JPH11205025A - Chip antenna - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a chip antenna the center frequency of which is not affected by the shape of a grounding electrode irrespective of the type of radio equipment the antenna may be mouthed on. SOLUTION: This chip antenna 10 is provided with a rectangular- parallelopiped substrate 11, a conductor 12 spirally wound in the longitudinal direction of the substrate 11, and a grounding electrode mutually opposite to the conductor 12, both of which are mounted inside of the substrate 11, and a power feeding terminal 14 one end of the conductor 12 is connected to for applying voltage to the conductor and a grounding terminal 15 to be connected to the electrode 13, both of which are mounted on the surface of the substrate 11. Since this chip antenna 10 is provided with a grounding electrode formed at least on one of the inside and surface of the substrate 11, capacitance components generated between the conductor 12 and the electrode 13 can maintained constant by fixing a distance between the conductor 12 and the electrode 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art Conventionally, monopole antennas and loop antennas have been used for radio equipment such as portable telephone terminals and pagers. And with the miniaturization of wireless devices,
Although miniaturization of antennas is required, monopole antennas and loop antennas require a radiating conductor having a length of 1/4 of the wavelength used. There was a problem that it could not respond to.

In order to solve this problem, the present applicant has proposed a chip antenna as shown in FIG. 9 in Japanese Patent Application Laid-Open No. 8-316725. The chip antenna 50 is
A rectangular parallelepiped base 51 made of a dielectric ceramic containing barium oxide, aluminum oxide and silica as main components is provided. A spirally wound conductor 52 is formed inside the base 51, and a surface of the base 51 is formed on the surface of the base 51. A power supply terminal 53 for applying a voltage to the conductor 52 is formed. And conductor 5
2 is pulled out to the surface of the base 51, and the power supply terminal 53
Connected to. The other end of the conductor 52 forms a free end 54 inside the base 51.

[0004]

However, in the above-described conventional chip antenna, a capacitance component is generated between the chip antenna and the ground of a wireless device on which the chip antenna is mounted.
Since the capacitance component changes depending on the shape of the ground of the wireless device, a shift occurs in the center frequency of the chip antenna.
Therefore, there is a problem that the center frequency of the chip antenna differs depending on the wireless device to be mounted.

The present invention has been made to solve such a problem, and provides a chip antenna in which the center frequency is not affected by the ground shape of the wireless device when mounted on any wireless device. The purpose is to do.

[0006]

In order to solve the above-mentioned problems, a chip antenna according to the present invention comprises: a base made of at least one of dielectric ceramics and magnetic ceramics; a conductor formed inside the base; A power supply terminal formed on the surface of the base and connected to one end of the conductor, and a ground electrode formed on at least one of the inside and the surface of the base.

[0007] Further, the semiconductor device is characterized in that a conductor land is formed on at least one of the inside and the surface of the base, and the other end of the conductor is connected to the conductor land.

According to the chip antenna of the present invention, since the ground electrode is provided on at least one of the inside and the surface of the base, the distance between the conductor and the ground electrode is maintained by keeping the distance between the conductor and the ground electrode constant. It is possible to keep the capacitance component generated between them constant.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 show a perspective perspective view and an exploded perspective view of a first embodiment of a chip antenna according to the present invention. The chip antenna 10 includes a rectangular parallelepiped base 11,
A conductor 12 spirally wound in the longitudinal direction of the base 11 and a ground electrode 1 facing the conductor 12 are provided inside the base 11.
3 and a power supply terminal 14 connected to one end of the conductor 12 to apply a voltage to the conductor 12 and a ground terminal 15 connected to the ground electrode 13 on the surface of the base 11.

The base 11 is made of a first to fifth rectangular sheet layers 16a made of a dielectric material (relative permittivity: about 6.1) containing barium oxide, aluminum oxide and silica as main components.
To 16e. Of these, the first sheet layer 1
A substantially rectangular ground pattern 17 made of copper or a copper alloy is provided on the surface of 6a by printing, vapor deposition, bonding, or plating.

Further, the third and fourth sheet layers 16c, 1
On the surface of 6d, conductive patterns 18a to 18h made of copper or a copper alloy and formed in a substantially L-shape or linear shape are provided by printing, vapor deposition, bonding, or plating. Further, via holes 19 are provided at predetermined positions (both ends of the conductive patterns 18e to 18g and one end of the conductive pattern 18h) of the fourth sheet layer 16d in the thickness direction.

The first to fifth sheet layers 16a to 16a-1
6e, the conductive patterns 18a to 18h are connected by via holes 19, and then sintered to form a rectangular cross section inside the base 11 and spirally wound in the longitudinal direction of the base 11. The conductor 12 to be formed and the ground electrode 13 facing the conductor 12 are formed.

Note that one end of the conductor 12 (the conductive pattern 18)
a) is drawn out to the surface of the base 11 and the conductor 12
Is connected to a power supply terminal 14 provided on the surface of the base 11 in order to apply a voltage to the substrate 11. On the other hand, the other end of the conductor 12 (the other end of the conductive pattern 18 h) forms a free end 12 a inside the base 11.

A part of the ground electrode 13 is drawn out to the surface of the base 11, and a ground terminal 15 provided on the surface of the base 11 to be connected to the ground electrode 13.
Connected to.

FIG. 3 shows an equivalent circuit of the chip antenna 10. The chip antenna 10 includes an inductance component L and a resistance component R of the conductor 12, the conductor 12 and the ground electrode 1.
3 constitutes an inverted L-shaped antenna composed of a capacitance component C generated between the antenna and the antenna element 3.

FIG. 4 is a perspective view showing a modification of the chip antenna 10 of FIG. The chip antenna 100 includes a rectangular parallelepiped base 11, a conductor 12 spirally wound in the longitudinal direction of the base 11, a ground electrode 13 facing the conductor 12, and a via hole 101 in the base 12.
And a power supply terminal 14 connected to one end of the conductor 12 for applying a voltage to the conductor 12 on the surface of the base 11, and a capacitance electrode 102 for generating a capacitance between the ground electrode 13 and the power supply terminal 14. And a ground terminal 15 connected to the ground electrode 13.

At this time, as shown in an equivalent circuit of FIG. 5, the chip antenna 100 includes an inductance component L and a resistance component R of the conductor 12, a gap between the conductor 12 and the ground electrode 13, and a gap between the capacitance electrode 101 and the ground electrode. 13
And an inverted L-shaped antenna composed of a combined capacitance component CC generated between the two components.

FIG. 6 shows a perspective view of another modification of the chip antenna 10 of FIG. The chip antenna 110 is
A rectangular parallelepiped base 11, a conductor 12 spirally wound in the longitudinal direction of the base 11, inside the base 11, a ground electrode 13 facing the conductor 12, and provided between the conductor 12 and the ground electrode 13. Inductance conductor 111,
On the surface of the base 11, a power supply terminal 14 to which one end of the conductor 12 is connected to apply a voltage to the conductor 12 and a ground terminal 15 to be connected to the ground electrode 13 are provided.

At this time, the chip antenna 110 includes an inductance component L and a resistance component R of the conductor 12, a capacitance component C generated between the conductor 12 and the ground electrode 13, as shown in an equivalent circuit of FIG. Inductance conductor 111
And an inductance component LL of the inverted F type.

As described above, according to the chip antenna of the first embodiment, since the ground electrode is provided inside the base and opposed to the conductor, the distance between the conductor and the ground electrode is kept constant. Thereby, the capacitance component generated between the conductor and the ground electrode can be kept constant. That is, the capacitance component generated between the conductor and the ground electrode is
It is constant regardless of the shape and position of the ground of the wireless device equipped with the chip antenna.

Therefore, if the center frequency is set to a desired value at the stage of the chip antenna, the center frequency does not shift even if the chip antenna is mounted on any wireless device.
There is no need to adjust the center frequency after mounting on the wireless device, and the manufacturing process of the wireless device is simplified.

FIG. 8 is a perspective view showing a chip antenna according to a second embodiment of the present invention. Chip antenna 20
Is different from the chip antenna 10 of the first embodiment in that the other end of the conductor 12 is not a free end but is connected to a conductor land 21 formed inside the base 11.
The conductive land 21 is formed by printing or vapor deposition on the surface of the fourth sheet layer 16d instead of the conductive pattern 18h of the fourth sheet layer 16d in FIG. 2, for example. The equivalent circuit of the chip antenna 20 is the same as that of the chip antenna 10 (FIG. 3).

As described above, according to the chip antenna of the second embodiment, since the conductor land is formed inside the base and the other end of the conductor is connected, the conductor land is trimmed. The capacitance component generated between the conductor land and the conductor can be changed, and as a result, the center frequency of the chip antenna can be easily adjusted.

In the first and second embodiments described above,
Although the case where the ground electrode and the conductor land are formed inside the base has been described, the same effects can be obtained even if they are formed on the surface of the base.

Also, the case has been described where the substrate is made of a dielectric material containing barium oxide, aluminum oxide, and silica as main components. However, the substrate is not limited to this dielectric material, but may be titanium oxide, neodymium oxide, or the like. A similar effect can be obtained by using a dielectric material mainly containing, a magnetic material mainly containing nickel, cobalt, and iron, or a combination of a dielectric material and a magnetic material.

Further, the case where the number of conductors is one has been described. However, a plurality of conductors may be provided, each of which is arranged in parallel. In this case, it is possible to have a plurality of resonance frequencies according to the number of conductors, so that one chip antenna or one antenna body can support multiband.

Although the case where the conductor is wound inside the base in the longitudinal direction of the base has been described, the conductor may be wound in the height direction of the base or meander in the longitudinal or height direction. The same effect can be obtained even if the conductor is formed in a shape, and the shape of the conductor is not limited to the embodiment.

Further, in the case of the second embodiment,
It is possible to apply to the chip antenna (inverted L-type antenna) of FIG. 4 and the chip antenna (inverted F-type antenna) of FIG. 6 shown in the first embodiment.

[0029]

According to the first aspect of the present invention, since the ground electrode formed inside the base is provided, the distance between the conductor and the ground electrode is kept constant by maintaining the distance between the conductor and the ground electrode constant. The generated capacitance component can be kept constant. That is, the capacitance component generated between the conductor and the ground electrode becomes constant without depending on the shape and position of the ground of the wireless device on which the chip antenna is mounted.

Therefore, if the center frequency is set to a desired value at the stage of the chip antenna, the center frequency does not shift even if the chip antenna is mounted on any wireless device.
There is no need to adjust the center frequency after mounting on the wireless device, and the manufacturing process of the wireless device is simplified.

According to the chip antenna of the second aspect, since the conductor antenna is formed inside the base and has the conductor land to which the other end of the conductor is connected, the conductor land is trimmed, so that the conductor land and the conductor are separated. The capacitance component generated between them can be changed, and as a result, the center frequency of the chip antenna can be easily adjusted.

[Brief description of the drawings]

FIG. 1 is a perspective view of a first embodiment of a chip antenna according to the present invention.

FIG. 2 is an exploded perspective view of the chip antenna of FIG.

FIG. 3 is a diagram showing an equivalent circuit of the chip antenna of FIG. 1;

FIG. 4 is a perspective view showing a modification of the chip antenna of FIG. 1;

FIG. 5 is a diagram showing an equivalent circuit of the chip antenna of FIG. 4;

FIG. 6 is a perspective view showing another modification of the chip antenna of FIG. 1;

FIG. 7 is a diagram showing an equivalent circuit of the chip antenna of FIG. 6;

FIG. 8 is a perspective view of a chip antenna according to a second embodiment of the present invention.

FIG. 9 is a diagram showing a conventional chip antenna.

[Explanation of symbols]

 10, 20 Chip antenna 11 Base 12 Conductor 13 Ground electrode 14 Power supply terminal 21 Conductor land

Claims (2)

[Claims] 1. A base comprising at least one of a dielectric ceramic and a magnetic ceramic, a conductor formed inside the base, and a power supply formed on a surface of the base and connected to one end of the conductor. A chip antenna comprising: a terminal for use; and a ground electrode formed on at least one of the inside and the surface of the base. 2. The chip antenna according to claim 1, further comprising a conductor land formed on at least one of the inside and the surface of the base and connected to the other end of the conductor.