JP2011193245A - Antenna device, radio communication device and radio communication terminal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an antenna device, a radio communication device and a radio communication terminal which improve gain of transmitted/received signals, are hard to be influenced by metal components to be arranged in the surroundings. <P>SOLUTION: The antenna device includes: a loop pattern 20 which emits and/or receives a prescribed high-frequency signal; a plane conductor 25 which has a plane approximately perpendicular to a winding axis of the loop pattern 20 and arranged opposite to the loop pattern 20; and a capacitive element which capacitatively couples the plane conductor 25 to the loop pattern 20. The loop pattern 20, the plane conductor 25 and the capacitive element are integrally formed in a dielectric body 10. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an antenna device, a wireless communication device, and a wireless communication terminal, and more particularly to an antenna device, a wireless communication device, and a wireless communication terminal used for NFC (Near Field Communication) and the like.

  In recent years, as an article and information management system, a reader / writer that generates an induced magnetic field and a wireless communication device such as an IC tag attached to an article and storing predetermined information are communicated in a non-contact manner using an electromagnetic field. RFID systems that transmit and receive predetermined information and power have been developed.

  For example, Patent Document 1 discloses a mobile phone incorporating a non-contact IC card. However, since wireless communication terminals such as mobile phones are small and multifunctional, various metal parts are mounted at high density in a small casing. For example, ground conductors and the like are arranged in a plurality of layers on a printed wiring board serving as a mother board, and components including metal such as IC chips and capacitors are mounted on the surface of the printed wiring board with high density. In addition, a battery pack serving as a power source is also arranged in the casing, and metal parts such as a frame are used for the battery pack.

  Therefore, an antenna device such as an IC card mounted in the housing has a problem that the communication performance deteriorates due to the influence of metal parts provided in the housing. In order to ensure the predetermined communication performance, it is necessary to increase the size of the antenna, and to reconsider the shape of the housing and the layout of the metal parts, but there are limits to this.

JP 2003-37861 A

  The present invention has been made in view of the above-described situation, and an object of the present invention is to improve the gain of transmission / reception signals and to be less susceptible to the influence of metal parts arranged around the antenna device, wireless communication device, and wireless communication terminal Is to provide.

In order to achieve the above object, an antenna device according to a first aspect of the present invention includes:
A loop pattern for emitting and / or receiving a predetermined high-frequency signal;
A planar conductor having a plane substantially perpendicular to the winding axis of the loop pattern, and disposed opposite to the loop pattern;
A capacitance element that capacitively couples the planar conductor and the loop pattern;
It is provided with.

The wireless communication device according to the second aspect of the present invention is:
In a wireless communication device comprising a wireless IC element that processes a high-frequency signal and an antenna device coupled to the wireless IC element,
The antenna device is
A loop pattern for emitting and / or receiving a predetermined high-frequency signal;
A planar conductor having a plane substantially perpendicular to the winding axis of the loop pattern, and disposed opposite to the loop pattern;
A capacitance element that capacitively couples the planar conductor and the loop pattern;
It is characterized by.

The wireless communication terminal according to the third aspect of the present invention is
In a wireless communication terminal including an antenna device connected to a power feeding unit that processes a high-frequency signal,
The antenna device is
A loop pattern for emitting and / or receiving a predetermined high-frequency signal;
A planar conductor having a plane substantially perpendicular to the winding axis of the loop pattern, and disposed opposite to the loop pattern;
A capacitance element that capacitively couples the planar conductor and the loop pattern;
It is characterized by.

  In the antenna device, since the planar conductor is disposed opposite to the loop pattern and the planar conductor and the loop pattern are capacitively coupled by the capacitance element, the capacitance and the mutual inductance formed by the loop pattern and the planar conductor are connected in parallel. A resonance circuit is formed, and the loop pattern functions as a radiating element that operates at a predetermined resonance frequency. Since the displacement current induced in the planar conductor from the loop pattern is returned to the loop pattern, the gain of the transmission / reception signal is improved and the communication distance is increased. Further, most of the induced magnetic field excited by the loop pattern is absorbed by the planar conductor, so that it can be transmitted / received without being influenced by the metal parts arranged in proximity. In other words, it is not necessary to redesign the antenna shape or the like according to the layout of the surrounding metal parts.

  ADVANTAGE OF THE INVENTION According to this invention, the gain of a transmission / reception signal can be improved and the antenna apparatus which is hard to be influenced by the metal components arrange | positioned around can be obtained.

1 is an exploded perspective view showing an antenna device that is Embodiment 1. FIG. It is sectional drawing which shows the state which mounted the antenna apparatus which is Example 1 on the printed wiring board of a mobile telephone. (A), (B) is the equivalent circuit schematic of the antenna apparatus which is Example 1. FIG. It is explanatory drawing of the operation principle of the antenna apparatus which is Example 1. FIG. It is a disassembled perspective view which shows the antenna apparatus which is Example 2. FIG. It is sectional drawing which shows the state which mounted the antenna apparatus which is Example 2 on the printed wiring board of a mobile telephone. It is a disassembled perspective view which shows the radio | wireless communication device provided with the antenna apparatus which is Example 3. FIG. FIG. 6 is an equivalent circuit diagram of an antenna apparatus that is Embodiment 3. FIG. 6 is an exploded perspective view showing a power supply circuit board that constitutes an antenna apparatus that is Embodiment 3. It is operation | movement explanatory drawing of the said electric power feeding circuit board. FIG. 6 is an exploded perspective view showing a wireless communication device including an antenna apparatus that is Embodiment 4. It is operation | movement explanatory drawing of the loop pattern which comprises the antenna apparatus which is Example 4. FIG. FIG. 10 is an exploded perspective view illustrating a wireless communication device including an antenna device that is Embodiment 5.

  Hereinafter, an antenna device, a wireless communication device, and a wireless communication terminal according to the present invention will be described based on specific embodiments. In addition, in each figure, the same code | symbol is attached | subjected to a common component and part, and the overlapping description is abbreviate | omitted.

(See Example 1, FIGS. 1 to 4)
An antenna apparatus 1A according to the first embodiment is used for an HF band. As shown in FIG. 1, a loop pattern 20 that radiates and receives a predetermined high-frequency signal, and a winding axis of the loop pattern 20 And a capacitance element that capacitively couples the planar conductor 25 and the loop pattern 20 to each other.

  The loop pattern 20 is a laminated type in which coil patterns 21a to 21c formed on a plurality of dielectric layers 11a to 11c are laminated, and both ends of the plurality of coil patterns 21a to 21c are connected to each other via an interlayer connection conductor 22a. It is. One end of the coil pattern 21a formed on the first dielectric layer 11a is a power supply terminal 31a, and another power supply terminal 31b is formed on the dielectric layer 11a. The planar conductor 25 forms a plane substantially perpendicular to the winding axis of the loop pattern 20 on the dielectric layer 11e, and is connected to the capacitor electrode 32 formed on the dielectric layer 11d via the interlayer connection conductor 22c. Yes. The capacitive electrode 32 faces the capacitive electrode 33 which is one end of the coil pattern 21c formed on the third dielectric layer 11c, and forms the capacitance element. The capacitor electrode 33 is connected to the power supply terminal 31b through the interlayer connection conductor 22b.

  That is, the loop pattern 20, the planar conductor 25, and the capacitance element are integrally formed on the dielectric element body 10 in which the dielectric layers 11a to 11e are laminated. The dielectric layers 11a to 11e constituting the dielectric body 10 are flexible thermoplastic resin sheets such as polyimide and liquid crystal polymer. Each of the coil patterns 21a to 21c and the planar conductor 25 may be formed by patterning a flexible metal film such as a metal foil such as copper or aluminum by a photolithography method or an etching method, or by screen printing a conductive paste. It may be formed. The dielectric body 10, the coil patterns 21a to 21c, and the planar conductor 25 are not limited to these materials.

  The dielectric layer 11a is preferably further covered with a dielectric layer as shown in FIG. In this case, the power supply terminals 31a and 31b are formed so as to be exposed on the covered dielectric layer.

  In the antenna device 1A, the planar conductor 25 is disposed opposite to the loop pattern 20, and the planar conductor 25 and the loop pattern 20 are capacitively coupled by a capacitance element. Therefore, the capacitance C, the loop pattern 20 and the planar conductor 25 are combined. A parallel resonance circuit is formed with the formed mutual inductance L, and the loop pattern 20 operates at a predetermined resonance frequency. That is, the loop pattern 20 radiates a signal including high frequency power supplied from the power supply terminals 31a and 31b and / or supplies a signal including high frequency power received to the power supply terminals 31a and 31b. Since displacement current induced from the loop pattern 20 to the planar conductor 25 is returned to the loop pattern 20 by capacitive coupling by the capacitance elements (capacitance electrodes 32 and 33), the gain of the transmission / reception signal is improved and the communication distance is increased. spread. The displacement current induced in the planar conductor 25 is normally consumed thermally as an eddy current, but in this embodiment, it is returned to the loop pattern 20 and used effectively.

  Incidentally, the planar conductor 25 is formed on the dielectric layer 11e so as to cover almost the entire surface of the dielectric layer 11e, forms a plane substantially perpendicular to the winding axis of the loop pattern 20, and is planar from the winding axis direction. When viewed, the loop pattern 20 is included including its opening region. As a result, the induced magnetic field excited by the loop pattern 20 is efficiently absorbed / transmitted to the planar conductor 25. Further, since the loop pattern 20 faces a metal component that is disposed in proximity via the planar conductor 25, transmission and reception are possible without being affected by the metal component. In other words, it is not necessary to redesign the antenna shape or the like according to the layout of the surrounding metal parts. Furthermore, since the loop pattern 20 is formed by stacking a plurality of coil patterns 21a to 21c, it is possible to impart directionality to the distribution of the induced magnetic field excited by the coil patterns 21a to 21c and improve the inductance value. Can do. The planar conductor 25 only needs to receive at least the magnetic field energy from the loop pattern 20 and may have an opening on the winding axis of the loop pattern 20.

  Capacitance elements (capacitance electrodes 32 and 33) are arranged in the vicinity of the power supply terminals 31a and 31b. Thereby, the energy of the displacement current generated in the planar conductor 25 by the induction magnetic field by the loop pattern 20 can be efficiently transmitted to the power supply terminals 31a and 31b.

  As shown in FIG. 2, the antenna device 1A is mounted on a printed wiring board 40 built in a wireless communication terminal such as a mobile phone. You may mount in the housing of a radio | wireless communication terminal. A power feeding unit 45 (see FIG. 3) for processing a predetermined high-frequency signal is connected to the power feeding terminals 31a and 31b. As shown in FIG. 2, even if a metal film 41 (ground conductor) close to the loop pattern 20 is arranged on the printed wiring board 40, most of the induced magnetic field generated in the loop pattern 20 is absorbed by the planar conductor 25. Therefore, the influence of the proximity of the metal film 41 is small, and the characteristics are not greatly deteriorated.

  In order to fix the antenna device 1A to the printed wiring board 40 or the housing, it may be affixed with an adhesive or the like, or a fixing tool such as a pin may be used. The antenna device 1A is preferably mounted with the planar conductor 25 facing the printed wiring board 40 or the housing. However, since the planar conductor 25 side also has some radiation / reception action, it may be mounted so that the planar conductor 25 is on the surface side.

  The antenna device 1A can be expressed as an equivalent circuit shown in FIG. That is, an equivalent circuit in which an inductance L1 due to the loop pattern 20, a capacitance C due to the capacitive electrodes 32 and 33, and an inductance L2 due to the planar conductor 25 (displacement current generated by the induction magnetic field of the loop pattern 20) are connected in series to the power feeding unit 45. It becomes. Here, since the current in the loop pattern 20 and the displacement current in the planar conductor 25 flow in opposite directions, the inductances L1 and L2 are coupled in a transformer to form a virtual transformer. Therefore, equivalently, as shown in FIG. 3B, an LC parallel resonant circuit of a mutual inductance L and a capacitance C formed by the loop pattern 20 and the planar conductor 25 is formed.

  That is, as shown in FIG. 4, first, when high-frequency power is supplied from the power supply units (power supply terminals 31 a and 31 b), a current I1 flows through the loop pattern 20. In the planar conductor 25, a displacement current I2 is generated in the direction opposite to the direction canceling the magnetic field generated by the current I1. Since the current I1 and the displacement current I2 flow in opposite directions, the loop pattern 20 and the planar conductor 25 are equivalently coupled with each other with a mutual inductance L. In this way, since a parallel resonant circuit of mutual inductance L and capacitance C is formed, the energy that the displacement current is about to be lost as heat in the planar conductor 25 is returned to the loop pattern 20 (feed terminals 31a and 31b). As a result, the gain is improved.

  The resonance point of the parallel resonance circuit of the mutual inductance L and the capacitance C is preferably set to be higher than the signal frequency (13.56 MHz in the present embodiment) so that the loop pattern 20 acts as a magnetic field antenna. .

(See Example 2, FIGS. 5 and 6)
As shown in FIG. 5, the antenna device 1B according to the second embodiment is formed by integrally forming a loop pattern 50 and a capacitance element in a dielectric element body 60 and forming a planar conductor on another base material. The planar conductor is formed as, for example, the ground conductor 55 of the printed wiring board 40 shown in FIG. The printed wiring board 40 is built in a wireless communication terminal such as a mobile phone. The planar conductor may be a planar conductor provided in the housing of the wireless communication terminal instead of the printed wiring board.

  Specifically, in the loop pattern 50, coil patterns 51a to 51c formed on the plurality of dielectric layers 61a to 61c are stacked, and both ends of the plurality of coil patterns 51a to 51c are connected to each other via the interlayer connection conductor 52a. It is a laminated type. The power supply terminal 55a formed on the back surface of the third dielectric layer 61c is connected to one end of the coil pattern 51c via an interlayer connection conductor 52b, and the power supply terminal 55b is connected to the first dielectric layer via the interlayer connection conductor 52c. The coil pattern 51a formed on the body layer 61a is connected to one end. The capacitance element is formed by capacitive electrodes 56 and 57 formed on the second and third dielectric layers 61b and 61c. The capacitive electrode 56 is connected to an intermediate portion of the coil pattern 51b, and the capacitive electrode 57 is connected to a ground terminal 58 formed on the back surface of the dielectric layer 61c via an interlayer connection conductor 52d.

  As shown in FIG. 6, the mounting electrode 54 formed on the back surface of the dielectric body 60 is soldered to the land 42 formed on the printed wiring board 40, and the power supply terminals 55 a and 55 b are connected to the power supply land 43. The ground terminal 58 is soldered to a land 45 connected to the ground conductor 55 (planar conductor) via the interlayer connection conductor 44. As a result, the dielectric body 60 is mounted on the printed wiring board 40.

  In a state where the antenna device 1B is mounted on the printed wiring board 40, the ground conductor 55 functions as the planar conductor 25 shown in the first embodiment. Therefore, the operational effects of the second embodiment are the same as those of the first embodiment. In particular, in the second embodiment, since the capacitance element is connected to the middle portion of the loop pattern 50, the balanced power supply is connected at the position where the voltage variation in the loop pattern 50 is the smallest. The energy generated in the conductor 55) can be efficiently returned to the loop pattern 50.

(See Example 3, FIGS. 7 to 10)
As shown in FIG. 7, the antenna device 1 </ b> C according to the third embodiment is configured as a wireless communication device including a wireless IC element 70 including a wireless IC chip 71 and a power feeding circuit board 75. In this case, the antenna device 1C functions as a boost antenna. In addition, as the wireless IC element 70, the wireless IC chip 71 can be used alone. The wireless IC chip 71 processes a high-frequency signal, and includes a clock circuit, a logic circuit, a memory circuit, and the like, and necessary information is stored in the memory.

  The loop pattern 80 and the capacitance element are integrally formed on the dielectric body 90. That is, the loop pattern 80 includes a coil pattern 81a having capacitive electrodes 86 and 87 formed on both ends formed on the dielectric layer 91a, and a coil pattern 81b having capacitive electrodes 88 and 89 formed on both ends formed on the dielectric layer 91b. The coil patterns 81a and 81b are wound in opposite directions. That is, the coil patterns 81a and 81b are wound in opposite directions in plan view so that current flows in the same direction. The capacitive electrodes 86 and 88 and the capacitive electrodes 87 and 89 are opposed to each other to form capacitances C1 and C2. The planar conductor 85 is formed on the dielectric layer 91c, forms a capacitance C with the capacitive electrode 89, and is capacitively coupled to the loop pattern 80. The planar conductor 85 has a plane substantially perpendicular to the winding axis of the loop pattern 80, and is disposed opposite to the loop pattern 80, as in the first embodiment.

  The antenna device 1C forms an equivalent circuit shown in FIG. That is, it has a series resonance circuit of an inductance L1 formed by the coil pattern 81a, a capacitance C1 by the capacitive electrodes 86 and 88, an inductance L2 formed by the coil pattern 81b, and a capacitance C2 by the capacitive electrodes 87 and 89, and A capacitance C is formed by the capacitive electrode 89 and the planar conductor 85.

  As shown in FIG. 9, the power supply circuit board 75 is formed by laminating a plurality of base material layers 76a to 76e, press-bonding them, and firing them as necessary, and has a built-in power supply circuit composed of coil patterns 78a to 78d. The base material layers 76a to 76e may be made of an insulating material (dielectric material, magnetic material), a thermoplastic resin such as a liquid crystal polymer, or a thermoplastic resin such as an epoxy polymer. Input / output terminals 77a and 77b and mounting terminals 77c and 77d are formed on the base material layer 76a, and coil patterns 78a to 78d are formed on the base material layers 76b to 76e. The ends of the coil patterns 78a to 78d are connected via an interlayer connection conductor 79a, the other end of the coil pattern 78a is connected to an input / output terminal 77a via an interlayer connection conductor 79b, and the other end of the coil pattern 78d is connected to an interlayer. The connection conductor 79c is connected to the input / output terminal 77b. The input / output terminals 77a and 77b and the coil patterns 78a to 78d may be formed by patterning a flexible metal film such as a metal foil such as copper or aluminum by a photolithography method or an etching method. May be formed.

  On the power supply circuit board 75, input / output terminal electrodes and mounting terminal electrodes (not shown) of the wireless IC chip 71 are connected to the input / output terminals 77a and 77b and mounting terminals 77c and 77d on the surface by solder bumps or the like. Thus, the wireless IC element 70 is obtained. When a high frequency signal is transmitted from the wireless IC chip 71 to the coil patterns 78a to 78d, a current flows in the coil patterns 78a to 78d in the same direction, and an induction magnetic field H shown in FIG. The induced magnetic field H magnetically couples the antenna device 1C and the feeding circuit.

  The antenna device 1C receives the induced magnetic field H by the loop pattern 80, an induced current caused by the induced magnetic field H flows through the DC resonance circuit, and magnetic field energy generated by the induced current is radiated to the outside. Since a parallel resonance circuit of mutual inductance L and capacitance C formed by the loop pattern 80 and the planar conductor 85 is formed, the displacement current generated in the planar conductor 85 is not lost as heat energy, and the loop pattern It is returned to 80 and the gain is improved. Other functions and effects of the third embodiment are the same as those of the first embodiment. In particular, in the third embodiment, since the interlayer connection conductor is not provided in each of the dielectric layers 91a to 91c, a process for forming the interlayer connection conductor is not required, and the antenna device 1C can be manufactured easily and inexpensively.

  Incidentally, in the feeder circuit board 75, an LC resonance circuit is formed by the inductances of the coil patterns 78a to 78d and the capacitance between the lines, and the frequency of the high frequency signal radiated from the antenna device 1C by this resonance frequency and the antenna device. The frequency of the high frequency signal received at 1C is substantially determined. In addition, the resonance frequency and impedance are adjusted by adjusting the electrical length, pattern width, and the like of the coil patterns 78a to 78d.

(See Example 4, FIGS. 11 and 12)
As shown in FIG. 11, the antenna device 1 </ b> D that is Embodiment 4 is configured as a wireless communication device including a wireless IC element 70 including a wireless IC chip 71 and a power feeding circuit board 75. In this case, the antenna device 1D functions as a boost antenna. The configurations and operations of the wireless IC chip 71 and the power feeding circuit board 75 are the same as those in the third embodiment. Further, the wireless IC chip 71 can be used alone as in the third embodiment.

  In the antenna device 1D, the loop pattern 100 and the planar conductor 105 are integrally formed with the dielectric element body 110. The loop pattern 100 is a metal film formed on the first dielectric layer 111a. The loop pattern 100 has an opening 101 in a part (substantially central part), and a slit that communicates with the opening 101 from the outer edge. 102 and a capacitor electrode 103 is formed. A capacitor electrode 104 is formed on the second dielectric layer 111b. The planar conductor 105 is formed on the third dielectric layer 111c, and the capacitor electrode 106 connected to the planar conductor 105 is formed on the dielectric layer 111c. The capacitance C1 is formed by the capacitive electrodes 103 and 104, and the capacitance C2 is formed by the capacitive electrodes 104 and 106. That is, the capacitance element that couples the loop pattern 100 and the planar conductor 105 is configured as a combined capacitance of the capacitances C1 and C2.

  When the induced magnetic field H generated in the wireless IC element 70 (feed circuit board 75) is received by the loop pattern 100, the induced current I3 shown in FIG. Magnetic field energy generated by the induced current I3 is radiated to the outside. Since a parallel resonant circuit of mutual inductance L and capacitance C (combined capacitance of C1 and C2) formed by the loop pattern 100 and the planar conductor 105 is formed, the displacement current generated in the planar conductor 105 is heated. The energy is returned to the loop pattern 100 without being lost as energy, and the gain is improved. Other functions and effects of the fourth embodiment are the same as those of the first embodiment. In the fourth embodiment, similarly to the third embodiment, since no interlayer connection conductor is provided in each of the dielectric layers 111a to 111c, a process for forming the interlayer connection conductor is not required, and the antenna device can be easily and inexpensively. 1D can be produced.

(See Example 5, FIG. 13)
As shown in FIG. 13, the antenna device 1E according to the fifth embodiment has basically the same configuration as that of the first embodiment, and connects the wireless IC chip 71 to the power feeding terminals 31a and 31b to thereby form a wireless IC device. It is constituted as follows. Therefore, the operational effects of the fifth embodiment are the same as those of the first embodiment.

(Other examples)
The antenna device, the wireless communication device, and the wireless communication terminal according to the present invention are not limited to the above-described embodiments, and can be variously changed within the scope of the gist.

  In particular, a mobile phone as a wireless communication terminal is merely an example, and the present invention can be applied to various wireless communication terminals.

  As described above, the present invention is useful for an antenna device, a wireless communication device, and a wireless communication terminal, and is particularly excellent in that the gain of a transmission / reception signal is improved and it is difficult to be affected by surrounding metal parts. ing.

DESCRIPTION OF SYMBOLS 1A-1E ... Antenna apparatus 10, 60, 90, 110 ... Dielectric body 11a-11e, 61a-61c, 91a-91c, 111a-111c ... Dielectric layer 20, 50, 80, 100 ... Loop pattern 21a-21c , 51a to 51c, 81a, 81b ... Coil pattern 25, 85, 105 ... Planar conductors 31a, 31b, 55a, 55b ... Feed terminals 32, 33, 56, 57, 86-89, 103, 104, 106 ... Capacitance electrodes 55 ... Ground conductor (planar conductor)
70 ... Wireless IC element 71 ... Wireless IC chip 75 ... Feed circuit board L, L1, L2 ... Inductance C, C1, C2 ... Capacitance

Claims (14)

A loop pattern for emitting and / or receiving a predetermined high-frequency signal;
A planar conductor having a plane substantially perpendicular to the winding axis of the loop pattern, and disposed opposite to the loop pattern;
A capacitance element that capacitively couples the planar conductor and the loop pattern;
An antenna device comprising:   The antenna device according to claim 1, wherein the loop pattern, the planar conductor, and the capacitance element are formed in a dielectric body.   The antenna device according to claim 2, wherein the dielectric element body is a laminated body formed by laminating a plurality of dielectric layers.   The antenna device according to claim 1, wherein the loop pattern and the capacitance element are formed on a dielectric body, and the planar conductor is formed on a base material different from the dielectric body. .   The antenna device according to any one of claims 1 to 4, wherein the loop pattern is included in the planar conductor including the opening region when viewed in plan from the winding axis direction.   6. The antenna device according to claim 1, wherein the capacitance element is disposed in the vicinity of a power supply terminal to the loop pattern.   The antenna device according to claim 1, wherein the capacitance element is connected to an intermediate portion of the loop pattern.   The loop pattern is a laminated type in which a plurality of coil patterns are laminated in a winding axis direction, and the plurality of coil patterns are connected to each other. The antenna device described. The loop pattern has first and second coil patterns stacked,
The first coil pattern and the second coil pattern are wound in opposite directions to each other, and end portions thereof are opposed to form the capacitance element;
The antenna device according to claim 1, wherein:   The antenna device according to any one of claims 1 to 7, wherein the loop pattern has an opening in a part thereof and a slit portion communicating with the opening from an outer edge. In a wireless communication device comprising a wireless IC element that processes a high-frequency signal and an antenna device coupled to the wireless IC element,
The antenna device is
A loop pattern for emitting and / or receiving a predetermined high-frequency signal;
A planar conductor having a plane substantially perpendicular to the winding axis of the loop pattern, and disposed opposite to the loop pattern;
A capacitance element that capacitively couples the planar conductor and the loop pattern;
A wireless communication device.   The wireless communication device according to claim 11, wherein the wireless IC element is a wireless IC chip.   The wireless communication device according to claim 11, wherein the wireless IC element includes a wireless IC chip and a power supply circuit board including a power supply circuit coupled to the wireless IC chip. In a wireless communication terminal including an antenna device connected to a power feeding unit that processes a high-frequency signal,
The antenna device is
A loop pattern for emitting and / or receiving a predetermined high-frequency signal;
A planar conductor having a plane substantially perpendicular to the winding axis of the loop pattern, and disposed opposite to the loop pattern;
A capacitance element that capacitively couples the planar conductor and the loop pattern;
A wireless communication terminal characterized by the above.

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