Patent Description:
Conventionally, an antenna corresponding to multiple bands is known (see PTL <NUM>, for example). The antenna device disclosed in PTL <NUM> includes a feeding element and a passive element, and switches a resonance frequency of the passive element by connecting or not connecting the passive element to ground. This configuration makes it possible for the antenna device disclosed in PTL <NUM> to transmit and receive radio waves in a plurality of frequency bands without increasing the size of the antenna element. PTL <NUM> discloses an antenna device reflecting the preamble of present claim <NUM>. PLT <NUM> and PLT <NUM> are further prior art.

The present disclosure provides an antenna device that corresponds to multiple bands and can achieve downsizing and wide band.

An antenna device according to one aspect of the present disclosure is defined in the appended claims.

The present disclosure can provide an antenna device that corresponds to multiple bands and can achieve downsizing and wide band.

The examples of <FIG> do not comprise all the features of the claimed invention but are nonetheless usefull for the understanding of the invention. <FIG> is a schematic diagram illustrating an overall configuration of an antenna device according to a first exemplary embodiment.

Hereinafter, exemplary embodiments will be specifically described with reference to the drawings.

Note that the exemplary embodiments described below provide comprehensive or specific examples of the present disclosure. Numerical values, shapes, materials, components, arrangement positions and connection configurations of the components, steps, processing order of the steps, and the like shown in the following exemplary embodiments are just an example, and are not intended to limit the present disclosure.

Each of the drawings is a schematic diagram, and is not necessarily precisely illustrated. In the drawings, identical components are denoted by identical reference marks.

An antenna device according to a first exemplary embodiment will be described.

First, an overall configuration of the antenna device according to the first exemplary embodiment will be described with reference to <FIG> is a schematic diagram illustrating the overall configuration of antenna device <NUM> according to the present exemplary embodiment. Antenna device <NUM> is an antenna that transmits and receives a signal in a first frequency band and a signal in a second frequency band. In the present exemplary embodiment, the second frequency band is a frequency band lower than the first frequency band. The first frequency band and the second frequency band are not particularly limited. In the present exemplary embodiment, the first frequency band is a band more than or equal to <NUM> and less than or equal to <NUM>, and the second frequency band is a band more than or equal to <NUM> and less than <NUM>.

As illustrated in <FIG>, antenna device <NUM> includes antenna element <NUM>, auxiliary element <NUM>, switch <NUM>, and ground member <NUM>.

Antenna element <NUM> is a conductive element that transmits and receives a signal in the first frequency band and a signal in the second frequency band. Antenna element <NUM> has feeding element <NUM>, high-band element <NUM>, and low-band element <NUM>. In the present exemplary embodiment, feeding element <NUM>, high-band element <NUM>, and low-band element <NUM> are connected at connection part <NUM>. In addition, high-band element <NUM> and low-band element <NUM> extend from connection part <NUM> in directions opposite to each other. High-band element <NUM> and low-band element <NUM> are disposed on the same straight line such that their respective longitudinal directions coincide with each other.

An antenna including a combination of feeding element <NUM> and high-band element <NUM> functions as a monopole antenna corresponding to the first frequency band. Specifically, an electrical length of the antenna including feeding element <NUM> and high-band element <NUM> is about <NUM>/<NUM> of a wavelength λ1 corresponding to one frequency f1 included in the first frequency band. In addition, an antenna including a combination of feeding element <NUM> and low-band element <NUM> functions as a monopole antenna corresponding to the second frequency band lower than the first frequency band. Specifically, an electrical length of the antenna including feeding element <NUM> and low-band element <NUM> is about <NUM>/<NUM> of a wavelength λ2 corresponding to one frequency f2 included in the second frequency band. Since the wavelength λ2 corresponding to the second frequency band is longer than the wavelength λ1 corresponding to the first frequency band, the electrical length of low-band element <NUM> is longer than the electrical length of high-band element <NUM>.

Antenna element <NUM> is made by using a conductive material. Antenna element <NUM> is made by using, for example, a metal such as Cu, Al, or Au, an alloy containing a plurality of metals, or the like. Note that a shape of antenna element <NUM> is not particularly limited. Antenna element <NUM> may have, for example, a rod shape, a plate shape, a sheet shape, or the like. Alternatively, antenna element <NUM> may be made of a conductive pattern patterned on an insulating substrate. A method for manufacturing antenna element <NUM> is not particularly limited, and antenna element <NUM> may be made of a sheet metal, or may be made by plating, vapor deposition, laser direct structuring (LDS), or the like.

Feeding element <NUM> is a conductive element having feedpoint <NUM> to which the signal in the first frequency band and the signal in the second frequency band are supplied. Feeding element <NUM> is a portion of antenna element <NUM> that both the signal in the first frequency band and the signal in the second frequency band resonate with. Feedpoint <NUM> is disposed at one end of feeding element <NUM>, and connection part <NUM> is disposed at the other end. To feedpoint <NUM>, a signal is supplied via, for example, a coaxial cable, a feed pin, or the like. When a coaxial cable is used, an inner conductor of the coaxial cable is connected to feedpoint <NUM>, and an outer conductor of the coaxial cable is connected to ground member <NUM>. Note that a lumped-constant circuit may be connected to feedpoint <NUM> to adjust the impedance.

High-band element <NUM> is a conductive element that is connected to feeding element <NUM> and that a signal in the first frequency band resonates with. High-band element <NUM> is a portion of antenna element <NUM> that the signal in the first frequency band mainly resonates with. High-band element <NUM> has an elongated shape, whose one end is connected to connection part <NUM> and the other end is an open end 21e.

Low-band element <NUM> is a conductive element that is connected to feeding element <NUM> and that a signal in the second frequency band resonates with. Low-band element <NUM> is a portion of antenna element <NUM> that the signal in the second frequency band mainly resonates with. Low-band element <NUM> has an elongated shape, whose one end is connected to connection part <NUM> and the other end is an open end 22e.

Auxiliary element <NUM> is a conductive element that is disposed adjacent to low-band element <NUM> and is capacitively coupled to low-band element <NUM> at open end 22e of low-band element <NUM>. One end of auxiliary element <NUM> is connected to input terminal <NUM> of switch <NUM>. A coupling capacitance between auxiliary element <NUM> and low-band element <NUM> can be adjusted to a desired value by adjusting a distance between auxiliary element <NUM> and adjacent low-band element <NUM> and adjusting an adjacent length (that is, a length of a part of auxiliary element <NUM> adj acent to low-band element <NUM>). A distance between auxiliary element <NUM> and low-band element <NUM> is less than <NUM>/<NUM> of a wavelength corresponding to the one frequency f2 included in the second frequency band. In the present exemplary embodiment, the distance between auxiliary element <NUM> and low-band element <NUM> is about <NUM>. An electrical length of auxiliary element <NUM> is less than <NUM>/<NUM> of the wavelength corresponding to the one frequency f2 included in the second frequency band. Auxiliary element <NUM> is made by using a conductive material. Auxiliary element <NUM> is made by using, for example, a metal such as Cu, Al, or Au, or an alloy containing a plurality of metals.

Ground member <NUM> is a conductive member that is grounded. Ground member <NUM> functions as a ground of antenna element <NUM>. Ground member <NUM> is connected to output terminal <NUM> of switch <NUM>. Ground member <NUM> is made by using a conductive material. Ground member <NUM> is made by using, for example, a metal such as Mg, Cu, Al, or Au, or an alloy containing a plurality of metals.

Switch <NUM> is an element that switches a conductive state and a non-conductive state between ground member <NUM> and auxiliary element <NUM>. Switch <NUM> switches a conductive state and a non-conductive state between input terminal <NUM> and output terminal <NUM>. Input terminal <NUM> is connected to auxiliary element <NUM>, and output terminal <NUM> is connected to ground member <NUM>. Switch <NUM> is not particularly limited as long as switch <NUM> is an element capable of switching the conductive state and the non-conductive state between ground member <NUM> and auxiliary element <NUM>. As switch <NUM>, a single-pole double-throw (SPDT) switch can be used, for example. In this case, as illustrated in <FIG>, switch <NUM> has one input terminal <NUM> and two output terminals <NUM>, <NUM>. Output terminal <NUM> is connected to ground member <NUM>, and output terminal <NUM> is opened. That is, when input terminal <NUM> and output terminal <NUM> of switch <NUM> are connected to each other, auxiliary element <NUM> and ground member <NUM> are brought into a conductive state, and when input terminal <NUM> and output terminal <NUM> are connected to each other, auxiliary element <NUM> and ground member <NUM> are brought into a non-conductive state.

Note that output terminals <NUM>, <NUM> may be configured such that each of the output terminals <NUM>, <NUM> is in a conductive state or a non-conductive state with ground member <NUM> through a desired impedance corresponding to a conductive state or a non-conductive state. For example, the impedance is configured with lumped elements such as an inductance (L) and a capacitance (C) suitable to adjust one frequency f3 included in the second frequency band. As switch <NUM>, it is possible to use a switch having three or more throws (SP3T, SP4T, and the like) can be used. Switch <NUM> may have the following configuration. Switch <NUM> has three or more switching paths, and the switching path with which switch <NUM> is in the conductive state includes two or more paths having different impedances. Further, switch <NUM> may have the following configuration. Switch <NUM> has three or more switching paths, and the switching path with which switch <NUM> is in the non-conductive state includes two or more paths having different impedances. Switch <NUM> is supplied with a control signal for switching between the one frequency f2 and the one frequency f3 included in the second frequency band of the present antenna in accordance with a communication band (frequency) used for wireless communication, for example.

Next, an action and advantageous effects of antenna device <NUM> according to the present exemplary embodiment will be described with reference to <FIG> is a graph illustrating a relationship between antenna efficiency and frequency of antenna device <NUM> according to the present exemplary embodiment. The solid line, broken line, and dashed-dotted line in the graph of <FIG> respectively indicate the antenna efficiencies at the resonance frequencies f1, f2, f3.

As described above, in antenna device <NUM>, there is formed a monopole antenna including feeding element <NUM> and high-band element <NUM> of antenna element <NUM> and corresponding to the first frequency band. Specifically, the electrical length of the monopole antenna including feeding element <NUM> and high-band element <NUM> is about <NUM>/<NUM> of the wavelength λ1 corresponding to the one frequency f1 included in the first frequency band.

When switch <NUM> is in a non-conductive state, there is formed a monopole antenna including feeding element <NUM> and low-band element <NUM> and corresponding to the second frequency band. Specifically, the electrical length of the monopole antenna including feeding element <NUM> and low-band element <NUM> is about <NUM>/<NUM> of the wavelength λ2 corresponding to the one frequency f2 included in the second frequency band. On the other hand, when switch <NUM> is in a conductive state, there is formed a loop antenna corresponding to the second frequency band and including feeding element <NUM>, low-band element <NUM>, auxiliary element <NUM>, and ground member <NUM>. At this time, an electrical length of the loop antenna including feeding element <NUM>, low-band element <NUM>, auxiliary element <NUM>, switch <NUM>, and ground member <NUM> is about <NUM>/<NUM> of a wavelength λ3 corresponding to the one frequency f3 included in the second frequency band. In addition, due to a capacitive coupling amount by auxiliary element <NUM> and an impedance amount by switch <NUM>, the electrical length of the loop antenna can be adjusted without changing a size of the antenna.

As described above, antenna device <NUM> functions as a multi-band antenna that transmits and receives a signal in the first frequency band and a signal in the second frequency band. In addition, a resonance frequency band in the second frequency band of antenna device <NUM> can be widened as illustrated in <FIG>, by differentiating the following two resonance frequencies from each other: the resonance frequency f2 of the monopole antenna that includes feeding element <NUM> and low-band element <NUM> and corresponds to the second frequency band; and the resonance frequency f3 of the loop antenna that includes feeding element <NUM>, low-band element <NUM>, auxiliary element <NUM>, and ground member <NUM> and corresponds to the second frequency band.

Further, in the present exemplary embodiment, auxiliary element <NUM> does not have to be a passive element that can resonate as an antenna by itself as described in PTL <NUM>, but only has to be an element that is adjacent to and capacitively coupled to low-band element <NUM>. Therefore, the electrical length of auxiliary element <NUM> only has to be less than <NUM>/<NUM> of the wavelength corresponding to one frequency included in the second frequency band. Therefore, in the present exemplary embodiment, since auxiliary element <NUM> can be downsized, the antenna device can be smaller than in the case of using a passive element as the antenna device described in PTL <NUM>.

Further, in the case of using a passive element, a frequency band that can be widened is limited to a narrow frequency band that the passive element can resonate with. On the other hand, in the present exemplary embodiment, since the loop antenna is formed to include a member such as ground member <NUM> that has a high degree of freedom in shape and dimension, it is possible to further widen a bandwidth as compared with the case of using a passive element.

Further, auxiliary element <NUM> is disposed adjacent to low-band element <NUM> and is capacitively coupled to low-band element <NUM> at open end 22e of low-band element <NUM>. That is, auxiliary element <NUM> is capacitively coupled at a part of low-band element <NUM> that is most distant from high-band element <NUM>. Therefore, influence of auxiliary element <NUM> on high-band element <NUM> can be reduced. That is, it is possible to reduce an influence on characteristics of high-band element <NUM> due to switching of the conductive state of switch <NUM>. Specifically, it is possible to reduce a change, caused by switching of switch <NUM>, in antenna efficiency at the resonance frequency f1 of antenna device <NUM> illustrated in <FIG>. In the present exemplary embodiment, the distance between auxiliary element <NUM> and low-band element <NUM> is less than <NUM>/<NUM> of a wavelength corresponding to one frequency included in the second frequency band. This arrangement makes it possible to capacitively couple auxiliary element <NUM> and low-band element <NUM> to each other reliably. In addition, since the distance between auxiliary element <NUM> and low-band element <NUM> can be shortened, antenna device <NUM> can be further downsized.

An antenna device according to a second exemplary embodiment will be described. The antenna device according to the present exemplary embodiment is different from antenna device <NUM> according to the first exemplary embodiment in that the antenna element constitutes a so-called inverted-F antenna. Hereinafter, the antenna device according to the present exemplary embodiment will be described mainly on differences from antenna device <NUM> according to the first exemplary embodiment.

An overall configuration and advantageous effects of the antenna device according to the present exemplary embodiment will be described with reference to <FIG> is a schematic diagram illustrating an overall configuration of antenna device <NUM> according to the present exemplary embodiment. As illustrated in <FIG>, antenna device <NUM> according to the present exemplary embodiment includes antenna element <NUM>, auxiliary element <NUM>, switch <NUM>, and ground member <NUM>, similarly to antenna device <NUM> according to the first exemplary embodiment. Antenna device <NUM> according to the present exemplary embodiment further includes short-circuit element <NUM>.

Short-circuit element <NUM> is a conductive element that connects between ground member <NUM> and feeding element <NUM>. Antenna element <NUM> and short-circuit element <NUM> constitute an inverted-F antenna. By configuring the inverted-F antenna as described above, a resonance frequency band in the second frequency band of the antenna device <NUM> can be widened.

In antenna device <NUM> illustrated in <FIG>, short-circuit element <NUM> connects ground member <NUM> and feeding element <NUM> to each other. However, short-circuit element <NUM> does not have to be connected to feeding element <NUM>. Hereinafter, a modified example of an antenna device including a short-circuit element will be described with reference to <FIG> is a schematic diagram illustrating an overall configuration of antenna device 110a according to a modified example according to the present exemplary embodiment.

As illustrated in <FIG>, antenna device 110a according to the present modified example includes antenna element <NUM>, auxiliary element <NUM>, switch <NUM>, ground member <NUM>, and short-circuit element 130a, similarly to antenna device <NUM>. Short-circuit element 130a according to the present modified example connect ground member <NUM> and low-band element <NUM> to each other. In addition, short-circuit element 130a is connected to low-band element <NUM> at a position closer to open end 22e than to a center of low-band element <NUM> in a longitudinal direction of low-band element <NUM>. With this arrangement, feeding element <NUM>, low-band element <NUM>, and short-circuit element 130a constitute a folded antenna. This configuration makes it possible to further widen the resonance frequency band in the second frequency band of the antenna device 110a.

An antenna device according to a third exemplary embodiment will be described. The antenna device according to the present exemplary embodiment is different from antenna device <NUM> according to the first exemplary embodiment in a configuration of the ground member. Hereinafter, the antenna device according to the present exemplary embodiment will be described mainly on differences from antenna device <NUM> according to the first exemplary embodiment.

An overall configuration of the antenna device according to the present exemplary embodiment will be described with reference to <FIG> is a schematic diagram illustrating an overall configuration of antenna device <NUM> according to the present exemplary embodiment. As illustrated in <FIG>, antenna device <NUM> according to the present exemplary embodiment includes antenna element <NUM>, auxiliary element <NUM>, switch <NUM>, and ground member <NUM>, similarly to antenna device <NUM> according to the first exemplary embodiment.

Ground member <NUM> according to the present exemplary embodiment includes coupling portion <NUM> disposed apart from open end 22e of low-band element <NUM> in the longitudinal direction of low-band element <NUM>. Coupling portion <NUM> is disposed to face open end 22e of low-band element <NUM> in the longitudinal direction of low-band element <NUM>. Auxiliary element <NUM> is disposed between open end 22e of low-band element <NUM> and coupling portion <NUM>, and auxiliary element <NUM> is disposed adjacent to coupling portion <NUM> to be capacitively coupled to coupling portion <NUM>. That is, auxiliary element <NUM> is capacitively coupled to both low-band element <NUM> and coupling portion <NUM>. A distance between auxiliary element <NUM> and coupling portion <NUM> may be less than <NUM>/<NUM> of a wavelength corresponding to the one frequency f1 included in the first frequency band. This arrangement makes it possible to capacitively couple auxiliary element <NUM> and coupling portion <NUM> to each other reliably. By capacitively coupling auxiliary element <NUM> and coupling portion <NUM> to each other in this manner, harmonic components of low-band element <NUM> are propagated to coupling portion <NUM>, which is a part of the ground member, via auxiliary element <NUM>. That is, the harmonic components can be prevented from reaching switch <NUM> side connected to auxiliary element <NUM>. Therefore, it is possible to largely reduce influence, caused by switching of the conductive state of switch <NUM>, on the one frequency f1 included in the first frequency band.

Furthermore, in a case where auxiliary element <NUM> and coupling portion <NUM> are capacitively coupled to each other, the distance between auxiliary element <NUM> and coupling portion <NUM> can be shortened, so that antenna device <NUM> can be further downsized. In the present exemplary embodiment, the distance between auxiliary element <NUM> and coupling portion <NUM> is about <NUM>.

An antenna device according to a fourth exemplary embodiment will be described. The antenna device according to the present exemplary embodiment is different from antenna device <NUM> according to the third exemplary embodiment in that the antenna element is formed on an insulating substrate. Hereinafter, the antenna device according to the present exemplary embodiment will be described mainly on differences from antenna device <NUM> according to the third exemplary embodiment.

First, an overall configuration and advantageous effects of the antenna device according to the present exemplary embodiment will be described with reference to <FIG> is a schematic perspective view illustrating an overall configuration of antenna device <NUM> according to the present exemplary embodiment. As illustrated in <FIG>, antenna device <NUM> according to the present exemplary embodiment includes antenna element <NUM>, auxiliary element <NUM>, switch <NUM>, and ground member <NUM>, similarly to antenna device <NUM> according to the third exemplary embodiment. Antenna device <NUM> according to the present exemplary embodiment further includes short-circuit element <NUM>, ground elements <NUM>, <NUM>, and insulating substrate <NUM>.

Ground member <NUM> according to the present exemplary embodiment has a rectangular parallelepiped outer shape. As the ground member, a metal housing for a mobile terminal or the like can be used, for example. Ground member <NUM> has recess <NUM>. Ground member <NUM> includes a coupling portion <NUM>, and coupling portion <NUM> includes at least a part of an inner surface of recess <NUM>.

Insulating substrate <NUM> is an insulating substrate on which switch <NUM> is mounted. Antenna element <NUM> and auxiliary element <NUM> are disposed on insulating substrate <NUM>. In the present exemplary embodiment, on insulating substrate <NUM> there are disposed ground elements <NUM>, <NUM> and short-circuit element <NUM>. As insulating substrate <NUM>, a printed circuit board or the like can be used, for example. As described above, since antenna device <NUM> includes insulating substrate <NUM>, antenna element <NUM> and the like having an arbitrary shape can be easily formed on insulating substrate <NUM> by patterning a conductive pattern.

In the present exemplary embodiment, insulating substrate <NUM> is a flexible substrate. Therefore, a shape of insulating substrate <NUM> can be deformed in accordance with shapes of ground member <NUM> and the like. Insulating substrate <NUM> includes first portion 312a having a width W1 in the thickness direction of ground member <NUM>, and second portion 312b having a height H1 and bent substantially perpendicularly to first portion 312a. The width W1 of first portion 312a of insulating substrate <NUM> and the height H1 of second portion 312b are approximately the same, and a length L1 of insulating substrate <NUM> (a dimension in a direction perpendicular to a direction of the width W1 and a direction of the height H1) is about five times the width W1 and the height H1.

Insulating substrate <NUM> is fixed to ground member <NUM>. Insulating substrate <NUM> is disposed in recess <NUM> of ground member <NUM>. Since this arrangement makes it possible to prevent insulating substrate <NUM> from protruding from ground member <NUM>, ground member <NUM> can surround insulating substrate <NUM> and at least a part of the elements disposed on insulating substrate <NUM>. Therefore, by making ground member <NUM> have a robust structure, robust antenna device <NUM> can be achieved. In addition, by disposing insulating substrate <NUM> in recess <NUM>, part of recess <NUM> facing auxiliary element <NUM> can be used as coupling portion <NUM>.

Insulating substrate <NUM> may be fixed with a conductive screw or the like that electrically connects ground member <NUM> and ground elements <NUM>, <NUM> formed on insulating substrate <NUM> to each other.

Antenna element <NUM> according to the present exemplary embodiment is a conductive pattern disposed on insulating substrate <NUM>. Antenna element <NUM> has feeding element <NUM>, high-band element <NUM>, and low-band element <NUM>. In the present exemplary embodiment, feeding element <NUM> is disposed on second portion 312b of insulating substrate <NUM>, and high-band element <NUM> and low-band element <NUM> are disposed on first portion 312a of insulating substrate <NUM>. As described above, antenna element <NUM> does not have to be disposed on the same plane, and may be disposed on a plurality of planes that are not parallel to each other.

Feeding element <NUM> has feedpoint <NUM>. Feeding element <NUM> is a conductive pattern having a rectangular shape. Since feeding element <NUM> has a width in a direction perpendicular to a resonance direction of a signal as described above, the resonance frequency band can be widened. To feedpoint <NUM>, there is connected an inner conductor of coaxial cable <NUM> that transmits a signal in the first frequency band and a signal in the second frequency band.

High-band element <NUM> is a conductive pattern having a rectangular shape with a width of about W1. Since high-band element <NUM> has a width in the direction perpendicular to the resonance direction of a signal as described above, a resonance frequency band in the first frequency band can be widened. One end of high-band element <NUM> is connected to connection part <NUM>, and the other end is open end 321e.

Low-band element <NUM> is a conductive pattern having a rectangular shape with a width of about W1, and is disposed on first portion 312a of insulating substrate <NUM>. Since low-band element <NUM> has a width in a direction perpendicular to the resonance direction of a signal as described above, the resonance frequency band can be widened. One end of low-band element <NUM> is connected to connection part <NUM>, and the other end is open end 322e.

Auxiliary element <NUM> is a conductive pattern provided on insulating substrate <NUM>. Auxiliary element <NUM> is capacitively coupled to at least part of open end 322e of low-band element <NUM>. In the present exemplary embodiment, as illustrated in <FIG>, auxiliary element <NUM> has a portion disposed on first portion 312a of insulating substrate <NUM> and a portion disposed on second portion 312b. The portion of auxiliary element <NUM> disposed on first portion 312a is capacitively coupled to open end 322e of low-band element <NUM> via gap G1. Further, the portion of auxiliary element <NUM> disposed on second portion 312b is capacitively coupled to an end edge connecting to open end 322e of low-band element <NUM> via gap G3. Since, as described above, auxiliary element <NUM> is capacitively coupled not only to open end 322e of low-band element <NUM> but also to the end edge connecting to open end 322e, the capacitive coupling can be established more reliably.

Auxiliary element <NUM> is capacitively coupled to coupling portion <NUM> of ground member <NUM> via gap G2. In the present exemplary embodiment, a distance between auxiliary element <NUM> and coupling portion <NUM> of ground member <NUM> is about <NUM>.

Ground element <NUM> is a conductive element that is made of a conductive pattern disposed on insulating substrate <NUM> and is connected to ground member <NUM>. Ground element <NUM> is disposed at a position, on second portion 312b of insulating substrate <NUM>, facing feedpoint <NUM> of feeding element <NUM>, and is connected to an outer conductor of coaxial cable <NUM>. It is not particularly limited how to connect ground element <NUM> and ground member <NUM> to each other. For example, ground element <NUM> may be connected to ground member <NUM> with a conductive screw or the like. Further, the screw may be used to fix insulating substrate <NUM> to ground member <NUM>. Alternatively, ground element <NUM> may be connected to ground member <NUM> with a conductive tape or the like.

Ground element <NUM> is a conductive element that is formed of a conductive pattern disposed on insulating substrate <NUM>, is connected to switch <NUM>, and is connected to ground member <NUM> to be grounded. Ground element <NUM> is disposed at a position, on second portion 312b of insulating substrate <NUM>, facing auxiliary element <NUM>. In the present exemplary embodiment, an area occupied by ground element <NUM> on insulating substrate <NUM> is larger than an area occupied by auxiliary element <NUM> on insulating substrate <NUM>. This configuration makes it possible to stably maintain a potential of ground element <NUM>, and when ground element <NUM> and auxiliary element <NUM> are electrically connected to each other by switch <NUM>, a potential of auxiliary element <NUM> can be stably maintained at a ground potential. Similarly to the connection form between ground element <NUM> and ground member <NUM>, it is not particularly limited how to connect ground element <NUM> and ground member <NUM> to each other.

Switch <NUM> is an element that switches a conductive state and a non-conductive state between ground member <NUM> and auxiliary element <NUM>. In the present exemplary embodiment, switch <NUM> is mounted on insulating substrate <NUM>, and is connected to ground member <NUM> via ground element <NUM>. Switch <NUM> is directly connected to ground element <NUM> and auxiliary element <NUM>. This arrangement can reduce to the minimum an electrical length between auxiliary element <NUM> and ground element <NUM>; therefore, when switch <NUM> is brought into the conductive state, the potential of auxiliary element <NUM> can be stably maintained at the ground potential.

In the present exemplary embodiment, switch <NUM> is controlled by a control signal. The control signal for controlling switch <NUM> is input from an outside of insulating substrate <NUM>. As a result, a control circuit or the like that outputs a control signal can be disposed outside insulating substrate <NUM>. For example, the control signal may be output from a communication module or the like for generating a signal in the first frequency band and a signal in the second frequency band that are input to feedpoint <NUM>. For example, the communication module may output to switch <NUM> a control signal corresponding to a frequency band to be used. Further, the communication module may be disposed on ground member <NUM>.

Switch <NUM> may be covered with resin. For example, switch <NUM> may be covered with insulating substrate <NUM> and a potting resin, and liquid-tight sealing may be provided between the potting resin and insulating substrate <NUM>. This can make switch <NUM> waterproof. In particular, when ground member <NUM> forms a chassis of a waterproof terminal, switch <NUM> is disposed outside the waterproof terminal; therefore, water could get into switch <NUM>. Even in such a case, when switch <NUM> is covered with resin, switch <NUM> can be waterproof.

Short-circuit element <NUM> connects ground member <NUM> and low-band element <NUM> to each other. In the present exemplary embodiment, short-circuit element <NUM> is disposed on second portion 312b of insulating substrate <NUM>, and is connected to ground member <NUM> via ground element <NUM>.

Next, application examples of antenna device <NUM> according to the present exemplary embodiment will be described with reference to <FIG> and <FIG>. <FIG> and <FIG> are respectively schematic diagrams illustrating application examples of antenna device <NUM> according to the present exemplary embodiment to tablet terminal <NUM> and laptop computer <NUM>.

As illustrated in <FIG> and <FIG>, antenna device <NUM> according to the present exemplary embodiment can be applied to tablet terminal <NUM>, laptop computer <NUM>, and the like.

As illustrated in <FIG>, antenna device <NUM> is disposed inside tablet terminal <NUM>. It is not particularly limited where to dispose antenna device <NUM> in tablet terminal <NUM>, and antenna device <NUM> may be disposed in a bezel portion of tablet terminal <NUM> as illustrated in <FIG>.

As illustrated in <FIG>, antenna device <NUM> is disposed inside laptop computer <NUM>. It is not particularly limited where to dispose antenna device <NUM> in laptop computer <NUM>, and antenna device <NUM> may be disposed in a bezel portion of a display of laptop computer <NUM> as illustrated in <FIG>.

As ground member <NUM> of antenna device <NUM>, it is possible to use a metal chassis of tablet terminal <NUM> or laptop computer <NUM>, for example.

The present disclosure has been described above on the basis of the exemplary embodiments. However, the present disclosure is not limited to the above exemplary embodiments. Various modifications made on the above exemplary embodiments by those skilled in the art may be included in the present disclosure without departing from the scope of the present disclosure.

For example, a meander structure that reduces propagation of a signal in the second frequency band may be used for part of the high-band element of the antenna device according to each of the above exemplary embodiments. As a result, it is possible to reduce influence of the high-band element on the signal in the second frequency band.

In addition, the shapes of the antenna elements included in the antenna devices according to the above exemplary embodiments are not limited to the shapes illustrated as examples in respective ones of the above exemplary embodiments. Each of the feeding element, the high-band element, and the low-band element of the antenna element may have an elliptical shape or the like, or may be curved.

In addition, a form realized by arbitrarily combining components and functions in the exemplary embodiments without departing from the gist of the present disclosure is also included in the present disclosure.

For example, antenna device <NUM> according to the third exemplary embodiment may further include short-circuit element <NUM> or short-circuit element 130a according to the second exemplary embodiment, and antenna device <NUM> according to the fourth exemplary embodiment may include short-circuit element <NUM> according to the second exemplary embodiment instead of short-circuit element <NUM>. Further, antenna device <NUM> according to the fourth exemplary embodiment may not include short-circuit element <NUM> or the like.

Claim 1:
An antenna device (<NUM>) comprising:
a feeding element (<NUM>) having a feedpoint that a signal in a first frequency band and a signal in a second frequency band lower than the first frequency band are supplied to;
a high-band element (<NUM>) connected to the feeding element (<NUM>), the high-band element (<NUM>) resonating with the signal in the first frequency band;
a low-band element (<NUM>) connected to the feeding element (<NUM>), the low-band element (<NUM>) resonating with the signal in the second frequency band;
an auxiliary element (<NUM>) capacitively coupled to the low-band element (<NUM>) at an open end (22e) of the low-band element (<NUM>);
a ground member (<NUM>) grounded;
a switch (<NUM>) switching a conductive state and a non-conductive state between the ground member (<NUM>) and the auxiliary element (<NUM>), and
a connection part (<NUM>) to which the high-band element (<NUM>) and low-band element (<NUM>) are connected,
wherein the high-band element (<NUM>) and the low-band element (<NUM>) are elongated elements that extend from the connection part (<NUM>) in directions opposite to each other and are disposed on the same straight line such that their respective longitudinal directions coincide with each other (<NUM>) and each have one end connected to the connection part and the other end being an open end, and
characterized in that the ground member (<NUM>) includes a coupling portion (<NUM>) disposed apart from and facing the open end (22e) of the low-band element (<NUM>) in a longitudinal direction of the low-band element (<NUM>),
the auxiliary element (<NUM>) is disposed between the open end (22e) of the low-band element (<NUM>) and the coupling portion (<NUM>), and
the auxiliary element (<NUM>) is capacitively coupled to the coupling portion (<NUM>).