JP2002190703A - Chip antenna and its characteristic adjustment method - Google Patents

Abstract

(57) [Summary] [Problem] While maintaining basic specifications such as external dimensions,
Provided is a chip antenna having a simple structure capable of variably adjusting its antenna characteristics. SOLUTION: An antenna conductor 10 having an antenna element portion 11, an adjustment element portion 13 provided on a side portion of the antenna element portion, a tip end portion of the adjustment element portion protruding outside, and the antenna element portion And a dielectric chip 20 embedded or laminated therein. Then, the antenna characteristics are adjusted by cutting or bending the adjustment element portion protruding from the dielectric chip.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chip antenna having a structure in which an antenna conductor is embedded in a dielectric chip, and a method for adjusting characteristics thereof.

[0002]

2. Related Art Recently, as a small antenna used for a mobile phone, a portable information terminal, a wireless LAN (local area network) device, and the like, an antenna conductor formed of a predetermined conductor plate is used as a dielectric chip. Attention has been paid to a chip antenna having a structure formed on a surface or embedded in a dielectric chip. The antenna conductor in this type of chip antenna is provided with an antenna element composed of a conductor portion meandering, for example,
It has an advantage that its overall shape can be reduced in size as compared with a conventional general whip antenna.

Incidentally, the chip antenna having such a structure is used by being mounted on a printed circuit board or the like together with various chip components such as a semiconductor integrated circuit.

[0004]

The antenna characteristics of the above-described chip antenna, particularly its resonance frequency and frequency band, largely depend on the height position of the antenna conductor when the chip antenna is mounted on a printed circuit board. Incidentally, the height position of the antenna conductor is defined by the thickness of the dielectric positioned on the lower surface side of the antenna conductor in the dielectric chip on which the antenna conductor is formed. I can't deny that. Therefore, when mounting and using a chip antenna on a printed circuit board or the like, it is desirable to be able to adjust the antenna characteristics (resonance frequency or frequency band).

Depending on the specifications of a communication system using this type of chip antenna, a plurality of types of chip antennas having different resonance frequencies may be required. However, in order to realize a plurality of types of chip antennas according to the specifications, generally, the pattern shape of the antenna element itself is changed, or the dielectric constant of the dielectric chip is changed, and further, the dielectric chip is changed. It is necessary to take measures such as changing the thickness of the sheet. As described above, it is very difficult to produce a plurality of types of chip antennas having different antenna specifications in a large variety and in a small amount, which also increases the development and manufacturing costs.

The present invention has been made in view of such circumstances, and its purpose is to maintain the antenna characteristics, particularly the resonance frequency of the antenna element and its frequency band, while keeping the basic specifications such as the external dimensions constant. Is to provide a chip antenna having a simple structure that can be variably adjusted according to specifications. Another object of the present invention is to provide a chip antenna characteristic adjusting method capable of easily and variably adjusting the antenna characteristics of a chip antenna, particularly the resonance frequency of an antenna element and its frequency band according to specifications. is there.

In particular, it is an object of the present invention to provide a method of adjusting the characteristics of a chip antenna which can adjust the antenna characteristics even when the chip antenna is mounted on a printed circuit board or the like.

[0008]

In order to achieve the above-mentioned object, a chip antenna according to the present invention comprises an antenna element, an antenna conductor having an adjusting element provided on a side of the antenna element, and a chip antenna. The antenna element is characterized in that a tip of the adjusting element portion of the antenna conductor projects outside and a dielectric chip in which the antenna element portion is embedded or the antenna element portion is laminated.

Incidentally, the antenna element portion is composed of a conductor portion meandering in a meandering shape, for example, as described in claim 2, and the adjusting element portion is
It is realized as a conductor piece protruding outward from a folded portion of the conductor in the antenna element portion.
In the case where there are a plurality of folded portions of the conductor in the antenna element portion, an adjusting element may be provided in each of the plurality of folded portions of the conductor.

Further, according to the method for adjusting a chip antenna according to the present invention, the antenna characteristic of the antenna element is adjusted by cutting or bending an adjustment element protruding from the dielectric chip in the chip antenna having the above-described structure. It is characterized by: When the antenna specifications for the chip antenna are determined, the cutting or bending of the adjustment element portion may be performed according to a procedure predetermined according to the specifications, or the chip antenna may be mounted on a printed circuit board or the like. With mounted,
For example, the measurement may be performed such that desired antenna characteristics are obtained while measuring the antenna characteristics.

Preferably, the adjusting element section is selectively cut or bent with respect to a plurality of adjusting element sections provided in the chip antenna, whereby resonance of the antenna element section is performed. The frequency and / or frequency band is adjusted.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a chip antenna according to an embodiment of the present invention and a method for adjusting characteristics thereof will be described with reference to the drawings. FIG. 1 is a perspective view showing a schematic configuration of a chip antenna according to this embodiment. This chip antenna basically embeds an antenna conductor 10 having an antenna element portion 11 made of a conductor having a pattern shape meandering in a meandering shape, for example, into a dielectric chip 20 having a substantially rectangular parallelepiped shape. The electrode terminal section 12 connected to the antenna element section 11 is led out from the end of the dielectric chip 20 and has a structure.

The antenna conductor 10 is formed by patterning a conductor plate plated with, for example, a copper alloy, phosphor bronze, or pure copper by punching, etching, or the like. The antenna device has a structure in which a meandering line is formed as an antenna element portion 11, and an electrode terminal portion 12 is formed at an end of the antenna element portion 11.

Specifically, the antenna element 11 of the antenna conductor 10 has a thickness of, for example, 0.12 mm.
Is formed by patterning a conductor plate having a conductor width of 0.2 mm, a meandering width of 3.2 mm, and a meandering pitch of 0.6 mm over five turns. Then, the antenna element portion 11 of the antenna conductor 10 is
The chip antenna having a substantially rectangular parallelepiped shape formed by being embedded in the inside of the antenna has a width of 4 mm, a length of 8 mm, and a thickness of 2.
It is realized as a size of 8 mm.

The feature of the chip antenna according to the present invention is that the antenna conductor 10 is connected to the antenna element 1 as shown in FIG.
1 in that it has an adjusting element portion 13 composed of a conductor piece protruding outwardly, particularly on the folded portion of the conductor. And the dielectric chip 2
Reference numeral 0 denotes a point that the adjustment element 13 has a structure in which the distal end protrudes outward from a side thereof over a predetermined length, and the antenna element 11 is mainly embedded therein.

That is, the chip antenna according to the present invention comprises:
A part of the antenna element portion 11 in the antenna conductor 10 embedded in the dielectric chip 20 is provided as an adjustment element portion 13 connected to the antenna element portion 11, and the adjustment element portion 13 extends outward from the side of the dielectric chip 20. It has a structure protruding and positioned in the external space.

Thus, according to the chip antenna having such a structure, the antenna characteristics are exclusively defined by the antenna element portion 11 which forms the main portion. However, as described above, since the adjustment element unit 13 is provided so as to be continuous with the antenna element unit 11, the presence of the adjustment element unit 13 is also an important factor for determining the antenna characteristics. However, since the adjusting element 13 is positioned in the space protruding from the dielectric chip 20, it can be said that the influence on the antenna characteristics is relatively small.

That is, the antenna characteristics of the chip antenna having the above structure are determined solely by the height of the antenna conductor 10 from the ground plane of the printed circuit board when the chip antenna is mounted on a printed circuit board or the like. . The antenna element 1 in the antenna conductor 10
1 from the ground plane is defined by the height (the thickness of the dielectric positioned below the antenna element 11) defined by the dielectric chip 20, and its antenna characteristics are different from the ground plane. Interposed dielectric chip 20
Is almost determined by the dielectric constant ε of On the other hand, the adjustment element section 13 is basically positioned at the same height as the antenna element section 11, but since there is only an air layer (dielectric constant ε _O ) between the adjustment element section 11 and the ground plane, the antenna The effect on properties is relatively small.

However, the adjusting element 13
Is positioned in the space, so that, for example, it is easy to cut the adjustment element section 13. If the length of the adjustment element section 13 is reduced by cutting, for example, the electrical length of the antenna can be shortened. it can. Also, as shown in FIG. 3, if the adjustment element 13 protruding outside the dielectric chip 20 is bent downward, not only does the height of the adjustment element 13 relative to the ground plane change,
A capacitance (capacitor) C is formed between the adjustment element section 13 and the ground plane, and this capacitance C has a great influence on the antenna characteristics.

When the adjusting element 13 is bent downward and approaches the ground plane, the antenna element 1
1, and the resonance frequency of the antenna element 11 decreases. Conversely, if the adjustment element portion 13 is bent upward to avoid a distance from the ground,
The effect on the antenna element 11 is slightly reduced, and the resonance frequency in the antenna element 11 is slightly increased. In addition, the resonance frequency band of the antenna element 11 also changes with the bending of the adjustment element 13. Therefore, by cutting or bending the adjustment element 13 protruding from the side of the dielectric chip 20, the resonance frequency and the frequency band can be adjusted.

Incidentally, if the length of the adjusting element portion 13 is reduced by cutting the adjusting element portion 13, the capacity formed between the adjusting element portion 13 and the ground plane becomes smaller, and the electrical length of the antenna becomes shorter. Thus, the resonance frequency of the antenna element 11 can be increased. FIG. 4 shows an experimental result showing an example of an antenna characteristic of the chip antenna which changes due to the bending of the adjustment element section 13, that is, an example of a change in the resonance frequency and its frequency band. In this experiment, for example, as shown in a plan view in FIG. 5, one end is provided with an electrode terminal section 12 that is short-circuited and terminated, and an electrode terminal section 12 for power supply, and an adjustment element 13 is provided on the other end. An experimental chip antenna in which the antenna conductor 10 was insert-molded with a dielectric chip 20 was prepared, and the test was performed using the experimental chip antenna.

The antenna element portion 11 of the antenna conductor 10 is basically designed for 2.5 GHz. Then, the antenna conductor 10 is placed on a dielectric chip 20 having a thickness of 2.8 mm and a height of 2.3 m.
Then, an insert chip antenna was manufactured by insert-molding so as to obtain a m. The length of the adjusting element 13 was 3.5 mm.

When the adjustment element 13 of the experimental chip antenna is kept in a horizontal state as shown in FIG. 6 (a), and the tip of the adjustment element 13 with respect to the ground plane as shown in FIG. 6 (b). Antenna frequency characteristics when bent to a height of 0.5 mm and further bent to a height of 0.1 mm with respect to the ground plane as shown in FIG. 6B. Was examined.

As shown by the characteristic a (solid line) in FIG. 4, the antenna characteristic when the adjustment element 13 is kept horizontal (the state shown in FIG. 6A) has a resonance frequency of 2.53 GHz. And its frequency band is 2.45 to 2.6
It was 3 GHz. On the other hand, when the adjusting element 13 is bent to the height position of 0.5 mm (the state shown in FIG. 6B), the characteristic b (broken line) in FIG.
As shown by the symbol, the antenna characteristic is 2.4 at the resonance frequency.
9 GHz, and its frequency band is 2.41 to 2.
It changed to 57 GHz. Further, when the adjusting element 13 is bent to the height position of 0.1 mm (the state shown in FIG. 6C), as shown by the characteristic c (dashed line) in FIG. At 2.45 GHz, and its frequency band is 2.37 GHz.
２2.53 GHz.

As is apparent from the above experimental results, according to the chip antenna of the present invention, the adjusting element portion 13 provided by projecting the antenna conductor 10 to the outside from the insert-molded dielectric chip 20 is bent. This makes it possible to easily change its antenna characteristics, particularly its resonance frequency. It is also apparent that the antenna characteristics (resonance frequency) can be enhanced by cutting the adjustment element portion 13 and changing its length. Therefore, the antenna characteristics of the chip antenna can be easily changed simply by cutting or bending the adjusting element portion 13, and it is possible to easily and effectively adapt to various antenna specifications. .

In this manner, the adjusting element 13
Is cut or bent, the antenna element portion 11, which is the main portion thereof, is embedded in the dielectric chip 20 and is stably held by the dielectric chip 20, so that the antenna element portion 11 is mainly determined by the antenna element portion 11. The basic antenna characteristics themselves do not change. Therefore, the antenna characteristics can be easily and effectively changed only in a range in which the adjustment element section 13 is involved.

As described above, the adjusting element 13
When adjusting the antenna characteristics of the chip antenna by cutting or bending the antenna, for example, for various antenna specifications, configure a chip antenna of an antenna specification serving as a reference, and in advance according to the required antenna specifications The adjustment element 13 of the chip antenna may be cut or bent in accordance with a predetermined procedure so as to realize a chip antenna having antenna specifications satisfying the requirements.

That is, the adjustment element 13 of the chip antenna prepared as a standard product is cut into a predetermined length by using a jig prepared according to the antenna specification, or the adjustment element 13 is obtained in advance. Bend to the right angle,
What is necessary is just to process so that the said antenna specification may be satisfied. Alternatively, after mounting the chip antenna prepared as the standard product on a printed circuit board or the like, adjusting the antenna characteristics so as to meet the specifications while cutting or bending the adjustment element 13 while monitoring the antenna characteristics. Is also possible. In this case, once the adjustment element 13 has been cut, it is difficult to return the adjustment element 13 to its original state. Therefore, after the antenna element is roughly adjusted by cutting the adjustment element 13, the adjustment element 13 is bent. It is desirable to finely adjust the antenna characteristics.

Thus, according to such a method of adjusting a chip antenna, its antenna characteristics can be easily variably set to a desired resonance frequency. Therefore, individual chip antennas are designed according to various antenna specifications. There is no need, and the development and manufacturing costs can be greatly reduced. Moreover, it is possible to adapt the chip antenna prepared as a standard product to various antenna specifications,
It is suitable for the production of chip antennas of various kinds in small quantities.

The present invention can be similarly applied to a chip antenna having a structure in which the antenna conductor 10 is laminated on the surface of a dielectric chip 20 as shown in FIG. Also in this case, the antenna characteristics can be changed by cutting or bending the adjustment element 13 protruding to the side of the dielectric chip 20 in the same manner as in the previous embodiment.

The present invention is not limited to the above embodiment. For example, a plurality of the adjusting element portions 13 are provided, and these adjusting element portions 13 are selectively (partially) cut or bent to adjust the resonance frequency or the frequency band as the antenna characteristic. By configuring the antenna, the adjustment range can be set large, and it is possible to cope with various antenna specifications. Also, here, a chip antenna in which a meandering meandering conductor is formed as the antenna element 11 has been described as an example of the antenna conductor 10, but the same applies to a patch antenna having a flat conductor or a microstrip antenna serving as the antenna element 11. Applicable to

Further, as for the dielectric chip 20, for example, PPS (polyphenylene sulfide) and BaO-
A resin-ceramic composite material in which Nd ₂ O ₃ -TiO ₂ -Bi ₂ O ₃ -based ceramic powder is mixed, or a resin material such as LCP (liquid crystal polymer) may be used as appropriate. The dielectric constant depends on the antenna specifications.
What is necessary is to use the one of [3.1] to [20]. In addition, the present invention can be variously modified and implemented without departing from the gist thereof.

[0033]

As described above, according to the present invention, since the adjusting element part which protrudes outside the dielectric chip in which the antenna conductor is embedded and forms a part of the antenna conductor is provided, this adjusting element is provided. The antenna characteristics can be easily adjusted by cutting or bending the portion. In particular, by cutting or bending the adjustment element according to the required antenna specifications, it can be adapted to the antenna specifications.
Practically great effects such as the production cost can be kept sufficiently low can be obtained.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a schematic configuration of a chip antenna according to an embodiment of the present invention.

FIG. 2 is a schematic plan view of the chip antenna shown in FIG. 1;

FIG. 3 is a diagram for explaining the principle of adjusting the antenna characteristics of the chip antenna shown in FIG. 1 and a method of adjusting the characteristics.

FIG. 4 is a frequency characteristic diagram showing an experimental result showing a change in antenna characteristics due to bending of an adjustment element.

FIG. 5 is a diagram showing a schematic configuration of an antenna chip used in the experiment shown in FIG. 4;

FIG. 6 is a diagram showing an aspect of the experiment shown in FIG. 4;

FIG. 7 is a perspective view showing a schematic configuration of a chip antenna according to another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Antenna conductor 11 Antenna element part 12 Electrode terminal part 13 Adjustment element part 20 Dielectric chip

Claims (4)

[Claims] An antenna conductor including an antenna element portion, an adjustment element portion provided on a side portion of the antenna element portion, and a tip end of the adjustment element portion of the dielectric chip protruding outside, A chip antenna comprising a dielectric chip having an antenna element portion embedded or laminated therein. 2. The antenna element portion is composed of a conductor portion meandering a conductor in a meandering shape, and the adjustment element portion is a conductor piece formed to project outward from a folded portion of the conductor in the antenna element portion. The chip antenna according to claim 1, comprising: 3. The chip antenna according to claim 1, wherein an adjustment element portion protruding from the dielectric chip in the chip antenna according to claim 1 or 2 is cut or bent to adjust antenna characteristics of the antenna element portion. Characteristics adjustment method. 4. The cutting or bending of the adjusting element portion is selectively performed on a plurality of adjusting element portions provided in the chip antenna, and adjusts a resonance frequency and / or a frequency band of the antenna element portion. 4. The method according to claim 3, wherein the characteristic of the chip antenna is adjusted.