattern CP3 is spirally wound over a plurality of turns, with an outer peripheral end 71 connected to a through-hole conductor 56 penetrating the substrate 2 and an inner peripheral end 72 connected to a through-hole conductor 73 penetrating the substrate 2. The through-hole conductor 73 is connected to a through-hole conductor 75 penetrating the substrate 2 via a connection pattern 74 formed on the front surface 2a of the substrate 2. The through-hole conductor 75 is connected to a through-hole conductor 57 penetrating the substrate 2 via a connection pattern 76 formed on the front surface 2b of the substrate 2.

[0036] The through-hole conductors 56, 57 are each connected to a division position of a predetermined turn (the second turn from the inner circumference side in the example shown in FIG. 9) of the conductor pattern 50 constituting the coil pattern CP1. As a result, the predetermined turn of the conductor pattern 50 passes through the coil pattern CP3. The coil pattern CP3 is electromagnetically coupled to an IC module (not shown). That is, in this example, the coil pattern CP1 and the IC module are not directly connected, but are electromagnetically coupled via the coil pattern CP3. As a result, an antenna module is formed by the antenna device according to the second modified example and an IC module (not shown).

[0037] As exemplified in the second modified example, a coil pattern CP3 connected to the coil pattern CP1 may be provided, and electromagnetic coupling may be established with the IC module via the coil pattern CP3. Also, as exemplified in the second modified example, a capacitor C1 connected to the coil pattern CP1 may be formed on the substrate 2. This makes it possible to further reduce the number of components.

[0038] Although the above describes preferred embodiments of the present disclosure, the present disclosure is not limited to the above-described embodiments, and various modifications are possible without departing from the spirit of the present disclosure, and it goes without saying that these modifications are also included within the scope of the present disclosure.

[0039] For example, in the above embodiment, both the coil pattern CP1 and the coil pattern CP2 are formed on the surface 2a of the substrate 2, but one may be formed on the surface 2a of the substrate 2 and the other may be formed on the surface 2b of the substrate 2. Also, the coil pattern CP1 and the coil pattern CP2 may be formed on the surfaces of different substrates.

[0040] The technology according to the present disclosure includes the following configuration examples, but is not limited to these.

[0041] The antenna device according to the present disclosure comprises a substrate, and a first coil pattern, a second coil pattern, and a first capacitor provided on a surface of the substrate, wherein the first coil pattern has an opening area smaller than that of the second coil pattern and is positioned so as to overlap with the opening area of ​​the second coil pattern, and one of the first and second coil patterns is connected to the first capacitor to form a closed circuit.

[0042] This reduces the distance between the first coil pattern and the second coil pattern, thereby reducing the required space, and also reduces the number of parts, since the first capacitor is provided on the surface of the substrate.

[0043] The first and second coil patterns may both be provided on one surface of the substrate, which further reduces the required space and the number of parts.

[0044] The first coil pattern may be arranged so that the distance between the first coil pattern and the second coil pattern has a section where the distance is relatively large and a section where the distance is relatively small when viewed from the coil axis direction of the first coil pattern, which makes it possible to adjust the coupling coefficient between the first coil pattern and the second coil pattern.

[0045] The first capacitor is composed of electrode patterns facing each other via a substrate, and the distance between the electrode patterns and one of the first and second coil patterns may be greater than the distance between adjacent patterns of one of the first and second coil patterns, thereby making it possible to suppress the magnetic field generated by one of the first and second coil patterns from being affected by the first capacitor.

[0046] The coupling coefficient between the first coil pattern and the second coil pattern may be 0.15 or more and 0.22 or less, or 0.17 or more and 0.19 or less, which makes it possible to increase the communication distance.

[0047] The antenna device according to the present disclosure further includes a second capacitor connected to the other of the first and second coil patterns, one of the first and second coil patterns and the first capacitor form a first resonant circuit, and the other of the first and second coil patterns and the second capacitor form a second resonant circuit, and the difference between the resonant frequency of the first resonant circuit and the resonant frequency of the second resonant circuit may be 3 MHz or more. This makes it possible to extend the communication distance. In this case, the resonant frequency of the first resonant circuit and the resonant frequency of the second resonant circuit may both be different from the frequency used for wireless communication, and the frequency used for wireless communication may be set between the resonant frequency of the first resonant circuit and the resonant frequency of the second resonant circuit. This makes it possible to further extend the communication distance.

[0048] The first and second coil patterns are both substantially rectangular when viewed in the axial direction, and the corners of the first coil pattern may have a smaller radius of curvature than the corners of the second coil pattern, which can alleviate electric field concentration in the second coil pattern and increase the opening area of ​​the first coil pattern.

[0049] The antenna module according to the present disclosure includes the antenna device, a metal member arranged at a position overlapping the antenna device, a magnetic body arranged between the antenna device and the metal member, and an IC module that transmits and receives signals via the other of the first and second coil patterns, making it possible to provide a small antenna module with a small number of parts.

[0050] The other of the first and second coil patterns may be connected to an IC module. This simplifies the configuration. In this case, the other of the first and second coil patterns may have a pattern width larger than one of the first and second coil patterns. This reduces the resistance value of the other of the first and second coil patterns connected to the IC module.

[0051] The antenna module according to the present disclosure may further include a third coil pattern connected to the other of the first and second coil patterns, and the third coil pattern and the IC module may be electromagnetically coupled, which makes it possible to eliminate the terminal electrodes. [Explanation of symbols]

[0052] 1 Antenna device 2 Base material 2a, 2b Surface of the substrate 3 Metallic parts 4 Magnetic material 5 IC Module 10,20,30,40,50,60 Conductor pattern 11,21,31,41,51,61,71 Outer edge 12,22,32,42,52,62,72 Inner end 13,15,23,33,34,36,38,43,53,56,57,64,73,75 Through hole conductor 14,35,37,74,76 Connection Pattern 19,29 Corner 24,25,44,45,54,55,63,65 Capacitor electrode pattern C1~C3 capacitors CP1~CP2 coil pattern E1~E4 terminal electrode

Claims

1. A substrate; a first coil pattern, a second coil pattern, a third coil pattern, and a first capacitor provided on a surface of the base material; the first coil pattern has an opening area smaller than that of the second coil pattern and is disposed at a position overlapping an opening area of ​​the second coil pattern, the third coil pattern has an opening area smaller than that of the first coil pattern, and is disposed at a position overlapping an opening region of the second coil pattern but not overlapping an opening region of the first coil pattern; one of the first and second coil patterns is connected to the first capacitor to form a closed circuit; The antenna device, wherein the third coil pattern is connected to a position where a predetermined turn of the other of the first and second coil patterns is separated.

2. The antenna device according to claim 1 , wherein the first and second coil patterns are both provided on one surface of the base material.

3. The third coil pattern is provided on the other surface of the substrate, The antenna device according to claim 2 , wherein the first capacitor is disposed at a position that overlaps with an opening region of the second coil pattern but does not overlap with an opening region of the first coil pattern.

4. 4. The antenna device according to claim 1, wherein the first coil pattern is arranged so that, when viewed from a coil axis direction of the first coil pattern, a distance between the first coil pattern and the second coil pattern has a section in which the distance is relatively large and a section in which the distance is relatively small.

5. the first capacitor is formed by electrode patterns opposed to each other via the base material, 5. The antenna device according to claim 1, wherein a distance between the electrode pattern and the one of the first and second coil patterns is greater than a spacing between adjacent patterns of the one of the first and second coil patterns.

6. The antenna device according to claim 1 , wherein a coupling coefficient between the first coil pattern and the second coil pattern is not less than 0.15 and not more than 0.

22.

7. The antenna device according to claim 6 , wherein a coupling coefficient between the first coil pattern and the second coil pattern is not less than 0.17 and not more than 0.

19.

8. a second capacitor connected to the other of the first and second coil patterns; the one of the first and second coil patterns and the first capacitor form a first resonant circuit; the other of the first and second coil patterns and the second capacitor form a second resonant circuit; 8. The antenna device according to claim 1, wherein a difference between a resonant frequency of the first resonant circuit and a resonant frequency of the second resonant circuit is 3 MHz or more.

9. The antenna device according to claim 8 , wherein a resonant frequency of the first resonant circuit and a resonant frequency of the second resonant circuit are both different from a frequency used for wireless communication.

10. The antenna device according to claim 9 , wherein a frequency used for the wireless communication is set between a resonant frequency of the first resonant circuit and a resonant frequency of the second resonant circuit.

11. The first and second coil patterns are both substantially rectangular when viewed in the axial direction, The antenna device according to claim 1 , wherein a corner of the first coil pattern has a smaller radius of curvature than a corner of the second coil pattern.

12. An antenna device according to any one of claims 1 to 11, a metal member disposed at a position overlapping the antenna device; a magnetic body disposed between the antenna device and the metal member; an IC module that performs transmission and reception by electromagnetically coupling with the third coil pattern via the other of the first and second coil patterns.

13. The antenna module according to claim 12 , wherein the other of the first and second coil patterns is connected to the IC module.

14. The antenna module according to claim 13 , wherein the other of the first and second coil patterns has a pattern width larger than that of the one of the first and second coil patterns.

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