Antenna device and electronic device

Abstract

Provided are an antenna device and an electronic apparatus with which a usable frequency band is broaden. An antenna device (100) is provided with: a plate-like conductor (20) having an opening (25); an excitation electrode (51) and an excitation electrode (52) disposed at positions corresponding to the opening (25); a coil (L1) that is electrically connected to the excitation electrode (51) at one end and connected to a power feeding circuit (30) at the other end; and a coil (L2) that is electrically connected to the excitation electrode (52) at one end. The coil (L1) and the coil (L2) are disposed at positions where magnetic-field coupling is achieved therebetween.

Description

[Technical Field]

[0001] The present disclosure relates to an antenna device and an electronic device. [Background technology]

[0002] In recent years, electronic devices have adopted a structure in which the antenna is built in rather than attached to the outside from the viewpoint of design. Furthermore, by building the antenna into the electronic device, it is possible to prevent the antenna from being damaged due to dropping, etc. A slot antenna is known as an antenna built into an electronic device (Patent Document 1: Japanese Patent Laid-Open Publication No. 9-74312). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 9-74312 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the resonant frequency of a slot antenna is determined by the length of the slot, making it unsuitable as a built-in antenna for electronic devices that must operate in multiple frequency bands.

[0005] Therefore, an object of the present disclosure is to provide an antenna device and an electronic device that widen the available frequency band. [Means for solving the problem]

[0006] An antenna device according to an embodiment of the present disclosure includes a plate-shaped conductor having an opening, a first excitation electrode and a second excitation electrode disposed at positions corresponding to the opening, a first coil having one end electrically connected to the first excitation electrode and the other end connected to a power feed circuit, and a second coil having one end electrically connected to the second excitation electrode, the first coil and the second coil being disposed at positions where they are magnetically coupled.

[0007] An electronic device according to an embodiment of the present disclosure includes the antenna device described above, a power supply circuit that supplies power to the first excitation electrode, and a housing that houses the antenna device and the power supply circuit. [Effects of the Invention]

[0008] According to one embodiment of the present disclosure, by connecting a first excitation electrode and a second excitation electrode arranged at a position corresponding to the opening to a first coil and a second coil that are magnetically coupled, respectively, a resonance point can be added to widen the usable frequency band. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a schematic diagram of an electronic device including an antenna device according to a first embodiment. [Figure 2] 2 is an enlarged view of a part of the antenna device according to the first embodiment. FIG. [Figure 3] 1 is a schematic cross-sectional view of an antenna device according to a first embodiment. [Figure 4] 2 is an equivalent circuit diagram of the antenna device according to the first embodiment. FIG. [Figure 5] FIG. 4 is a diagram illustrating frequency characteristics of the reflection coefficient of the antenna device according to the first embodiment. [Figure 6] FIG. 2 is a diagram showing a Smith chart of the antenna device according to the first embodiment. [Figure 7] FIG. 10 is a schematic diagram of a comparative antenna device. [Figure 8] FIG. 10 is a diagram showing frequency characteristics of the reflection coefficient of a comparative antenna device. [Figure 9]FIG. 10 is a diagram showing a Smith chart of a comparative antenna device. [Figure 10] FIG. 2 is a perspective view of an antenna coupling element according to the first embodiment. [Figure 11] FIG. 2 is a plan view of the antenna coupling element according to the first embodiment. [Figure 12] 1 is a first exploded plan view illustrating the configuration of an antenna coupling element according to the first embodiment. [Figure 13] 4 is a second exploded plan view showing the configuration of the antenna coupling element according to the first embodiment. FIG. [Figure 14] FIG. 10 is a schematic diagram of another comparative antenna device. [Figure 15] FIG. 10 is a diagram showing frequency characteristics of the reflection coefficient of another antenna device for comparison. [Figure 16] FIG. 10 is a diagram showing a Smith chart of another antenna device for comparison. [Figure 17] FIG. 10 is a schematic diagram of yet another comparative antenna device. [Figure 18] FIG. 10 is a diagram showing the frequency characteristics of the reflection coefficient of yet another antenna device for comparison. [Figure 19] FIG. 10 is a diagram showing a Smith chart of yet another antenna device for comparison. [Figure 20] 10A and 10B are diagrams illustrating frequency characteristics of the reflection coefficient of an antenna device in which the capacitance value of the capacitive element is changed. [Figure 21] 10A and 10B are diagrams showing Smith charts of antenna devices in which the capacitance values ​​of the capacitance elements are changed. [Figure 22] FIG. 10 is a cross-sectional view of an antenna device according to a modified example. [Figure 23] FIG. 10 is a schematic diagram of an electronic device including an antenna device according to a second embodiment. [Figure 24] FIG. 10 is a diagram illustrating frequency characteristics of the reflection coefficient of the antenna device according to the second embodiment. [Figure 25] FIG. 10 is a diagram illustrating the antenna efficiency of the antenna device according to the second embodiment. [Figure 26] 10 is a schematic diagram of an electronic device including an antenna device according to a first modification of the second embodiment. [Figure 27] 10 is a schematic diagram of an electronic device including an antenna device according to a second modification of the second embodiment. FIG. [Figure 28] 13 is a schematic diagram of an electronic device including an antenna device according to a third modification of the second embodiment. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0010] Antenna devices and electronic devices according to embodiments will be described in detail below with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference numerals and description thereof will not be repeated.

[0011] (Embodiment 1) First, an electronic device including an antenna device will be described. Fig. 1 is a schematic diagram of an electronic device including an antenna device 100 according to a first embodiment. As shown in Fig. 1, the electronic device includes the antenna device 100, a power supply circuit 30 that supplies power to an excitation electrode 51 (first excitation electrode), and a housing 300 that houses the antenna device 100 and the power supply circuit 30. The electronic device is, for example, a notebook computer, a mobile phone, a smartphone, or a tablet that incorporates the antenna device 100 that is capable of communication in bands including the 2.4 GHz band and the 5 GHz to 7 GHz band.

[0012] [Antenna device configuration] The antenna device 100 has an opening 25 (slot) that is long in the X direction provided in the plate-like conductor 20, and excitation electrodes 51 and 52 (also referred to as excitation conductors, feed lines, or simply microstrip lines) are arranged at positions corresponding to the opening 25. Here, the excitation electrodes 51 and 52 arranged at positions corresponding to the opening 25 mean that they at least partially overlap the opening 25 when viewed from above. In other words, the antenna device 100 is a slot antenna in which the excitation electrodes 51 and 52 function as capacitive feed elements for the opening 25. In the antenna device 100, which is a slot antenna, the length of the long side 25a of the opening 25 (slot length) is approximately half the resonant wavelength (λ / 2). Therefore, when the antenna device 100 is used in the 2 to 3 GHz band, the length of the long side 25a of the opening 25 is approximately 40 mm to 70 mm. On the other hand, the length of the short side 25b of the opening 25 (slot width) is approximately 1 to 5 mm, which is shorter than the long side 25a. That is, opening 25 has a rectangular shape with short side 25b (second side) shorter than long side 25a (first side). Here, conductor 20 is, for example, a metal plate such as copper foil, copper plate, or aluminum plate.

[0013] The configuration of the antenna device 100 will be described in more detail. FIG. 2 is an enlarged view of a portion of the antenna device 100 according to the first embodiment. FIG. 3 is a schematic cross-sectional view of the antenna device 100 according to the first embodiment. As shown in FIG. 1, the excitation electrodes 51 and 52 are arranged at positions overlapping with the opening 25 when the opening 25 is viewed from above. As shown in FIG. 3, the excitation electrodes 51 and 52 are formed on the substrate 40 disposed on the conductor 20, and are therefore arranged at positions different from the opening 25 in the Z direction. Note that the excitation electrodes 51 and 52 only need to be arranged at positions corresponding to the opening 25, and may be arranged at positions overlapping with the opening 25 when the opening 25 is viewed from above and in the Z direction. Note that the excitation electrodes 51 and 52 have a strip shape extending along the long side 25a of the opening 25.

[0014] Furthermore, the excitation electrodes 51 and 52 are electrically connected to the antenna coupling element 10 mounted on the substrate 40. Here, the substrate 40 is, for example, a PWB (Printed Wired Board), and the antenna coupling element 10 is connected to it with solder or conductive paste. As shown in FIG. 1 , the excitation electrode 51 is connected to the power supply circuit 30 via the antenna coupling element 10, and is supplied with power from the power supply circuit 30. On the other hand, the excitation electrode 52 (second excitation electrode) is connected to the substrate 40 via the antenna coupling element 10, and is connected to GND (grounded). In other words, the slot antenna formed by the opening 25 and the excitation electrode 51 functions as a power supply antenna, and the slot antenna formed by the opening 25 and the excitation electrode 52 functions as a parasitic antenna.

[0015] The excitation electrode 51 extends from the antenna coupling element 10 in a leftward direction (first direction) in the figure, while the excitation electrode 52 extends from the antenna coupling element 10 in a rightward direction (second direction) in the figure. In other words, the directions in which the excitation electrode 51 and the excitation electrode 52 extend are opposite to each other along the long side 25a of the opening 25. Note that the directions in which the excitation electrode 51 and the excitation electrode 52 extend may be the same.

[0016] As will be described later, the antenna coupling element 10 includes a coil L1 (first coil) and a coil L2 (second coil), and the coils L1 and L2 are magnetically coupled. As shown in FIG. 2, the excitation electrode 51 is connected to a first external electrode 11 of the antenna coupling element 10, thereby electrically connected to the coil L1. The power feed circuit 30 is connected to a second external electrode 12 of the antenna coupling element 10 via a wiring 53, thereby electrically connected to the coil L1. The excitation electrode 52 is connected to a third external electrode 13 of the antenna coupling element 10, thereby electrically connected to the coil L2. However, the excitation electrode 52 is connected to the third external electrode 13 via a capacitance element 60 to adjust impedance, as will be described later. The fourth external electrode 14 of the antenna coupling element 10 is connected to the substrate 40 via a wiring 54, and the coil L2 is connected to GND.

[0017] The antenna device 100 has a configuration in which the resonances of two excitation electrodes 51, 52 in a slot antenna are coupled using an antenna coupling element 10. Fig. 4 is an equivalent circuit diagram of the antenna device 100 according to the first embodiment. In the antenna device 100, the excitation electrode 51 of the slot antenna connected to the feed circuit 30 is coupled to the excitation electrode 52 of the slot antenna that is not fed by the feed circuit 30 using the antenna coupling element 10.

[0018] 4, the excitation electrode 51 and the opening 25 form a slot antenna (first antenna). The excitation electrode 51 is electrically connected to the first external electrode 11 of the antenna coupling element 10, and the feed circuit 30 is electrically connected to the second external electrode 12 of the antenna coupling element 10. In other words, the coil L1 of the antenna coupling element 10 is connected in series to the excitation electrode 51 and the feed circuit 30.

[0019] Meanwhile, in the equivalent circuit diagram of the antenna device 100, the excitation electrode 52 and the opening 25 form a slot antenna (second antenna). The excitation electrode 52 is electrically connected to the third external electrode 13 of the antenna coupling element 10, and the fourth external electrode 14 of the antenna coupling element 10 is connected (grounded) to GND. In other words, the antenna coupling element 10 is connected in series to the excitation electrode 52 and GND. A capacitance element 60 is provided between the excitation electrode 52 and the third external electrode 13.

[0020] The coils L1 and L2 are arranged in a position within the antenna coupling element 10 where they are magnetically coupled, generating a mutual inductance M. The antenna coupling element 10 is a chip coil component formed by laminating multiple ceramic green sheets. Of course, the antenna device 100 is not limited to a configuration in which the excitation electrodes 51 and 52 are connected to the antenna coupling element 10, which is a chip coil component, and any configuration is possible as long as the coils L1 and L2 are arranged in a position where they are magnetically coupled.

[0021] Next, the characteristics of the antenna device 100 will be described. Fig. 5 is a diagram showing the frequency characteristics of the reflection coefficient of the antenna device 100 according to the first embodiment. In Fig. 5, the horizontal axis represents frequency, and the vertical axis represents reflection coefficient (return loss). Here, reflection coefficient A is the reflection coefficient when looking from the feed circuit 30 toward the antenna coupling element 10 in Fig. 4 (that is, of the antenna device 100). Note that reflection coefficient A is a simulation result of the antenna device 100 when coil L1 = 1.7 nH, coil L2 = 1.1 nH, coupling coefficient k = 0.33, and capacitance element 60 = 0.3 pF.

[0022] At reflection coefficient A, resonance occurs at mark M1 (approximately 2.5 GHz) at the resonance frequency of the fundamental wave of the antenna device 100. Furthermore, at reflection coefficient A, resonance occurs at mark M2 (approximately 5.4 GHz) and mark M3 (approximately 6.6 GHz) at the resonance frequencies of harmonics of the antenna device 100. In the antenna device 100, by coupling a slot antenna including excitation electrode 52 in the antenna coupling element 10 to a slot antenna including excitation electrode 51, the number of resonance points can be increased, making it possible to generate resonance in a wide band including approximately 5.0 GHz to approximately 7.0 GHz.

[0023] 6 is a diagram showing a Smith chart of the antenna device 100 according to the first embodiment. The Smith chart shown in Fig. 6 illustrates a case where the impedance of the antenna device 100 is adjusted by providing a capacitance element 60 between the coil L2 and the excitation electrode 52 of the antenna device 100 shown in Fig. 4. Furthermore, the antenna device 100 also adjusts the impedance by making the length of the excitation electrode 52 in the X direction shorter than that of the excitation electrode 51, as shown in Fig. 1.

[0024] In the Smith chart shown in Fig. 6, the target frequency line from 2 GHz to 8 GHz forms large circles near each of mark M1 (approximately 2.5 GHz), mark M2 (approximately 5.4 GHz), and mark M3 (approximately 6.6 GHz). Therefore, it can be seen from the Smith chart shown in Fig. 6 that the antenna device 100 generates resonance in a wide band including approximately 5.0 GHz to approximately 7.0 GHz by increasing the number of resonance points in addition to the fundamental wave resonance frequency (approximately 2.5 GHz).

[0025] Here, the characteristics of a comparative antenna device will be described. Fig. 7 is a schematic diagram of a comparative antenna device 200. Unlike the antenna device 100, the antenna device 200 does not couple a slot antenna including an excitation electrode 52 to a slot antenna including an excitation electrode 51 in the antenna coupling element 10, but is configured with only a slot antenna including the excitation electrode 51. Note that in the antenna device 200, the same components as those in the antenna device 100 shown in Fig. 1 are designated by the same reference numerals, and detailed description thereof will not be repeated.

[0026] In antenna device 200, excitation electrode 51 is disposed at a position corresponding to opening 25. Excitation electrode 51 is connected to power feed circuit 30 (not shown) via wiring on substrate 40, and is supplied with power from power feed circuit 30. A slot antenna formed by opening 25 and excitation electrode 51 functions as a power feed antenna.

[0027] Next, the characteristics of antenna device 200 will be described. Fig. 8 is a diagram showing the frequency characteristics of the reflection coefficient of antenna device 200 for comparison. In Fig. 8, the horizontal axis represents frequency and the vertical axis represents reflection coefficient (return loss). Here, reflection coefficient B is the reflection coefficient of antenna device 200.

[0028] For reflection coefficient B, resonance occurs at mark M4 (approximately 2.5 GHz) at the resonance frequency of the fundamental wave of antenna device 200. Furthermore, for reflection coefficient B, resonance occurs at mark M5 (approximately 5.5 GHz) at the resonance frequency of the harmonic of antenna device 200. Antenna device 200 only generates resonance near approximately 5.5 GHz, and cannot generate resonance in a wide band including approximately 5.0 GHz to approximately 7.0 GHz like antenna device 100.

[0029] Furthermore, Fig. 9 is a diagram showing a Smith chart of the comparative antenna device 200. In the Smith chart shown in Fig. 9, the target frequency line from 2 GHz to 8 GHz forms large circles near the marks M4 (approximately 2.5 GHz) and M5 (approximately 5.5 GHz). Therefore, it can be seen from the Smith chart shown in Fig. 9 that the antenna device 200 resonates at approximately 5.5 GHz in addition to the fundamental resonant frequency (approximately 2.5 GHz).

[0030] [Antenna coupling element structure] Next, the configuration of the antenna coupling element 10 that couples a slot antenna including an excitation electrode 52 to a slot antenna including an excitation electrode 51 will be described. Fig. 10 is a perspective view of the antenna coupling element 10 according to the first embodiment. Fig. 11 is a plan view of the antenna coupling element 10 according to the first embodiment. Here, in Figs. 10 and 11, the short side direction of the antenna coupling element 10 is the X direction, the long side direction is the Y direction, and the height direction is the Z direction. The stacking direction of the substrates is the Z direction, and the arrow indicates the upward direction.

[0031] The antenna coupling element 10 is a rectangular parallelepiped chip component that couples the resonances of two excitation electrodes 51, 52 in the slot antenna. A first external electrode 11, a second external electrode 12, a third external electrode 13, and a fourth external electrode 14 are formed on the outer surface of the antenna coupling element 10, as shown in Fig. 1. The antenna coupling element 10 also has a pair of mutually opposing main surfaces, with the lower main surface in Fig. 1 being the mounting surface that faces the circuit board.

[0032] The antenna coupling element 10 includes two coils L1 and L2 to magnetically couple the resonances of the two excitation electrodes 51 and 52 in the slot antenna, and the coils L1 and L2 form a transformer that is magnetically coupled.

[0033] The specific configuration of the antenna coupling element 10 will be described. As shown in Figs. 10 and 11, the antenna coupling element 10 is configured with an insulator 1 (ceramic element body) made of ceramic layers in which a plurality of substrates (ceramic green sheets) on which coil wiring is formed are stacked. The insulator 1 has a pair of main surfaces facing each other and side surfaces connecting the main surfaces. A plurality of first conductor patterns 21, a second conductor pattern 22, a plurality of third conductor patterns 23, and a fourth conductor pattern 24 are stacked parallel to the main surfaces of the insulator 1 to configure the antenna coupling element 10 containing the coil L1 and the coil L2.

[0034] The coil L1 has two layers of first conductor patterns 21a and 21b stacked on top of one layer of the second conductor pattern 22, and the conductor patterns are electrically connected by via conductors 31. Specifically, the coil L1 has two layers of first conductor patterns 21, i.e., the first conductor pattern 21a and the first conductor pattern 21b, connected in parallel by the via conductors 31, and the second conductor pattern 22 connected in series to the first conductor pattern 21 on the second layer by the via conductors 31. Therefore, the coil L1 can have a smaller inductance component than when the first conductor pattern 21a and the second conductor pattern 22 are connected in series. Note that the first conductor pattern 21 may be a conductor pattern having two or more layers.

[0035] The coil L2 has two layers of third conductor patterns 23a, 23b and one layer of fourth conductor pattern 24 stacked on top of each other, with the conductor patterns electrically connected by via conductors 32. Specifically, the coil L2 has two layers of third conductor patterns 23a, 23a, connected in parallel by via conductors 32, and the fourth conductor pattern 24 connected in series to the third conductor pattern 23 on the second layer by via conductors 32. Therefore, the coil L2 can have a smaller inductance component than when the third conductor pattern 23a and the fourth conductor pattern 24 are connected in series. Note that the third conductor pattern 23 may be a conductor pattern having two or more layers.

[0036] The coils L1 and L2 are disposed within the insulator 1 such that, when viewed from the lamination direction of the insulator 1, the opening of the coil L1 at least partially overlaps the opening of the coil L2. As shown in FIG. 11 , when viewed from the lamination direction of the insulator 1, the openings of the coils L1 and L2 are disposed such that the openings of the coils L1 and L2 are offset in the long-side direction relative to the center of the antenna coupling element 10 and are disposed in a direction approaching the second external electrode 12 provided on the short side of the antenna coupling element 10. However, the arrangement of the coils L1 and L2 shown in FIG. 11 is merely an example, and other arrangements may be used. Specifically, the coils L1 and L2 are disposed within the insulator 1 such that the second conductor pattern 22 and the fourth conductor pattern 24 face each other. Because the coils L1 and L2 are configured such that the second conductor pattern 22 of one layer and the fourth conductor pattern 24 of the first layer face each other across an insulating layer, the capacitance component is smaller than in a configuration in which conductor patterns of three layers face each other across an insulating layer.

[0037] Furthermore, when the coils L1 and L2 are arranged so that the second conductor pattern 22 and the fourth conductor pattern 24 face each other, the coupling coefficient between the coils L1 and L2 can be maintained high compared to when the coils L1 and L2 are arranged so that the first conductor pattern 21 of the second layer and the third conductor pattern 23 of the second layer face each other. Therefore, by arranging the coils L1 and L2 so that the second conductor pattern 22 and the fourth conductor pattern 24 face each other, the antenna coupling element 10 does not decrease the mutual inductance M between the coils L1 and L2.

[0038] As shown in FIG. 10, a first external electrode 11 is provided on one of the short sides of the side of the insulator 1, a second external electrode 12 is provided on the other short side, a third external electrode 13 is provided on one of the long sides, and a fourth external electrode 14 is provided on the other long side.

[0039] Each of the multiple first conductor patterns 21 is electrically connected to the first external electrode 11. Of the multiple first conductor patterns 21, only the lower-layer first conductor pattern 21b may be electrically connected to the first external electrode 11, and the upper-layer first conductor pattern 21a may be electrically connected to the first conductor pattern 21b via a via conductor. The second conductor pattern 22 is electrically connected to the second external electrode 12.

[0040] Each of the multiple third conductor patterns 23 is electrically connected to the third external electrode 13. Of the multiple third conductor patterns 23, only the lower-layer third conductor pattern 23b may be electrically connected to the third external electrode 13, and the upper-layer third conductor pattern 23a may be electrically connected to the third conductor pattern 23b via a via conductor. The fourth conductor pattern 24 is electrically connected to the fourth external electrode 14.

[0041] [Exploded plan view of antenna coupling element] Next, the configuration of each layer will be described using exploded plan views. Fig. 12 is a first exploded plan view showing the configuration of the antenna coupling element 10 according to the first embodiment. Fig. 13 is a second exploded plan view showing the configuration of the antenna coupling element 10 according to the first embodiment. First, as shown in Figs. 12 and 13, the first to fourth conductor patterns 21 to 24 are formed by printing a conductive paste (Ni paste) on ceramic green sheets 1a to 1o, which serve as substrates, by screen printing.

[0042] As shown in FIG. 12(a), conductive patterns 11a to 14a are formed on the ceramic green sheet 1a at positions corresponding to the first external electrode 11 to the fourth external electrode 14. The ceramic green sheet 1a is provided with a direction identification mark DDM indicating that it is the top surface, which is the surface opposite to the mounting surface. This direction identification mark DDM is used to detect the direction of a chip component, for example, when mounting the antenna coupling element 10 on a circuit board using a mounting machine. As shown in FIGS. 12(b) to 12(e), no conductive patterns are formed on the ceramic green sheets 1b to 1e.

[0043] As shown in Fig. 12(f), a third conductor pattern 23a is formed on the ceramic green sheet 1f. The third conductor pattern 23a is formed clockwise from the center of the upper long side of the ceramic green sheet 1f in the figure, extending approximately 1 / 2 to 3 / 4 of the way around. The starting end of the third conductor pattern 23a is formed to the outer periphery of the ceramic green sheet 1f so as to be electrically connected to the third external electrode 13. Meanwhile, a connecting portion 32a that connects to the via conductor 32 is provided at the end of the third conductor pattern 23a.

[0044] As shown in Fig. 12(g), a third conductor pattern 23b is formed on the ceramic green sheet 1g. The third conductor pattern 23b is formed clockwise from the center of the upper long side of the ceramic green sheet 1g in the figure, extending approximately 1 / 2 to 3 / 4 of the way around. The starting end of the third conductor pattern 23b is formed to the outer periphery of the ceramic green sheet 1g so as to be electrically connected to the third external electrode 13. Meanwhile, a connecting portion 32b that connects to the via conductor 32 is provided at the end of the third conductor pattern 23b.

[0045] 12(h), a fourth conductor pattern 24 is formed on the ceramic green sheet 1h. The fourth conductor pattern 24 is formed counterclockwise from the center of the lower long side of the ceramic green sheet 1h in the figure, extending approximately 1 / 2 to 3 / 4 of the way around. The starting end of the fourth conductor pattern 24 is formed to the outer periphery of the ceramic green sheet 1h so as to be electrically connected to the fourth external electrode 14. Meanwhile, a connecting portion 32c that connects to the via conductor 32 is provided at the end of the fourth conductor pattern 24.

[0046] 13(i), no conductor pattern is formed on the ceramic green sheet 1i. That is, in the antenna coupling element 10, the inter-layer distance between the fourth conductor pattern 24 and the second conductor pattern 22 is longer than the inter-layer distance between the third conductor pattern 23a and the third conductor pattern 23b or the inter-layer distance between the third conductor pattern 23b and the fourth conductor pattern 24. In this way, in the antenna coupling element 10, the degree of coupling between the coil L1 and the coil L2 can be adjusted by adjusting the inter-layer distance between the fourth conductor pattern 24 and the second conductor pattern 22.

[0047] 13(j), a second conductor pattern 22 is formed on the ceramic green sheet 1j. The second conductor pattern 22 is formed counterclockwise from the center of the short side on the left side of the ceramic green sheet 1j in the figure, and extends approximately halfway around the circumference. The starting end of the second conductor pattern 22 is formed to the outer periphery of the ceramic green sheet 1j so as to be electrically connected to the second external electrode 12. Meanwhile, a connecting portion 31a that connects to the via conductor 31 is provided at the end of the second conductor pattern 22.

[0048] 13(k), a first conductor pattern 21a is formed on the ceramic green sheet 1k. The first conductor pattern 21a is formed clockwise from the center of the short side on the right side of the ceramic green sheet 1k in the figure, making approximately ¾ to one turn. The starting end of the first conductor pattern 21a is formed to the outer periphery of the ceramic green sheet 1k so as to be electrically connected to the first external electrode 11. Meanwhile, a connecting portion 31b that connects to the via conductor 31 is provided at the end of the first conductor pattern 21a.

[0049] 13(l), the ceramic green sheet 1l is provided with only connection portions 31c that connect to the via conductors 31, and no conductor patterns are formed on the ceramic green sheet 1l. That is, in the antenna coupling element 10, the inter-layer distance between the first conductor pattern 21a and the first conductor pattern 21b is longer than the inter-layer distance between the third conductor pattern 23a and the third conductor pattern 23b or the inter-layer distance between the first conductor pattern 21b and the second conductor pattern 22. The first conductor pattern 21b is the first conductor pattern among the multiple first conductor patterns 21 that faces the second conductor pattern 22. In this way, the antenna coupling element 10 can adjust the inductance component of the coil L1 by adjusting the inter-layer distance between the first conductor pattern 21a and the first conductor pattern 21b.

[0050] 13(m), a first conductor pattern 21b is formed on the ceramic green sheet 1m. The first conductor pattern 21b is formed clockwise from the center of the short side on the right side of the ceramic green sheet 1m in the figure, making approximately 3 / 4 to one turn. The starting end of the first conductor pattern 21b is formed to the outer periphery of the ceramic green sheet 1m so as to be electrically connected to the first external electrode 11. Meanwhile, a connecting portion 31d that connects to the via conductor 31 is provided at the end of the first conductor pattern 21b.

[0051] No conductive patterns are formed on the ceramic green sheet 1n as shown in Fig. 13(n). Furthermore, the ceramic green sheet 1o has conductive patterns 11b to 14b formed in positions corresponding to the first external electrode 11 to the fourth external electrode 14 as shown in Fig. 13(o).

[0052] Although the substrate constituting the insulator 1 has been described as a ceramic green sheet, it may be a non-magnetic ceramic insulator made of LTCC (Low Temperature Co-fired Ceramics) or the like, or a resin insulator made of a resin material such as polyimide or liquid crystal polymer. In this way, by using a non-magnetic material for the substrate constituting the insulator 1 (rather than magnetic ferrite), the antenna coupling element 10 can function as an antenna coupling element even in high frequency bands exceeding several hundred MHz.

[0053] Each conductor pattern and via conductor are made of a conductive material with low resistivity, primarily composed of Ag or Cu. If the substrate constituting the insulator 1 is ceramic, they are formed, for example, by screen printing and firing a conductive paste primarily composed of Ag or Cu. If the substrate constituting the insulator 1 is resin, they are formed, for example, by patterning a metal foil, such as Al foil or Cu foil, by etching or the like. The antenna coupling element 10 shown in FIGS. 10 to 13 is an example, and the antenna coupling element 10 is not limited to this configuration as long as it includes at least two coils L1 and L2 and forms a transformer in which the coils L1 and L2 are magnetically coupled. For example, the antenna coupling element 10 may include, among the multiple conductor patterns constituting the coil L1, a conductor pattern that is not electrically connected to the first external electrode 11 or the second external electrode 12, and may include, among the multiple conductor patterns constituting the coil L2, a conductor pattern that is not electrically connected to the third external electrode 13 or the fourth external electrode 14.

[0054] [Coupling of two antennas using an antenna coupling element] In the antenna device 100, a slot antenna including an excitation electrode 52 in the antenna coupling element 10 is coupled to a slot antenna including an excitation electrode 51. That is, in the antenna device 100, resonances of the two excitation electrodes 51, 52 in the slot antenna are magnetically coupled via the coils L1 and L2 that form a transformer. Specifically, the power feed circuit 30 is connected to the second external electrode 12 of the antenna coupling element 10, and the excitation electrode 51 is connected to the first external electrode 11. Therefore, when power is supplied from the power feed circuit 30 to the excitation electrode 51, a current I1 flows through the first conductor patterns 21a, 21b and the second conductor pattern 22. The current I1 flows through the second conductor pattern 22 in a direction toward the connection portion 31a, as indicated by the arrows in FIG. 13(j), and flows through the first conductor patterns 21a, 21b in a direction away from the connection portions 31b, 31d, as indicated by the arrows in FIG. 13(k) and (m). A current I2 flows through the coil L2, which generates a magnetic field in the opposite direction so that the magnetic field generated in the coil L1 by the current I1 is canceled out by the coil L2 constituting the transformer. That is, the current I2 flows through the third conductor patterns 23a and 23b in the direction toward the connecting portions 32a and 32b as shown by the arrows in Figures 12(f) and (g), and flows through the fourth conductor pattern 24 in the direction away from the connecting portion 32c as shown by the arrow in Figure 12(h).

[0055] In this way, coupling a slot antenna including an excitation electrode 52 in the antenna coupling element 10 to a slot antenna including an excitation electrode 51 has the effect of increasing the number of resonance points in the antenna device 100 and causing resonance over a wide band, which will be described in comparison with another comparative antenna device. Fig. 14 is a schematic diagram of another comparative antenna device 201. The antenna device 201 is configured such that the excitation electrodes 51 and 52 are not connected to the antenna coupling element 10 as in the antenna device 100, but are connected in parallel to the substrate 40. Note that in the antenna device 201, the same components as those in the antenna device 100 shown in Fig. 1 are designated by the same reference numerals, and detailed description thereof will not be repeated.

[0056] In the antenna device 201, excitation electrodes 51 and 52 are arranged at positions corresponding to the opening 25. The excitation electrode 51 is not connected to the antenna coupling element 10, but is connected to a feed circuit 30 (not shown) via wiring on the substrate 40, and is supplied with power from the feed circuit 30. On the other hand, the excitation electrode 52 is not connected to the antenna coupling element 10, but is connected to the substrate 40 and is connected to GND (grounded). In other words, in the antenna device 201, the slot antenna formed by the opening 25 and the excitation electrode 51 functions as a feed antenna, and the slot antenna formed by the opening 25 and the excitation electrode 52 functions as a parasitic antenna, but the excitation electrodes 51 and 52 are only electric field coupled and not magnetic field coupled.

[0057] Next, the characteristics of antenna device 201 will be described. Fig. 15 is a diagram showing the frequency characteristics of the reflection coefficient of another antenna device 201 for comparison. In Fig. 15, the horizontal axis represents frequency and the vertical axis represents reflection coefficient (return loss). Here, reflection coefficient C is the reflection coefficient of antenna device 201.

[0058] At a reflection coefficient of C, resonance occurs at mark M6 (approximately 2.6 GHz) at the resonance frequency of the fundamental wave of antenna device 201. Furthermore, at a reflection coefficient of C, resonance occurs at mark M7 (approximately 5.6 GHz) at the resonance frequency of a harmonic of antenna device 201. Antenna device 201 only generates resonance near approximately 5.6 GHz, and does not add a resonance point like antenna device 100, nor can it generate resonance in a wide band including approximately 5.0 GHz to approximately 7.0 GHz.

[0059] Furthermore, Fig. 16 is a diagram showing the Smith chart of another comparative antenna device 201. In the Smith chart shown in Fig. 16, the target frequency line from 2 GHz to 8 GHz forms large circles near each of mark M6 (approximately 2.6 GHz) and mark M7 (approximately 5.6 GHz). Therefore, it can be seen from the Smith chart shown in Fig. 16 that antenna device 201 only resonates at approximately 5.6 GHz in addition to the fundamental resonant frequency (approximately 2.6 GHz).

[0060] 17 is a schematic diagram of yet another comparative antenna device 202. Unlike the antenna device 100, the antenna device 202 does not connect the excitation electrodes 51 and 52 to the antenna coupling element 10, but has a configuration in which the connection portions of the excitation electrodes 51 and 52 cross and are connected to the substrate 40. Note that in the antenna device 202, the same components as those in the antenna device 100 shown in FIG. 1 are denoted by the same reference numerals, and detailed description thereof will not be repeated.

[0061] In the antenna device 202, excitation electrodes 51 and 52 are disposed at positions corresponding to the opening 25. The excitation electrode 51 is not connected to the antenna coupling element 10, but is connected to a feed circuit 30 (not shown) via wiring on the substrate 40, and is supplied with power from the feed circuit 30. On the other hand, the excitation electrode 52 is not connected to the antenna coupling element 10, but is connected to the substrate 40 across the connection portion of the excitation electrode 51, and is connected to GND (grounded). In other words, in the antenna device 202, the slot antenna formed by the opening 25 and the excitation electrode 51 functions as a feed antenna, and the slot antenna formed by the opening 25 and the excitation electrode 52 functions as a parasitic antenna, but the connection portions of the excitation electrodes 51 and 52 intersect, so that the excitation electrodes 51 and 52 are only electric field coupled, but are not magnetic field coupled.

[0062] Next, the characteristics of antenna device 202 will be described. Fig. 18 is a diagram showing the frequency characteristics of the reflection coefficient of yet another antenna device 202 for comparison. In Fig. 18, the horizontal axis represents frequency and the vertical axis represents reflection coefficient (return loss). Here, reflection coefficient D is the reflection coefficient of antenna device 202.

[0063] For reflection coefficient D, resonance occurs at mark M8 (approximately 2.5 GHz) at the resonance frequency of the fundamental wave of antenna device 202. Furthermore, for reflection coefficient D, resonance occurs at mark M9 (approximately 5.5 GHz) at the resonance frequency of the harmonic of antenna device 202. Antenna device 202 only generates resonance near approximately 5.5 GHz, and does not add any resonance points like antenna device 100, nor can it generate resonance in a wide band including approximately 5.0 GHz to approximately 7.0 GHz.

[0064] Furthermore, Fig. 19 is a diagram showing the Smith chart of yet another comparative antenna device 202. In the Smith chart shown in Fig. 19, the target frequency line from 2 GHz to 8 GHz forms large circles near each of mark M8 (approximately 2.5 GHz) and mark M9 (approximately 5.5 GHz). Therefore, it can be seen from the Smith chart shown in Fig. 19 that antenna device 202 only resonates at approximately 5.5 GHz in addition to the fundamental resonant frequency (approximately 2.5 GHz).

[0065] It can be seen that simply adding a slot antenna that functions as a parasitic antenna to a slot antenna that functions as a fed antenna, compared to the antenna devices 201 and 202, does not increase the number of resonance points and cause resonance over a wide frequency band. Therefore, it can be seen that in the antenna device 100, the effect of coupling the slot antenna including the excitation electrode 52 to the slot antenna including the excitation electrode 51 in the antenna coupling element 10 is to increase the number of resonance points and cause resonance over a wide frequency band.

[0066] [Impedance adjustment] The antenna device 100 can change the width of the band in which resonance occurs by changing the frequency characteristics near the added resonance point by adjusting the impedance of the slot antenna including the excitation electrode 52 coupled to the slot antenna including the excitation electrode 51 by the antenna coupling element 10. Possible methods for adjusting the impedance of the slot antenna including the excitation electrode 52 include, for example, changing the length of the excitation electrode 52 in the X direction, or changing the capacitance value of the capacitance element 60 connected between the coil L2 and the excitation electrode 52.

[0067] In the antenna device 100, the length of the excitation electrode 52 in the X direction is set to about half the length of the excitation electrode 51 in the X direction, and the capacitance value of the capacitive element 60 is set to 0.3 pF to adjust the impedance. The following describes how adjusting the impedance in this way changes the frequency characteristics near the added resonance point. Specifically, the characteristics of the antenna device 100 in which the impedance is adjusted to a capacitance value of 0 (zero) F will be described.

[0068] 20 is a diagram showing the frequency characteristics of the reflection coefficient of antenna device 100 in which the capacitance value of the capacitive element is changed. In Fig. 20, the horizontal axis represents frequency and the vertical axis represents reflection coefficient (return loss). Here, reflection coefficient E is the reflection coefficient of antenna device 100 in which the capacitance value of capacitive element 60 is changed to 0 (zero) F.

[0069] With the reflection coefficient E, resonance occurs at the mark M11 (approximately 2.5 GHz) at the resonance frequency of the fundamental wave of the antenna device 100. Furthermore, with the reflection coefficient E, resonance occurs at the mark M12 (approximately 5.2 GHz) and the mark M13 (approximately 6.5 GHz) at the resonance frequency of the harmonic of the antenna device 100. Therefore, even in the antenna device 100 in which the capacitance value of the capacitive element 60 is changed to 0 (zero) F, it is possible to increase the number of resonance points. However, the reflection coefficient E only causes resonance near the mark M12 (approximately 5.2 GHz) and the mark M13 (approximately 6.5 GHz), and is unable to cause resonance in a wide band including approximately 5.0 GHz to approximately 7.0 GHz, as with the reflection coefficient A shown in FIG. 5.

[0070] 21 is a diagram showing the Smith chart of the antenna device 100 in which the capacitance value of the capacitive element is changed. In the Smith chart shown in FIG. 21, the target frequency line from 2 GHz to 8 GHz draws circles near each of the marks M11 (approximately 2.5 GHz), M12 (approximately 5.2 GHz), and M13 (approximately 6.5 GHz). However, in the Smith chart shown in FIG. 21, the circles drawn near each of the marks M12 (approximately 5.2 GHz) and M13 (approximately 6.5 GHz) are smaller than the large circles drawn near each of the marks M2 and M3 in the Smith chart shown in FIG. 6. Therefore, it can be seen from the Smith chart shown in FIG. 21 that the antenna device 100 in which the capacitance value of the capacitive element 60 is changed to 0 (zero) F is able to increase the number of resonance points but does not cause resonance in a wide band including approximately 5.0 GHz to approximately 7.0 GHz.

[0071] [Variations] In the antenna device 100 described above, the excitation electrodes 51 and 52 are formed on the substrate 40 disposed on the conductor 20, and are therefore disposed at positions different from the opening 25 in the Z direction, as shown in Fig. 3. However, the excitation electrodes 51 and 52 may be disposed at positions overlapping with the opening 25 in the Z direction.

[0072] FIG. 22 is a cross-sectional view of an antenna device 100A according to a modified example. Note that in the antenna device 100A, the same components as those in the antenna device 100 shown in FIGS. 1 to 3 are denoted by the same reference numerals, and detailed description thereof will not be repeated. In the antenna device 100, as shown in FIG. 3, excitation electrodes 51 and 52 are formed on the surface of the substrate 40 opposite the surface of the substrate 40 that contacts the conductor 20. On the other hand, in the antenna device 100A, as shown in FIG. 22, the excitation electrodes 51 and 52 are formed on the surface of the substrate 40 that contacts the conductor 20. That is, in the antenna device 100A, the opening 25 and the excitation electrodes 51 and 52 are arranged at positions where they overlap in the Z direction. Here, an example is shown in which the antenna coupling element 10 is arranged at a position where it does not overlap with the conductor 20 in the Z direction. However, the antenna coupling element 10 may also be arranged at a position where it overlaps with the same opening 25 in the Z direction as the excitation electrodes 51 and 52, or the excitation electrodes 51 and 52 may be arranged on different surfaces of the substrate 40.

[0073] (Embodiment 2) In the antenna device 100 according to the first embodiment, an opening 25 (slot) that is long in the X direction is provided in the plate-like conductor 20, and excitation electrodes 51 and 52 are arranged at positions corresponding to the opening 25. The excitation electrodes 51 and 52 are provided along the long side 25a of the opening 25, and are excited as an antenna by electric field coupling (capacitive coupling) between the excitation electrodes 51 and 52 and the peripheral portion of the opening 25. In the antenna device according to the second embodiment, in order to widen the usable frequency band, an antenna that is excited by electric field coupling between the excitation electrode and the peripheral portion of the opening is combined with an antenna that is excited by passing a current through the peripheral portion of the opening.

[0074] Fig. 23 is a schematic diagram of an electronic device including antenna device 100B according to embodiment 2. As shown in Fig. 23, the electronic device includes antenna device 100B, a power supply circuit 30 that supplies power to excitation electrode 51a (first excitation electrode), and a housing 300 that houses antenna device 100B and power supply circuit 30. Note that in the electronic device including antenna device 100B, the same components as those in the electronic device including antenna device 100 shown in Fig. 1 are denoted by the same reference numerals, and detailed description thereof will not be repeated.

[0075] The antenna device 100B has an opening 25 (slot) that is long in the X direction provided in the plate-like conductor 20, and an excitation electrode 51a (also referred to as an excitation conductor, a feed line, or simply a microstrip line) disposed near the opening 25. The antenna device 100B is excited as a slot antenna by causing the excitation electrode 51a to operate as a capacitive feed element for the opening 25, and electric field coupling (capacitive coupling) between the excitation electrode 51a and the periphery of the opening 25.

[0076] The excitation electrode 51a is electrically connected to one end (first external electrode 11) of the coil L1 of the antenna coupling element 10 mounted on the substrate 40. As shown in FIG. 23 , the excitation electrode 51a is connected to the power feed circuit 30 via the antenna coupling element 10, and is supplied with power from the power feed circuit 30. In other words, the slot antenna formed by the opening 25 and the excitation electrode 51a functions as a power feed antenna. The other end (second external electrode 12) of the coil L1 of the antenna coupling element 10 is electrically connected to the power feed circuit 30.

[0077] Unlike the antenna device 100, the antenna device 100B does not have an excitation electrode 52, and one end (fourth external electrode 14) of the coil L2 of the antenna coupling element 10 is connected to a GND electrode 41 (substrate electrode) of the substrate 40. By connecting one end of the coil L2 to the GND electrode 41, the antenna device 100B is excited when a current from the feed circuit 30 flows to the periphery of the opening 25 via the coil L1 that is magnetically coupled with the coil L2. As a result, the antenna device 100B has the resonant frequency of the antenna excited by the connection between the antenna coupling element 10 and the GND electrode 41 in addition to the resonant frequency of the slot antenna excited by the excitation electrode 51a, and the usable frequency band can be widened.

[0078] The other end of the coil L2 (third external electrode 13) may or may not be connected to the substrate 40, but is not electrically connected to an electrode such as a GND electrode. Connecting the other end of the coil L2 to the substrate 40 improves the mounting strength of the antenna coupling element 10 to the substrate 40.

[0079] 23 is a strip-like electrode provided in the X direction of the substrate 40 parallel to the opening 25, but is not limited to this shape and may have any shape as long as it allows connection of one end of the power supply circuit 30 and one end of the coil L2. The GND electrode 41 may also be divided into a portion electrically connected to one end of the power supply circuit 30 and a portion electrically connected to one end of the coil L2, as long as both portions are electrically connected to the conductor 20 arranged on the housing 300.

[0080] In antenna device 100B, one end of coil L2 is connected to GND electrode 41, and thereby current from power feed circuit 30 is passed through magnetically coupled coil L1 to the periphery of opening 25, exciting the antenna. Therefore, depending on the relationship between the position where one end of power feed circuit 30 is electrically connected to GND electrode 41 and the position where one end of coil L2 is electrically connected to GND electrode 41, the current flowing through the periphery of opening 25 changes, and the resonant frequency of the antenna excited by this current also changes.

[0081] Simulation results of the antenna device 100B will be described. Fig. 24 is a diagram showing frequency characteristics of the reflection coefficient of the antenna device 100B according to the second embodiment. Fig. 25 is a diagram showing antenna efficiency of the antenna device 100B according to the second embodiment. In Fig. 24, the horizontal axis represents frequency, and the vertical axis represents reflection coefficient (return loss). In Fig. 25, the horizontal axis represents frequency, and the vertical axis represents antenna efficiency.

[0082] 24 indicates the reflection coefficient of antenna device 100B, and reflection coefficient G indicates the reflection coefficient of the slot antenna without an antenna coupling element. At reflection coefficient G, resonance occurs at approximately 2.3 GHz, the resonant frequency of the slot antenna excited by excitation electrode 51a. Furthermore, at reflection coefficient F, resonance occurs at approximately 3.0 GHz, the resonant frequency of the antenna excited by connecting antenna coupling element 10 and GND electrode 41. Therefore, the antenna efficiency H of antenna device 100B shown in FIG. 25 remains high in the frequency range from approximately 2.3 GHz to approximately 3.0 GHz.

[0083] 24 and 25 show, for comparison, the reflection coefficient G and antenna efficiency I of only the slot antenna excited by the excitation electrode. The reflection coefficient G only resonates at the resonant frequency of the slot antenna excited by the excitation electrode at approximately 2.2 GHz, and no other resonance points exist. Therefore, it can be seen that the antenna efficiency I shown in Fig. 25 decreases as the frequency increases above approximately 2.4 GHz.

[0084] 24 and 25, the antenna device 100B can increase the number of resonance points and generate resonance in a wide band including approximately 2.3 GHz to approximately 3.0 GHz by adding an antenna excited by the connection between the antenna coupling element 10 and the GND electrode 41 in addition to the slot antenna excited by the excitation electrode 51a. Furthermore, the antenna device 100B can achieve good antenna efficiency over a wide band.

[0085] [Variation 1] 23, the position where one end of the feed circuit 30 is electrically connected to the GND electrode 41 and the position where one end of the coil L2 is electrically connected to the GND electrode 41 are on the same side of the opening 25. In Modification 1, an antenna device will be described in which the position where one end of the feed circuit is electrically connected to the GND electrode and the position where one end of the coil L2 is electrically connected to the GND electrode are on different sides of the opening 25.

[0086] Fig. 26 is a schematic diagram of an electronic device including an antenna device 100C according to a first modification of the second embodiment. As shown in Fig. 26, the electronic device includes the antenna device 100C, a power supply circuit 30 that supplies power to an excitation electrode 51a (excitation electrode), and a housing 300 that houses the antenna device 100C and the power supply circuit 30. Note that in the electronic device including the antenna device 100C, the same components as those in the electronic device including the antenna device 100 shown in Fig. 1 and the antenna device 100B shown in Fig. 23 are designated by the same reference numerals, and detailed description thereof will not be repeated.

[0087] In the antenna device 100C, an opening 25 that is long in the X direction is provided in the plate-like conductor 20, and an excitation electrode 51a is disposed near the opening 25. That is, in the antenna device 100C, the excitation electrode 51a operates as a capacitive feeding element for the opening 25, and the excitation electrode 51a and the peripheral portion of the opening 25 are excited as a slot antenna by electric field coupling (capacitive coupling) between the excitation electrode 51a and the peripheral portion of the opening 25. The slot antenna formed by the opening 25 and the excitation electrode 51a functions as a feeding antenna.

[0088] Furthermore, in the antenna device 100C, one end (fourth external electrode 14) of the coil L2 is connected to the GND electrode 42 (substrate electrode) of the substrate 40. When one end of the coil L2 is connected to the GND electrode 42, the antenna device 10C is excited by a current flowing from the power supply circuit 30 to the periphery of the opening 25 via the coil L1 that is magnetically coupled with the coil L2.

[0089] 26 is L-shaped and includes a portion that is provided in the X direction of the substrate 40 parallel to the opening 25 and a portion that is provided in the Y direction of the substrate 40 and partially overlaps with the opening 25. Because the opening 25 and a portion of the GND electrode 42 overlap when viewed from the Z direction, the opening of the slot antenna is the portion of the opening 25 excluding the portion that is partially overlapped by the GND electrode 42. Note that, although a configuration in which the opening 25 and a portion of the GND electrode 42 overlap when viewed from the Z direction has been described in FIG. 26, the GND electrode 42 may be L-shaped so as not to overlap with the opening 25 when viewed from the Z direction.

[0090] In the antenna device 100C, the position where one end of the power feed circuit 30 is electrically connected to the GND electrode 42 and the position where one end of the coil L2 is electrically connected to the GND electrode 42 are located on different sides of the opening 25. Specifically, one end of the power feed circuit 30 is located on the X-direction side of the GND electrode 42, and one end of the coil L2 is located on the Y-direction side of the GND electrode 42. Therefore, in the antenna device 100C, the position where one end of the coil L2 is electrically connected to the GND electrode 42 is located away from the position where one end of the power feed circuit 30 is electrically connected to the GND electrode 42, thereby preventing the resonances of the two antennas from interfering with each other and improving the antenna characteristics.

[0091] The GND electrode 42 may be configured as an electrode electrically connected to one end of the power supply circuit 30 and an electrode electrically connected to one end of the coil L2, and both electrodes may be electrically connected to the conductor 20 and the housing 300 and provided on different sides of the opening 25.

[0092] [Variation 2] 23, one end of the power supply circuit 30 and one end of the coil L2 are electrically connected to the GND electrode 41. In Modification 2, an antenna device in which the number of portions electrically connected to the GND electrode is increased will be described.

[0093] Fig. 27 is a schematic diagram of an electronic device including an antenna device 100D according to Variation 2 of Embodiment 2. As shown in Fig. 27, the electronic device includes antenna device 100D, a power supply circuit 30 that supplies power to excitation electrode 51a (first excitation electrode), and a housing 300 that houses antenna device 100D and power supply circuit 30. Note that in the electronic device including antenna device 100D, the same components as those in the electronic device including antenna device 100 shown in Fig. 1 and antenna device 100B shown in Fig. 23 are designated by the same reference numerals, and detailed description thereof will not be repeated.

[0094] In the antenna device 100D, an opening 25 that is long in the X direction is provided in the plate-like conductor 20, and an excitation electrode 51b is disposed at a position corresponding to the opening 25. That is, in the antenna device 100D, the excitation electrode 51b operates as a capacitive feeding element for the opening 25, and the excitation electrode 51b and the peripheral portion of the opening 25 are excited as a slot antenna by electric field coupling (capacitive coupling) between the excitation electrode 51b and the peripheral portion of the opening 25. The slot antenna constituted by the opening 25 and the excitation electrode 51b functions as a feeding antenna.

[0095] Unlike the excitation electrode 51a shown in Figure 23, the excitation electrode 51b has a shape that is long in the X direction along the opening 25, and one end is electrically connected to one end of the coil L1 (first external electrode 11) and the other end is electrically connected to the GND electrode 41 of the substrate 40.

[0096] Furthermore, in the antenna device 100D, one end (fourth external electrode 14) of the coil L2 is electrically connected to the GND electrode 41 of the substrate 40, and the other end (third external electrode 13) of the coil L2 is also electrically connected to the GND electrode 41. When the coil L2 is connected to the GND electrode 41, a current from the power supply circuit 30 flows to the periphery of the opening 25 via the coil L1 that is magnetically coupled with the coil L2, and thus the antenna device 100D is excited.

[0097] 27, in the antenna device 100D, not only one end of the feed circuit 30 and one end of the coil L2 but also one end of the coil L1 and the other end of the coil L2 are electrically connected to the GND electrode 41. Therefore, compared to the antenna device 100B shown in FIG. 23, the antenna device 100D has more starting points for current flowing to the GND electrode 41, thereby increasing the number of paths for current flowing from the feed circuit 30 to the periphery of the opening 25 via the antenna coupling element 10, thereby widening the bandwidth. Note that the configuration described in Modification 2 may be combined with the configuration described in Modification 1. Also, in FIG. 27, the excitation electrode 51b and the line connecting the excitation electrode 51b and the GND electrode 41 are depicted separately, but in reality, the boundary between them may not be clear.

[0098] [Variation 3] 23 uses the antenna coupling element 10 to form a slot antenna excited by the excitation electrode 51a fed by the feed circuit 30, and a parasitic slot antenna. In Modification 3, an antenna device will be described that does not use the antenna coupling element 10 and forms a powered slot antenna and a parasitic slot antenna.

[0099] Fig. 28 is a schematic diagram of an electronic device including antenna device 100E according to Variation 3 of Embodiment 2. As shown in Fig. 28, the electronic device includes antenna device 100E, a power supply circuit 30 that supplies power to excitation electrode 51a (first excitation electrode), and a housing 300 that houses antenna device 100E and power supply circuit 30. Note that in the electronic device including antenna device 100E, the same components as those in the electronic device including antenna device 100 shown in Fig. 1 and antenna device 100B shown in Fig. 23 are designated by the same reference numerals, and detailed description thereof will not be repeated.

[0100] The antenna device 100E has an opening 25 that is long in the X direction provided in the plate-shaped conductor 20, and an excitation electrode 51a disposed near the opening 25. That is, the antenna device 100E is excited as a slot antenna by the excitation electrode 51a operating as a capacitive feeding element with respect to the opening 25 and the excitation electrode 51a and the periphery of the opening 25 being electric field coupled (capacitively coupled). The slot antenna formed by the opening 25 and the excitation electrode 51a functions as a feeding antenna.

[0101] Furthermore, in the antenna device 100E, an excitation electrode 52a is disposed near the excitation electrode 51a, and one end of the excitation electrode 52a is connected to the GND electrode 41 (substrate electrode) of the substrate 40. The excitation electrode 52a has an L-shape including a portion that is provided parallel to the excitation electrode 51a (Y direction) and a portion that is provided parallel to the GND electrode 41 (X direction). Since the excitation electrodes 51a and 52a are electromagnetically coupled at the portion where they are provided parallel to each other, a current that flows from the power feed circuit 30 to the excitation electrode 51a causes a current to flow in the excitation electrode 52a.

[0102] The antenna device 100E is excited when one end of the excitation electrode 52a is connected to the GND electrode 41 and a current from the feed circuit 30 flows through the periphery of the opening 25 via the portion where the excitation electrodes 51a and 52a are arranged in parallel, thereby causing the antenna device 100E to have a slot antenna fed by the feed circuit 30 and a parasitic slot antenna without using the antenna coupling element 10, thereby reducing manufacturing costs. Note that the configuration described in Modification 3 may be combined with the configurations described in Modifications 1 and 2.

[0103] [Aspect] (1) a plate-shaped conductor having an opening; a first excitation electrode and a second excitation electrode disposed at positions corresponding to the opening; a first coil having one end electrically connected to the first excitation electrode and the other end connected to a power supply circuit; a second coil, one end of which is electrically connected to the second excitation electrode; The antenna device is configured such that the first coil and the second coil are magnetically coupled.

[0104] As a result, the antenna device according to the present disclosure can add a resonance point to widen the usable frequency band by connecting the first excitation electrode and the second excitation electrode, which are arranged at positions corresponding to the opening, to the magnetically coupled first coil and second coil, respectively.

[0105] (2) The antenna device according to (1), The first excitation electrode and the second excitation electrode are disposed at positions that overlap with the opening when the opening is viewed from above.

[0106] (3) The antenna device according to (2), The device further includes a substrate disposed between the first and second excitation electrodes and the conductor.

[0107] (4) The antenna device according to any one of (1) to (3), The opening is rectangular with the second side shorter than the first side, The first excitation electrode and the second excitation electrode are strip-shaped and extend along the first side.

[0108] (5) The antenna device according to (4), The first direction in which the first excitation electrode extends and the second direction in which the second excitation electrode extends are opposite to each other along the first side.

[0109] (6) The antenna device according to any one of (1) to (5), The device further includes a capacitive element connected in series between the second coil and the second excitation electrode.

[0110] (7) The antenna device according to any one of (1) to (6), The antenna coupling element including the first coil and the second coil comprises: An insulator; a first external electrode, a second external electrode, a third external electrode, and a fourth external electrode formed on a surface of an insulator; a first coil and a second coil each formed of a plurality of conductor patterns within an insulator; the plurality of conductor patterns constituting the first coil are electrically connected to the first external electrode or the second external electrode; the plurality of conductor patterns constituting the second coil are electrically connected to the third external electrode or the fourth external electrode; When viewed from the lamination direction of the insulators, the opening of the first coil at least partially overlaps with the opening of the second coil.

[0111] (8) The antenna device according to (7), the first excitation electrode is electrically connected to the first outer electrode of the antenna coupling element; the feed circuit is electrically connected to the second external electrode of the antenna coupling element; the second excitation electrode is electrically connected to the third outer electrode of the antenna coupling element; The fourth external electrode of the antenna coupling element is grounded.

[0112] (9) The antenna device according to any one of (7) and (8), The first coil is a first conductor pattern having at least two layers electrically connected to the first external electrode; a second conductor pattern laminated on the first conductor pattern and electrically connected to the second external electrode, The layers of the first conductor pattern are connected in parallel to each other, and the second conductor pattern is connected in series to the first conductor pattern; The second coil is a third conductor pattern having at least two layers, electrically connected to the third external electrode; a fourth conductor pattern laminated on the third conductor pattern and electrically connected to the fourth external electrode, The layers of the third conductor pattern are connected in parallel to each other, and the fourth conductor pattern is connected in series to the third conductor pattern; The first coil and the second coil are arranged in the insulator so that the second conductor pattern and the fourth conductor pattern face each other in the stacking direction.

[0113] (10) The antenna device according to any one of (1) to (9), a power supply circuit for supplying power to the first excitation electrode; An electronic device comprising: a housing that houses an antenna device and a power supply circuit.

[0114] (11) A plate-shaped conductor having an opening; an excitation electrode disposed at a position corresponding to the opening; a first coil having one end electrically connected to the excitation electrode and the other end connected to a power supply circuit; a second coil having one end electrically connected to a substrate electrode electrically connected to the conductor; The first coil and the second coil are disposed in a position where they are magnetically coupled.

[0115] As a result, the antenna device according to the present disclosure can add a resonance point to widen the usable frequency band by magnetically coupling a first coil having one end electrically connected to an excitation electrode and the other end connected to a power supply circuit, and a second coil having one end electrically connected to a substrate electrode electrically connected to a conductor.

[0116] (12) The antenna device according to (11), The other end of the second coil is further electrically connected to the substrate electrode.

[0117] (13) The antenna device according to any one of (11) and (12), the substrate electrodes are provided along at least two sides of the opening; a power supply circuit is electrically connected to a portion of the substrate electrode provided along the first side of the opening; One end of the second coil is electrically connected to a portion of the substrate electrode that is provided along a second side of the opening that is different from the first side.

[0118] (14) The antenna device according to any one of (11) to (13), The antenna coupling element including the first coil and the second coil comprises: An insulator; a first external electrode, a second external electrode, a third external electrode, and a fourth external electrode formed on a surface of an insulator; a first coil and a second coil each formed of a plurality of conductor patterns within an insulator; the plurality of conductor patterns constituting the first coil are electrically connected to the first external electrode or the second external electrode; the plurality of conductor patterns constituting the second coil are electrically connected to the third external electrode or the fourth external electrode; When viewed from the lamination direction of the insulators, the opening of the first coil at least partially overlaps with the opening of the second coil.

[0119] (15) The antenna device according to (14), a power supply circuit for supplying power to the excitation electrodes; and a housing that houses the antenna device and the power supply circuit.

[0120] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims, not by the above description, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0121] 10 antenna coupling element, 11 first external electrode, 12 second external electrode, 13 third external electrode, 14 fourth external electrode, 20 conductor, 21, 21a, 21b first conductor pattern, 22, 22A second conductor pattern, 23, 23a, 23b third conductor pattern, 24, 24A fourth conductor pattern, 25 opening, 31, 32 via conductor, 30 power supply circuit, 40 substrate, 51, 52 excitation electrode, 60 capacitance element, 100, 100A, 200, 201, 202 antenna device, 300 housing.

Claims

1. a plate-shaped conductor having an opening; a first excitation electrode and a second excitation electrode disposed at positions corresponding to the opening; a first coil having one end electrically connected to the first excitation electrode and the other end connected to a power supply circuit; a second coil, one end of which is electrically connected to the second excitation electrode; The antenna device, wherein the first coil and the second coil are positioned so as to be magnetically coupled.

2. The antenna device according to claim 1 , wherein the first excitation electrode and the second excitation electrode are arranged at positions overlapping the opening when the opening is seen in a plan view.

3. The antenna device according to claim 2 , further comprising a substrate disposed between the first excitation electrode, the second excitation electrode and the conductor.

4. The opening has a rectangular shape with a second side shorter than a first side, 4. The antenna device according to claim 1, wherein the first excitation electrode and the second excitation electrode are strip-shaped and extend along the first side.

5. The antenna device according to claim 4 , wherein a first direction in which the first excitation electrode extends and a second direction in which the second excitation electrode extends are opposite to each other along the first side.

6. 4. The antenna device according to claim 1, further comprising a capacitive element connected in series between the second coil and the second excitation electrode.

7. The antenna coupling element including the first coil and the second coil is An insulator; a first external electrode, a second external electrode, a third external electrode, and a fourth external electrode formed on a surface of the insulator; the first coil and the second coil are configured by a plurality of conductor patterns within the insulator, the plurality of conductor patterns constituting the first coil include a conductor pattern electrically connected to the first external electrode or the second external electrode, the plurality of conductor patterns constituting the second coil include a conductor pattern electrically connected to the third external electrode or the fourth external electrode, 4. The antenna device according to claim 1, wherein an opening of the first coil at least partially overlaps an opening of the second coil when viewed from a stacking direction of the insulator.

8. the first excitation electrode is electrically connected to the first external electrode of the antenna coupling element; the feed circuit is electrically connected to the second external electrode of the antenna coupling element; the second excitation electrode is electrically connected to the third external electrode of the antenna coupling element; The antenna device according to claim 7 , wherein the fourth external electrode of the antenna coupling element is grounded.

9. The first coil is a first conductor pattern having at least two layers electrically connected to the first external electrode; a second conductor pattern laminated on the first conductor pattern and electrically connected to the second external electrode, the layers of the first conductor patterns are connected in parallel with each other, and the second conductor patterns are connected in series to the first conductor patterns; The second coil is a third conductor pattern having at least two layers, electrically connected to the third external electrode; a fourth conductor pattern laminated on the third conductor pattern and electrically connected to the fourth external electrode, the layers of the third conductor pattern are connected in parallel with each other, and the fourth conductor pattern is connected in series to the third conductor pattern; The antenna device according to claim 7 , wherein the first coil and the second coil are arranged within the insulator such that the second conductor pattern and the fourth conductor pattern face each other in the stacking direction.

10. The antenna device according to any one of claims 1 to 3; the power supply circuit for supplying power to the first excitation electrode; and a housing that houses the antenna device and the power supply circuit.

11. a plate-shaped conductor having an opening; an excitation electrode disposed at a position corresponding to the opening; a first coil having one end electrically connected to the excitation electrode and the other end connected to a power supply circuit; a second coil having one end electrically connected to a substrate electrode electrically connected to the conductor; The antenna device, wherein the first coil and the second coil are positioned so as to be magnetically coupled.

12. The antenna device according to claim 11 , wherein the other end of the second coil is further electrically connected to the substrate electrode.

13. the substrate electrode is provided along at least two sides of the opening, the power supply circuit is electrically connected to a portion of the substrate electrode provided along a first side of the opening, 13. The antenna device according to claim 11, wherein one end of the second coil is electrically connected to a portion of the substrate electrode that is provided along a second side of the opening that is different from the first side.

14. The antenna coupling element including the first coil and the second coil is An insulator; a first external electrode, a second external electrode, a third external electrode, and a fourth external electrode formed on a surface of the insulator; the first coil and the second coil are configured by a plurality of conductor patterns within the insulator, the plurality of conductor patterns constituting the first coil include a conductor pattern electrically connected to the first external electrode or the second external electrode, the plurality of conductor patterns constituting the second coil include a conductor pattern electrically connected to the third external electrode or the fourth external electrode, 13. The antenna device according to claim 11, wherein an opening of the first coil at least partially overlaps an opening of the second coil when viewed from a stacking direction of the insulator.

15. The antenna device according to claim 14; the power supply circuitry for supplying power to the excitation electrodes; and a housing that houses the antenna device and the power supply circuit.

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