Antenna device and electronic apparatus

Abstract

Provided are an antenna device and an electronic apparatus with which it is possible to obtain required double resonance characteristics and widen a frequency band. An antenna device (100) according to the present disclosure comprises: a plate-form conductor (10) that has an opening (10a); a signal line (20a) that is electrically connected or indirectly connected to the conductor (10) on a first side of the opening (10a) and supplies a signal from a power supply circuit (30); a GND line (20c) that is electrically connected to the conductor (10) on a second side of the opening (10a), the second side facing the first side; an excitation electrode (40) disposed at a position corresponding to the opening (10a); a coil (L1) of which one end is electrically connected to the excitation electrode (40) and the other end is electrically connected or indirectly connected to the conductor (10) on the second side; and a coil (L2) of which one end is electrically or indirectly connected to the conductor (10) on the first side and the other end is electrically connected or indirectly connected to the conductor (10) on the second side. The coil (L1) and the coil (L2) are disposed at positions where magnetic-field coupling is achieved therebetween.

Description

Antenna device and electronic device

[0001] The present disclosure relates to technologies for an antenna device and an electronic device.

[0002] In recent years, electronic devices that operate in multiple frequency bands have been developed. Antenna devices used in these electronic devices need to have a wide usable frequency band, and for example, a slot antenna with multi-resonance characteristics has been proposed (see, for example, U.S. Patent Application Publication No. 2023 / 0008815). In this antenna device, a signal line from a feed circuit is electrically connected to a slot (opening) to excite the slot with a current, and an impedance element with frequency characteristics bypasses the slot to artificially change the slot size, thereby achieving multi-resonance characteristics.

[0003] US Patent Application Publication No. 2023 / 0008815

[0004] However, in the antenna device disclosed in Patent Document 1 (U.S. Patent Application Publication No. 2023 / 0008815), in frequency bands where a large current flows through an impedance element provided to bypass the slot, excitation does not occur in the portion of the slot on the side of the impedance element to which the feed circuit is not connected. As a result, the antenna device may not be able to obtain the required multi-resonance characteristics.

[0005] The present disclosure has been made to solve such problems, and its purpose is to provide an antenna device and electronic device that can obtain the required multi-resonance characteristics and widen the frequency band.

[0006] An antenna device according to the present disclosure includes a plate-shaped conductor having an opening, a signal line electrically connected or indirectly connected to the conductor on a first side of the opening and supplying a signal from a power supply circuit, a GND line electrically connected to the conductor on a second side of the opening opposite the first side, an excitation electrode arranged at a position corresponding to the opening, a first coil having one end electrically connected to the excitation electrode and the other end electrically connected or indirectly connected to the conductor on the second side, and a second coil having one end electrically connected or indirectly connected to the conductor on the first side and the other end electrically connected or indirectly connected to the conductor on the second side, where the first coil and the second coil are arranged at positions where they are magnetically coupled.

[0007] An electronic device according to the present disclosure includes a power supply circuit and the above-described antenna device.

[0008] In the antenna device according to the present disclosure, the opening is bypassed using a first coil and a second coil arranged in a magnetically coupled position, and an excitation electrode is electrically connected to the first coil, thereby obtaining the required multi-resonance characteristics and widening the frequency band.

[0009] Fig. 1 is a schematic diagram of an antenna device according to an embodiment; Fig. 2 is a diagram showing frequency characteristics of the reflection coefficient of the antenna device according to an embodiment; Fig. 3 is a diagram for explaining a current flow at a resonance point of the antenna device according to an embodiment; Fig. 4 is a schematic diagram of an antenna device according to a first modification; Fig. 5 is a schematic diagram of an antenna device according to a second modification; Fig. 6 is a schematic diagram of an antenna device according to a third modification; Fig. 7 is a schematic diagram of an antenna device according to a fourth modification; Fig. 8 is a schematic diagram of an antenna device according to a fifth modification;

[0010] Hereinafter, embodiments of the present disclosure will be described in detail 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] FIG. 1 is a schematic diagram of an antenna device 100 according to an embodiment. The antenna device 100 constitutes a slot antenna, and an opening 10a (slot) is formed in a conductor 10. The antenna device 100 is a current-excited slot antenna in which a signal line from a power feed circuit 30 is electrically connected to the opening 10a, and the opening 10a is excited by the current in the signal line. The antenna device 100 has multi-resonance characteristics in bands including, for example, the 2.4 GHz band and the 5 GHz to 7 GHz band, and is capable of communication in these bands. The antenna device 100 is also built into electronic devices such as notebook computers, mobile phones, smartphones, or tablets. The electronic devices include at least the antenna device 100 and the power feed circuit 30.

[0012] In the antenna device 100, a signal line 20a that supplies a signal from a power supply circuit 30 is electrically connected to the conductor 10 on the upper side (first side) of the opening 10a on the left side of Fig. 1. Here, "electrically connecting the conductor 10 and the signal line 20a" means that the conductor 10 and the signal line 20a are physically directly connected and conductive. Note that the conductor 10 and the signal line 20a may be indirectly connected. "Indirectly connecting the conductor 10 and the signal line 20a" means that the conductor 10 and the signal line 20a are not physically directly connected, but are connected via another circuit element or by electric field coupling, etc. Hereinafter, the terms "electrically connected" and "indirectly connected" will have the same definition.

[0013] The signal line 20a is the inner conductor of the coaxial cable 20 that connects the antenna device 100 and the power supply circuit 30. The coaxial cable 20 has an insulator 20b on the outside of the signal line 20a and a GND line 20c as an outer conductor on the outside of the insulator 20b, and the GND line 20c is electrically connected to the conductor 10 at a fixing part 20d by soldering or the like. The conductor 10 is at GND potential.

[0014] In the antenna device 100, the GND line 20c is electrically connected to the conductor 10 on the lower side (second side) of the opening 10a, which faces the conductor 10 on the upper side (first side) of the opening 10a to which the signal line 20a is electrically connected. As a result, the signal line 20a is wired so as to straddle from the lower side (second side) to the upper side (first side) of the opening 10a.

[0015] The opening 10a shown in FIG. 1 is rectangular, with the Y-direction side shorter than the X-direction side. However, the opening 10a is not limited to a rectangular shape and may have any other shape, such as a polygon, as long as the signal line 20a can extend from one side (second side) to the other side (first side). The conductor 10 is, for example, copper foil formed on a PCB (Printed Circuit Board) and functions as a GND electrode. The conductor 10 is not limited to copper foil formed on a PCB and may be a metal plate such as a copper plate or an aluminum plate.

[0016] A signal line 20a is wired so as to straddle from the lower side (second side) to the upper side (first side) of the opening 10a, and a current is passed from the feed circuit 30 to the signal line 20a. The antenna device 100 functions as a current-excited slot antenna that excites the opening 10a (slot) by passing a current through the signal line 20a. Furthermore, the antenna device 100 is provided with an electromagnetic coupling element 50 and a capacitor 60 on the right side of FIG. 1 to bypass the opening 10a.

[0017] The electromagnetic coupling element 50 is a rectangular parallelepiped chip component that includes two coils L1 (first coil) and L2 (second coil), forming a transformer in which the coils L1 and L2 are magnetically coupled. The electromagnetic coupling element 50 is composed of an insulator (ceramic element) made of ceramic layers in which multiple substrates (ceramic green sheets) on which coil wiring is formed are stacked.

[0018] One end of the coil L1 is electrically connected to the excitation electrode 40, and the other end of the coil L1 is electrically connected to the conductor 10 on the lower side (second side) of the opening 10a. The excitation electrode 40 (also referred to as an excitation conductor, feed line, or simply a microstrip line) is positioned so as to overlap the opening 10a when viewed from above. Furthermore, the excitation electrode 40 has a strip shape extending in the positive X direction (the direction of the arrow) along the long side of the opening 10a, and is positioned in the portion of the opening 10a on the side of the coil L1 to which the signal line 20a is not connected when viewed from above (the opening 10a on the right side in the figure). In the antenna device 100, the excitation electrode 40 functions as a slot antenna with respect to the opening 10a as a capacitive feed element, functioning as a parasitic antenna.

[0019] One end of the coil L2 is electrically connected to one end of the capacitor 60, and the other end of the coil L2 is electrically connected to the conductor 10 on the lower side (second side) of the opening 10a. The other end of the capacitor 60 is electrically connected to the conductor 10 on the upper side (first side) of the opening 10a. Therefore, one end of the coil L2 is indirectly connected to the conductor 10 on the upper side (first side) of the opening 10a. In other words, one end of the coil L2 is connected to the conductor 10 on the upper side (first side) of the opening 10a via the capacitor 60, which is another circuit element. Note that the other circuit element provided between one end of the coil L2 and the conductor 10 on the upper side (first side) of the opening 10a is not limited to the capacitor 60 and may be a passive element such as an inductor.

[0020] Fig. 2 is a diagram showing the frequency characteristics of the reflection coefficient of the antenna device 100 according to the embodiment. In Fig. 2, the horizontal axis represents frequency, and the vertical axis represents the reflection coefficient. Here, reflection coefficient A (solid line) is the reflection coefficient when looking at the antenna device 100 from the feed circuit 30 in Fig. 1. Furthermore, reflection coefficient B (dashed line) is the reflection coefficient of a comparative antenna device. The comparative antenna device has a configuration in which only a capacitor 60 is provided to bypass the opening 10a of the antenna device 100 shown in Fig. 1.

[0021] As shown in Fig. 2, at a reflection coefficient A, resonance occurs in a band including approximately 2.5 GHz, a band including approximately 5.5 GHz, and a band including approximately 7.5 GHz. The current distribution around the opening 10a differs in each frequency band where resonance occurs. Fig. 3 is a diagram for explaining the current flow at the resonance point of the antenna device according to the embodiment.

[0022] 3A shows the current distribution around the opening 10a when resonance occurs in a band including approximately 2.5 GHz. In the current distribution shown in FIG. 3A, a strong current Ia flows around the opening 10a between the signal line 20a and the electromagnetic coupling element 50, while a weak current Ib flows around the opening 10a to the right of the electromagnetic coupling element 50. The current Ia is the current that flows around the opening 10a when the opening 10a is excited by passing a current through the signal line 20a. A similar current also flows in the comparative antenna device. In other words, when the opening 10a is excited by passing a current through the signal line 20a, the current that flows around the opening 10a at the resonant frequency of the fundamental wave of the slot antenna is the current Ia. Furthermore, when the opening 10a is viewed from above, in the portion of the opening 10a on the side of the coil L1 where the signal line 20a is not connected (the opening 10a on the right side in the figure), the excitation electrode 40 functions as a parasitic antenna, and a current Ib flows.

[0023] 3(b) shows the current distribution around the opening 10a in the case of resonance in a band including approximately 5.5 GHz. In the current distribution shown in FIG. 3(b), a weak current Ic flows around the opening 10a between the signal line 20a and the electromagnetic coupling element 50, and a strong current Id flows around the opening 10a on the right side of the electromagnetic coupling element 50 in the figure. The current Id is the current flowing around the opening 10a on the side where the excitation electrode 40 is located, which is excited via the electromagnetic coupling element 50 by passing a current through the signal line 20a. In other words, the current Id is the current flowing around the opening 10a on the side where the excitation electrode 40 is located at the resonant frequency of the fundamental wave of the parasitic antenna of the excitation electrode 40.

[0024] 3(c) shows the current distribution around the opening 10a in the case of resonance in a band including approximately 7.5 GHz. In the current distribution shown in FIG. 3(c), a strong current Ie flows around the opening 10a between the signal line 20a and the electromagnetic field coupling element 50, and a strong current If flows around the opening 10a on the left side of the signal line 20a in the figure. The currents Ie and If are currents that flow around the opening 10a at the harmonic resonance frequency of the slot antenna when the opening 10a is excited by passing a current through the signal line 20a.

[0025] As described above, in the antenna device 100, as shown in FIG. 1, the opening 10a is bypassed using the coils L1 and L2 arranged in a magnetically coupled position, and the excitation electrode 40 is electrically connected to the coil L2, thereby obtaining the required multi-resonance characteristics and widening the frequency band.

[0026] The connection configuration of the electromagnetic coupling element 50 and the capacitor 60 provided to bypass the opening 10a is not limited to the connection configuration shown in Fig. 1. Below, modified examples of the connection configuration of the electromagnetic coupling element 50 and the capacitor 60 will be described. Note that the modified examples described below are just examples, and the connection configurations described in each modified example may be combined as appropriate.

[0027] (Modification 1) Fig. 4 is a schematic diagram of an antenna device 100A in Modification 1. In antenna device 100A shown in Fig. 4, the same components as those in antenna device 100 shown in Fig. 1 are denoted by the same reference numerals, and detailed description thereof will not be repeated. Antenna device 100A forms a slot antenna, and an opening 10a (slot) is formed in conductor 10.

[0028] 4, in the antenna device 100A, a signal line 20a that supplies a signal from the power supply circuit 30 is electrically connected to the conductor 10 on the upper side (first side) of the opening 10a. A GND line 20c is electrically connected to the conductor 10 on the lower side (second side) of the opening 10a.

[0029] Furthermore, the antenna device 100A is provided with an electromagnetic field coupling element 50 for bypassing the opening 10a on the right side of Fig. 4. One end of the coil L1 is electrically connected to the excitation electrode 40, and the other end of the coil L1 is electrically connected to the conductor 10 on the lower side (second side) of the opening 10a. One end of the coil L2 is electrically connected to the conductor 10 on the upper side (first side) of the opening 10a, and the other end of the coil L2 is electrically connected to the conductor 10 on the lower side (second side) of the opening 10a.

[0030] That is, in the antenna device 100A, one end of the coil L2 is directly connected to the conductor 10 on the upper side (first side) of the opening 10a, rather than indirectly connected via the capacitor 60. Therefore, the antenna device 100A does not require the capacitor 60, compared to the antenna device 100, and therefore components costs can be reduced. Note that, in the antenna device 100A, by electrically connecting one end of the coil L2 to the conductor 10 on the upper side (first side) of the opening 10a, the resonant frequency of the resonant point at approximately 2.5 GHz shown in FIG. 2 becomes lower than approximately 2.5 GHz.

[0031] (Modification 2) Fig. 5 is a schematic diagram of an antenna device 100B in Modification 2. In antenna device 100B shown in Fig. 5, the same components as those in antenna device 100 shown in Fig. 1 are denoted by the same reference numerals, and detailed description thereof will not be repeated. Antenna device 100B forms a slot antenna, and an opening 10a (slot) is formed in conductor 10.

[0032] 5, in the antenna device 100B, a signal line 20a that supplies a signal from the power supply circuit 30 is electrically connected to the conductor 10 on the upper side (first side) of the opening 10a. A GND line 20c is electrically connected to the conductor 10 on the lower side (second side) of the opening 10a.

[0033] Furthermore, the antenna device 100B is provided with an electromagnetic field coupling element 50 and a capacitor 60 for bypassing the opening 10a on the right side of Fig. 5. One end of the coil L1 is electrically connected to the excitation electrode 40, and the other end of the coil L1 is electrically connected to the conductor 10 on the lower side (second side) of the opening 10a. One end of the coil L2 is electrically connected to the capacitor 60, and the other end of the coil L2 is electrically connected to the conductor 10 on the lower side (second side) of the opening 10a.

[0034] The excitation electrode 40 has a band shape extending in the negative X direction (opposite to the arrow direction) along the long side of the opening 10a, and is arranged in the portion of the opening 10a on the side where the signal line 20a is connected across the coil L1 when the opening 10a is viewed in plan view (the opening 10a on the left side in the drawing). Therefore, in the antenna device 100B, the resonant path of the parasitic antenna in which the excitation electrode 40 operates as a capacitive feed element relative to the opening 10a is longer than the resonant path of the parasitic antenna of the antenna device 100.

[0035] When the parasitic antenna of antenna device 100 resonates in a band including approximately 5.5 GHz, the resonant frequency of the parasitic antenna of antenna device 100B, which has an opening 10a of the same size, will be lower than that of the band including approximately 5.5 GHz. Conversely, when the parasitic antenna of antenna device 100B is made to resonate in a band including approximately 5.5 GHz, the size of opening 10a of antenna device 100B can be made smaller than that of opening 10a of antenna device 100. In other words, antenna device 100B can be made smaller than antenna device 100 if they have the same resonant frequency.

[0036] (Variation 3) Fig. 6 is a schematic diagram of an antenna device 100C in Variation 3. In the antenna device 100C shown in Fig. 6, 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. The antenna device 100C forms a slot antenna, and an opening 10a (slot) is formed in the conductor 10.

[0037] 6, in the antenna device 100C, a signal line 20a that supplies a signal from the power supply circuit 30 is electrically connected to the conductor 10 on the upper side (first side) of the opening 10a. A GND line 20c is electrically connected to the conductor 10 on the lower side (second side) of the opening 10a.

[0038] Furthermore, the antenna device 100C is provided with an electromagnetic field coupling element 50 and a capacitor 60 for bypassing the opening 10a on the right side of Fig. 6. One end of the coil L2 is electrically connected to the capacitor 60, and the other end of the coil L2 is electrically connected to the conductor 10 on the lower side (second side) of the opening 10a.

[0039] One end of the coil L1 is electrically connected to the excitation electrode 40 (first excitation electrode), and the other end of the coil L1 is electrically connected to the excitation electrode 42 (second excitation electrode). That is, in the antenna device 100C, the excitation electrodes 40 and 42 are provided on both ends of the coil L1, and the parasitic antenna is configured as a dipole antenna.

[0040] In the antenna device 100 shown in Fig. 1, the other end of the coil L1 is electrically connected to the conductor 10 on the lower side (second side) of the opening 10a. On the other hand, in the antenna device 100C shown in Fig. 6, the other end of the coil L1 is electric field coupled to the conductor 10 on the lower side (second side) of the opening 10a via the excitation electrode 42. In other words, the other end of the coil L1 is electrically connected to the excitation electrode 42 in order to be indirectly connected to the conductor 10 on the lower side (second side) of the opening 10a.

[0041] In the antenna device 100C, excitation electrodes 40, 42 are provided on both ends of the coil L1, and the parasitic antenna is made into a dipole, which increases the excitation current of the excitation electrodes 40, 42 and improves the radiation efficiency in a band including approximately 5.5 GHz. Note that, in the antenna device 100C, when the opening 10a is viewed from above, the area of ​​the excitation electrodes 40, 42 that overlap with the opening 10a is large, which may affect resonant frequencies other than the resonant frequency of the parasitic antenna.

[0042] (Modification 4) Fig. 7 is a schematic diagram of an antenna device 100D in Modification 4. In antenna device 100D shown in Fig. 7, the same components as those in antenna device 100 shown in Fig. 1 are denoted by the same reference numerals, and detailed description thereof will not be repeated. Antenna device 100D forms a slot antenna, and an opening 10a (slot) is formed in conductor 10.

[0043] 7, in the antenna device 100D, a signal line 20a that supplies a signal from the power supply circuit 30 is electrically connected to the conductor 10 on the upper side (first side) of the opening 10a. A GND line 20c is electrically connected to the conductor 10 on the lower side (second side) of the opening 10a.

[0044] Furthermore, the antenna device 100D is provided with an electromagnetic coupling element 50 for bypassing the opening 10a on the right side of Fig. 7. One end of the coil L1 is electrically connected to the excitation electrode 40, and the other end of the coil L1 is electrically connected to the conductor 10 on the lower side (second side) of the opening 10a. One end of the coil L2 is electrically connected to the conductor 10 on the upper side (first side) of the opening 10a, and the other end of the coil L2 is electrically connected to the conductor 10 on the lower side (second side) of the opening 10a.

[0045] Furthermore, the antenna device 100D has a capacitor 70 connected in parallel to the electromagnetic coupling element 50. In other words, the antenna device 100D has a parallel circuit bypassing the opening 10a, as shown in FIG. 7 . The element connected in parallel to the electromagnetic coupling element 50 is not limited to a capacitor, but may be any passive element such as an inductor. By paralleling the circuit bypassing the opening 10a, the antenna device 100D has a lower resonant frequency at the same resonance than the resonant frequency of approximately 2.5 GHz shown in FIG. 2 . Furthermore, the antenna device 100D can be more compact than the antenna device 100, provided that it has the same resonant frequency. In addition to the antenna device 100 having a capacitor 60 connected in series to the electromagnetic coupling element 50, a capacitor 70 may be connected in parallel to the electromagnetic coupling element 50.

[0046] (Modification 5) Fig. 8 is a schematic diagram of an antenna device 100E in Modification 5. In antenna device 100E shown in Fig. 8, the same components as those in antenna device 100 shown in Fig. 1 are denoted by the same reference numerals, and detailed description thereof will not be repeated. Antenna device 100E forms a slot antenna, and an opening 10a (slot) is formed in conductor 10.

[0047] 8, in the antenna device 100E, a signal line 20a that supplies a signal from the power supply circuit 30 is electrically connected to the conductor 10 on the upper side (first side) of the opening 10a. A GND line 20c is electrically connected to the conductor 10 on the lower side (second side) of the opening 10a.

[0048] Furthermore, the antenna device 100E is provided with an electromagnetic field coupling element 50 and a capacitor 60 for bypassing the opening 10a on the right side of Fig. 8. One end of the coil L1 is electrically connected to the excitation electrode 40, and the other end of the coil L1 is electrically connected to the conductor 10 on the lower side (second side) of the opening 10a. One end of the coil L2 is electrically connected to the capacitor 60, and the other end of the coil L2 is electrically connected to the conductor 10 on the lower side (second side) of the opening 10a.

[0049] The excitation electrode 40 has a band shape extending in the positive X direction (arrow direction) along the long side of the opening 10a, and is electrically connected to the conductor 10 on the upper side (first side) of the opening 10a by a wiring 80. In other words, the excitation electrode 40 is electrically connected to the conductor 10 on the upper side (first side) of the opening 10a, not by electric field coupling. Therefore, in the antenna device 100E, the parasitic antenna formed by the excitation electrode 40 is a current-excited type, and the length (length in the X direction) of the excitation electrode 40 needs to be half the resonant frequency, not one-fourth the resonant frequency.

[0050] In the antenna device 100E shown in Fig. 8, the length of the excitation electrode 40 is longer than that of the antenna device 100 shown in Fig. 1. In the antenna device 100E, the excitation electrode 40 is electrically connected to the conductor 10 on the upper side (first side) of the opening 10a by the wiring 80, thereby making it possible to reduce manufacturing variations due to misalignment of the excitation electrode 40.

[0051] 1 and 4 to 8, the other end of the coil L2 is electrically connected to the conductor 10 on the lower side (second side) of the opening 10a. However, the other end of the coil L2 is not limited to being electrically connected to the conductor 10 on the lower side (second side) of the opening 10a, and may be indirectly connected to the conductor 10 on the lower side (second side) of the opening 10a via another circuit element or by electric field coupling or the like.

[0052] (Aspects) (1) An antenna device according to the present disclosure comprises: a plate-shaped conductor having an opening; a signal line electrically connected or indirectly connected to the conductor on a first side of the opening and supplying a signal from a power supply circuit; a GND line electrically connected to the conductor on a second side of the opening opposite the first side; an excitation electrode arranged at a position corresponding to the opening; a first coil having one end electrically connected to the excitation electrode and the other end electrically connected or indirectly connected to the conductor on the second side; and a second coil having one end electrically connected or indirectly connected to the conductor on the first side and the other end electrically connected or indirectly connected to the conductor on the second side, wherein the first coil and the second coil are arranged at positions where they are magnetically coupled.

[0053] (2) The antenna device described in (1) further includes a capacitor disposed between one end of the second coil and the conductor on the first side, and capacitively coupling the one end of the second coil and the conductor on the first side.

[0054] (3) The antenna device according to (1) or (2), further comprising a passive element connected in parallel to the second coil.

[0055] (4) In the antenna device described in any one of (1) to (3), the excitation electrode is positioned so as to overlap the opening on the side of the first coil to which the signal line is not connected when the opening is viewed in a plan view.

[0056] (5) In the antenna device described in any one of (1) to (3), the excitation electrode is positioned so as to overlap the opening on the side of the first coil to which the signal line is connected when the opening is viewed in a plan view.

[0057] (6) In the antenna device described in any one of (1) to (5), the excitation electrode includes a first excitation electrode and a second excitation electrode, and one end of the first coil is electrically connected to the first excitation electrode and the other end is electrically connected to the second excitation electrode.

[0058] (7) In the antenna device described in any one of (1) to (6), the excitation electrode is electrically connected to the conductor via a wiring.

[0059] (8) An electronic device according to the present disclosure includes the power supply circuit and the antenna device according to any one of (1) to (7).

[0060] 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 description of the above embodiments, and is intended to include all modifications within the meaning and scope of the claims.

[0061] 10 Conductor, 10a Opening, 20 Coaxial cable, 20a Signal line, 20b Insulator, 20c GND line, 20d Fixed portion, 30 Power supply circuit, 40, 42 Excitation electrode, 50 Electromagnetic field coupling element, 60, 70 Capacitor, 80 Wiring, 100, 100A to 100E Antenna device.

Claims

1. An antenna device comprising: a plate-shaped conductor having an opening; a signal line electrically connected or indirectly connected to the conductor on a first side of the opening and supplying a signal from a power supply circuit; a GND line electrically connected to the conductor on a second side of the opening opposite the first side; an excitation electrode arranged at a position corresponding to the opening; a first coil having one end electrically connected to the excitation electrode and the other end electrically connected or indirectly connected to the conductor on the second side; and a second coil having one end electrically connected or indirectly connected to the conductor on the first side and the other end electrically connected or indirectly connected to the conductor on the second side, wherein the first coil and the second coil are arranged at a position where they are magnetically coupled.

2. The antenna device according to claim 1, further comprising a capacitor disposed between one end of the second coil and the conductor on the first side, for capacitively coupling the one end of the second coil and the conductor on the first side.

3. The antenna device according to claim 1 or 2, further comprising a passive element connected in parallel with the second coil.

4. An antenna device described in any one of claims 1 to 3, wherein the excitation electrode is positioned so that, when the opening is viewed in a plane, it overlaps with the opening on the side of the first coil to which the signal line is not connected.

5. An antenna device described in any one of claims 1 to 3, wherein the excitation electrode is positioned so as to overlap the opening on the side of the first coil to which the signal line is connected when the opening is viewed in a plan view.

6. An antenna device according to any one of claims 1 to 5, wherein the excitation electrodes include a first excitation electrode and a second excitation electrode, and one end of the first coil is electrically connected to the first excitation electrode and the other end is electrically connected to the second excitation electrode.

7. The antenna device according to any one of claims 1 to 6, wherein the excitation electrode is electrically connected to the conductor via wiring.

8. An electronic device comprising: the power supply circuit; and the antenna device according to any one of claims 1 to 7.

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