JP3307237B2 - Antenna device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antenna device, and more particularly to an antenna device used for a mobile communication device for mobile communication and a local area network (LAN).

[0002]

2. Description of the Related Art FIG. 8 shows a conventional monopole antenna 50.
Is shown. The monopole antenna 50 has a single conductor 51 that stands substantially perpendicular to the ground plane 52 in the air (relative permittivity ε = 1, relative magnetic permeability μ = 1). The power supply V is connected to one end of the conductor 51, and the other end 53 is open.

[0003]

However, in the above-mentioned conventional monopole antenna, when the human body approaches, the center frequency moves to the low frequency side, so that the frequency f0 to be used is used.
, There is a problem that the gain of the antenna is reduced.

The present invention has been made in order to solve such a problem, and an object of the present invention is to provide a small-sized antenna device in which the gain of the antenna does not decrease at a frequency f0 to be used even when a human body approaches. Aim.

[0005]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention provides a substrate comprising at least one of a dielectric material and a magnetic material, and at least one substrate formed on at least one of the surface and the inside of the substrate. and the conductor, formed on a surface of the substrate, first with at least one feeding terminal for applying a voltage to said conductor comprises a second antenna body, when the frequency to be used was f0, the First
Of the center frequency of the antenna body and f0, the center frequency of the second antenna body higher than f0, and human
When the body approaches, the center frequency of the second antenna is
It is characterized in that it is set to move near f0 .

[0006]

According to the antenna device of the present invention, any one of the plurality of antenna bodies is used for the frequency f0 to be used.
Since the center frequencies of the two antenna bodies are higher than f0, when the human body approaches and the center frequencies of the plurality of antenna bodies move to the lower frequency side, the antennas whose center frequencies are higher than f0 are used. The center frequency of the main body moves to around f0.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a block diagram of a first embodiment of the antenna device according to the present invention. Antenna device 10
Are switching means, for example, switch 11 and switch 1
Antenna body 12 connected to one first port 11a
a, an antenna body 12b connected to the second port 11b of the switch 11. At the same time, switch 11
The third port 11c is connected to the RF circuit unit 13 of the mobile communication device on which the antenna device 10 is mounted.

FIG. 2 is a perspective view of the antenna device 10 shown in FIG. The antenna device 10 includes a switch 11 and antenna bodies 12a and 12b, and transmission lines 14a to 14c.
Is mounted on a mounting board 15 formed on the surface.

Then, the first port 11 of the switch 11
a is connected to the antenna body 12a via the transmission line 14a, and the second port 11b of the switch 11 is connected to the transmission line 1
4b, the third port 11c of the switch 11 is connected to the antenna main body 12b via the transmission line 14c.
Connected to the F circuit unit 13.

FIG. 3 shows a perspective perspective view of an antenna body used in the antenna device 10 of FIG. Here, the antenna main body 12a will be described.

The antenna body 12a includes a rectangular parallelepiped base 16 made of a dielectric material (relative permittivity: about 6.1) containing barium oxide, aluminum oxide, and silica as main components, and copper and copper inside the base 16. The substrate 16 is made of an alloy or the like and provided by printing, vapor deposition, lamination, or plating.
A conductor 17 spirally wound in the longitudinal direction of the
And a power supply terminal 18 for applying a voltage to the conductor 17. At this time, one end of the conductor 17 is
And is connected to the power supply terminal 18. The other end of the conductor 17 forms a free end 19 inside the base 16.

FIGS. 4 and 5 show the antenna body 12 shown in FIG.
The perspective view of the modification of a is shown. Antenna body 1 of FIG.
21a is a rectangular parallelepiped base 16 and a conductor 1 spirally wound in the longitudinal direction of the base 16 along the surface of the base 16.
7 a and a power supply terminal 18 for applying a voltage to the conductor 17 a on the surface of the base 16. At this time, the conductor 17
a one end of the power supply terminal 18 on the surface of the base 16.
Connected to. The other end of the conductor 17 a forms a free end 19 on the surface of the base 16. In this case, since the conductor can be easily formed spirally on the surface of the base by screen printing or the like, the manufacturing process of the antenna body can be simplified.

The antenna body 122a shown in FIG. 5 has a rectangular parallelepiped base 16, a conductor 17b formed in a meandering shape on the surface of the base 16, and a power supply for applying a voltage to the conductor 17b on the surface of the base 16. Terminal 18. At this time, one end of the conductor 17 b is connected to the power supply terminal 18 on the surface of the base 16. The other end of the conductor 17b forms a free end 19 on the surface of the base 16. In this case, since the meandering conductor is formed only on one main surface of the base, the height of the base can be reduced, and accordingly the height of the antenna body can be reduced. The meandering conductor may be formed inside the base as shown in FIG.

Next, a specific operation of the antenna device 10 will be described. When the frequency to be used is 930 MHz, the center frequency is 930M when the human body approaches.
Antenna body 12a that moves from 1 Hz to 890 MHz
Then, the antenna main body 12b whose center frequency moves from 970 MHz to 930 MHz when the human body approaches is prepared.

When the human body approaches, the switch 11 causes the antenna main body 12a to move from the antenna main body 1a.
Switch to 2b. By doing so, it is possible to prevent deterioration of the gain at the frequency of 930 MHz used.

Table 1 shows the gain at 930 MHz of the antenna main body 12a having the center frequency of 930 MHz and the antenna main body 12b having the center frequency of 970 MHz for the normal case, that is, when the human body is not approaching and when the human body is approaching. This will be described specifically.

[0018]

[Table 1]

According to Table 1, when the human body approaches, the antenna body 12a having the center frequency of 930 MHz is approximately 6 dB.
(−3 dB → −9 dB) Although the gain decreases, the switch 1
1 to switch the antenna frequency to the antenna main body 12b having the center frequency of 980 MHz, thereby reducing the gain deterioration by about 1 dB.
(−3 dB → −4 dB).

As described above, in the first embodiment described above,
When the frequency to be used is 930 MHz, the center frequency of the one antenna main body 12a is 930 MHz, and the center frequency of the other antenna main body 12b is higher than 930 MHz, for example, 980 MHz. A decrease in gain at a used frequency of 930 MHz can be suppressed to about 1 dB.

Further, since the center frequency of the one antenna main body 12a is 930 MHz, the reduction in gain can be suppressed even in a normal case where a human body is not approaching.

FIG. 6 shows a second example of the antenna device according to the present invention.
FIG. 2 shows a perspective view of the embodiment of FIG. The antenna device 20 includes two antenna main bodies 12a and 12b having different resonance frequencies, and the antenna main bodies 12a and 12b are mounted on a mounting substrate 22 having a substantially T-shaped transmission line 21.

At this time, the first end 21a of the transmission line 21
Is connected to the antenna body 12a, the second end 21b of the transmission line 21 is connected to the antenna body 12b, and the third end 21c of the transmission line 21 is connected to the mobile communication device on which the antenna device 20 is mounted. Connected to the RF circuit unit 23 of the machine.

Specifically, the center frequency is 930 MHz,
FIG. 7 shows the gain of an antenna device including two antenna bodies 12a and 12b of 80 MHz. In the figure, the solid line is normal, that is, when the human body is not approaching,
The broken line indicates the case where the human body approaches.

FIG. 7 shows that when the human body approaches, the center frequency of each of the antenna main bodies 12a and 12b moves to the lower frequency side. That is, as the human body approaches, the center frequency of the antenna body 12b becomes 980.
Move from 930 MHz to 930 MHz. Therefore, for example, when the frequency to be used is 930 MHz, the two antenna main bodies 12 having the center frequencies of 930 MHz and 980 MHz are used.
By using a and 12b, even if the human body approaches,
1d reduction in gain at 930 MHz frequency
B can be suppressed.

As described above, in the second embodiment,
In addition to the effects of the first embodiment, a switch for switching the antenna body can be omitted.

In the above-described first embodiment, each switching circuit is provided inside a substrate made of a dielectric material (relative permittivity: about 6.1) containing barium oxide, aluminum oxide and silica as main components. When a high-frequency switch having elements is used, the two antenna bodies and the high-frequency switch can be formed on the same base, so that the antenna device can be downsized.

In the first and second embodiments described above, the case where there are two antenna bodies has been described.
If the center frequency of any one of the plurality of antenna bodies is higher than f0,
There may be three or more antenna bodies.

Further, the case where the base of the antenna body is made of a dielectric material has been described. However, the base is not limited to a dielectric material. May be.

Although the case where the antenna body has one conductor has been described, a plurality of conductors each having a power supply terminal and arranged in parallel with each other may be provided inside the base. In this case, the antenna main body can have a plurality of center frequencies according to the number of conductors. Therefore, one antenna body can cope with a plurality of resonance frequencies, so that the antenna device can be downsized.

[0031]

According to the antenna device of the first aspect, when the frequency to be used is f0, the center frequency of any one of the plurality of antenna bodies is set to f.
Since it is higher than 0, it is possible to suppress a decrease in the gain at the frequency f0 to be used even when the human body approaches and the center frequency of the plurality of antenna bodies moves to the lower frequency side.

Further, according to the antenna device according to claim 1,
Since the center frequency of any one of the plurality of antenna bodies except for the antenna body whose center frequency is higher than f0 is set to the frequency f0 to be used, the gain can be reduced even in a normal case where the human body is not approaching. Can be suppressed.

[Brief description of the drawings]

FIG. 1 is a block diagram of a first embodiment according to the antenna device of the present invention.

FIG. 2 is a perspective view of the antenna device of FIG.

FIG. 3 is a perspective view of an antenna main body constituting the antenna device of FIG. 2;

FIG. 4 is a perspective view showing a modification of the antenna main body of FIG. 3;

FIG. 5 is a transparent perspective view showing another modification of the antenna body of FIG. 3;

FIG. 6 is a perspective view of a second embodiment according to the antenna device of the present invention.

FIG. 7 is a diagram illustrating a gain of the antenna device of FIG. 6;

FIG. 8 is a diagram showing a conventional monopole antenna.

[Explanation of symbols]

10, 20 Antenna device 11 Switching means (switch) 12a, 12b, 121a, 122a Antenna body 16 Base 17, 17a, 17b Conductor 18 Power supply terminal

Claims (1)

(57) [Claims] 1. A substrate made of at least one of a dielectric material and a magnetic material, at least one conductor formed on at least one of the surface and the inside of the substrate, and a voltage formed on the surface of the substrate, and applying a voltage to the conductor. first with at least one feeding terminal for applying includes a second antenna body, when the frequency to be used was f0, the first
The center frequency of the first antenna body and f0, the center frequency of the second antenna body higher than f0, and,
Center frequency of the second antenna when a human body approaches
Is set to move near f0 .