JPH11186832A - Antenna system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high gain antenna system that is used for radio equipment in a low frequency band. SOLUTION: An antenna system 10 consists of an antenna main body 13 provided with a conductor 11 and a feeder electrode 12 to which one end of the conductor 11 connects, of a high frequency circuit section 15 having a metal- made chassis 14, and of a mount board 19 on one major side of which a linear conductor pattern 16 and a linear ground electrode 17 are formed through printing of a conductive material and on the other major size of which a linear conductor pattern 18 is formed through printing of a conductive material. Then the antenna main body 13 and the high frequency circuit 15 are mounted on the one major side of the mount board 19, and the feeding electrode 12 of the antenna main body 13 and the high frequency circuit 15 are connected through the conductor patterns 16, 18 on both the major sides of the mount board 19, and through throughhole electrodes 20 that penetrate through the mount board 19.

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 radio equipment used in a low frequency band.

[0002]

2. Description of the Related Art FIG. 7 shows a monopole antenna 50 which is a typical example of a linear antenna. This monopole antenna 5
Numeral 0 has one conductor 52 that stands substantially perpendicular to the ground plane 51 in the air (relative permittivity ε = 1, relative magnetic permeability μ = 1). And one end 5 of this conductor 52
3 is connected to a power supply V, and the other end 54 is open.

[0003]

However, in the above-mentioned conventional monopole antenna, since the conductor of the antenna exists in the air, the size of the conductor of the antenna becomes large. For example, if the wavelength in vacuum is λo, λo
/ 4 conductor length is required, 400M for specified low power
In the low frequency band of the Hz band, the length of the monopole antenna is about 19 cm. Therefore, there is a problem that it is difficult to use a wireless device for a low frequency band when a small antenna is required.

An object of the present invention is to solve such a problem, and an object of the present invention is to provide a high-gain antenna device that can be used for a radio device for a low frequency band.

[0005]

In order to solve the above-mentioned problems, an antenna device according to the present invention comprises a base made of at least one of a dielectric ceramic and a magnetic ceramic, and formed on at least one of the inside and the surface of the base. An antenna body provided with at least one conductor and a power supply electrode formed on the surface of the base and for applying a voltage to the conductor; and a metal chassis for covering the antenna body with the power supply electrode. A high-frequency circuit portion connected to an electrode, and a mounting substrate on which the antenna body and the high-frequency circuit portion are mounted and a ground electrode is formed on the surface thereof, and at least the ground electrode radiates the antenna body. It is characterized by making means.

Further, the ground electrode is formed in a linear shape, and the radiating means is constituted by the ground electrode and a chassis of the high frequency circuit connected to the ground electrode. You.

According to the antenna device of the present invention, since the radiating means of the antenna main body is provided, the current distribution of the antenna main body spreads to the radiating means, and the current distribution of the antenna main body becomes large.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a top view of a first embodiment of the antenna device according to the present invention. The antenna device 10 includes a conductor 11 and a power supply electrode 12 to which one end of the conductor 11 is connected.
Antenna body 13 having: a metal chassis 14
A high-frequency circuit portion 15 having a linear conductive pattern 16 and a linear ground electrode 17 formed by printing a conductive material on one main surface, and a conductive material printed on the other main surface. The formed linear conductor pattern 1
8 is provided.

The antenna body 13 and the high-frequency circuit section 15 are mounted on one main surface of the mounting substrate 19, and the power supply electrode 12 and the high-frequency circuit section 15 of the antenna body 13 are
Conductor patterns 16, 18 on both main surfaces of the mounting board 19;
It is connected via a through-hole electrode 20 penetrating the mounting board 19.

In the antenna device 10 configured as described above, the conductor 11 of the antenna main body 13 and the ground electrode 17 on one main surface of the mounting board 19 are capacitively coupled, and the ground electrode 17 is Becomes

The antenna body 13 is, as shown in FIG.
A rectangular parallelepiped base 21, a conductor 11 helically wound inside the base 21 in the longitudinal direction of the base 21, and a power supply electrode formed on the surface of the base 21 for applying a voltage to the conductor 11 12 is provided.

FIG. 3 is an exploded perspective view of the antenna body 13 shown in FIG. The base 21 is formed by laminating rectangular sheet layers 22a to 22c made of a dielectric ceramic containing barium oxide, aluminum oxide, and silica as main components. Among these, the substantially linear conductive patterns 23a to 2 made of copper or copper alloy are formed on the surfaces of the sheet layers 22a and 22b by screen printing, vapor deposition, or plating.
3h are provided. In addition, predetermined positions of the sheet layer 22b (both ends of the conductive patterns 23e to 23g,
At one end of 3h), a via hole 24 is provided in the thickness direction.

After the sheet layers 22a to 22c are laminated, the conductive patterns 23a to 23h are connected by via holes 24, and then sintered to form a helical winding inside the base 21 in the longitudinal direction of the base 21. The conductor 11 to be formed is formed.

At this time, one end of the conductor 11 (the conductive pattern 2
3a) is drawn out to the end face of the base 21 and the power supply section 2
5 and connected to the power supply electrode 12 provided on the surface of the base 21. The other end of the conductor 11 (the other end of the conductive pattern 23h) forms a free end 26 inside the base 21.

FIGS. 4 and 5 show the antenna body 13 shown in FIG.
The perspective view of the modification of FIG. Antenna body 13 of FIG.
a is a rectangular parallelepiped base 21a and a conductor 1 spirally wound in the longitudinal direction of the base 21a along the surface of the base 21a.
1a and the power supply electrode 12 formed on the surface of the base 21a
a. At this time, one end of the conductor 11a is
On the surface of a, it is connected to a power supply electrode 12a for applying a voltage to the conductor 11a. The other end of the conductor 11a forms a free end 26a on the surface of the base 21a. According to the antenna body 13a configured as described above,
Since the conductor 11a can be easily formed spirally on the surface of the base 21a by screen printing or the like, the manufacturing process of the antenna body 13a can be simplified.

The antenna body 13b shown in FIG. 5 includes a rectangular parallelepiped base 21b, a conductor 11b formed in a meandering shape on the surface of the base 21b, and a power supply electrode 12b formed on the surface of the base 21b. At this time, one end of the conductor 11b is connected to the power supply electrode 12b for applying a voltage to the conductor 21b on the surface of the base 21b. The other end of the conductor 12b is connected to the free end 2 on the surface of the base 21b.
6b is formed. Antenna body 13 configured as above
According to b, since the meandering conductor 11b is formed only on one main surface of the base 21b, the height of the base 21b can be reduced, and accordingly the height of the antenna body 13b can be reduced. Note that the meandering conductor 11b is
The same effect can be obtained even if it is formed inside 1b.

As described above, according to the antenna device of the first embodiment, since the ground electrode on one main surface of the mounting board serves as the radiation means of the antenna body, the current distribution of the antenna body spreads to the ground electrode. As a result, the current distribution of the antenna body becomes large. Therefore, current radiation from the antenna body is increased, and the gain of the antenna device is improved.

Further, since the ground electrode has a linear shape and the ground electrode functions as an inductor, the length of the ground electrode becomes apparently longer due to a wavelength shortening effect. Therefore, since the radiation means becomes larger, current radiation from the antenna body becomes stronger, and the gain of the antenna device is further improved.

For example, in the 400 MHz band for specific low power, the antenna device 10 (FIG. 1) of the embodiment can obtain an average gain of about -4.6 dBd.
Compared with 0 (FIG. 7), the average gain is improved by about 8 dBd.

FIG. 6 shows a second example of the antenna device according to the present invention.
1 shows a top view of the embodiment of FIG. The antenna device 30 includes the conductor 1
1 and an antenna body 13 having a power supply electrode 12 to which one end of the conductor 11 is connected, a high-frequency circuit unit 15 having a metal chassis 14, and a conductive material formed on one main surface by printing a conductive material. It comprises a linear conductive pattern 16 and a wide ground electrode 31, and a mounting substrate 19 having a linear conductive pattern 18 formed by printing a conductive material on the other main surface.

The antenna body 13 and the high-frequency circuit section 15 are mounted on one main surface of the mounting board 19, and the power supply electrode 12 and the high-frequency circuit section 15 of the antenna body 13 are
Conductor patterns 16, 18 on both main surfaces of the mounting board 18,
It is connected via a through-hole electrode 20 penetrating the mounting board 19. Further, the chassis 15 of the high-frequency circuit section 14 and the ground electrode 31 on one main surface of the mounting board 19 are connected.

According to the antenna device 30 configured as described above, the conductor 11 of the antenna body 13 and the ground electrode 31 on one main surface of the mounting board 19 are capacitively coupled and connected to the ground electrode 31 and the ground electrode 31. The chassis 14 of the high-frequency circuit unit 15 thus formed serves as a radiation unit of the antenna body 13.

As described above, according to the antenna device of the second embodiment, the ground electrode on one main surface of the mounting board is
Since the chassis of the high-frequency circuit unit mounted on the mounting board serves as a radiation means of the antenna body, the current distribution of the antenna body spreads to the ground electrode and the chassis of the high-frequency circuit unit, and the current distribution of the antenna body further increases. Therefore, current radiation from the antenna body is further increased, and the gain of the antenna device is further improved.

In the antenna devices of the first and second embodiments, the case has been described where the antenna body and the high-frequency circuit are mounted on the same main surface of the mounting board. The mounting may be performed separately on one main surface and the other main surface of the mounting substrate. Alternatively, a plurality of mounting boards may be prepared, and the antenna body and the high-frequency circuit unit may be mounted on different mounting boards. In these cases, the horizontal size of the antenna device can be reduced.

Also, the case where the base of the chip antenna is made of a dielectric material containing barium oxide, aluminum oxide, and silica as main components has been described, but the base is not limited to this dielectric material, but may be titanium oxide. The same effect can be obtained by using a dielectric material containing neodymium oxide as a main component, a magnetic material containing nickel, cobalt, or iron as a main component, or a combination of a dielectric material and a magnetic material.

Furthermore, in the antenna device of the first embodiment, the case where the ground electrode has a substantially linear shape has been described. However, the ground electrode may have a meandering shape or a substantially L shape. In this case, since the length of the ground electrode becomes longer and the size of the radiating means becomes larger, the current radiation from the antenna body is further increased, and the effect of further improving the gain of the antenna device is obtained.

In the antenna device according to the second embodiment,
Although the case where the ground electrode has a wide shape has been described,
The ground electrode may be linear as in the first embodiment. In this case, the length of the ground electrode becomes longer and the radiating means becomes larger, so that the current radiation from the antenna main body becomes stronger and the effect that the gain of the antenna device is further improved is obtained.

[0028]

According to the antenna device of the first aspect, at least the ground electrode provided on the mounting board forms the radiating means of the antenna main body. Therefore, the current distribution of the antenna main body spreads to the ground electrode, and the current distribution of the antenna main body is reduced. growing. Therefore, current radiation from the antenna body is increased, and the gain of the antenna device is improved.

According to the antenna device of the second aspect, since the ground electrode is formed in a linear shape, the ground electrode functions as an inductor. Therefore, apparently, the length of the ground electrode becomes longer due to the wavelength shortening effect, and the radiation means becomes larger, so that the current radiation from the antenna body becomes stronger and the gain of the antenna device is further improved.

According to the antenna device of the third aspect, the radiating means is constituted by the ground electrode and the chassis of the high-frequency circuit connected to the ground electrode. It spreads to the chassis of the circuit section, and the current distribution of the antenna body further increases. Therefore, current radiation from the antenna body is further increased, and the gain of the antenna device is further improved.

[Brief description of the drawings]

FIG. 1 is a partial top view of a first embodiment according to the antenna device of the present invention.

FIG. 2 is a transparent perspective view of an antenna main body constituting the antenna device of FIG. 1;

FIG. 3 is an exploded perspective view of the antenna main body of FIG. 2;

FIG. 4 is a perspective view showing a modification of the antenna main body of FIG. 2;

FIG. 5 is a perspective view showing another modification of the antenna body of FIG. 2;

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

FIG. 7 is a perspective view of a conventional antenna device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10, 30 Antenna device 11 Conductor 12 Power supply electrode 13 Antenna main body 14 Chassis 15 High-frequency circuit part 17, 31 Ground electrode 19 Mounting substrate 21 Base

Claims (3)

[Claims] 1. A base made of at least one of a dielectric ceramic and a magnetic ceramic, at least one conductor formed on at least one of the inside and the surface of the base, and a conductor formed on a surface of the base, An antenna body including a power supply electrode for applying a voltage,
A high-frequency circuit portion that is covered with a metal chassis and that is connected to a power supply electrode of the antenna body, and a mounting board on which the antenna body and the high-frequency circuit portion are mounted and a ground electrode is formed on the surface thereof Wherein the radiating means of the antenna main body is constituted by at least the ground electrode. 2. The antenna device according to claim 1, wherein the ground electrode is formed in a linear shape. 3. The radiating means includes: the ground electrode;
3. The antenna device according to claim 1, further comprising a chassis of the high-frequency circuit connected to the ground electrode.