JP2010148067A - Antenna, antenna device, and communication apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a built-in type antenna capable of obtaining a low VSWR and high gain even in a low-frequency side band and being efficiently packaged in a communication apparatus, and to provide an antenna device using the antenna and a communication apparatus using the antenna device. <P>SOLUTION: The antenna is composed of a first radiation electrode, a connection part, a matching circuit, a feeder, a second radiation electrode, and a ground part. A ground line of the feeder is connected to the first radiation electrode through a connection conductor, a signal line of the feeder is connected to the second radiation electrode through the matching circuit, the ground part is connected to a ground electrode of the matching circuit and the ground line of the feeder, and the second radiation electrode has a base composed of an insulator. Since the antenna is configured with the radiation electrode composed of a metal conductor plate and the radiation electrode obtained by piercing a conductor into the other base, radiation characteristics can be improved and a low VSWR and high gain can be obtained in receiving digital terrestrial television broadcasting by the antenna built in a communication apparatus or the like. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an antenna used for an electronic device having a communication function, particularly a communication device such as a mobile phone or a portable information terminal device, and further relates to an antenna device using the antenna and a communication device.

  In recent years, a general-purpose information terminal apparatus is also required to have a reception function for digital terrestrial television broadcasting. In terrestrial digital television broadcasting, the use frequency band is wide from 470 MHz to 770 MHz in Japan, and high gain and high efficiency are required over the entire band, but high gain over the entire band with one antenna is required. In addition, it is difficult to achieve high efficiency. In particular, there are many broadcasting stations in the metropolitan area in the lower band, so that high gain and high efficiency are required on the lower band side.

  2. Description of the Related Art Conventionally, as a receiving antenna for digital terrestrial television broadcasting built in a mobile phone or the like, an antenna that performs a diversity operation by combining two whip antennas and a ground electrode to stabilize reception quality has been proposed (Patent Document 1). . In addition, as an antenna built in a foldable mobile phone or the like, an antenna has been proposed that can ensure the antenna performance even when the upper housing and the lower housing are opened and closed by combining a monopole antenna and a conductor plate ( Patent Document 2).

  Furthermore, as an antenna built in a folding cellular phone or the like, a dipole antenna is configured with a plate-like conductor built in the upper housing and a plate-like conductor built in the lower housing, and the mobile phone can be held by hand. An antenna that can obtain a relatively high antenna gain in a held state has been proposed (Patent Document 3).

  The antenna is advantageous for diversity reception when receiving terrestrial digital TV broadcasts, and for obtaining a relatively high antenna gain in a specific band such as a cellular phone, but in a wide band such as a terrestrial digital TV broadcast band. There are the following problems in increasing the gain and efficiency during reception. For example, when a whip antenna or monopole antenna is used as the radiation electrode, the resonance point has a specific resonance point determined by the antenna length, so even if a conductor plate with a large area is simply used in combination as a radiation electrode, the band has a high gain. The voltage standing wave ratio (VSWR) becomes high on the low side and the high side even if it is intended to cover a wide band of 300 MHz such as the digital terrestrial television broadcasting band. As a result, the gain is lowered, and it is not preferable to apply it to receiving applications such as terrestrial digital television broadcasting that requires a wide band.

JP 2007-13442 A JP 2004-229048 A JP 2004-56426 A

  If an antenna element that combines a whip antenna or monopole antenna as described in the above-mentioned patent document and a radiation electrode to be added separately from this is used, a high gain can be obtained within a specific frequency range within the band. Although it is possible to obtain a uniform and high gain from a low frequency to a high frequency band used in digital terrestrial television broadcasting, etc., especially in a low frequency band, a VSWR is low and a high metropolitan area where a high gain is required There is a problem that it is not suitable for applications such as digital terrestrial television broadcasting.

  Therefore, in the present invention, in an antenna such as a general-purpose information terminal device that requires a wide band such as a terrestrial digital television broadcast band, a high gain is obtained with a low VSWR even in a low frequency band of the broadcast band, It is an object of the present invention to provide a built-in antenna device that enables efficient mounting in a communication device casing, and a communication device using the same.

  The antenna device (A) of the present invention includes a first radiation electrode (1), a connection part (3), a matching circuit (4), a feeder line (8), and a second radiation electrode (2). The ground line (81) of the feeder line (8) is connected to the ground of the first radiation electrode (1) and the matching circuit (4) via the connection part (3). The signal line (82) of the feeder line (8) is connected to the second radiation electrode (2) via the matching circuit (4), and is connected to the electrode (411, 431). The electrode (2) preferably has a base (22) made of an insulator.

  According to such a configuration, the main part of the antenna device (A) of the present invention is constituted by the first radiation electrode (1), the second radiation electrode (2), the connection portion (3), and the matching circuit (4). The The first radiation electrode (1) is made of a metal conductive plate, and is connected to the ground part (6) via the connection part (3). Since the first radiation electrode (1) can be configured with a rectangular surface, the wavelength corresponding to the frequency of the terrestrial digital television broadcasting station, for example, is within the range of approximately one side to diagonal length. It can be easily resonated. In addition, a copper plate or the like is used for the first radiation electrode (1), and the first radiation electrode (1) also has a function as a shield plate of a display (hereinafter referred to as LCD screen) of the portable information terminal device (M). ) To form a regular square. Further, since the second radiation electrode (2) has a structure in which the conductor penetrates the magnetic chip (22), the magnetic body exists on the entire circumference of the conductor. For this reason, when a high-frequency current flows through the conductor, the generated magnetic field can be made concentric so as to pass through the magnetic body surrounding the entire circumference of the conductor, and therefore the wavelength can be shortened by using the permeability of the base body (22). Can be effectively obtained.

  Further, the first radiating electrode (1) and the second radiating electrode (2) function as one antenna via the connecting portion (3), the grounding portion (6), and the matching circuit (4). Since the surface of the first radiation electrode (1) and the axial direction of the second radiation electrode (2) are arranged on the same plane, the antenna characteristics with high radiation efficiency in a specific polarization Can be obtained.

  The second radiation electrode (2) is connected to the feed line via a matching circuit (4) comprising an inductor and a capacitance. For this reason, the matching is improved as compared with the case where the radiation electrode is directly connected to the feed line, the voltage standing wave ratio (VSWR) is low, and a wide frequency band with high gain can be obtained.

In the antenna device (A) of the present invention, it is preferable that the connection portion (3) is made of a connection conductor.

  According to this configuration, since the connection portion (3) can be a connection conductor (31) made of a metal conductive plate, a metal conductive wire, or a metal conductive foil, the first radiation electrode (1) and the ground portion This is electrically the same potential as (6) and is directly connected also in terms of high frequency. At this time, since the first radiation electrode (1) is connected to the grounding part (6) via the connection conductor (31), the received signal is superimposed on the feeder (8) and flows from the main circuit. The incoming noise can be released to the first radiation electrode side. Therefore, noise does not flow to the second radiation electrode side, and the relative reception signal intensity of the digital terrestrial television broadcast received on the second radiation electrode side increases, and a good reception state can be ensured.

  In the antenna device (A) of the present invention, it is preferable that the connecting portion (3) is composed of an impedance element (32).

  According to such a configuration, the main part of the antenna includes the first radiation electrode (1), the impedance element (32) as a passive element, the matching circuit (4), the feeder line (8), and the second radiation. It is comprised from an electrode (2) and a grounding part (6). At this time, since the first radiation electrode (1) is connected to the ground part (6) via the connection part (3) made of an impedance element (32) such as an inductor and / or a capacitance, the matching is further improved. Antenna characteristics with high electromagnetic wave radiation efficiency can be obtained. On the other hand, since the first radiation electrode (1) is electrically at the same potential as the grounding part (6), it can be used as a shield plate for the LCD screen (M1) of the portable information terminal (M). .

  The second radiation electrode (2) preferably comprises a base body (22) made of an insulator and a conductor penetrating the base body (22).

  According to this configuration, the second radiation electrode (2) uses a magnetic chip for the base (22) made of the insulator. The magnetic chip is formed in a structure in which a conductor made of a conductive wire is penetrated like a skewer. The magnetic chip may have a structure in which a plurality of magnetic chips are serially penetrated by a conductor. Unlike a chip antenna with a helical electrode, a magnetic chip does not have a conductive wire wound around it, and because of the penetrating structure, there is no portion where the conductors face each other in the base, so the line capacitance component Is difficult to form. In addition, since the conductor (22) penetrates the magnetic chip, the magnetic body exists on the entire circumference of the conductor. For this reason, when a high-frequency current flows through the conductor, the generated magnetic field can be made concentric so as to pass through the magnetic body surrounding the entire circumference of the conductor, and therefore the wavelength can be shortened by using the permeability of the base body (22). Can be effectively obtained. In other words, since the magnetic chip can use the effect of magnetic permeability, it can easily resonate over a wide frequency band such as terrestrial digital television broadcasting. In addition, since the substrate (22) can be made of not only magnetic ceramics but also insulating materials such as dielectric ceramics, it can contribute to downsizing and widening of the band.

  The substrate (22) made of an insulator of the antenna device (A) of the present invention is preferably made of a magnetic chip.

  In such a configuration, if the magnetic chip has an initial permeability of 2 GHz or more at 1 GHz and a loss factor of 0.1 or less, more preferably 0.05 or less, it is advantageous in obtaining a broadband and high gain antenna element. is there. Further, since the substrate (22) is a prismatic chip, it can be composed of a plurality. That is, it can be considered that the chip antenna which is one substrate (22) is divided into a plurality of chip antennas. According to this configuration, the conductors of the plurality of chip antennas are electrically connected in series, and the plurality of chip antennas constitute one chip antenna. Therefore, the individual length of the chip antenna having the base can be made smaller than the length of the base necessary for the antenna characteristics in the target frequency band. As a result, impact resistance can be enhanced. Further, since the chip antennas are connected in series with a conductor penetrating the chip antenna, the arrangement of the chip antennas can be changed, for example, in a meander shape or an arc shape according to the mounting space.

  In the antenna device (A) of the present invention, one end of the connection portion (3), the ground portion (6), the matching circuit (4), and the second radiation electrode (2) are formed of a substrate (5). ) Is preferably mounted.

  According to such a configuration, the main components of the antenna other than the first radiation electrode (1) can be integrated, so that the impact resistance can be improved, and the antenna can be efficiently carried in a casing of the portable information terminal (M) or the like. It can be mounted on communication equipment. Further, if the main components of the antenna other than the first radiation electrode are integrated and assembled in advance with the substrate (5), the manufacturing process can be shortened.

  The antenna device (A) of the present invention includes an edge portion of the first radiating electrode (1) on the side close to the second radiating electrode (2), and a longitudinal direction of the second radiating electrode (2). Are preferably parallel.

  According to such a configuration, the portion of the first radiation electrode (1) extending from the upper side to the lower side on the side close to the second radiation electrode (2), and the second radiation electrode (2) ), A portion having a high density of high-frequency current is formed over the entire length. An edge portion (11) on the side close to the grounding portion (6) of the first radiation electrode (1) and a portion having a high density of high-frequency current are formed in the axial direction of the second radiation electrode (2). In this configuration, the first radiating electrode (1) and the second radiating electrode (2) function effectively in the same polarization plane, so that antenna characteristics with high radiation efficiency of electromagnetic waves can be obtained. . In particular, when the portable information terminal device (M) is used, the LCD screen (M1) is used in a substantially vertical state, so the surface of the first radiation electrode (1) and the second radiation electrode are used. Since the axial direction of (2) is on the same plane and is substantially perpendicular to the ground surface, antenna characteristics with high radiation efficiency can be obtained in vertically polarized waves.

  In the antenna device (A) of the present invention, the length of one side of the first radiation electrode (1) is approximately λ / 4 of the higher wavelength band used and the length of the diagonal line is the frequency band. The lower wavelength is preferably approximately λ / 4.

  According to such a configuration, when the first radiation electrode (1) is configured with a rectangular surface, the first radiating electrode (1) has a range of approximately one side (vertical side of the LCD screen) and diagonal length, for example, terrestrial digital It is possible to easily resonate at approximately λ / 4 of the wavelength corresponding to the frequency of television broadcasting. The diagonal length of the first radiation electrode (1) can correspond to approximately λ / 4 of the lower wavelength of the frequency band of digital terrestrial television broadcasting. The short side of the first radiation electrode (1) can correspond to approximately λ / 4 of the higher wavelength in the frequency band.

  Furthermore, the antenna device (A) of the present invention is preferably built in a communication device such as a mobile phone, a wireless LAN, a personal computer, a terrestrial digital TV broadcast receiving device. According to such a configuration, it contributes to a wide band in communication using the communication device.

  According to the present invention, since the radiation electrode is composed of a metal conductor, and a radiation electrode having a conductor penetrating a base made of a magnetic chip separate from the metal electrode and a matching circuit, the radiation characteristic can be improved. When receiving digital terrestrial television broadcasting mounted on a type information terminal device or the like, a high gain can be stably obtained from a low frequency to a high frequency band. In particular, it is possible to provide a built-in wideband antenna that is remarkably improved in the characteristics of vertical polarization. Further, by using the antenna, it is possible to provide an antenna device and a communication device that are excellent in space flexibility when the antenna is mounted.

  Hereinafter, although this invention is demonstrated, showing specific embodiment, this invention is not limited to these embodiment. In addition, the same code | symbol is attached | subjected about the same components.

  FIG. 2 shows an example of an embodiment of the antenna device A according to the present invention. The antenna device A of FIG. 2 includes a second radiation electrode 1 made of a metal conductive plate, a connection conductor 31, and a conductor 22 and a base 22 (magnetic chip or dielectric chip) through which the conductor penetrates. Radiation electrode 2 and matching circuit 4. The antenna device A is disposed in a housing of a portable information terminal device or the like M, but the second radiation electrode 2 can be mounted on a substrate 5 and used. FIG. 1 is a bird's eye view when the antenna device A of the present embodiment is arranged in a portable information terminal device M. FIG.

  Next, the details of the configuration of the antenna device A according to the embodiment of the present invention shown in FIG. 2 will be described with reference to FIG. The components are arranged in such a manner that one end of the connection conductor 31 that is a connection portion on one surface of the substrate 5, the matching circuit 4, the second radiation electrode 2, the ground portion 6, the power supply portion 7, and the power supply line 8. Is installed. The grounding portion 6 is also provided at the same position on the surface opposite to the surface on which the second radiation electrode 2 and the like of the substrate 5 are mounted. On the back of the LCD screen M1 of the portable information terminal device M, the first radiation electrode 1 made of a metal conductive plate having a rectangular shape corresponding to the shape of the LCD screen M1 is provided.

  The connection conductor 31 is provided between the first radiation electrode 1 and the ground portion 6. An end 311 of the connection conductor 31 is connected to the first radiation electrode 1, and the other end 312 of the connection conductor is connected to the ground portion 6. When a conductor such as a metal conductive wire or a metal conductive plate is used as the connection conductor 31, the first radiation electrode 1 is connected to the ground of the main circuit including the reception circuit 9 in the housing on the keyboard mounting side. Since the conductor 31 is electrically connected directly via the outer covering conductor 81 of the feeder line 8, various noises generated in the main circuit can be diffused to the first radiation electrode 1 side. Therefore, the noise generated in the various main circuits does not circulate toward the second radiation electrode 2 connected to the receiving circuit 9 to increase the noise level at the time of reception, and increase the relative received signal strength. Can do. In place of the connection conductor 31, an inductor and / or a capacitance can be used. At this time, the first radiation electrode 1 is improved in consistency as compared with the case where the first connecting electrode 31 is directly connected to the outer conductor 81 of the feeder 8 and the voltage standing wave ratio (hereinafter referred to as VSWR) is low. A wide frequency band with high gain can be obtained.

  The feeder 8 connected to the feeder 7 generally uses a coaxial line, but the outer sheathed conductor 81 that is the ground wire is connected to the ground 6 and the core wire 82 that is the signal wire is the receiving circuit 9 side of the matching circuit 4. Connected to. Further, the ground side of the matching circuit 4 is connected to the ground unit 7. The second radiation electrode 2 side of the matching circuit 4 is connected to the conductor 21 of the second radiation electrode 2. The second radiation electrode 2 includes a base body 22 that is a magnetic chip and a conductor 21 that penetrates the base body 22. The substrate 22 is not limited to one but can be arranged in series with the conductor 21 as an axis. If a conductor that can be bent is used as the conductor 21, for example, when the end surface of the substrate 5 has an arch shape in accordance with the inner shape of the housing, the chips may be aligned in accordance with the arch-shaped end surface. It is possible to provide flexibility in arrangement.

  First, the positional relationship of each component is described. The metal conductive plate which is the first radiation electrode 1 is mounted between the LCD screen M1 of the portable information terminal device M and the housing with substantially the same dimensions as the LCD screen M1. The substrate 5 on which the second radiation electrode 2 and the like are mounted is disposed adjacent to the edge 11 of the first radiation electrode 1 so as to be parallel to the surface of the first radiation electrode 1. . The distance between the edge 11 and the edge 12 on the side close to the first radiation electrode 1 of the grounding part 6 provided on the substrate 5 is secured so that the connection conductor 31 or the impedance element 32 can be bridged. To do.

  When the portable information terminal device M is used, the LCD screen M1 is in a substantially vertical state. At this time, since the second radiation electrode 2 is a monopole antenna extending substantially perpendicular to the ground direction, the plane of polarization is vertically polarized. On the other hand, since the first radiation electrode 1 has a rectangular surface, the first radiation electrode 1 has a wavelength of a frequency corresponding to terrestrial digital television broadcasting in a range from the length of one side (vertical side of the LCD screen) to the length of a diagonal line (diagonal). Resonance can be achieved corresponding to approximately λ / 4. At this time, the first radiation electrode 1 is a radiation electrode that resonates with substantially horizontal polarization. For this reason, unlike an antenna constituted by only a monopole antenna, the antenna can simultaneously cope with not only vertically polarized waves but also horizontally polarized waves. That is, an antenna having high radiation efficiency and being resistant to disturbance of the polarization plane of a radio wave transmitted from a broadcasting station can be obtained. As shown in FIG. 13, the first radiation electrode 1 is functioning effectively. As shown in FIG. 13, the current density decreases toward the lower side at the edge 11 near the grounding portion 6 of the first radiation electrode 1. It can also be seen from the fact that it is distributed to the same extent as the current density of the two radiation electrodes 2.

  Next, the specific size of the first radiation electrode 1 will be described. In the antenna A of the embodiment of the present invention shown in FIG. 1, the size of the metal conductive plate that is the first radiation electrode 1 is a rectangle of about 100 mm × 200 mm. The wavelength λ / 4 at 470 MHz, which is the lower end of the frequency band of digital terrestrial television broadcasting, is about 160 mm, and the wavelength λ / 4 at 770 MHz, which is the upper end, is about 100 mm (vertical side of the LCD screen M1). The length of the radiating electrode at which λ / 4 of the wavelength in the frequency band corresponding to terrestrial digital television broadcasting resonates can be secured on the 100 mm × 200 mm surface portion of the metal conductive plate.

  The first radiation electrode 1 has a rectangular shape because it is mounted between the LCD screen M1 of the portable information terminal device M and the housing with the same dimensions as the LCD screen M1. The first radiating electrode 1 is electrically connected to the ground of the main circuit including the first radiating electrode 1 and the receiving circuit 9 through the connecting portion 3 and the grounding portion 6 at the same potential. Therefore, it also serves as an electromagnetic shield for the LCD screen M1.

  A member in the case where a metal conductive plate is used for the first radiation electrode will be described. The material of the metal conductive plate is not particularly limited. For example, in the case where the metal conductive plate is made of sheet metal or foil, in addition to metals such as Cu, Ag, Ni, Pt, Au, Al, 42 alloy, Kovar, phosphor bronze Alloys such as brass and corson copper alloys can be used. Of these, a low-hardness conductor material such as Cu is suitable when the electrode or the like is bent in accordance with the shape of the housing, and a high-hardness conductor material such as 42 alloy, Kovar, phosphor bronze, or Corson copper alloy is used as described above. This is suitable when an electrode or the like is used as a strong single plate member.

  When a material form such as a foil shape or a lattice shape that is easy to process is used as an aspect of the first radiation electrode 1, it is more flexible than a plate shape and can be adapted to a housing having a complicated shape. The foil shape refers to a metal conductive foil having a thickness of about 10 μm formed mainly on a substrate by printing means. The material is Cu or Ag. The lattice shape is a plate shape, but it has many holes of about several tens of μm on the plate surface, or a large number of linear conductors with a diameter of about several tens of μm are soldered into a net-like shape. It is connected by. The material is Cu or Ag. Furthermore, the first radiation electrode 1 may be a conductor pattern formed on the substrate as long as it has substantially the same dimensions as the LCD screen M1.

  Next, the second radiation electrode 2 will be described. The second radiation electrode 2 includes a conductor 21 and a base 22 made of an insulator, and the conductor penetrates the base 22. The base 22 can be a magnetic material or a dielectric. In the antenna device A according to the embodiment of the present invention shown in FIG. 1, when the base 22 is a magnetic body, unlike the dielectric chip antenna in which electrodes are helically wound around the base, the conductor is attached to the base 22. Since the structure penetrates without winding, a portion where the conductors substantially face each other is not formed in the structure. Therefore, it is difficult to form a line capacitance component like the helical dielectric chip antenna, and it is effective for reducing the capacitance component of the antenna. Therefore, the Q value of the antenna can be lowered, which is effective for widening the band.

  When the substrate 22 is a magnetic body, the material is Ni—Zn ferrite, spinel ferrite represented by Li ferrite, Z-type or Y-type hexagonal ferrite called a planar, and a composite material containing these ferrite materials. Etc. can be used, but a sintered body of ferrite is preferable. In particular, it is preferable to use hexagonal ferrite such as Y-type for the chip antenna because the receiving sensitivity (that is, noise is reduced and S / N is improved) is obtained. A ferrite sintered body has a high volume resistivity and is advantageous for insulation from a conductor. If a ferrite sintered body having a high volume resistivity is used, an insulating coating is not necessary between the conductor and the conductor.

  When ferrite is used for a chip antenna, the loss of the chip antenna is generally proportional to the magnetic loss tan δ × the magnetic permeability μ, but the magnetic loss tan δ is preferably as small as possible, and the magnetic permeability μ is preferably about 2 to 6. The Y-type ferrite has a magnetic permeability μ maintained at about 2 to 6 up to a high frequency of 3 GHz or higher, and a magnetic loss tanδ is small in a frequency band up to 3 GHz. It is suitable for an antenna element having a wide frequency band such as 770 MHz. In such a case, it is better to use a sintered body of Y-type ferrite as the magnetic substrate. The sintered body of Y-type ferrite is not limited to a Y-type ferrite single phase, and may contain other phases such as Z-type and W-type. The sintered body does not need to be processed if it has sufficient dimensional accuracy as a magnetic member after sintering, but it is desirable that the bonded surface be polished to ensure flatness.

  When the Y-type ferrite is prepared so that the initial permeability at 1 GHz is 2 or more and the loss coefficient is 0.1 or less, more preferably 0.05 or less, the Y-type ferrite has a wide bandwidth in the frequency band of digital terrestrial television broadcasting. This is advantageous in obtaining a high gain antenna element. If the initial permeability is too low, it is difficult to achieve a wide band. Further, when the loss coefficient, that is, the magnetic loss increases, the gain of the chip antenna decreases. In order to obtain an average gain of −5 dBi or more as an antenna element, the loss coefficient is preferably 0.05 or less. By reducing the loss factor to 0.03 or less, an antenna element having a particularly high gain can be obtained.

  Here, when the base 22 is a magnetic body, the base material of the base 22 is ceramics, so that it may crack when an excessive impact is applied. In communication equipment, in particular, portable information terminal devices and the like, impacts such as dropping are applied, so that higher impact resistance is required to improve the reliability of the antenna. If the longitudinal direction of the magnetic substrate is shortened, the reliability of the magnetic substrate against external force can be increased. Next, a specific example in which the substrate is divided will be described.

  The antenna device A according to the present embodiment shown in FIG. 2 has a structure with a base 22, but the base that is originally one is divided into five, and one linear conductor penetrates the base. You can also see it. The number of divisions can be 5 or more. In other words, the magnetic path formed in the magnetic chip through which the conductor penetrates is formed so as to go around the central axis of the conductor, so the magnetic path is not divided, and the number of divisions of the base is 6, 7, 8,. Even if it increases, the performance of the chip antenna does not decrease. For this reason, the length of the base part per piece can be shortened, and the freedom degree of arrangement | positioning of an antenna can be obtained. Further, the structural strength is improved, which contributes to the improvement of the antenna reliability.

  In the antenna device A of the present embodiment shown in FIG. 2, the plurality of bases are aligned in a straight line with the conductor as an axis. However, as shown in FIG. 4, the plurality of bases 22 penetrated by the conductor are meandered in a crank shape. The layout can be changed according to the mounting space. That is, the arrangement in which the bases penetrated by the conductor are arranged may be a meander shape or an L shape. Moreover, you may arrange | position in arc shape.

  Next, actual dimensions of the antenna device A of the present embodiment shown in FIG. 2 will be described. The actual length of the second radiation electrode 2 is a total length of a total of 36 mm including a conductor-only portion, a conductor portion between the substrate and the substrate, and a conductor of a portion 54 mm penetrating the substrate 22, and is approximately 90 mm. It is. On the other hand, the effective length of the magnetic chip antenna portion is 54 mm, since a magnetic material having an initial permeability μ of 2.5 is used for the magnetic chip antenna portion of 54 mm in length. X√2.5≈85 mm. In other words, the effective length of the second radiation electrode 2 is about 121 mm, which is the sum of the effective length of 85 mm due to the wavelength shortening effect and the portion of 36 mm consisting only of the conductor, and has a resonance point at λ / 4 of a wavelength of 617 MHz. It becomes an antenna.

  A dielectric can also be used as the substrate 22. In this case, a dielectric is present as a substrate around the entire circumference of the conductor penetrating the dielectric. Therefore, the effective wavelength of the linear conductor in the substrate can be substantially shortened by the relative dielectric constant, and the chip antenna can be miniaturized. Further, the other end and one end of the conductor can be used for electrical connection and joining with other circuit elements and electrodes, and the degree of freedom in design and the fixing strength can be increased.

  As described above, in the present invention, even if a dielectric is used instead of a magnetic substance for the base, it is difficult to form a line capacitance component if the conductor penetrates the dielectric base. Therefore, even if the relative dielectric constant is somewhat increased, the line capacitance component is small, so that an increase in internal loss of the chip antenna is suppressed. From the viewpoint of loss, it is preferable that the relative dielectric constant is low, but in the structure in which the conductor penetrates the substrate as in the present invention, the internal loss of the chip antenna is not easily affected by the relative dielectric constant. In order to suppress variation in resonance frequency, a dielectric material having a large dielectric constant can be used for the substrate. In this case, the relative dielectric constant is preferably 2 or more, more preferably 4 or more.

  As described above, in the configuration in which the base is divided and one linear conductor penetrates the base, the conductor in the base and the conductor are formed by a single conductor, so the conductor between the bases is It also serves as a connecting conductor. However, the connecting conductor and the protruding portion of the conductor do not necessarily have to be constituted by a single conducting wire. For example, a conductor that passes through the base and protrudes from the end of the base may be connected to a conductor that passes through and protrudes from another base using a connection conductor that is a separate member from the conductor. Further, as the connection conductor of the separate member, an electrode 23 provided on a substrate as shown in FIG. 6 may be used, and the protruding conductor portion may be soldered to the electrode. Alternatively, the conductors may be connected by using a substrate having a plurality of through holes and electrodes that electrically connect the through holes, inserting the protruding conductor portions into the through holes, and soldering them. . According to this method, the base body can be more firmly fixed on the substrate used in the communication device. However, if the respective conductors and the respective connection conductors are constituted by continuous linear conductors, the number of connection points can be reduced, the manufacturing process of the chip antenna and the communication device can be simplified, and the product reliability can be reduced. It is possible to improve the performance.

  The shape of the substrate is not particularly limited, but the cross section can be rectangular, square or circular. Further, the external shape may be a rectangular parallelepiped, a cylinder, or the like. In order to realize stable mounting, a rectangular parallelepiped shape is preferable. In the case of a rectangular parallelepiped, it is preferable to provide chamfers at corner portions located in a direction perpendicular to the longitudinal direction. By providing chamfering, for example, when a magnetic substrate is used as the substrate, magnetic flux is less likely to leak, and problems such as chipping can be prevented. The method of chamfering may be a method of cutting off the corners in a straight line or a method of providing a radius. The width of the chamfer (the length lost by the chamfered portion on the side surface of the magnetic substrate) is preferably 0.2 mm or more in order to exhibit the substantial effect. On the other hand, if the chamfer is increased, even if it is a rectangular parallelepiped shape, stable mounting becomes difficult, so 1 mm or less (1/3 or less of the width or height of the substrate) is preferable. The lengths of the substrates are not necessarily the same, but the manufacturing process can be simplified by making them the same.

  When a magnetic material is used for a base made of an insulator, the resonance frequency decreases as the length, width, and height of the base increase. For example, in order to cover a frequency band such as 470 MHz to 770 MHz, which is a frequency band of digital terrestrial television broadcasting, in the antenna according to the embodiment of the present invention shown in FIG. In consideration of the size of the substrate, the width is 5 mm and the height is 5 mm or less. Even when the substrate is divided, the total length in the longitudinal direction is preferably 60 mm or less. More preferably, as in the present invention, the length of one substrate is about 10 mm, the width is 2 to 4 mm, and the height is 2 to 4 mm.

In addition, a conductor material having a high hardness such as 42 alloy, Kovar, phosphor bronze, and Corson copper alloy is preferable for the conductor used through the substrate. These materials are particularly suitable for use in a straight line without bending both ends of the conductor. The conductor may be provided with an insulating coating such as polyurethane or enamel. For example, it is possible to secure insulation without providing an insulating coating by using a magnetic substrate having a high volume resistivity, for example, 1 × 10 ⁵ Ω · m or more, but by providing an insulating coating, High insulation is obtained. In this case, the thickness of the insulating coating is preferably 25 μm or less. If this becomes too thick, the gap between the substrate and the conductor becomes large, and the inductance component decreases.

  In addition, a matching circuit 4 including an inductor and a capacitance is provided on the power supply side of the second radiation electrode 2 so as to match the balanced second radiation electrode 2 and the unbalanced coaxial line. When the connection between the first radiation electrode 1 and the grounding portion 6 is directly connected by the connection conductor 31, the matching circuit 4 is configured by the capacitors Ca41 and Cb42 and the inductor La43 as shown in FIG. An example of the circuit configuration is shown in FIG. With such a configuration, not only can the VSWR and gain in the band be flattened, but also various noises flowing from the main circuit superimposed on the received signal on the feeder 8 via the connection conductor 31. It can escape to the first radiation electrode side. Therefore, various noises hardly flow to the second radiation electrode side, the relative reception signal strength (S / N) of digital terrestrial television broadcasting received on the second radiation electrode side is increased, and a good reception state is achieved. Can be secured. When the connection between the first radiation electrode 1 and the grounding portion 6 is connected via the impedance element 32, the matching circuit 4 is configured by the capacitors Ca41, Cb42, the inductor La43, and the impedance element 3 (inductor) as shown in FIG. To do. In this case, the 1st radiation electrode 1 and the 2nd radiation electrode 2 are not directly connected like the connection conductor 31, but are connected via the impedance element 32 (inductor in FIG. 3). An example of the circuit configuration is shown in FIG. By adopting such a configuration, impedance matching between the first radiation electrode 1 and the second radiation electrode 2 is improved, and the VSWR and gain in the band can be made flatter.

  Next, the point that the configuration of the antenna device according to the present invention is excellent will be described. In the present invention, a monopole-type magnetic chip antenna is connected to the signal line of the receiving circuit, and the plate-shaped ground wire of the receiving circuit is connected. It can be regarded as an antenna having two radiation electrodes in different modes to which a conductor is added. Therefore, first, the effect of the magnetic chip portion constituted by the base body and the conductor passing through the base body will be described.

  In the present invention, the magnetic chip portion is an antenna element having a configuration in which a linear conductor passes through the base body (magnetic chip), and therefore, the portion where the conductor faces structurally is not formed in the base body. Therefore, it is difficult to form a stray capacity between the lines, which is effective in reducing the capacitance component. That is, the inductance L can be increased by the magnetic permeability of the magnetic chip. That is, the Q value can be lowered by avoiding the formation of the line-to-line capacitance, and a particularly remarkable effect is exerted for widening the antenna. Of course, even if a dielectric is used as the substrate, the same effect can be obtained to some extent, but it is more advantageous to use a magnetic chip in order to broaden the frequency band.

  Further, the effect when the magnetic chip is divided as the base according to the present invention will be described. A magnetic path in the case of using a magnetic chip through which a conductor passes is formed so as to go around the central axis of the conductor. For this reason, even if the base is divided into a plurality of conductors in the longitudinal direction, the conductor has a structure that penetrates the divided bases, and the influence of the division on the formation of the inductance component L is extremely high in principle. small. For this reason, it is possible to divide the base into a plurality of antennas. Further, since the magnetic permeability of the substrate can be increased, a wavelength shortening effect is produced, and the entire antenna can be reduced in size. On the other hand, when the helical electrode is wound around the base, the magnetic path in the base is formed in the axial direction of the helical electrode (so as to penetrate the longitudinal direction of the base). Since the path is divided for each substrate, the inductance component L is significantly reduced. Therefore, in an antenna that is configured in series by dividing a magnetic chip on which a helical electrode is formed into a plurality of parts, the effect of an antenna that is configured in series by dividing a magnetic chip in which a conductor has penetrated the base is divided into I can't expect it.

  Next, the effect obtained by combining the antenna element having a structure in which the conductor penetrates the magnetic chip described above and the antenna element made of a metal conductive plate will be described in detail. In a conventional monopole chip antenna composed of a base (magnetic chip) and a conductor passing through the base, the gain of the band can be improved as a whole, but on the lower side of the center frequency of the frequency band The decrease in gain is large at frequency. On the other hand, since the first radiation electrode 1 made of a metal conductive plate has substantially the same size as the LCD screen M1 of the portable information terminal device M, a monopole antenna having a wide radiation electrode is arranged in a substantially horizontal direction. Therefore, it is effective for horizontal polarization. Therefore, in the present invention, a monopole magnetic chip antenna in which a conductor passes through the substrate is arranged in the housing so as to be substantially perpendicular to the ground direction, and a monopole composed of a metal conductive plate which is a plate-like conductor. The first radiation electrode 1 of the type is provided on the back side of the LCD screen M1 of the general-purpose information terminal device M so as to substantially match the size of the LCD screen M1, so that not only the vertical polarization but also the radiation efficiency of the horizontal polarization can be obtained. I was able to improve.

  At this time, within the range of the length of one side of the first radiation electrode 1 (vertical side of the LCD screen) and the length of the diagonal line, the length corresponds to approximately λ / 4 of the upper and lower wavelengths of the operating frequency. In this way, by determining the size of the first radiation electrode 1, resonance is facilitated in a wide frequency band. As a result, compared to the case of using only a monopole magnetic chip antenna, for example, the VSWR at the lower frequency of 470 MHz to 770 MHz, which is the frequency band of terrestrial digital television broadcasting, can be lowered and the gain can be improved. Further, the ground of the main circuit including the first radiation electrode 1 and the receiving circuit 9 in the housing on the keyboard mounting side is connected via the connection conductor 31 such as a metal conductive line and the outer covering conductor 81 of the feeder line 8. When electrically connected, various noises generated in the main circuit can be diffused to the first radiation electrode 1 side. Accordingly, the various noises wrap around the second radiation electrode 2 connected to the receiving circuit 9 and the noise level at the time of reception hardly increases, and the relative received signal strength (S / N) can be increased. Further, since Y-type hexagonal ferrite is used for the second radiation electrode 2, noise is reduced, and relative received signal strength (S / N) is further improved.

  The antenna part constituted by the first radiation electrode 1 and the second radiation electrode 2 according to the present invention can itself cover the frequency band of digital terrestrial television broadcasting, but the matching circuit 4 is provided. As a result, it is possible to obtain antenna characteristics with a flat and low VSWR and high radiation efficiency.

  A specific fixing method of the substrate 5 on which the first radiation electrode 1 and the second radiation electrode 2 are mounted will be described. The LCD screen M1 is provided on the casing of the portable information terminal device M on the side where the keyboard and main circuit are not mounted. The first radiation electrode 1 is fixed to the back side of the LCD screen M1 with an adhesive or the like. Next, the LCD screen M1 to which the first radiation electrode 1 is attached is attached and fixed inside the casing. Next, the substrate 5 on which the second radiation electrode and the grounding portion are mounted is attached and fixed at a position adjacent to the first radiation electrode 1 inside the housing. The first radiation electrode 1 and the substrate 5 are connected by a mounting bracket. The electrical connection between the ground portion and the first radiation electrode 1 is connected by the connection conductor 13 or the impedance element 32. The second radiation electrode 2, the grounding portion, and the matching circuit 6 are integrally mounted on the substrate 5, and are fixed to the inside of the casing adjacent to the LCD screen M1 with an adhesive or a mounting bracket.

  Since the portable information terminal device M and the like mainly have a notebook personal computer structure, the main circuit board including the receiving circuit 9 and the like is built in a casing on the side where a keyboard or the like is mounted, and the first radiation electrode 1 is It is mounted on the side on which the LCD screen M1 is mounted. Accordingly, during operation of the terminal device M, the distance between the ground portion on the main circuit board and the antenna (the first radiation electrode and the second radiation electrode) is sufficiently widened. For this reason, the capacitive coupling between the main circuit board and the antenna is reduced and the gain and bandwidth are improved. In addition, the noise radiated from the main circuit is difficult to receive on the antenna side, and the relative receiving sensitivity of the receiving unit is improved. There is also.

  FIG. 2 shows another example of the embodiment of the antenna device A according to the present invention. Another example which is an embodiment of the antenna device A according to the present invention is only described by replacing the connecting conductor 31 with the impedance element 32 and will be described with reference to FIG. The antenna device A in FIG. 2 includes a first radiation electrode 1 made of a metal conductive plate, an impedance element 32, a metal conductor 21 and a second base 22 (a magnetic chip or a dielectric chip) through which the conductor passes. Radiation electrode 2 and matching circuit 4. The antenna device A is disposed in a casing of the portable information terminal device M or the like, but the second radiation electrode portion 2 can be mounted on a substrate 5 and used.

  Next, details of the configuration of another antenna apparatus A according to the embodiment of the present invention shown in FIG. 2 will be described with reference to FIG. Each component is arranged in such a manner that an impedance element 32, a matching circuit 4, a power feeding unit 7, a second radiation electrode 2, a grounding unit 6, a power feeding unit 7, and a power feeding line 8 are provided on one surface of the substrate 5. Installed. The grounding portion 6 is also provided at the same position on the surface opposite to the surface on which the second radiation electrode 2 and the like of the substrate 5 are mounted. On the back of the LCD screen M1 of the portable information terminal device M, the first radiation electrode 1 made of a metal conductive plate having a rectangular shape corresponding to the shape of the LCD screen M1 is provided. The impedance element 3 is provided between the first radiation electrode 1 and the ground portion 7. An end portion 321 of an impedance element 32 made of an inductor is connected to a specific portion of the edge 11 near the ground portion 6 of the first radiation electrode 1. The other end 322 of the impedance element 32 is connected to the ground unit 6 through the substrate 5. The power supply line 8 connected to the power supply unit 7 generally uses a coaxial line, but the outer sheathed conductor 81 serving as the ground wire is connected to the ground unit 6, and the core wire 82 serving as the signal line is connected to the receiving circuit 9 side of the matching circuit 4. Connected. Further, the ground side of the matching circuit 4 is connected to the ground unit 7. The radiation electrode side of the matching circuit 4 is connected to the conductor 21 of the second radiation electrode 2. The second radiation electrode 2 includes a base body 22 that is a magnetic chip and a conductor 21 that penetrates the base body 22. The substrate 22 is not limited to one but can be arranged in series with the conductor 21 as an axis.

  For example, in the case where the impedance element 32 is used for the connecting portion 3, the matching circuit 4 uses a circuit as shown in the second embodiment of FIG. In the example of FIG. 3, the matching circuit 4 is configured by the capacitors Ca <b> 41 and Cb <b> 42, the inductor La <b> 43, and the impedance element 3. One end side of the capacitor Ca42 and one end side of the inductor La43 are connected to the second radiation electrode 2. The other end of the inductor La43 and the other end of the capacitor Cb41 are connected to the ground unit 6 and then connected to the first radiation electrode 1 via the impedance element 32. The other end of the capacitor Ca42 and one end of the capacitor Ca41 are connected to a core wire 82 (signal line) of a coaxial line. Here, a single-stage matching circuit is used. However, as shown in the matching circuit example of FIG. With such a configuration, the VSWR and gain within the band can be made flatter. In the example of FIG. 3, the impedance element 32 is composed only of an inductor, but the matching between the first radiation electrode 1 and the second radiation electrode 2 is improved by appropriately combining the inductor and the capacitance. be able to.

Next, a method for adjusting the resonance frequency of the antenna device will be described. To determine the band used by the antenna device of the present invention, it is necessary to first determine the center frequency f _0. For this purpose, it is determined from the specifications of the radiation electrode. In the case of the first radiation electrode 1, first, the material is selected and the length is adjusted in accordance with the resonance frequency of the frequency band to be used in consideration of the constraints on the space in the housing. Approximate width, thickness, etc. In the case of the second radiation electrode 2, when the substrate is formed of a magnetic substrate, a magnetic substrate having a permeability μ preferable for the target frequency band is selected in advance. Since the resonance frequency decreases as the size of the magnetic substrate increases, the width and height of the magnetic substrate are determined to be slightly larger. Then mounting them each radiating electrode at a predetermined position, the length of the respective radiation electrodes to match the center frequency f ₀ of the frequency band of interest in connection with the receiver circuit 9 and the magnitude of the magnetic base fine adjust. In addition, the interval between the first radiation electrode 1 and the second radiation electrode 2 is also finely adjusted. Similarly, in the case of a dielectric, a dielectric substrate having a dielectric constant preferable for the target frequency band is selected. Others are determined similarly to the case of the magnetic substrate.

  If the antenna apparatus A according to the present invention is used, the operating frequency band of the antenna apparatus can be widened. In general, when the frequency bands used are separated by several hundred MHz or more, it is necessary to use a plurality of antenna devices. In that case, the mounting area and the mounting space increase. According to the present invention, the size of the metal conductive plate that is the first radiation electrode 1 is a rectangle of about 100 mm × 200 mm, which is large as an antenna of a portable information terminal, but also serves as a shield plate for the LCD screen M1, so that the mounting area is small. It has not increased. The wavelength λ / 4 at 470 MHz, which is the lower end of the frequency band of terrestrial digital television broadcasting, is about 160 mm, and the wavelength λ / 4 at 770 MHz, which is the upper end, is about 100 mm. That is, the radiation electrode length corresponding to the λ / 4 length of the wavelength of the frequency used in terrestrial digital television broadcasting can be secured on the surface portion of the metal conductive plate of 100 mm × 200 mm. For this reason, in particular, the VSWR is low over the entire frequency band 470 MHz to 770 MHz of terrestrial digital television broadcasting, and a high gain can be obtained. Furthermore, by providing and adjusting a matching circuit, it is possible to cover not only the frequency band of digital terrestrial television broadcasting but also the frequency band of 800 MHz to 900 MHz used for mobile phones.

  Next, the performance of the antenna device A according to the present invention will be described. As a device used in an actual measurement example of antenna performance (VSWR, gain), an antenna device A mounted on a portable information terminal device M was configured. The embodiment in which the antenna device A is mounted is the same as that shown in FIG. That is, a power supply line, a power supply unit, a second radiation electrode, and the like are formed on the substrate, and the first radiation electrode is provided on the back side of the LCD screen M1. In the apparatus of this actual measurement example, the above-described antenna dimensions (first radiation electrode size: 100 mm × 200 mm, second radiation electrode length: 90 mm) were used. A measurement antenna (installed on the right side of the antenna device in FIG. 1 (not shown)) is provided at a position 3 m away from the antenna device A, and the measurement antenna is connected to a network analyzer via a 50Ω coaxial cable. The antenna characteristics were measured. Specifically, as shown in FIG. 1, the horizontal direction of the keyboard mounting surface of the casing of the portable information terminal device M is X, the direction perpendicular thereto is Y, and the direction perpendicular to the keyboard mounting surface of the casing is Z. The average gain on the XY plane and VSWR were measured. The measured frequency band is 450 to 850 MHz. This frequency band includes a terrestrial digital television broadcast frequency band (470 to 770 MHz).

  FIG. 9 shows an average gain when the connecting portion is the impedance element 32 in the antenna apparatus A shown in FIGS. 1, 2, and 3 as an embodiment of the present invention and when the magnetic chip antenna of the conventional example is used. And the relationship between frequencies. The average gain shown in FIG. 9 is higher by about 1 db in the embodiment of the present invention than the conventional example at about 600 MHz or less, which is the lower side of the frequency band of digital terrestrial television broadcasting, for both vertical polarization and vertical polarization. The improvement in vertical polarization is particularly remarkable. The required average gain of the vertical polarization plane of the antenna device used in the lower frequency band of terrestrial digital television broadcasting is preferably -10 dBi or more, but according to the present invention, the gain is also obtained in the lower frequency band. -10 dBi or more can be secured. Regarding horizontal polarization, -8 dBi or more is secured over the entire frequency band of digital terrestrial television broadcasting.

  FIG. 10 shows measurement data on the relationship between VSWR and frequency by the magnetic chip antenna of the above example and the conventional example. The VSWR shown in FIG. 10 is high in the conventional example below about 600 MHz, which is the lower frequency band of digital terrestrial television broadcasting, and low in the example. In particular, it was confirmed that the VSWR was low on the low frequency band side of terrestrial digital television broadcasting, indicating excellent antenna characteristics. In the lower frequency band of about 600 MHz or less for terrestrial digital television broadcasting, VSWR is preferably 5 or less, but according to the present invention, VSWR of 5 or less can be ensured in the above frequency band.

  FIG. 11 shows measurement data of directivity and gain at 470 MHz and 620 MHz of the antenna apparatus of the conventional example, and FIG. 12 shows the antenna apparatus A of the embodiment. For example, comparing the directivities in the XY plane, the concentric circles in the XY plane do not change much in the conventional example and the embodiment at 470 MHz, but the concentric circles become smoother at 620 MHz and the directivity in the vertical polarization is improved. You can see that

  Regarding the gain, the average gain in the XY plane of the antenna device A of the embodiment is improved at both 470 MHz and 620 MHz in the embodiment as compared with the conventional example. In particular, it can be seen that at 470 MHz, −8.91 db at −10.21 db is improved by 1 db or more, and the lower side of the terrestrial digital television broadcast band is further improved.

  When the connection part 3 is the connection conductor 31, the actual measurement data has not yet been compiled, but the relative reception strength (S / N) is increased and the noise is clearly reduced with a measuring instrument. It can be confirmed that the gain is substantially improved.

  The antenna device is used for communication equipment. For example, the antenna and the antenna device can be used for communication devices such as a mobile phone, a wireless LAN, a personal computer, a digital terrestrial television broadcasting related device, and the like, and contribute to a broadband response in communication using these devices. In particular, by mounting the antenna according to the present invention or the antenna device using the antenna on the communication device, it is possible to stably obtain a low VSWR and a high gain in receiving digital terrestrial television broadcasting.

It is a figure when the antenna apparatus of embodiment of this invention is mounted in a portable information terminal device. It is a figure which shows the antenna apparatus of embodiment of this invention. It is a figure which shows the principal part of the antenna device of embodiment of this invention. It is a figure which shows the antenna apparatus of other embodiment of the 2nd radiation | emission electrode of this invention. It is a figure which shows the base | substrate of this invention. It is a figure which shows the example of fixation of the base | substrate used for the antenna apparatus of this invention. It is a figure which shows the matching circuit used for the antenna apparatus of this invention. It is a figure which shows the example of another matching circuit used for the antenna apparatus of this invention. It is a figure which shows the actual measurement example of the average gain of the Example of this invention, and the antenna apparatus of a prior art example. It is a figure which shows the actual measurement example of VSWR of the Example of this invention, and the antenna apparatus of a prior art example. It is a figure which shows the measurement example of the directivity of the antenna apparatus of a prior art example. It is a figure which shows the measurement example of the directivity of the antenna apparatus of the Example of this invention. It is a figure which shows the current density distribution in the Example of this invention, and the antenna apparatus of a prior art example.

Explanation of symbols

A: Antenna device, M: General-purpose information terminal device, M1: LCD screen,
1: the first radiation electrode 1, 11: the edge of the first radiation electrode on the side close to the ground,
12: The edge of the grounding part on the side close to the first radiation electrode feeding,
2: second radiation electrode, 21: conductor,
22: Substrate (magnetic chip or dielectric chip),
3: connection part, 31: connection conductor, 32: impedance element,
311: the end of the connection conductor, 312: the other end of the connection conductor,
321: the end of the impedance element 3, 322: the other end of the impedance element 3,
4: Matching circuit, 41: Capacitor Ca,
42: capacitor Cb, 43: inductor La, 411: ground electrode, 431: ground electrode,
412: Ungrounded electrode, 422: Ungrounded electrode, 432: Ungrounded electrode,
5: Board, 6: Grounding part, 7: Feeding part,
8: Power supply line, 81: Grounding wire (outer sheathed conductor), 82: Signal wire (core wire),
9: receiving circuit,
f _0: Center frequency

Claims (9)

  A first radiation electrode, a connection portion, a matching circuit, a feed line, a second radiation electrode, and a grounding portion, and the ground line of the feed line is connected to the first radiation via the connection portion. An electrode and a ground electrode of the matching circuit; a signal line of the feeder line is connected to the second radiation electrode through the matching circuit; and the second radiation electrode has a base made of an insulator. An antenna device characterized by the above. The antenna device according to claim 1, wherein the connection portion is formed of a connection conductor. The antenna device according to claim 1, wherein the connection portion is an impedance element.   4. The antenna device according to claim 1, wherein the second radiation electrode includes a base made of an insulator and a conductor penetrating the base.   5. The antenna device according to claim 4, wherein the base is made of a magnetic chip. 6. The antenna device according to claim 1, wherein one end of the connection portion, the ground portion, the matching circuit, and the second radiation electrode are mounted on a substrate.   7. The antenna device according to claim 1, wherein an edge portion of the first radiating electrode closer to the second radiating electrode and a longitudinal direction of the second radiating electrode are parallel to each other.   The length of one side of the first radiation electrode is approximately λ / 4 of the higher wavelength in the frequency band to be used and the length of the diagonal line is approximately λ / 4 of the lower wavelength of the frequency band. 8. The antenna device according to claim 1, wherein the antenna device is characterized in that:   A communication apparatus comprising the antenna device according to claim 1.