JP2018152694A - Antenna device and electronic equipment including antenna device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain good antenna isolation with a simple structure, even if a distance between first and second antenna elements having substantially the same operation frequency band is small.SOLUTION: An antenna device has a ground conductor, first and second feeding points arranged on the ground conductor or in the vicinity thereof while being separated from each other, first and second antenna elements electrically connected with the first and second feeding points, respectively, and having substantially the same operation frequency band, a strip conductor extending along a strip region in the ground conductor extending along a surface of the ground conductor, and along the strip region while being separated from the strip region of the ground conductor, and constituting a parasitic antenna resonating in the operation frequency band along with the strip region, and a resistive element connected between the strip region of the ground conductor and the ground conductor.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an antenna device having a plurality of antenna elements and an electronic apparatus equipped with such an antenna device.

  2. Description of the Related Art In recent years, an antenna device employing MIMO (Multi-Input Multi-Output) technology has been used as an antenna device for electronic devices such as smartphones and tablet terminals in order to increase communication capacity and realize high-speed communication. An antenna device compatible with the MIMO technology includes a plurality of (for example, two) antenna elements.

  Since the space in the electronic device is limited, when a plurality of antenna devices are accommodated in the electronic device, the plurality of antenna elements are arranged close to each other. For this reason, interference between antenna elements occurs, and desired antenna performance may not be obtained. Therefore, there is a need for a technique for reducing interference between antenna elements, that is, improving isolation between antenna elements.

  In Patent Document 1, in order to provide an electronic apparatus capable of reducing radio wave interference between antennas, a casing in which a conductive layer functioning as an electromagnetic wave shielding layer is formed on an inner surface, and a back surface of the conductive layer. A flat panel display housed in the housing so as to face the surface, and disposed between the back surface of the flat panel display and the conductive layer at a predetermined distance from the surface of the conductive layer. A first antenna disposed so as to be positioned on the outer peripheral side of the side of the conductive layer, and between the back surface of the flat panel display and the conductive layer in a state of being spaced a predetermined distance from the surface of the conductive layer. And a second antenna disposed so that a part thereof is positioned on the outer peripheral side of the side of the conductive layer, and the conductive layer includes the first antenna and the first antenna. An electronic apparatus having a notch portion formed at a predetermined position on the side of the conductive layer and having a length of ¼ of a wavelength corresponding to the resonance frequency of the first antenna, located between the antenna and the antenna. Is disclosed.

  Patent Document 2 discloses a wireless terminal having a ground conductor and a transceiver, wherein the transceiver includes at least two antenna feeders and at least two parallel plate capacitors, and each of the parallel plate capacitors is insulated from each other. First and second plates, each of the first plates comprising a conductor plate insulated from the ground conductor, and each of the second plates being the ground under the conductor plate. Comprising a portion of the surface of the conductor, each of the at least two antenna feed lines being connected between a corresponding conductor plate and a corresponding radio frequency output / input, and a second plate each providing an impedance transformation A wireless terminal characterized by being separated from each other by a groove is disclosed.

  In Patent Document 3, in order to provide an antenna device capable of reducing space and miniaturization while maintaining certain characteristics as an antenna element by reducing interference between antenna elements, a conductor plate and an end of the conductor plate are provided. At least two antenna elements arranged in the vicinity of the part, a first slot line having a characteristic impedance Z1 formed on the conductor plate, and an arbitrary impedance greater than Z1 formed on the conductor plate A second slot line having a value Z2 of the first slot line, one end of the first slot line being an open end in a region between the antenna elements in the end portion of the conductor plate, The other end is connected to one end of the second slot line, and the other end of the second slot line is short-circuited inside the conductor plate. Antenna apparatus is disclosed. According to this, the total line length of the first slot line and the second slot line is larger than that in the case of forming a slot line having a line length of 1/4 of the wavelength corresponding to the resonance frequency of the antenna element. Since the interference between the antenna elements can be reduced in a shorter state, an antenna device that can save space or be miniaturized while maintaining certain characteristics as the antenna element is provided.

Japanese Patent No. 4738380 Japanese Patent No. 4347567 International Publication No. 2013/140770

  In the technique described in Patent Literature 1, when the distance between the antennas is small (for example, less than ¼ of the wavelength corresponding to the resonance frequency of the antenna), the notch portion operates as a parasitic notch antenna. Because of the secondary radiation from the antenna, the isolation between the antennas deteriorates.

  In the technique described in Patent Document 2, since it is necessary to provide at least two grooves corresponding to at least two parallel plate capacitors in the ground conductor, when the ground conductor forms a circuit board, the circuit element mounted on the circuit board When the layout is greatly restricted and the ground conductor is a casing, the rigidity of the casing may be reduced.

  With the technique described in Patent Document 3, it may be possible to reduce the total length of the first and second slot lines (slits) formed on the conductor plate, but in particular the characteristic impedance of the second slot line. Since it is necessary to increase the width of the second slot line in order to set Z2 to a desired value, the area occupied by the conductor plate increases. In addition, the structure of the slit becomes complicated.

  The present invention has first and second antenna elements having substantially the same operating frequency band, and provides good isolation between antennas with a simple structure even when the distance between the first and second antenna elements is small. It is a main object of the present invention to provide an antenna device capable of obtaining the above and an electronic apparatus including such an antenna device.

  The antenna device of the present invention includes a ground conductor, first and second feed points that are spaced apart from each other on or near the ground conductor, and the first and second feed points, respectively. First and second antenna elements that are electrically connected and have substantially the same operating frequency band, a strip region in the ground conductor extending along the surface of the ground conductor, and the strip region of the ground conductor A band-shaped conductor that forms a parasitic antenna that extends along the band-shaped region and is resonated in the operating frequency band together with the band-shaped region, and between the band-shaped region and the band-shaped conductor of the ground conductor. And a connected resistance element.

  The electronic device of the present invention is electrically connected to the antenna device and the first and second feed points of the antenna device via first and second feed lines, and the antenna device is interposed between the antenna device and the antenna device. And a wireless communication unit that communicates with the outside.

  According to the present invention, even when the first and second antenna elements having substantially the same operating frequency band are provided and the distance between the first and second antenna elements is small, a good structure between the antennas can be obtained. Provided are an antenna device capable of obtaining isolation, and an electronic apparatus including such an antenna device.

The block diagram which shows schematic structure of the electronic device provided with the antenna device which concerns on 1st Embodiment. The top view which shows the antenna device which concerns on 1st Embodiment The perspective view of the antenna apparatus shown in FIG. The isolation characteristic between the antenna elements with respect to the resistance value of the resistance element shown in FIGS. 1 and 2 (left vertical axis), and the antenna efficiency of the first and second antenna elements with respect to the resistance value of the resistance element (right vertical axis) Figure showing In the antenna device of the first embodiment, the frequency characteristic of isolation between antenna elements when the resistance value of the resistance element is 100Ω is shown in Comparative Example 1 (except that the notch and the resistance element are not formed in the ground conductor). The figure shown by contrast with the antenna apparatus of the same structure as the antenna apparatus of 1st Embodiment The figure which shows antenna efficiency in contrast with the comparative example 1 when the resistance value of a resistive element is 100 ohms in the antenna device of 1st Embodiment. The top view which shows electric current distribution when it supplies with electric power to a 2nd antenna element in the frequency within an operating frequency band in the comparative example 1. Current when power is supplied to the second antenna element at a frequency within the operating frequency band in Comparative Example 2 (antenna apparatus having the same configuration as the antenna apparatus of the first embodiment except that no resistive element is arranged in the notch) Top view showing distribution FIG. 3 is a plan view showing a current distribution when power is supplied to the second antenna element at a frequency within the operating frequency band in the antenna device of the first embodiment. The top view which shows the antenna apparatus which concerns on 2nd Embodiment. The perspective view which shows the antenna apparatus which concerns on 3rd Embodiment. Sectional drawing of the antenna apparatus along the XII-XII line of FIG. Schematic diagram showing an example of the electric field distribution around the notch Schematic diagram showing an example of magnetic field distribution around a notch The top view of the antenna device which concerns on 4th Embodiment The perspective view of the antenna apparatus shown in FIG. The principal part schematic diagram which shows the modification of the antenna apparatus shown in FIG.

  An antenna device according to a first aspect of the present invention made to solve the above problems includes a ground conductor, and first and second feed points that are spaced apart from each other on or near the ground conductor. The first and second antenna elements electrically connected to the first and second feeding points, respectively, having substantially the same operating frequency band, and the ground conductor extending along the surface of the ground conductor. A band-shaped region, a band-shaped conductor that extends along the band-shaped region apart from the band-shaped region of the ground conductor, and forms a parasitic antenna that resonates in the operating frequency band together with the band-shaped region, and the ground conductor A resistive element connected between the belt-like region and the belt-like conductor.

  According to this configuration, when power is supplied to one of the first and second antenna elements at a frequency within the operating frequency band, the strip-shaped region of the ground conductor and the strip-shaped conductor that extends along the strip-shaped region apart from the strip-shaped region. Since the mutual impedance between the first and second antenna elements can be increased by the parasitic antenna and the resistance element constituted by the first and second antenna elements, the first and second antenna elements can be used even when the distance between the first and second antenna elements is small. Current generated in the other of the two antenna elements can be reduced. That is, the isolation between the first and second antenna elements can be improved. Further, this configuration can be realized by a simple configuration in which a resistance element is connected between the strip-shaped region of the ground conductor and the strip-shaped conductor. Therefore, even when the first and second antenna elements having substantially the same operating frequency band are provided and the distance between the first and second antenna elements is small, good inter-antenna isolation is obtained with a simple structure. It is possible to provide an antenna device that can be used.

  In the second aspect of the invention, the belt-like region of the ground conductor is separated from one of a pair of regions of the ground conductor that are separated by a notch formed on one side of the ground conductor and face each other through the notch. The band-shaped conductor is composed of the other of the pair of regions of the ground conductor facing each other through the notch.

  According to this configuration, a parasitic antenna that resonates in the operating frequency band of the first and second antenna elements is realized with a simple configuration in which a notch is formed on one side of the ground conductor, and isolation between the antennas is improved. be able to.

  In the third aspect of the invention, the notch has a length that is approximately ¼ of the wavelength corresponding to the representative frequency in the operating frequency band.

  According to this configuration, while the length of the notch is shortened, the parasitic antenna constituted by the notch (or a pair of regions of the ground conductor facing each other separated by the notch) is operated in the operating frequency band of the antenna element. Can be easily resonated and the isolation between antenna elements in the operating frequency band can be improved.

  In the fourth invention, the first and second antenna elements are arranged in the vicinity of the one side of the ground conductor, and the first and second feeding points are directions along the one side of the ground conductor. The notch is formed at a position between the first feeding point and the second feeding point on one side.

  According to this configuration, the isolation effect between the first and second antenna elements due to the notch is further improved.

  In the fifth invention, at least one of the first and second antenna elements is disposed in the vicinity of the one side of the ground conductor, and has a portion extending along the one side. The dimension in the direction perpendicular to the one side is less than about 1/10 of the wavelength corresponding to the representative frequency in the operating frequency band.

  According to this configuration, a decrease in the antenna efficiency of at least one of the first and second antenna elements due to the notch formed in the ground conductor is suppressed.

  In the sixth invention, a dielectric material or a magnetic material is disposed in the notch, and the thickness of the dielectric material or the magnetic material is larger than the thickness of the ground conductor.

  According to this configuration, due to the wavelength shortening effect of the dielectric material or the magnetic material, the length of the notch can be shortened compared to the case where the dielectric material or the magnetic material is not disposed in the notch. .

  In the seventh invention, the strip conductor is a member different from the ground conductor, and is separated from the strip region of the ground conductor in a direction away from the surface of the ground conductor, and the strip conductor of the ground conductor. It is arranged facing the area.

  According to this configuration, it is possible to realize a parasitic antenna that resonates in the operating frequency band of the first and second antenna elements without forming a notch in the ground conductor, thereby improving isolation between the antennas.

  In the eighth invention, the strip conductor has a length of about ¼ of the wavelength corresponding to the representative frequency in the operating frequency band.

  According to this configuration, while the length of the strip conductor is shortened, the parasitic antenna composed of the strip conductor (or the strip conductor and the strip conductor region) easily resonates in the operating frequency band of the antenna element. The isolation between the antenna elements in the band can be improved.

  In the ninth invention, the first and second antenna elements are arranged in the vicinity of one side of the ground conductor, and the first and second feeding points are in a direction along the one side of the ground conductor. The strip conductors are spaced apart from each other, and one end of the strip conductor is located between the first feeding point and the second feeding point.

  According to this configuration, the isolation between the first and second antenna elements is further improved.

  In the tenth invention, a capacitive element is connected in parallel with the resistive element.

  According to this configuration, the band-shaped region of the ground conductor constituting the parasitic antenna and the length of the band-shaped conductor extending along the band-shaped region (the band-shaped region and the pair of ground conductors facing each other through the cutout) In the case of the portion, the length of the notch) can be shortened compared to the case where the capacitor is not connected.

  In the eleventh aspect of the invention, at least a part of the band-shaped region of the ground conductor and the band-shaped conductor constituting the parasitic antenna is from the second feeding point or the open end of the second antenna element. It is located at a distance less than about ¼ of the wavelength corresponding to the representative frequency of the operating frequency band.

  According to this configuration, when the second antenna element is fed at a frequency within the operating frequency band, the parasitic antenna and the second antenna element configured by the band-shaped region of the ground conductor and the band-shaped conductor extending along the band are provided. The current generated in the first antenna element can be reduced by strong electromagnetic coupling.

  In the twelfth aspect, the distance between the first feeding point and the second feeding point is less than about ¼ of the wavelength corresponding to the representative frequency in the operating frequency band.

  According to this configuration, the first and second antennas when the distance between the first feeding point and the second feeding point is less than about ¼ of the wavelength corresponding to the representative frequency of the operating frequency band. Isolation between elements can be improved.

  In the thirteenth aspect of the invention, the resistance value of the resistance element is measured at a position where the resistance element is connected, and the resonance of the parasitic antenna configured by the band-shaped region of the ground conductor and the band-shaped conductor is measured. It is approximately equal to the input impedance at frequency.

  According to this configuration, the isolation between the first and second antenna elements can be reliably improved.

  According to a fourteenth aspect of the present invention, there is provided an electronic apparatus, wherein the antenna device is electrically connected to the first and second feeding points of the antenna device via first and second feeding lines, and the antenna device A wireless communication unit that communicates with the outside via the device.

  According to this configuration, even when the first and second antenna elements having substantially the same operating frequency band are included and the distance between the first and second antenna elements is small, a good structure between the antennas can be obtained with a simple structure. It is possible to provide an electronic device provided with an antenna device that can obtain an adjustment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a block diagram illustrating a schematic configuration of an electronic apparatus including the antenna device according to the first embodiment. An electronic device 1 illustrated in FIG. 1 is, for example, a smartphone or a tablet terminal. As shown in FIG. 1, an electronic device 1 includes an input unit 2 for inputting user instructions, an output unit 3 for outputting information such as images and sounds, and a memory 4 for storing programs and data. A controller (processor) 5 that operates based on a program stored in the memory 4 and processes an operation signal input from the input unit 2 or controls the output unit 3; and an antenna device under the control of the controller 5 And a wireless communication unit 7 that performs wireless communication with the outside via the wireless communication unit 6. The input unit 2 includes a touch panel and a microphone, for example. The output unit 3 includes, for example, a liquid crystal display and a speaker.

  The antenna device 6 is electrically connected to the radio communication unit 7 via the first antenna element 10 electrically connected to the radio communication unit 7 via the first feed line 8 and the second feed line 9. And a second antenna element 11 connected thereto. The connection point between the first feed line 8 and the first antenna element 10 is the first feed point 12, and the connection point between the second feed line 9 and the second antenna element 11 is the second feed point 12. A feeding point 13 is provided. The first and second antenna elements 10, 11 are adapted to have substantially the same operating frequency band (in this example, but not limited to about 718-890 MHz used in a cellular system). .

  Next, the configuration of the antenna device 6 will be described in detail. FIG. 2 is a plan view showing the antenna device 6 according to the first embodiment, and FIG. 3 is a perspective view of the antenna device 6 shown in FIG.

  As shown in FIGS. 2 and 3, the antenna device 6 includes a substantially rectangular ground conductor (also referred to as a ground plane) 21 having a flat surface provided on a first surface of a substrate 20 mainly made of an insulator. ing. The first and second antenna elements 10 and 11 are disposed in the vicinity of the upper side 22 of the ground conductor 21. The first antenna element 10 is a plate-shaped inverted F antenna. The second antenna element 11 is a low-profile inverted L antenna and has a portion extending along the upper side 22 of the ground conductor 21. Here, “low profile” means that the dimension in the direction perpendicular to the upper side 22 is the representative frequency of the operating frequency band of the antenna elements 10 and 11 (in this example, 760 MHz. For example, the frequency may be less than about 1/10 of the wavelength corresponding to the center frequency (which may be 804 MHz in this example). The first and second antenna elements 10 and 11 may be the same type of antenna element. The ground conductor 21 is made of, for example, a copper foil or a ground pattern printed on the substrate 20. The ground conductor 21 is not necessarily provided on the substrate 20 and may be provided, for example, on the housing of the electronic device 1.

  Although not shown, wiring is printed on the second surface opposite to the first surface of the substrate 20. That is, in this embodiment, the substrate 20 is configured as a printed wiring board. The circuit modules and circuit elements that constitute the memory 4, the controller 5, the wireless communication unit 7, and the like illustrated in FIG. 1 are mounted on the second surface of the substrate 20. The wireless communication unit 7 is connected to the first and second antenna elements 10 and 11 by the first and second feeder lines 8 and 9 on the second surface side of the substrate 20.

  As shown in FIG. 2, in the present embodiment, the first feeding point 12 is located on the ground conductor 21 in the vicinity of the right end of the upper side 22 of the ground conductor 21 (that is, overlaps with the ground conductor 21 in plan view). ing). The second feeding point 13 is located on the ground conductor 21 in the vicinity of the left end of the upper side 22 of the ground conductor 21 (that is, overlaps with the ground conductor 21 in plan view). As a result, the first feeding point 12 and the second feeding point 13 are separated from each other and located on the ground conductor 21. In this example, the distance between the first feeding point 12 and the second feeding point 13 is approximately ¼ of the wavelength corresponding to the representative frequency in the operating frequency band of the first and second antenna elements 10 and 11. (When the representative frequency is 760 MHz, it is about 98.6 mm) (for example, about 50 mm). The first feeding point 12 and the second feeding point 13 do not necessarily have to be located on the ground conductor 21 and are arranged in the vicinity of the ground conductor 21 so as not to overlap the ground conductor 21 in plan view. Also good. In FIG. 3, symbols indicating the feeding points 12 and 13 are omitted to clearly show the shapes of the antenna elements 10 and 11.

  At a position between the first feeding point 12 and the second feeding point 13 on the upper side 22 of the ground conductor 21 of the antenna device 6, it extends in a direction intersecting with the upper side 22 (in this example, a vertical direction). A notch (slit) 30 is formed. The notch 30 includes a first end portion 31 (see FIG. 3) opened at the upper side 22, a second end portion 32 closed at a position away from the upper side 22, and the first end portion 31 and the second end portion. It has a pair of side edges 33 and 34 facing each other and extending between the parts 32. The portions of the ground conductor 21 that extend along the side edges 33 and 34 of the notch 30 are a pair of regions 25 and 26 of the ground conductor that are separated by the notch 30 and face each other through the notch 30. Yes. Each of the regions 25 and 26 is a band-shaped region along the notch 30. Such a notch 30 (or a pair of regions 25 and 26 of the ground conductor 21 opposed via the notch 30) constitutes a parasitic antenna (a parasitic notch antenna). Here, one of the pair of regions 25 and 26 of the ground conductor 21 facing each other through the notch 30 is an example of the “strip-like region in the ground conductor” of the present invention, and the other is separated from the “strip-like region” of the present invention. This is an example of a “band-shaped conductor extending along the band-shaped region”.

  The length from the first end 31 to the second end 32 of the notch 30 is set to approximately ¼ of the wavelength corresponding to the representative frequency in the operating frequency band of the antenna elements 10 and 11. Thereby, the parasitic antenna constituted by the notch 30 resonates in the operating frequency band. In order to reduce the length of the notch 30 as much as possible and make the parasitic antenna formed thereby easily resonate in the operating frequency band of the antenna elements 10 and 11, the length of the notch 30 is set to the operating frequency. It is preferable to set the wavelength corresponding to the representative frequency of the band to approximately ¼, but if the space can be secured, the length of the notch 30 can be set to approximately ½ of the wavelength corresponding to the representative frequency of the operating frequency band. It may be the length of.

  In addition, at least a part of the pair of regions 25 and 26 of the ground conductor 21 facing each other through the notch 30 constituting the parasitic antenna is from the second feeding point 13 or the open end 11a of the second antenna element 11. The distance is less than about 1/4 of the wavelength corresponding to the representative frequency of the operating frequency band (in this example, equal to the length of the notch 30).

  Furthermore, a resistance element 40 connected between a pair of regions 25 and 26 of the ground conductor facing each other through the notch 30 is disposed at the first end portion 31 which is an open end of the notch 30. .

  4 shows the isolation characteristics (left vertical axis) between the antenna elements with respect to the resistance value of the resistance element 40 shown in FIGS. 1 and 2, and the first and second antenna elements 10 with respect to the resistance value of the resistance element 40, 11 is a diagram showing antenna efficiency (right vertical axis).

  In FIG. 4, S21 is a coupling coefficient of the second antenna element 11 with respect to the first antenna element 10, and the smaller the value of the coupling coefficient S21, the better the isolation. The coupling coefficient S21 varies depending on the operating frequency of the antenna elements 10 and 11. In FIG. 4, a circular marker indicates the average value (also referred to as an isolation average value) of the coupling coefficient S21 in the operating frequency band of the antenna elements 10 and 11 for each resistance value, and the rhombus marker operates. The maximum value (sometimes referred to as the minimum isolation value) of the coupling coefficient S21 in the frequency band is shown for each resistance value. In FIG. 4, the square marker indicates the average value of the antenna efficiency of the first antenna element 10 in the operating frequency band for each resistance value, and the triangular marker indicates the antenna of the second antenna element 11 in the operating frequency band. The average efficiency is shown for each resistance value.

  As shown in FIG. 4, the value of the coupling coefficient S21 varies depending on the resistance value of the resistance element 40. For example, when the resistance value of the resistance element 40 is about 300Ω, the value of the coupling coefficient S21 is the maximum value ( Both the rhombus marker) and the average value (circular marker) are significantly lower than when the resistance value of the resistance element 40 is about 900Ω. That is, when the resistance value of the resistance element 40 is about 300Ω, the isolation between the antennas is greatly improved as compared to when the resistance value of the resistance element 40 is about 900Ω. Here, the larger the value of the resistance element 40 (that is, the closer to the right side in FIG. 4), the closer to the case where the resistance element 40 is not provided (that is, the resistance value of the resistance element 40 is infinite). As described above, in the antenna device 6 according to the first embodiment, the resistance element 40 is connected between the pair of regions 25 and 26 of the ground conductor 21 facing each other through the notch 30 formed in the ground conductor 21. Compared with the case where the resistance element 40 is not provided, the isolation between the antennas can be improved.

  Table 1 shows that power is fed at the first end portion 31 of the notch 30 (that is, the connection position of the resistance element 40) while changing the frequency within the operating frequency band of the first and second antenna elements 10 and 11 (that is, The input impedance of the parasitic antenna (notch antenna) constituted by the notch 30 measured by applying a signal) is shown.

  In Table 1, R represents a resistance component of impedance, and X represents a reactance component of impedance. As shown in Table 1, in this example, the parasitic antenna (notch antenna) constituted by the notch 30 resonates at about 760 MHz, which is the representative frequency of the operating frequency band of the antenna elements 10 and 11, and the reactance component X Becomes substantially zero, and then the input impedance is approximately equal to the value of the resistance component R of about 346.6Ω. As described above, this is because the length of the notch 30 is set to approximately ¼ of the wavelength corresponding to 760 MHz. According to an experiment by the inventor of the present invention, the input impedance (in this example) at the resonance frequency of the parasitic antenna constituted by the notch 30 in which the resistance value of the resistance element 40 is measured at the position where the resistance element 40 is connected. , About 346.6 Ω), it has been found that the isolation between the antennas is generally maximized (that is, the coupling coefficient S21 is minimized). However, as shown in FIG. 4, since the effect of improving the isolation is seen over a relatively wide range (about 100 to 600Ω) of the resistance value of the resistance element 40, the resistance value of the resistance element 40 is the isolation value. You may select suitably according to a requirement specification from the range from which the effect of an improvement is acquired.

  Referring again to FIG. 4, the antenna efficiency of the first antenna element 10 in the first embodiment is not provided with the resistance element 40 in the range where the resistance value of the resistance element 40 with improved isolation is about 100 to 600Ω. The antenna efficiency of the second antenna element 11 in the first embodiment is slightly higher than that in the case where the resistance element 40 is not provided. Slightly lower. The decrease in the antenna efficiency in the second antenna element 11 is considered to be due to the current being consumed as heat in the resistance element 40. However, when the resistance value of the resistance element 40 is in the range of about 100 to 600Ω, the reduction in antenna efficiency of the second antenna element 11 due to the provision of the resistance element 40 is the isolation between the antenna elements due to the provision of the resistance element 40. Small enough compared to the improvement.

  FIG. 5 shows the frequency characteristic of isolation between antenna elements (coupling coefficient S21) when the resistance value of the resistance element 40 is 100Ω in the antenna device 6 of the first embodiment. It is a figure shown by contrast with the antenna apparatus of the same structure as the antenna apparatus 6 of 1st Embodiment except the point which does not have the notch 30 and the resistive element 40). As shown in FIG. 5, in the first embodiment, the operation of the antenna elements 10 and 11 as well as the resonance frequency of the parasitic notch antenna configured by the notch 30 is compared with the comparative example 1. Isolation is improved (coupling coefficient S21 is reduced) in a wide frequency band including 718 to 890 MHz which is the frequency band.

  FIG. 6 is a diagram showing the antenna efficiency in comparison with the comparative example 1 when the resistance value of the resistance element 40 is 100Ω in the antenna device 6 of the first embodiment. In FIG. 6, the antenna efficiency of each antenna element is an average value in the operating frequency band (718 to 890 MHz) of the antenna element. As shown in FIG. 6, the antenna efficiency of the first antenna element 10 in the first embodiment is slightly lower than that of Comparative Example 1 (that is, the antenna device in which the notch 30 and the resistance element 40 are not provided). Thus, the antenna efficiency of the second antenna element 11 in the first embodiment is slightly higher than that in the first comparative example. The amount of reduction in antenna efficiency of the first antenna element 10 due to the provision of the notch 30 and the resistance element 40 is the amount of improvement in isolation between the antenna elements due to the provision of the notch 30 and the resistance element 40 (FIGS. 4 and 5) and sufficiently small. Note that the antenna efficiency of the second antenna element 11 in the first embodiment is slightly higher than that of the first comparative example because the effect of lowering the antenna efficiency due to the provision of the resistance element 40 is notched 30. This is considered to be because the effect of improving the antenna efficiency due to the decrease in the electromagnetic coupling between the antenna elements was exceeded.

  Here, in the antenna device 6 of the first embodiment, the antenna efficiency of the second antenna element 11 is not lowered (rather improved slightly) because the second antenna element 11 is composed of a low-profile antenna. That is, the second antenna element 11 has a portion extending along the upper side 22 of the ground conductor 21 (that is, the side where the notch 30 is formed), and the dimension in the direction perpendicular to the upper side 22 is the antenna. One of the reasons is considered to be less than about 1/10 of the wavelength corresponding to the representative frequency in the operating frequency band of the elements 10 and 11. This is because when the notch 30 is not provided in the ground conductor 21 and the power is supplied to the second antenna element 11 composed of a low-profile inverted L antenna, the upper side 22 of the ground conductor 21 of the second antenna element 11 is supplied. The current flowing in the portion extending along the line and the current flowing along the upper side 22 of the ground conductor 21 are canceled, and the current flowing along the upper side 22 is emitted from the second antenna element 11 (far-field radiation). ) And the second antenna element 11 radiates a radio wave mainly by a current in a direction perpendicular to the upper side 22, so that a notch 30 is formed in the upper side 22 of the ground conductor 21 as in the first embodiment. This is because even if the resistance element 40 is provided there, the influence on the radio wave radiated from the second antenna element 11 (that is, antenna efficiency) is small.

  FIG. 7 is a plan view showing a current distribution when power is supplied to the second antenna element 11 at a frequency within the operating frequency band in the first comparative example. As shown in FIG. 7, in the antenna device of Comparative Example 1 in which the notch 30 and the resistance element 40 are not provided, when the second antenna element 11 is fed at a frequency within the operating frequency band, the second The antenna current of the antenna element 11 flows to the first antenna element 10 through the ground conductor 21, particularly along the upper side 22 of the ground conductor 21, and the current is distributed to the first antenna element 10. That is, the isolation between the first and second antenna elements 10 and 11 is not sufficient, and interference occurs between these antenna elements.

  FIG. 8 shows the second antenna at a frequency within the operating frequency band in Comparative Example 2 (an antenna device having the same configuration as the antenna device 6 of the first embodiment except that the resistor element 40 is not disposed in the notch 30). 3 is a plan view showing a current distribution when power is supplied to an element 11. FIG. As shown in FIG. 8, the antenna device of Comparative Example 2 is configured by a notch 30 formed in the ground conductor 21 when the second antenna element 11 is fed at a frequency within the operating frequency band. The notch antenna resonates, and a current is distributed along a pair of regions 25 and 26 of the ground conductor 21 facing each other through the notch 30. In the first comparative example, it is considered that the current coupling between the first and second antenna elements 10 and 11 through the ground conductor 21 is suppressed by the notch 30 formed in the ground conductor 21 as compared with the first comparative example. Note that a large amount of current is distributed in the first antenna element 10. This is considered to be due to the influence of secondary radiation from the notch antenna (notch 30).

  FIG. 9 is a plan view showing a current distribution when power is supplied to the second antenna element 11 at a frequency within the operating frequency band in the antenna device 6 of the first embodiment. As shown in FIG. 9, the antenna device 6 of the first embodiment is also formed on the ground conductor 21 when power is supplied to the second antenna element 11 at a frequency within the operating frequency band, as in Comparative Example 2. The notch antenna constituted by the cutouts 30 resonates, and current is distributed along the pair of regions 25 and 26 of the ground conductor 21 opposed via the cutouts 30. However, since the resistance element 40 connected between the pair of regions 25 and 26 of the grounding conductor 21 facing each other through the notch 30 is provided, the mutual connection between the first and second antenna elements 10 and 11 is achieved. Impedance is increased and electromagnetic coupling due to secondary radiation due to resonance of the notch antenna is reduced. As a result, the current distributed in the first antenna element 10 is greatly reduced as compared with Comparative Examples 1 and 2. That is, according to the first embodiment, the first and second antenna elements 10 and 11 having substantially the same operating frequency band are included, and the distance between the first and second antenna elements 10 and 11 is small. However, an antenna device 6 is provided that can obtain good isolation between antennas with a simple structure. The current distribution shown in FIGS. 7 to 9 was measured by supplying power at 760 MHz as a frequency within the operating frequency band.

  In the antenna device 6 of the first embodiment, the notch 30 is formed on one side (upper side 22) of the ground conductor 21, and the operating frequency band of the first and second antenna elements 10 and 11 is used. A resonant parasitic antenna can be realized and isolation between antennas can be improved.

  Further, as described above, the notch 30 has a length of approximately ¼ of the wavelength corresponding to the representative frequency (760 MHz in this example) of the operating frequency band of the antenna elements 10 and 11. The parasitic antenna formed by the notch 30 (or the pair of regions 25 and 26 of the ground conductor 21 facing each other separated by the notch 30) is shortened while the operating frequency band of the antenna elements 10 and 11 is reduced. Can be easily resonated and the isolation between antenna elements in the operating frequency band can be improved.

  Further, as described above, in the antenna device 6 of the first embodiment, the first and second antenna elements 10 and 11 are disposed in the vicinity of one side (upper side 22) of the ground conductor 21, and the first and second power feedings are performed. The points 12 and 13 are separated from each other in the direction along the upper side 22 of the ground conductor 21, and the notch 30 is formed at a position between the first feeding point 12 and the second feeding point 13 on the upper side 22. Therefore, the isolation effect between the first and second antenna elements 10 and 11 by the notch 30 is further improved.

  Further, as described above, in the antenna device 6 of the first embodiment, the second antenna element 11 has a portion extending along the upper side 22 of the ground conductor 21 (that is, the side where the notch 30 is formed). And the dimension in the direction perpendicular to the upper side 22 is less than about 1/10 of the wavelength corresponding to the representative frequency in the operating frequency band of the antenna elements 10, 11. The decrease in the antenna efficiency of the second antenna element 11 due to is suppressed. The first antenna element 10 has a portion extending along the side of the ground conductor 21 in which the notch 30 is formed, and the dimension in the direction perpendicular to the side corresponds to the representative frequency in the operating frequency band. It is good also as a low-profile antenna (for example, inverted L antenna) which has a dimension less than about 1/10 of the wavelength to carry out.

  As described above, in the antenna device 6 according to the first embodiment, the resistance value of the resistance element 40 is measured at the position where the resistance element 40 is connected, and is opposed to each other separated by the notch 30. Is substantially equal to the input impedance (about 346.4Ω in this example) at the resonance frequency of the parasitic antenna (notch antenna) configured by the pair of regions 25 and 26) of the grounding conductor 21 to be Isolation between the antenna elements 10 and 11 can be reliably improved.

  As described above, in the antenna device 6 according to the first embodiment, at least a part of the pair of regions 25 and 26 of the ground conductor 21 facing each other through the notch 30 constituting the parasitic antenna is the second power feeding. From the point 13 or the open end 11a of the second antenna element 11, approximately ¼ of the wavelength corresponding to the representative frequency in the operating frequency band of the antenna elements 10, 11 (in this example, equal to the length of the notch 30) When the power is supplied to the second antenna element 11 at a frequency within the operating frequency band, the notch 30 (or the pair of regions 25 of the ground conductor 21 facing each other via the notch 30; 26) and the second antenna element 11 are strongly electromagnetically coupled to each other, and the current generated in the first antenna element 10 can be reduced.

(Second Embodiment)
Next, a second embodiment of the present invention will be described. FIG. 10 is a plan view showing an antenna apparatus according to the second embodiment. Note that points not particularly mentioned in the description of the second embodiment are the same as those in the first embodiment.

  As shown in FIG. 10, the antenna device 6 a of the second embodiment is different from the antenna device 6 of the first embodiment in that a capacitive element 41 is connected in parallel with the resistance element 40. Thus, by setting the capacitive element 41 in parallel with the resistance element 40, the resonance frequency of the notch antenna constituted by the notch 30 is set to the same value as the antenna device 6 of the first embodiment (for example, 760 MHz). ) And the length of the notch 30 can be shortened. Thereby, the strength reduction of the ground conductor 21 due to the provision of the notch 30 is suppressed, and the circuit on the surface (first surface) opposite to the surface (first surface) on which the ground conductor 21 is disposed of the substrate 20. The effect of the cutout 30 on the mounting of the module or the like is reduced.

(Third embodiment)
Next, a third embodiment of the present invention will be described. FIG. 11 is a perspective view showing an antenna device according to the third embodiment, and FIG. 12 is a cross-sectional view of the antenna device along the line XII-XII in FIG. FIG. 13A is a schematic diagram illustrating an example of the electric field distribution around the notch, and FIG. 13B is a schematic diagram illustrating an example of the magnetic field distribution around the notch. The points not particularly mentioned in the description of the third embodiment are the same as those in the first embodiment.

  As shown in FIGS. 11 and 12, the antenna device 6 b according to the third embodiment is disposed near the first antenna element 110 disposed near the lower side 23 of the ground conductor 21 and the upper side 22 of the ground conductor 21. The second antenna element 111 is provided. The first and second antenna elements 110 and 111 have substantially the same operating frequency band (for example, 718 to 890 MHz). The first and second antenna elements 110 and 111 are both low-profile inverted L antennas. Thus, in the antenna device 6b of the third embodiment, the first and second antenna elements 110 and 111 are arranged in the vicinity of different sides of the ground conductor 21.

  In the antenna device 6b, a material 50 made of a dielectric or magnetic material is disposed in a notch 30 (see also FIGS. 2 and 3) formed in the upper side 22 of the ground conductor 21. As well shown in FIG. 12, a notch 28 is also formed in the portion of the substrate 20 aligned with the notch 30 of the ground conductor 21. The material 50 has a thickness larger than the thickness of the ground conductor 21, and extends in the thickness direction of the ground conductor 21 through the notch 30 of the ground conductor 21 and the notch 28 of the substrate 20. In addition, the material 50 covers the surface (upper surface) of the region near the notch 28 of the ground conductor 21 (regions 25 and 26 shown in FIG. 2) and the surface (lower surface) of the region near the notch 30 of the substrate 20. Covering. With such a configuration, the resonance frequency of the notch antenna formed by the notch 30 is set to the antenna device 6 of the first embodiment by the wavelength shortening effect by the material 50 made of a dielectric or magnetic material disposed in the notch 30. The length of the notch 30 can be shortened while maintaining the same value as (for example, 760 MHz).

  As shown in FIGS. 13A and 13B, the electric field and magnetic field around the notch 30 are distributed over a wide range exceeding the thickness of the ground conductor 21. Therefore, by making the material 50 have a thickness larger than the thickness of the ground conductor 21, the electric field or magnetic field penetrating the material 50 can be obtained compared to the case where the material 50 has a thickness equal to or less than the thickness of the ground conductor 21. Increases, and the wavelength shortening effect by the material 50 increases (that is, the length of the notch 30 can be shortened).

(Fourth embodiment)
Next, a fourth embodiment of the present invention will be described. FIG. 14 is a plan view of the antenna device according to the fourth embodiment, and FIG. 15 is a perspective view of the antenna device shown in FIG. The points not particularly mentioned in the description of the fourth embodiment are the same as in the first embodiment.

  As shown in FIGS. 14 and 15, the antenna device 6 c according to the fourth embodiment is disposed near the first antenna element 210 disposed near the lower side 23 of the ground conductor 21 and the upper side 22 of the ground conductor 21. The second antenna element 211 is provided. The first and second antenna elements 210 and 211 have substantially the same operating frequency band (for example, 718 to 890 MHz). The first and second antenna elements 210 and 211 are both low-profile inverted L antennas. The feeding point (first feeding point) 212 of the first antenna element 210 is provided on the lower side 23 of the ground conductor 21, and the feeding point (second feeding point) 213 of the second antenna element 211 is grounded. It is provided on the upper side 22 of the conductor 21. The first feeding point 212 and the second feeding point 213 are not necessarily located on the ground conductor 21, and are arranged in the vicinity of the ground conductor 21 so as not to overlap the ground conductor 21 in a plan view. Also good.

  In the antenna device 6c, unlike the antenna device 6 of the first embodiment, the ground conductor 21 is not formed with a notch, and instead extends in a direction intersecting with the upper side 22 (in this example, a vertical direction). A belt-like conductor 60 is provided which is a separate member from the ground conductor 21 to be performed. The strip conductor 60 has one end (first end) 61 electrically connected to the ground conductor 21 and the other end (second end) 62 which is an open end not connected to the ground conductor 21. The strip conductor 60 is disposed away from the ground conductor 21 in a direction away from the surface of the ground conductor 21 and is opposed to the surface of the ground conductor 21. The ground conductor 21 has a strip region 29 facing the strip conductor 60. Have. The strip conductor 60 forms a parasitic antenna (parasitic monopole antenna) in cooperation with the strip region 29.

  The length from the first end 61 to the second end 62 of the strip conductor 60 is set to approximately ¼ of the wavelength corresponding to the representative frequency in the operating frequency band of the antenna elements 210 and 211. Thereby, the parasitic antenna constituted by the strip conductor 60 resonates in the operating frequency band. In order to reduce the length of the strip conductor 60 as much as possible and to make the parasitic antenna formed thereby easily resonate in the operating frequency band of the antenna elements 210 and 111, the length of the strip conductor 60 is set to the operating frequency. It is preferable to set the wavelength corresponding to the representative frequency of the band to approximately ¼, but when the space can be secured, the length of the strip-shaped conductor 60 is set to be approximately ½ of the wavelength corresponding to the representative frequency of the operating frequency band. It may be the length of.

  In addition, at least a part of the strip-shaped conductor 60 (and the strip-shaped region 29 of the grounding conductor 21 opposite to the strip-shaped conductor 60) has a representative frequency in the operating frequency band from the second feeding point 213 or the open end 211a of the second antenna element 211. It is located at a distance less than about 1/4 of the corresponding wavelength (in this example, equal to the length of the strip conductor 60).

  In addition, a resistance element 240 connected between the strip conductor 60 and the strip region 29 of the ground conductor 21 is disposed at the first end 61 of the strip conductor 60.

  In the antenna device 6c configured as described above, for example, when power is supplied to the second antenna element 211 at a frequency within the operating frequency band, the first end 61 is disposed so as to face the surface of the ground conductor 21 and the ground conductor 21. The parasitic antenna constituted by the strip-shaped conductor 60 electrically connected to the first and second antenna elements 210 and 211 via the resistance element 240 resonates and weakens the electromagnetic coupling between the first and second antenna elements 210 and 211 (that is, isolation is achieved). Improve) work. Further, the resistance element 240 connected between the strip conductor 60 and the ground conductor 21 increases the mutual impedance between the first and second antenna elements 210 and 211, and is caused by secondary radiation due to resonance of the parasitic antenna. Since the electromagnetic coupling is reduced, even when the distance between the first and second antenna elements 210 and 211 is small, the current generated in the first antenna element 211 due to secondary radiation is reduced to such a resistance element. Compared with the case where 240 is not provided, it can be greatly reduced. That is, according to the fourth embodiment, when the first and second antenna elements 210 and 111 having substantially the same operating frequency band are included and the distance between the first and second antenna elements 210 and 211 is small. However, an antenna device 6c is provided that can obtain good isolation between antennas with a simple structure.

  In the antenna device 6c of the fourth embodiment, the strip conductor 60 that is separated from the strip region 29 of the ground conductor 21 in a direction away from the surface of the ground conductor 21 and is opposed to the strip region 29 of the ground conductor 21 Without forming a cutout in the ground conductor 21, a parasitic antenna that resonates in the operating frequency band of the first and second antenna elements 210 and 211 can be realized, and the isolation between the antennas can be improved.

  Further, as described above, since the strip conductor 60 has a length that is approximately ¼ of the wavelength corresponding to the representative frequency in the operating frequency band of the antenna elements 210 and 211, the strip conductor 60 is shortened while the strip conductor 60 is shortened. The parasitic antenna constituted by the conductor 60 (or the band-shaped region 29 of the band-shaped conductor 60 and the ground conductor 21) can easily resonate in the operating frequency band of the antenna elements 210 and 211, and the isolation between antenna elements in the operating frequency band is improved. can do.

  In addition, as described above, at least a part of the strip-shaped conductor 60 (and the strip-shaped region 29 of the ground conductor 21 opposed thereto) extends from the second feeding point 213 or the open end 211a of the second antenna element 211 to the operating frequency band. Is located at a distance less than about 1/4 of the wavelength corresponding to the representative frequency (in this example, equal to the length of the strip conductor 60), the second antenna element 211 has a frequency within the operating frequency band. When the power is supplied, the parasitic antenna constituted by the strip-shaped conductor 60 (and the strip-shaped region 29 of the ground conductor 21 opposed thereto) and the second antenna element 211 are strongly electromagnetically coupled to the first antenna element 210. The generated current can be reduced.

  In the fourth embodiment as well, the resistance value of the resistance element 240 is a value determined by the strip conductor 60 measured at the position where the resistance element 240 is connected (in this example, the first end 61 of the strip conductor 60). It is preferable that it is substantially equal to the input impedance at the resonance frequency of the power feeding antenna in order to reliably obtain the effect of improving the isolation by the resistance element 240. Further, the first and second antenna elements 210 and 211 are arranged in the vicinity of one side (for example, the upper side 22) of the ground conductor 21, and the first and second feeding points 212 and 213 are along the one side of the ground conductor. When spaced apart from each other in the direction, the first end 61 of the strip conductor 60 is preferably located between the first feeding point 212 and the second feeding point 213.

  As described above, the embodiments have been described as examples of the technology disclosed in the present application. However, the technology in the present disclosure is not limited to this, and can be applied to embodiments in which changes, replacements, additions, omissions, and the like have been performed. Moreover, it is also possible to combine each component demonstrated by said embodiment into a new embodiment.

  For example, as shown in FIG. 16, in order to adjust the electrical length of the strip-shaped conductor 60 shown in the fourth embodiment (that is, the resonant frequency of the parasitic antenna formed by the strip-shaped conductor 60), the resistor element 240 is connected in series. An inductance element 42 may be connected.

  Moreover, although the notch 30 and the strip | belt-shaped conductor 60 which were shown in the said embodiment were linear, these notches 30 and the strip | belt-shaped conductor 60 may be bent by the L shape by planar view, and are bent smoothly. May be. Further, it may extend in an inclined direction instead of being perpendicular to the upper side 22. In the first embodiment, the position where the resistance element 40 is disposed is not limited to the open end portion (first end portion 31) of the notch 30, but must be the closed end portion (second end portion 32) of the notch 30. For example, any position in the direction along the notch 30 may be used. However, since the input impedance at the time of resonance of the parasitic antenna (notch antenna) constituted by the notch 30 changes according to the position where the resistance element 40 is arranged, The appropriate resistance value can change (the closer the second end 32 of the notch 30 is, the smaller the appropriate resistance value tends to be). Similarly, the position where the resistance element 240 is arranged in the fourth embodiment is not limited to the first end portion (end portion on the upper side 22 side) of the strip-shaped conductor 60, and may be any position in the direction along the strip-shaped conductor 60. . Further, the ground conductor 21 is not limited to a generally rectangular one as illustrated. For example, a plate-like conductor on which the first feeding point of the first antenna element is arranged and a plate-like conductor on which the second feeding point of the second antenna element is arranged are provided separately. Two conductors may be electrically connected to form one ground conductor.

  The antenna device and the electronic apparatus according to the present invention have an effect that a good inter-antenna isolation can be obtained with a simple structure even when the distance between the first and second antenna elements is small. It is useful as an antenna device having first and second antenna elements having the operating frequency band and an electronic apparatus equipped with the antenna device.

DESCRIPTION OF SYMBOLS 1 Electronic device 2 Input part 3 Output part 4 Memory 5 Controller 6, 6a, 6b, 6c Antenna apparatus 7 Radio | wireless communication part 8 1st feed line 9 2nd feed line 10, 110, 210 1st antenna element 11, 111, 211 Second antenna element 11a, 211a Open end 12, 212 First feeding point 13, 213 Second feeding point 20 Substrate 21 Grounding conductor 22 Upper side 23 Lower side 25, 26, 29 Banded region 28 Notch 30 Notch Notch (slit)
31 First end 32 Second end 33, 34 Side edge 40, 240 Resistance element 41 Capacitance element 42 Inductance element 50 Dielectric or magnetic material 60 Strip conductor 61 First end 62 Second end

Claims (14)

A ground conductor;
First and second feeding points that are spaced apart from each other on or in the vicinity of the ground conductor;
First and second antenna elements electrically connected to the first and second feed points, respectively, having substantially the same operating frequency band;
A strip region in the ground conductor extending along a surface of the ground conductor;
A band-shaped conductor that extends along the band-shaped region apart from the band-shaped region of the ground conductor, and that forms a parasitic antenna that resonates in the operating frequency band together with the band-shaped region;
The antenna apparatus which has the resistive element connected between the said strip | belt-shaped area | region of the said ground conductor, and the said strip | belt-shaped conductor.   The band-shaped region of the ground conductor is one of a pair of regions of the ground conductor that are separated by a notch formed on one side of the ground conductor and that face each other through the notch. The antenna device according to claim 1, comprising the other of the pair of regions of the ground conductor facing each other through a notch.   The antenna device according to claim 2, wherein the notch has a length of approximately ¼ of a wavelength corresponding to a representative frequency in the operating frequency band. The first and second antenna elements are disposed in the vicinity of the one side of the ground conductor, and the first and second feeding points are separated from each other in a direction along the one side of the ground conductor;
The antenna device according to claim 2 or 3, wherein the notch is formed at a position between the first feeding point and the second feeding point on the one side.   At least one of the first and second antenna elements is disposed in the vicinity of the one side of the ground conductor, has a portion extending along the one side, and has a dimension in a direction perpendicular to the one side of the ground conductor. The antenna device according to claim 2 or 3, wherein is less than about 1/10 of a wavelength corresponding to a representative frequency of the operating frequency band.   The dielectric material or the magnetic material is disposed in the notch, and the thickness of the dielectric material or the magnetic material is larger than the thickness of the ground conductor. Antenna device.   The strip conductor is a member different from the ground conductor, and is spaced from the strip region of the ground conductor in a direction away from the surface of the ground conductor, and is disposed to face the strip region of the ground conductor. The antenna device according to claim 1.   The antenna device according to claim 7, wherein the strip conductor has a length of approximately ¼ of a wavelength corresponding to a representative frequency in the operating frequency band. The first and second antenna elements are disposed in the vicinity of one side of the ground conductor, and the first and second feeding points are separated from each other in a direction along the one side of the ground conductor,
The antenna device according to claim 7 or 8, wherein one end of the strip conductor is located between the first feeding point and the second feeding point.   The antenna device according to claim 1, wherein a capacitive element is connected in parallel with the resistive element.   At least a part of the band-shaped region of the ground conductor and the band-shaped conductor constituting the parasitic antenna is set to a representative frequency in the operating frequency band from the second feeding point or the open end of the second antenna element. The antenna device according to any one of claims 1 to 10, wherein the antenna device is located at a distance less than about ¼ of a corresponding wavelength.   12. The distance between the first feeding point and the second feeding point is less than about ¼ of a wavelength corresponding to a representative frequency in the operating frequency band. Antenna device.   The resistance value of the resistance element is substantially equal to an input impedance at a resonance frequency of the parasitic antenna configured by the band-shaped region of the ground conductor and the band-shaped conductor measured at a position where the resistance element is connected. Item 13. The antenna device according to any one of Items 1 to 12. The antenna device according to any one of claims 1 to 13,
An electronic apparatus comprising: a wireless communication unit that is electrically connected to the first and second feeding points of the antenna device via first and second feeding lines and communicates with the outside via the antenna device.