JP2004186730A - Chip antenna, chip antenna unit, and wireless communication apparatus using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a chip antenna in which a predetermined patten antenna among a plurality of pattern antennas can have an arbitrarily set resonant frequency. <P>SOLUTION: The chip antenna 10 has a structure having the plurality of pattern antennas A1, A2 which are formed on a plurality of layers of a base 11 of a stacked structure and in which at least one part of the patterns are not overlapped with each other in a stacked direction, and a feeding terminal 12 which is formed on the surface of the base 11 and is connected to the pattern antennas A1, A2. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a chip antenna used as a built-in antenna of a mobile phone or a mobile terminal as a wireless communication device.
[0002]
[Prior art]
As a chip antenna used for a mobile terminal such as a mobile phone, a small chip antenna for diversity reception that can be used in a plurality of frequency bands is disclosed in JP-A-11-31913. Japanese Patent Application Laid-Open No. 2002-111344 discloses a technique for obtaining two resonances with a chip antenna and a pattern antenna formed on a substrate.
[0003]
[Patent Document 1]
JP-A-11-31913 [Patent Document 2]
JP-A-2002-111344
[Problems to be solved by the invention]
According to the technique described in Japanese Patent Application Laid-Open No. 11-31913, two resonances can be obtained, but the structure becomes complicated and the antenna efficiency is deteriorated due to the resistance of the trap circuit. Further, according to the technique described in Japanese Patent Application Laid-Open No. 2002-111344, since an antenna is formed on a substrate using a conductor line pattern, the antenna portion becomes extremely large, which is against the demand for miniaturization.
[0005]
In order to solve such a problem, a chip antenna having a plurality of resonances can be reduced in size with a simple structure by arranging a plurality of pattern antennas in a stacked structure with the antenna element having a stacked structure.
[0006]
However, if the frequency characteristics are adjusted by changing the shape of one pattern antenna, the frequency characteristics of the other pattern antenna also change. This makes it difficult to set an arbitrary resonance frequency.
[0007]
By the way, when the chip antenna is mounted on the mounting board, the frequency characteristics of the antenna may slightly change under the influence of the line pattern or the like.
[0008]
In this case, since the frequency characteristics cannot be finely adjusted with the existing chip antenna, the antenna itself must be replaced. Then, it is necessary to prepare several types of antennas having slightly different frequency characteristics. In this case, productivity is significantly deteriorated.
[0009]
Therefore, an object of the present invention is to provide a chip antenna that can set a predetermined pattern antenna to an arbitrary resonance frequency without affecting the frequency characteristics of the other pattern antenna.
[0010]
Another object of the present invention is to provide a chip antenna capable of easily adjusting frequency characteristics.
[0011]
[Means for Solving the Problems]
In order to solve the above problems, a chip antenna according to the present invention is formed of a dielectric or a magnetic material, and has a base having a laminated structure, and is formed in a plurality of layers of the base, and at least a part of a pattern is formed in a stack direction. It is characterized by having a plurality of pattern antennas that do not overlap each other and a feed terminal formed on the surface of the base and connected to the pattern antenna.
[0012]
Since the patterns do not overlap with each other in the stacking direction, it is possible to set a predetermined pattern antenna to an arbitrary resonance frequency without affecting the frequency characteristics of the other pattern antenna.
[0013]
In order to solve the above problems, a chip antenna unit according to the present invention includes a mounting substrate, a base mounted on the mounting substrate, and formed of a dielectric or magnetic material, and a pattern antenna formed on the base. A power supply terminal formed on the surface of the base and connected to the pattern antenna; a fixed terminal formed on the surface of the base and connected to the pattern antenna; and a fixed terminal formed on the mounting board and connected to the fixed terminal to mount the base on the mounting board. And a fixing portion made of a conductor to be fixed.
[0014]
According to this, since the resonance frequency can be finely adjusted by adjusting the area of the fixed portion, the frequency characteristics can be easily adjusted.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described more specifically with reference to the drawings. Here, in the attached drawings, the same members are denoted by the same reference numerals, and duplicate description is omitted. The embodiment of the present invention is a particularly useful embodiment in which the present invention is implemented, and the present invention is not limited to the embodiment.
[0016]
FIG. 1 is a perspective view showing a chip antenna unit according to an embodiment of the present invention, FIG. 2 is an exploded perspective view showing a chip antenna in the chip antenna unit in FIG. 1, and FIG. 3 is a chip antenna in the chip antenna unit in FIG. FIG. 4 is a graph showing the frequency characteristics of the VSWR when the area of the fixed portion of the chip antenna unit of FIG. 1 is large or small.
[0017]
As shown in FIGS. 1, 2, and 3, a chip antenna 10 of the present embodiment has a rectangular base having a laminated structure formed of a high-frequency ceramic dielectric material having a relative permittivity εr of about 10, for example. 11 is provided. Note that the base 11 may be made of a magnetic material.
[0018]
A pattern antenna is formed on a plurality of layers of the base 11, and in the illustrated case, a pattern antenna A1 having a meandering first pattern is provided on the first pattern layer 10a, and a pattern antenna A1 having a meandering first pattern is provided on the second pattern layer 10b. In the figure, pattern antennas A2 each having a meandering second pattern different from the first pattern are formed. In the present embodiment, the pattern antennas A1 and A2 have a meandering pattern. Various patterns, such as a plurality of layers for securing, can be used.
[0019]
A power supply terminal 12 is formed from the bottom surface of the base 11 to the upper surface through one side surface. In addition, fixed terminals 16a and 16b are formed on two opposing side surfaces of the base 11 and adjacent adjacent surfaces. As shown in detail in FIG. 2, the power supply terminal 12 formed on the surface of the base 11 in this manner is provided at one end of the two pattern antennas A1 and A2, the fixed terminal 16a is provided at the other end of the pattern antenna A1, and the fixed terminal 16b is provided. Are connected to the other end of the pattern antenna A2, respectively.
[0020]
As shown in FIG. 1, the chip antenna 10 is mounted on a mounting substrate 13, and the chip antenna 10 and the mounting substrate 13 constitute a chip antenna unit. The mounting substrate 13 includes a ground electrode 14, a power supply line 15 that supplies a signal from a signal source (not shown) to the power supply terminal 12 while matching the impedance of the circuit, for example, 50Ω, and fixed terminals 16 a and 16 b. Fixing portions 17a and 17b, which are connected and fix conductors to fix the base 11 to the mounting board 13, are provided.
[0021]
In the present embodiment, the fixed terminals 16a and 16b and the fixed portions 17a and 17b are respectively formed at two places, but may be formed at one place.
[0022]
The pattern antennas A1 and A2, the power supply terminal 12, the ground electrode 14, the power supply line 15, the fixed terminals 16a and 16b, and the fixed portions 17a and 17b are formed by patterning a metal conductor layer such as copper or silver. Specifically, it is formed by, for example, a method of pattern printing and baking a metal paste such as silver, a method of forming a metal pattern layer by plating, and a method of patterning a thin metal film by etching.
[0023]
Here, as shown in FIG. 2, the pattern antenna A1 having the first pattern and the pattern antenna A2 having the second pattern do not overlap in the stacking direction.
[0024]
That is, in the chip antenna 10 of the present embodiment, the first resonance frequency is obtained by the pattern antenna A1. Further, a second resonance frequency different from the first resonance frequency is obtained by the pattern antenna A2. Therefore, overlapping of the pattern antennas A1 and A2 in the stacking direction is avoided.
[0025]
In this way, even if the frequency characteristics are adjusted by changing the shape of one pattern antenna (for example, pattern antenna A1), the influence on the frequency characteristics of the other pattern antenna (for example, pattern antenna A2) is almost eliminated. Therefore, it is possible to set a predetermined pattern antenna (for example, pattern antenna A1) to an arbitrary resonance frequency without affecting the frequency characteristics of the other pattern antenna (for example, pattern antenna A2).
[0026]
Since the resonance frequencies of the respective pattern antennas are independent of each other, the antenna design is facilitated.
[0027]
Here, the pattern antenna A1 and the pattern antenna A2 inevitably overlap with each other in the portion connected to the power supply terminal 12 and in the vicinity of the portion. Therefore, in this specification, “not overlapping” means that portions other than these portions do not overlap.
[0028]
Although a part of the patterns may overlap, the variation of the frequency characteristics of the other pattern antenna during the adjustment of the resonance frequency of one pattern antenna increases as the ratio of the overlap in the stacking direction increases. I will. Therefore, it is desirable that the portions other than the unavoidable portions described above do not overlap.
[0029]
Further, in the present embodiment, two pattern antennas A1 and A2 that do not overlap each other are shown, but other pattern antennas can be formed. In this case, all the pattern antennas may not overlap, and some pattern antennas may overlap each other. That is, it is sufficient that at least some of the pattern antennas do not overlap each other in the stacking direction.
[0030]
Furthermore, it is sufficient that at least two pattern antennas are formed, that is, a plurality of pattern antennas are formed.
[0031]
When the chip antenna 10 is mounted on the mounting board 13, the frequency characteristics of the antenna may slightly change due to the influence of the pattern of the feed line 8 and other electronic components.
[0032]
In such a case, in the present chip antenna 10, the frequency characteristics are adjusted by changing the area of the fixing portions 17a and 17b when mounting the antenna, that is, by cutting or expanding a part of the fixing portions 17a and 17b. You can do it.
[0033]
That is, as shown in FIG. 4, if the area of the fixing portions 17a and 17b is large, the resonance frequency shifts to the low frequency side, and conversely, if the area is small, the resonance frequency shifts to the high frequency side. Therefore, when the resonance frequency of the chip antenna 10 is lower than a predetermined numerical value in the mounted state, the fixing portions 17a and 17b are cut and shifted to a higher frequency side. On the other hand, when the height is high, the area of the fixing portions 17a and 17b is increased to shift to the low frequency side.
[0034]
As described above, since the resonance frequency can be finely adjusted by adjusting the areas of the fixing portions 17a and 17b, the frequency characteristics can be easily adjusted. Thus, even if the frequency characteristics of the chip antenna 10 mounted on the mounting substrate 13 change, it is not necessary to replace the antenna itself.
[0035]
Since the antenna itself does not need to be replaced, only one type of the chip antenna 10 having a predetermined frequency characteristic is sufficient, and it is necessary to prepare several types of chip antennas having slightly different frequency characteristics. Disappears.
[0036]
In the present embodiment, there are two structures: a structure in which the patterns of a plurality of pattern antennas are not overlapped in the laminating direction, and a structure in which the areas of the fixing portions 17a and 17b are adjusted to finely adjust the resonance frequency. Although they are adopted, they can be adopted independently. When a structure for adjusting the area of the fixing portions 17a and 17b is adopted, even if the pattern antenna is formed on the surface or inside of the base, or on both the surface and inside, that is, the number of pattern antennas is one. And the substrate may not have a laminated structure.
[0037]
The chip antenna of the present invention can be used for various wireless communication devices such as a mobile phone, a mobile terminal, and a built-in antenna of a wireless LAN card.
[0038]
【The invention's effect】
As is clear from the above description, according to the present invention, the following effects can be obtained.
[0039]
That is, since the patterns do not overlap with each other in the stacking direction, it is possible to set a predetermined pattern antenna to an arbitrary resonance frequency without affecting the frequency characteristics of the other pattern antenna.
[0040]
Further, since the resonance frequency can be finely adjusted by adjusting the area of the fixed portion, the frequency characteristics can be easily adjusted.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a chip antenna unit according to an embodiment of the present invention.
FIG. 2 is an exploded perspective view showing a chip antenna in the chip antenna unit of FIG.
FIG. 3 is a plan view showing a chip antenna in the chip antenna unit of FIG. 1;
FIG. 4 is a graph showing VSWR frequency characteristics when the area of a fixed portion of the chip antenna unit of FIG. 1 is large and small.
[Explanation of symbols]
Reference Signs List 10 chip antenna 10a first pattern layer 10b second pattern layer 11 base 12 power supply terminal 13 mounting substrate 14 ground electrode 15 power supply lines 16a, 16b fixed terminals 17a, 17b fixed parts A1, A2 pattern antenna

Claims (4)

A base made of a dielectric or magnetic material and having a laminated structure;
A plurality of pattern antennas formed on a plurality of layers of the base body, at least a part of the pattern does not overlap each other in the stacking direction,
A feed terminal formed on the surface of the base and connected to the pattern antenna. A mounting board,
A substrate mounted on the mounting substrate and formed of a dielectric or magnetic material;
A pattern antenna formed on the base,
A power supply terminal formed on the surface of the base and connected to the pattern antenna;
A fixed terminal formed on the surface of the base and connected to the pattern antenna;
A fixing portion made of a conductor formed on the mounting board and connected to the fixing terminal to fix the base to the mounting board;
A chip antenna unit, wherein a frequency characteristic is adjusted by an area of the fixed portion. A mounting board,
A substrate mounted on the mounting substrate and formed of a dielectric or magnetic material and having a laminated structure,
A plurality of pattern antennas formed on a plurality of layers of the base body, at least a part of the pattern does not overlap each other in the stacking direction,
A power supply terminal formed on the surface of the base and connected to the pattern antenna;
A fixed terminal formed on the surface of the base and connected to the pattern antenna;
A fixing portion made of a conductor formed on the mounting board and connected to the fixing terminal to fix the base to the mounting board;
A chip antenna unit, wherein a frequency characteristic is adjusted by an area of the fixed portion. A wireless communication device using the chip antenna according to claim 1 or the chip antenna unit according to claim 2 or 3.

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