JP7425554B2 - antenna device - Google Patents

Description

The present invention relates to a small antenna device suitable for use in a telemeter terminal installed close to metal.

As a technique related to miniaturization of folded dipole antennas, for example, the technology described in Japanese Patent Application Laid-Open No. 2013-131839 (hereinafter referred to as "Patent Document 1") and Japanese Patent Application Laid-Open No. 2014-150334 (hereinafter referred to as "Patent Document 2") There are things, etc. In addition, as a general method of reducing the size of an antenna, there is a technique described in Japanese Patent Application Laid-open No. 2010-074842 (hereinafter referred to as "Patent Document 3") that uses a chip antenna. Along with this, various devices have been developed, ranging from those with an inductor component to those with a capacitor component, in order to operate the base plate of a mobile terminal as an excitation source as a radiation source.

The folded dipole antenna described in Patent Document 1 has a pair of folded meander line parts spaced apart from each other by a predetermined distance and arranged symmetrically, a first straight line part parallel to each other, and a separation part in the center. The second straight line section is connected to the parallel line section to form a substantially loop-shaped folded dipole element section, which is provided in a direction perpendicular to the second straight line section and connected to both ends of the separation section, and is connected to the left and right sides. By having a configuration in which a power supply line section having a pair of symmetrically formed meander-like power supply line sections is attached,
Despite its compact design, it is said to be able to stably reduce VSWR over a wide frequency band.

Further, the folded dipole antenna described in Patent Document 2 includes a dielectric substrate, a first line-shaped conductor provided on the first main surface or inside of the dielectric substrate, and a first line-shaped conductor provided through the dielectric. A second line-shaped conductor that is provided to face the line-shaped conductor and is connected to the feed line, and a first connection that connects both ends of the first line-shaped conductor and the second line-shaped conductor. The characteristic impedance of the transmission line, which has a conductor and a second connection conductor and is composed of the first line-shaped conductor, the second line-shaped conductor, and the dielectric substrate, is the same as that of the dielectric substrate and the second line-shaped conductor. It is characterized by a radiation impedance that is less than four times the radiation impedance of a dipole antenna constructed solely of the same material, making it possible to obtain a dipole antenna with high radiation resistance.

Japanese Patent Application Publication No. 2013-131839 Japanese Patent Application Publication No. 2014-150334 Japanese Patent Application Publication No. 2010-074842

However, in the dipole antenna described in Patent Document 1, it is possible to reduce the size by lowering the resonant frequency by using a meander configuration, but the radiation resistance is reduced due to the parasitic capacitance between the meanders, resulting in a narrow band. There was a problem that the radiation efficiency decreased.
Further, in the dipole antenna described in Patent Document 2, a total of four inductors are loaded near the center of each of the first line-shaped conductor and the second line-shaped conductor, but inductors using chip inductors or conductor patterns are not used. , the radiation resistance decreases depending on the operating frequency, and the four chip inductors required are placed near the feeding point where the current distribution is high. When using a chip antenna, due to variations in inductance value, etc. There was a problem in that variations in the input impedance of the antenna occurred.
Furthermore, when the antenna module described in Patent Document 3 is mounted on a telemeter, when the telemeter is brought close to metal, the radiation resistance becomes even smaller than the dipole antenna described in Patent Document 1 and Patent Document 2, and the band becomes narrower. There was a problem that the radiation efficiency decreased.

The present invention has been made in view of the above-mentioned circumstances, and its first purpose is to provide a high-gain antenna device with little impedance deterioration when it comes close to metal, and its second purpose is to provide a high-gain antenna device with little impedance deterioration when approaching metal. The purpose is to provide an antenna device that can be made smaller, and the third purpose is to provide an antenna device that can be simplified in configuration and reduced in cost. It is in.

In order to achieve the above-mentioned first to third objects, the antenna device according to the invention described in claim 1 has the following features:
A first linear conductor provided on the main surface of the dielectric substrate and having a power feeding section in the center, and a first linear conductor facing or parallel to the first linear conductor on the other surface side with the dielectric substrate interposed therebetween. A folded dipole antenna in which both ends of each of the second linear conductors arranged so as to be connected to each other by a pair of connecting conductors,
A chip antenna having an impedance component of 39+j278Ω to 48+j306Ω in the operating frequency band of 2.4 GHz to 2.6 GHz is placed at a symmetrical position of the first linear conductor or the second linear conductor that is separated from the power feeding part by a predetermined distance or more. A wireless board is disposed at a predetermined distance from the chip antenna at its upper edge, and is configured as a telemeter terminal that can be installed as close as 5 mm to metal. It is said that

In order to achieve the above-mentioned first to third objects, the antenna device according to the invention described in claim 2,
A first linear conductor provided on the main surface of the dielectric substrate and having a power feeding part in the center thereof, and a first linear conductor provided on the other surface side of the dielectric substrate so as to be opposite or parallel to the first linear conductor. A folded dipole antenna in which both ends of each of the second linear conductors arranged in A chip antenna is disposed at each end of either the first linear conductor or the second linear conductor, and a wireless board is disposed with an upper edge separated from the chip antenna by a predetermined distance. It is characterized by being configured for a telemeter terminal that can be installed as close as 5 mm to metal.

In order to achieve the above-mentioned object, the antenna device according to the invention described in claim 3 has the following features:
A first linear conductor provided on the main surface of a multilayer dielectric substrate having two or more layers, and a first linear conductor provided on the other surface side of the multilayer dielectric substrate opposite to or parallel to the first linear conductor through the multilayer dielectric substrate. and a third linear conductor placed in the middle of the multilayer dielectric substrate so as to be opposite to or parallel to the first linear conductor. A folded dipole antenna connected by a connecting conductor, the chip antenna having an impedance component of 39+j278Ω to 48+j306Ω in the operating frequency band of 2.4 GHz to 2.6 GHz, is connected to the first linear conductor or the second wire. A telemeter comprising one each placed at each end of either one of the shaped conductors, the upper edge of which is separated from the chip antenna by a predetermined distance from the wireless board, and which can be installed as close as 5 mm to the metal. It is characterized by being configured for terminal use.

The antenna device according to the invention set forth in claim 4 includes:
A first linear conductor provided on the main surface of the first layer dielectric substrate of the multilayer dielectric substrate;
A second linear conductor disposed on the other side of the second layer dielectric substrate of the multilayer dielectric so as to face or be parallel to the first linear conductor;
Both ends of a third linear conductor disposed opposite or parallel to the first linear conductor on the other side of the first layer dielectric substrate are respectively connected to a pair of connecting conductors. The folded dipole antenna is characterized in that the first layer dielectric substrate and the second layer dielectric substrate are provided with an opening at a predetermined interval.

The antenna device according to the invention set forth in claim 5 includes:
One chip antenna having an impedance component of 39+j278 Ω to 48+j306 Ω in an operating frequency band of 2.4 GHz to 2.6 GHz is arranged at each end of the first linear conductor or the second linear conductor. It is characterized by being configured as follows.
The chip antenna of the antenna device according to the invention described in claim 6 is characterized in that an impedance component at an operating frequency is around 40+j300Ω.

According to the present invention, it is possible to provide an antenna device that has a simple and compact configuration, has little impedance deterioration even when used in close proximity to metal, and has excellent characteristics in both band and gain.
That is, according to the invention described in claim 1, the first linear conductor is provided on the main surface of the dielectric substrate and has the power feeding section in the center, and the first linear conductor is provided on the main surface of the dielectric substrate, and A folded dipole antenna in which both ends of each of the second linear conductors arranged opposite to or parallel to the first linear conductor are respectively connected by a pair of connecting conductors,
A chip antenna having an impedance of 39+j278Ω to 48+j306Ω in an operating frequency band of 2.4 GHz to 2.6 GHz is placed at a symmetrical position of the first linear conductor or the second linear conductor that is a predetermined distance or more away from the power feeding section. A wireless board is arranged with the upper edge separated from the chip antenna by a predetermined distance, and the chip is configured for a telemeter terminal that can be installed as close as 5 mm to the metal. Only two antennas are required, which not only simplifies the configuration, but also makes it possible to reduce the size and cost of the entire device, especially for telemeter terminals that are installed as close as 5 mm to metal. It is possible to provide an antenna device that exhibits little impedance deterioration even when used and has excellent characteristics in both band and gain.

Further, according to the invention described in claim 2, the first linear conductor is provided on the main surface of the dielectric substrate and has a power feeding section in the center, and the first linear conductor is provided on the main surface of the dielectric substrate and the A folded dipole antenna in which both ends of a second linear conductor arranged to face or parallel to the first linear conductor are respectively connected by a pair of connecting conductors, and the impedance component at the operating frequency is 39+j278Ω. ~48+j306Ω chip antennas are arranged one each at both ends of either the first linear conductor or the second linear conductor, and the upper edge is spaced apart from the chip antenna by a predetermined distance from the wireless board. By configuring it as a telemeter terminal that can be installed as close as 5 mm to metal, only two chip antennas are required, which not only simplifies the configuration but also reduces the overall size of the device. It is possible to reduce costs, and in particular, the antenna device has extremely low impedance deterioration even when used in telemeter terminals installed as close as 5 mm to metal, and has excellent characteristics in both band and gain. can be provided.

Further, according to the invention described in claim 3, the first linear conductor provided on the main surface of the multilayer dielectric substrate having two or more layers, and the first linear conductor provided on the other surface side through the multilayer dielectric substrate a second linear conductor arranged to face or be parallel to the first linear conductor; and a second linear conductor arranged to be opposed to or parallel to the first linear conductor between the multilayer dielectric substrates. A folded dipole antenna in which both ends of each of the third linear conductors are connected with a pair of connecting conductors, and the chip antenna has an impedance component of 39+j278Ω to 48+j306Ω in the operating frequency band of 2.4 GHz to 2.6 GHz. One wireless board is arranged at each end of either the first linear conductor or the second linear conductor, and the upper edge is spaced a predetermined distance from the chip antenna. By arranging it for a telemeter terminal that can be installed as close as 5 mm to metal, only two chip antennas are required, simplifying the configuration and increasing the step-up ratio by making it multi - layered. , we have realized an antenna device that is even more compact and has excellent characteristics in both band and gain, with little impedance deterioration even when used in telemeter terminals installed as close as 5 mm to metal. can be provided.

Further, according to the invention described in claim 4, a first linear conductor provided on the main surface of a first layer dielectric substrate of the multilayer dielectric substrate;
A second linear conductor disposed on the other side of the second layer dielectric substrate of the multilayer dielectric so as to face or be parallel to the first linear conductor;
Both ends of a third linear conductor disposed opposite or parallel to the first linear conductor on the other side of the first layer dielectric substrate are respectively connected to a pair of connecting conductors. The folded dipole antenna according to claim 1, wherein the first layer dielectric substrate and the second layer dielectric substrate are separated by a predetermined distance and have an opening. In addition to the effects of the invention described in claim 3, it is possible to provide an antenna device that can be significantly downsized.

Further, according to the invention described in claim 5, the chip antenna having an impedance component of 39+j278 Ω to 48+j306 Ω in the operating frequency band of 2.4 GHz to 2.6 GHz is connected to the first linear conductor or the second linear conductor. By arranging one at each end of the linear conductor, the step-up ratio is improved and further miniaturization is possible. It is possible to provide an antenna device that exhibits extremely little deterioration in impedance even when used, and has excellent characteristics in both band and gain.
According to the invention described in claim 6, by limiting the impedance component at the operating frequency to a range of around 40+j300Ω, impedance deterioration is extremely small and high gain can be obtained even when used in close proximity to metal. It is possible to provide an antenna device having excellent characteristics such as:

1 is a perspective view schematically showing the external configuration of an antenna device according to a first embodiment of the present invention. FIG. 2 is a perspective view schematically showing the external configuration of an antenna device according to a second embodiment of the present invention. FIG. 7 is a perspective view showing an external configuration of an antenna device according to a second embodiment of the present invention with a wireless board added thereto. 4A and 4B are diagrams showing a specific configuration of a first example of the antenna device shown in FIG. 3, in which (a) is a front view and (b) is a left side view. FIG. 7 is a perspective view schematically showing the external configuration of an antenna device according to a third embodiment of the present invention. FIG. 7 is a perspective view schematically showing the external configuration of an antenna device according to a fourth embodiment of the present invention. FIG. 7 is a perspective view schematically showing the configuration of a second example, which is a modification of the third embodiment of the present invention. It is an impedance characteristic diagram of a single chip antenna in which the single impedance component is around 40+j300Ω. FIG. 5 is an impedance characteristic diagram when a chip antenna having a single impedance component of about 40+j300Ω is connected in the antenna device according to the first embodiment shown in FIG. 4. FIG. FIG. 5 is an impedance characteristic diagram when a matching circuit is loaded between the antenna device according to the first example shown in FIG. 4 and the power feeding section. 5 is a radiation characteristic diagram obtained by simulation of the radiation characteristics of the antenna device shown in the first example shown in FIG. 4. FIG. FIG. 14 is a schematic perspective view showing each direction of the x-axis, y-axis, and z-axis of the radiation characteristic diagrams of FIGS. 11 and 13. FIG. 5 is a radiation characteristic diagram obtained by actually measuring the radiation characteristics of the antenna device according to the first example shown in FIG. 4. FIG. 2 is a diagram comparing the radiation characteristics in free space of the antenna device according to the first embodiment and the radiation characteristics when the antenna device is brought close to metal; FIG. FIG. 4 is a schematic perspective view showing all directions of the x-axis, y-axis, and z-axis in a state where the 1 is a perspective view showing a state where the antenna device of Example 1 is molded with epoxy resin and placed close to a metal plate (at a distance of 5 mm); (d) is an impedance characteristic diagram of Example (c); e) to (h) are radiation characteristic diagrams showing the radiation characteristics at different frequencies when the antenna device of the first embodiment is placed in free space, and (i) to (l) are radiation characteristic diagrams showing the radiation characteristics at different frequencies. FIG. 2 is a radiation characteristic diagram showing radiation characteristics for different frequencies when a metal is placed close to the antenna device as shown in FIG. 3(c) above.

EMBODIMENT OF THE INVENTION Hereinafter, the antenna device of the present invention will be described in detail based on embodiments and examples of the present invention with reference to the drawings.

[First embodiment]
FIG. 1 is a perspective view showing the configuration of main parts of an antenna device (corresponding to claim 1) according to a first embodiment of the present invention.
The antenna device shown in FIG. 1 includes a dielectric substrate 1, a divided first linear conductor 2 (2a, 2b), a second linear conductor 3, two chip antennas 4 (4a, 4b), and two It includes connection conductors 5 (5a, 5b), a power feeding section 6, a grounding section 8, and a wireless board (ground board) 7.
The dielectric substrate 1 is a substrate made of glass epoxy resin, but dielectric ceramic or Teflon (registered trademark) may be used instead, and the material is not particularly limited.
The first linear conductors 2 (2a, 2b) are divided into two at the center with the power supply section 6 as a border, and each is provided on the main surface of the dielectric substrate 1 (the front surface in FIG. 1). There is.
A pair of feeder lines are connected to the longitudinal center of the first linear conductors 2 (2a, 2b), one line is connected to the feeder 6, and the other line is connected to the earther (ground) 8. It is connected.

The second linear conductor 3 is connected to the other side of the dielectric substrate 1 (the back side in FIG. side).
The first connection conductor 5 (5a) is provided in a through-hole shape so as to penetrate the dielectric substrate 1, and connects one end (right end) of the first linear conductor 2 (2a) and the second linear conductor One end (right end) of 3 is connected to each other.
The second connection conductor 5 (5b) is similarly provided in the form of a through hole so as to penetrate the dielectric substrate 1, and connects to one end (left end) of the first linear conductor 2 (2b) and the second connection conductor 5 (5b). The other ends (left ends) of the linear conductors 3 are connected to each other.

The first linear conductor 2 (2a, 2b), the second linear conductor 3, the power supply line (power supply part 6, grounding part 8), and the first and second connection conductors 5a and 5b have good conductivity. It can be formed using various materials such as metals with good conductivity such as gold, silver, copper, and alloys thereof.
A power feeding part 6 is provided at the center of the first linear conductors 2a and 2b, and a first wire conductor 6 is provided at a symmetrical position between the first linear conductors 2a and 2b, which is more than a predetermined distance away from the power feeding part 6. A chip antenna 4a and a second chip antenna 4b are each inserted into a circuit.
The arrangement positions of the chip antennas 4a, 4b on the first linear conductors 2a, 2b are required to be set at intermediate symmetrical positions separated from the position (center) of the power feeding section 6 by a predetermined distance or more.
The reason for this is that the current distribution is high near the feeding section 6 and the grounding section 8, and if the chip antenna is placed near these areas, variations in the input impedance of the folded dipole antenna will occur due to variations in the inductance value. This is because it is necessary to set a symmetrical position separated by a predetermined distance or more so that such a problem does not occur.

The antenna device according to the present embodiment includes chip antennas 4a and 4b disposed at intermediate portions of first linear conductors 2a and 2b whose respective ends are connected to a power feeding section 6 and a grounding section 8; It has a circuit configuration in which it is connected to both ends of the second linear conductor 3 via the second connecting conductors 5a and 5b, respectively.
A radio board 7 is superimposed on the main surface side at a predetermined distance (for example, 5 mm) from the dielectric board 1 on which the dipole antenna is arranged.
Further, it is common to provide a matching circuit on the input end side of the power feeding section 6 and the grounding section 8 to match the impedance of the antenna device alone and the rated impedance of the system equipment. An example of improving impedance characteristics when a matching circuit is loaded will be described later with reference to FIG.
According to the first embodiment configured as described above, the number of chip antennas to be loaded is only two compared to the conventional example, and the size can be reduced accordingly. It is possible to realize an antenna device with less deterioration in impedance during proximity.

[Second embodiment]
2, 3, and 4 show the configuration of an antenna device according to a second embodiment of the present invention. Of these, FIG. 2 is a perspective view schematically showing the external configuration of the antenna device according to the second embodiment, and FIG. 3 is an external appearance of the antenna device shown in FIG. 2 with a wireless board added. FIG. 4 is a perspective view schematically showing the configuration of the antenna device according to the second embodiment shown in FIG. 3; FIG. 4(a) is a front view, and FIG. 4(b) is a left side view.
The antenna device according to the second embodiment differs from the antenna device according to the first embodiment only in the arrangement positions of the first and second chip antennas, and the other configurations are different. , is common. That is, the chip antennas 4 (4a, 4b) of the antenna device according to the second embodiment are arranged at both ends of the first linear conductors 2a and 2b or at both ends of the second linear conductor 3. The difference is that they are configured to be arranged respectively (corresponding to claim 2).

Therefore, regarding the other components of the antenna device according to the second embodiment, the description of the antenna device according to the first embodiment will be used, and redundant explanation will be omitted.
As shown in FIG. 8 , a chip antenna 4 (4a, 4b) with an impedance component of 39+j278 Ω to 48+j306 Ω is connected to both ends of the first linear conductor 2 (2a, 2b) or to the second linear conductor. By disposing it at both ends of the dipole antenna, compared to the antenna device according to the first embodiment, there is no variation in the input impedance of the dipole antenna, there is little impedance deterioration even when used close to metal, and the band An antenna device having excellent characteristics in both gain and gain can be realized.

[First embodiment]
A first example specifically illustrating the second embodiment described above will be described with reference to the antenna device shown in FIG. 4 (corresponding to claim 4).
As shown in FIG. 4, the dielectric substrate 1 is made of a glass epoxy substrate and has a width of 52 mm, a height of 33 mm, and a thickness of 2 mm when viewed from the front.
The first linear conductor 2 (2a, 2b) and the second linear conductor 3 are made of (material: copper foil), and are formed to have a thickness of several tens of μm and a line width of 2 mm.
The chip antenna 4 (4a, 4b) has an impedance component of approximately 40+j300Ω, and an operating frequency in the 2.4 GHz band.
The material of the connection conductor 5 (5a, 5b) is copper foil.
The wireless board 7 is made of copper foil and has a width of 52 mm, a height of 26 mm, and a thickness of 2 mm when viewed from the front, and the distance from the upper edge of the wireless board 7 to the chip antenna 4 (4a, 4b) is , about 5mm apart.
In the actual measurement of the radiation characteristics of the antenna device according to this example, the proximity distance between the antenna device and metal is set to 5 mm.

Next, various characteristics of the antenna device shown in FIG. 4 according to this embodiment will be explained based on FIGS. 8 to 14.
FIG. 8 is an impedance characteristic diagram of a single chip antenna when a chip antenna with a single impedance component of 40+j300Ω is connected, and FIG. 9 is an impedance characteristic diagram of the antenna device according to the first embodiment shown in FIG. FIG. 10 is an impedance characteristic diagram when a matching circuit is loaded between the antenna device according to the first embodiment shown in FIG. 4 and the power feeding section.
In these FIGS. 8 to 10, the operating frequency band is the 2.4 GHz band. Normally, the impedance of a dipole antenna is 73.1+j42.5Ω, and the impedance characteristic of a folded dipole antenna with a folded configuration is approximately 293Ω, which is four times that, but the dielectric substrate 1 and the wireless substrate 7 are spaced at a distance of 5 mm. Since they are close to each other and the opening of the folded part is 2 mm, when the two chip antennas 4a and 4b are connected, it becomes a folded dipole antenna of about 25Ω, as shown in FIG. I understand.

However, since the impedance characteristic of the above structure cannot be used as an antenna yet, it is actually necessary to pass it through a matching circuit in order to make it close to 50Ω.
If the impedance of the antenna and the impedance of the system (for example, an amplifier) are not matched, the signal that should be radiated from the antenna will be reflected back to the system.
Usually, with a matching circuit consisting of a discrete inductor or capacitor and a transmission line, the impedance value of the characteristic impedance on the antenna side as seen from the feed line is determined by the impedance value of the characteristic impedance of the feed line (system side) (coaxial cable is usually 50Ω However, in this embodiment, it is made to match 50Ω (impedance matching) to prevent energy reflection between the feed line and the antenna.

Therefore, an impedance characteristic diagram is shown when a matching circuit is loaded between the power feeding section 6 and the grounding section 8 of the antenna device shown in FIG. 4(a).
As shown in the impedance characteristic diagram of FIG. 10, the above antenna device has an impedance value of approximately 50Ω in the frequency band of 2.4 to 2.5 GHz, and a VSWR (voltage standing wave ratio) of , 1.6 or less. Voltage Standing Ware Radio (VSWR) is the maximum voltage (standing wave) of a signal (standing wave) that occurs when an input signal is affected by a reflected signal due to impedance mismatch, etc. Vmax) and the minimum voltage (Vmin), and it is said that the smaller the VSWR value, the less loss due to reflection.
Generally, the ideal VSWR value is 1.5 or less, and the practical limit is 3 or less.As in this example, a VSWR of 1.6 means that there is almost no loss from the ideal state. It can be said that it is an antenna with no antenna.

Next, the radiation characteristics of the antenna device of this example will be explained with reference to FIGS. 11 to 13.
FIG. 11 is a radiation characteristic diagram obtained by simulation of the antenna device shown in the first embodiment shown in FIG.
Moreover, FIG. 13 is a radiation characteristic diagram obtained by actually measuring the radiation characteristics of the antenna device shown in the first embodiment shown in FIG.
In FIGS. 11 and 13, the gain of the horizontally polarized wave [E(ψ) component], which is an orthogonal polarized wave component, depicted by a thin line, differs greatly between the simulation and the actual measurement.
On the other hand, in FIGS. 11 and 13, the main polarization component [E(θ) component] drawn with a thick line is in good agreement with both calculations and measurements, and the maximum gain is +1 in both cases. The loss is about .5 dBi, making it an antenna with relatively little loss.

Next, with reference to FIGS. 14(a) to (l), we will compare the radiation characteristics in free space of the antenna device according to the first embodiment and the radiation characteristics when the antenna device is brought close to metal at a certain distance. and explain.
In FIG. 14, (a) is a schematic perspective view showing the x-axis, y-axis, and z-axis directions when the antenna device is placed in free space, and (b) is a schematic perspective view of the antenna device in the first embodiment. It is an impedance characteristic diagram in free space, and (c) is a perspective view showing the state in which the antenna device of the first embodiment is molded with epoxy resin and placed close to a metal plate (at a distance of 5 mm); ) is an impedance characteristic diagram of the embodiment shown in (c), and (e) to (h) are diagrams showing the radiation characteristics at different frequencies when the antenna device of the first embodiment is placed in free space. FIG. 2 is a radiation characteristic diagram showing the radiation characteristics at different frequencies, in which (i) to (l) are radiation characteristics when a metal is placed close to the antenna device as shown in the above-mentioned diagram (c), respectively. It is a diagram.

As shown in Figure 14, the radiation characteristics are shown separately when the operating frequencies are 2.2 GHz, 2.4 GHz, 2.5 GHz and 2.6 GHz, when placed in free space and when placed in close proximity to metal. Figure (radiation pattern) is arranged correspondingly.
Since the folded dipole antenna is a self-balanced antenna, the main polarization should be horizontal polarization H (depicted by a thin line in FIG. 14), but the dipole antenna according to this example As shown in FIGS. 14(e) to (h) in free space, when the frequency is lower than around 2.5 GHz, the main polarization becomes vertical polarization V (in FIG. 14). is drawn with a thick line), and when it is higher than around 2.5 GHz, it is horizontally polarized H, indicating that the operation mode is changing.
That is, in the case of a frequency lower than 2.5 GHz, the antenna element and the main polarization are orthogonal, and the main radiation source is the housing (wireless board).

As seen in Figures 14(i) to (l), between 2.2 GHz and 2.6 GHz, the magnitude of the vertically polarized wave V gradually decreases, while the magnitude of the horizontally polarized wave ( The size of H) is gradually increasing, which is one of its characteristics.
Therefore, when the antenna device is placed close to metal, the impedance characteristics become somewhat lower as shown in FIGS. 14(i) to (l), but when the frequency is lower than 2.5 GHz, Even when the main polarization is orthogonal to the antenna element, the vertical polarization component (waveform component of V) makes a large contribution and acts to compensate for the lack of the horizontal polarization component.
In other words, there is a phenomenon in which there is almost no loss due to the self-balancing effect. Therefore, according to the present invention, it is possible to provide an antenna device that exhibits little impedance deterioration and excellent characteristics in both band and gain even when used in close proximity to metal (at a distance of 5 mm).

[Third embodiment]
FIG. 5 is a perspective view schematically showing the configuration of main parts of an antenna device according to a third embodiment of the present invention (corresponding to claim 3). The antenna device shown in FIG. 5 includes two or more multilayer dielectric substrates 1 (1a, 1b), a divided first linear conductor 2 (2a, 2b), a second linear conductor 3, a third wire It includes two chip antennas 4 (4a, 4b) of shaped conductors 9, two connecting conductors 5 (5a, 5b), a power feeding section 6, and a grounding section 8. The multilayer dielectric substrate 1 consists of two layers: a dielectric substrate 1a on the main surface side (upper surface side) and a dielectric substrate 1b on the other surface side (lower surface side), and a third linear conductor 9 is attached thereto. Therefore, a thin dielectric substrate 1c (not shown) may be inserted between the dielectric substrates 1a and 1b, and in that case, a three-layer structure is formed. The material of these multilayer dielectric substrates 1a, 1b, and 1c may be glass epoxy resin, dielectric ceramic, or Teflon (registered trademark) as in the first embodiment.

The first linear conductors 2 (2a, 2b) are divided into two at the center with the power feeding part 6 as the border, and each is attached to the main surface (the upper surface in FIG. 5) of the first dielectric substrate 1a. It is provided.
A pair of feeder lines are connected to the longitudinal center of the first linear conductors 2 (2a, 2b), one line is connected to the feeder 6, and the other line is connected to the earther (ground) 8. It is connected.
The second linear conductor 3 is connected to a second dielectric substrate so as to face or be parallel to the first linear conductor 2 (2a, 2b) via the first and second dielectric substrates 1a and 1b. It is provided on the other surface side (lower surface side in FIG. 5) of the substrate 1b.
The third linear conductor 9 is connected to the other surface of the first dielectric substrate 1a so as to face or be parallel to the first linear conductor 2 (2a, 2b) via the first dielectric substrate 1a. It is provided on the side (bottom side).

The first connection conductor 5a is provided in a through hole shape so as to penetrate the first and second dielectric substrates 1a and 1b, and is connected to the first linear conductor 2 (2a) and the third linear conductor. 9 are connected to each other.
The second connection conductor 5b is similarly provided in the form of a through-hole so as to penetrate the first and second dielectric substrates 1a and 1b, and includes the first linear conductor 2 (2b), the second The other ends of the linear conductor 3 and the third linear conductor 9 are connected to each other.
First linear conductor 2 (2a, 2b), second linear conductor 3, third linear conductor 9, feeding line (power feeding part 6, grounding part 8), first and second connecting conductor 5a and 5b can be formed using various materials with good conductivity, for example, metals with good conductivity such as gold, silver, copper, and alloys thereof.
Note that the first and second connection conductors 5a and 5b are not limited to being provided in the form of through holes in the dielectric substrates 1a and 1b, and may be any means for electrically connecting a plurality of linear conductors.

A power feeding part 6 is provided at the center of the first linear conductors 2a and 2b, and a first chip antenna 4a and a second chip antenna 4b are placed at symmetrical positions at both ends of the power feeding part 6. A circuit is inserted in each.
The antenna device according to the third embodiment includes chip antennas 4a and 4b disposed at both ends of first linear conductors 2a and 2b, each end of which is connected to a power feeding section 6 and a grounding section 8. , has a circuit configuration in which it is connected to both ends of the second linear conductor 3 and the third linear conductor 9 via the first and second connecting conductors 5a and 5b, respectively.
Furthermore, a matching circuit is provided on the input end sides of the power feeding section 6 and the grounding section 8 to match the impedance of the antenna device alone and the rated impedance of the system equipment.

According to the third embodiment configured as described above, the step-up ratio is improved by the amount of multilayering compared to the first and second embodiments, so that further miniaturization can be achieved. As with the antenna devices in the first and second embodiments, it is possible to realize an antenna device with a small number of chip antennas and excellent characteristics in terms of band and gain.

[Fourth embodiment]
FIG. 6 is a perspective view schematically showing the external configuration of an antenna device according to a fourth embodiment of the present invention.
The antenna device according to the fourth embodiment differs from the antenna device according to the third embodiment only in that the number of chip antennas disposed is increased, and the other configurations are basically the same. It is common. That is, the arrangement position of the chip antenna 4 of the antenna device according to the fourth embodiment is such that the circuit is inserted at both ends of the first linear conductors 2a and 2b and at both ends of the second linear conductor 3. The difference is that it is configured as follows, that is, it is equipped with four chip antennas.
Therefore, regarding the other components of the antenna device according to the fourth embodiment, the description of the antenna device according to the third embodiment will be used, and duplicate explanations will be omitted.

As described above, the first and second chip antennas 4 (4a, 4b) with impedance components of 39+j278 Ω to 48+j306 Ω are arranged at both ends of the first linear conductor 2 (2a, 2b), and the third By arranging the fourth chip antennas 4c and 4d at both ends of the second linear conductor 3, a synergistic effect between the chip antenna and the step-up ratio is achieved compared to the antenna device according to the third embodiment. , it is possible to realize further miniaturization, and it is possible to realize an antenna device that exhibits little impedance deterioration even when used in close proximity to metal, and has excellent characteristics in both band and gain.

[Second example]
FIG. 7 is a perspective view specifically showing the configuration of a second embodiment that is a modification of the third embodiment of the present invention shown in FIG. 5 (corresponding to claim 4).
As shown in FIG. 7, the first dielectric substrate 1a is made of a glass epoxy substrate, and its dimensions are the same as those shown in FIGS. 4(a) and 4(b), although illustration is omitted.
The difference from the first embodiment is that in the first embodiment, the dielectric substrate 1a of the first layer and the dielectric substrate 1b of the second layer are in close contact with each other; The difference in the embodiment is that the openings are provided at intervals of 4 mm.
Another point is that the length of the folded dipole antenna when viewed from the front is 33 mm in the first embodiment, as shown in FIG. 4, while it is suppressed to 20 mm in the second embodiment. It's different.
As mentioned above, by increasing the aperture diameter of the dipole antenna in the second embodiment to 4 mm, it was possible to further shorten the element length.
That is, the dipole antenna of the first example had a front dimension and a back dimension of 33 mm, and the thickness of the multilayer dielectric substrate was 2 mm, so the total length was 33 mm x 2 + 2 mm x 2 = 70 mm.

On the other hand, the dipole antenna of the second embodiment has a front dimension and a back dimension of 20 mm, and the thickness of the multilayer dielectric material is 4 mm, so the total length can be miniaturized to 20 mm x 2 + 4 mm x 2 = 48 mm. It has become possible.
According to each of the embodiments described in detail above, an antenna device is realized that is compact, has no impedance deterioration even when used in close proximity to metal, and has excellent characteristics in terms of band and gain. can be provided.

1 (1a, 1b) Dielectric substrate 2 (2a, 2b) First linear conductor 3 Second linear conductor 4 (4a, 4b, 4c, 4d) Chip antenna 5 (5a, 5b) Connection conductor 6 Power supply Part 7 Wireless board 8 Grounding part 9 Third linear conductor

Claims (6)

A first linear conductor provided on the main surface of the dielectric substrate and having a power feeding section in the center, and a first linear conductor facing or parallel to the first linear conductor on the other surface side with the dielectric substrate interposed therebetween. A folded dipole antenna in which both ends of each of the second linear conductors arranged so as to be connected to each other by a pair of connecting conductors,
A chip antenna having an impedance component of 39+j278Ω to 48+j306Ω in the operating frequency band of 2.4 GHz to 2.6 GHz is placed at a symmetrical position of the first linear conductor or the second linear conductor that is separated from the power feeding part by a predetermined distance or more. A wireless board is disposed at a predetermined distance from the chip antenna at its upper edge, and is configured as a telemeter terminal that can be installed as close as 5 mm to metal. antenna device. A first linear conductor provided on the main surface of the dielectric substrate and having a power feeding part in the center thereof, and a first linear conductor provided on the other surface side of the dielectric substrate so as to be opposite or parallel to the first linear conductor. A folded dipole antenna in which both ends of each of the second linear conductors arranged in the antenna are respectively connected by a pair of connecting conductors,
One chip antenna having an impedance component of 39+j278Ω to 48+j306Ω in an operating frequency band of 2.4 GHz to 2.6 GHz is arranged at each end of either the first linear conductor or the second linear conductor. What is claimed is: 1. An antenna device comprising: a wireless board disposed with an upper edge separated from the chip antenna by a predetermined distance; and configured for use in a telemeter terminal, which can be installed as close as 5 mm to metal. A first linear conductor provided on the main surface of a multilayer dielectric substrate having two or more layers, and a first linear conductor provided on the other surface side of the multilayer dielectric substrate opposite to or parallel to the first linear conductor through the multilayer dielectric substrate. and a third linear conductor placed in the middle of the multilayer dielectric substrate so as to be opposite to or parallel to the first linear conductor. A folded dipole antenna each connected by a connecting conductor,
One chip antenna having an impedance component of 39+j278Ω to 48+j306Ω in an operating frequency band of 2.4 GHz to 2.6 GHz is arranged at each end of either the first linear conductor or the second linear conductor. What is claimed is: 1. An antenna device comprising: a wireless board disposed with an upper edge separated from the chip antenna by a predetermined distance; and configured for use in a telemeter terminal, which can be installed close to metal up to 5 mm. A first linear conductor provided on the main surface of the first layer dielectric substrate of the multilayer dielectric substrate;
A second linear conductor disposed on the other side of the second layer dielectric substrate of the multilayer dielectric so as to face or be parallel to the first linear conductor;
Both ends of a third linear conductor disposed opposite or parallel to the first linear conductor on the other side of the first layer dielectric substrate are respectively connected to a pair of connecting conductors. A folded dipole antenna,
4. The antenna device according to claim 3, wherein the first layer dielectric substrate and the second layer dielectric substrate are spaced apart from each other by a predetermined distance and an opening is provided. One chip antenna having an impedance component of 39+j278Ω to 48+j306Ω in an operating frequency band of 2.4 GHz to 2.6 GHz is arranged at each end of the first linear conductor or the second linear conductor. The antenna device according to claim 3, characterized in that the antenna device is configured as follows. 5. The antenna device according to claim 1, wherein the chip antenna has an impedance component of about 40+j300Ω at an operating frequency.

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