JPH0993033A - Resonance frequency adjusting method for chip antenna - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a frequency adjusting method for chip antenna with which a prescribed resonance frequency is secured. SOLUTION: A chip antenna 10 is formed by providing a conductor 12 helically wound in the lengthwise direction of dielectric substrate 11 inside the parallelopiped dielectric substrate 11. One end of conductor 12 is pulled out onto the surface of dielectric substrate 11 and forms a power feeding terminal 17 connected to a terminal 16 for feeding power for impressing a voltage to the conductor 12, and the other end forms a free terminal 18 inside the dielectric substrate 11. Then, the conductor 12 is cut near the free terminal 18 by a cutting line 19. Thus, since the conductor 12 is trimmed by laser or the like together with the dielectric substrate 11 and the full length of conductor 12 is adjusted, the inductance and electrostatic capacitance of conductor 12 are changed and the resonance frequency of chip antenna 10 is adjusted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a frequency adjustment method for a chip antenna used for mobile communication and local area network (LAN).

[0002]

2. Description of the Related Art FIG. 4 is a sectional view of a conventional chip antenna 50. 51 is an insulator, 52 is a coiled conductor, 5
3 is a magnetic material, and 54a and 54b are external connection terminals.

Next, a method of manufacturing the conventional chip antenna 50 will be described with reference to FIGS. First, as shown in FIG. 5A, an insulating layer 55 having one main surface serving as a mounting surface of the insulator 51 is formed, and a substantially L-shaped conductive pattern 56 having a lead-out end S is formed on the other main surface. Printing is performed on the insulating layer 55, and a magnetic pattern 57 having a high magnetic permeability is printed on the central portion of the insulating layer 51. Then, FIG.
As shown in (b), a substantially U-shaped nonmagnetic insulator layer 58 that covers the right half of the conductive pattern 56 and the right half of the insulator layer 55 (excluding the magnetic material pattern 57 portion) is printed. Next, as shown in FIG. 5C, a substantially L-shaped conductive pattern 59 is printed with one end thereof overlapped with the end of the conductive pattern 56, and the magnetic pattern 60 is also formed on the magnetic pattern 57. Print.

Next, as shown in FIG. 5D, a substantially inverted U-shaped nonmagnetic insulator layer 61 is printed on the left half except for the magnetic material pattern 60. Then, FIG. 5A to FIG.
The step (d) (however, the leading end is not formed) is repeated until a predetermined number of times is reached, and when a predetermined number of windings is obtained, as shown in FIG. 5E, the substantially U-shaped conductive pattern 62 is formed. Is printed with one end thereof overlapping the end of the conductive pattern 59, and the other end is exposed to the end of the non-magnetic insulating layer 61 to form the lead-out end F. In this way, the coil-shaped conductor 52 having the lead-out ends S and F is formed by the conductive patterns 56, 59 and 62.

Finally, as shown in FIG. 5F, the insulating layer 63 is printed on the entire surface, and the stacking is completed. In this way, the insulator 51 is formed by the insulator layers 55, 58, 61 and 63, and the magnetic body 53 is formed by the magnetic patterns 57 and 6.
It is formed by 0. This laminated body is fired at a predetermined temperature and time to form an integrated sintered body, and then the external connection terminals 54a and 54 are attached to the lead-out ends S and F.
The chip antenna 50 is obtained by depositing and baking b.

[0006]

However, the above-mentioned conventional chip antenna is smaller in size than the whip antenna generally used for mobile communication and can be surface-mounted. Was relatively narrow. Therefore, in the manufacturing process, when the resonance frequency moves beyond a predetermined value, the gain of the antenna is significantly reduced, and it is necessary to adjust the resonance frequency to a predetermined value. The adjustment of the resonance frequency, that is, the adjustment amount of the resonance frequency is the inductance and capacitance of the conductor,
That is, it is possible to adjust the total length of the conductor, but it was difficult to easily adjust the resonance frequency because the relationship between the adjustment amount of the resonance frequency and the adjustment amount of the total length of the conductor was not clear.

The present invention has been made to solve such a problem, and an object thereof is to provide a frequency adjusting method for a chip antenna for ensuring a predetermined resonance frequency.

[0008]

In order to solve the above problems, the present invention provides a substrate made of at least one of a dielectric material and a magnetic material, and at least one of the surface and the inside of the substrate. A chip antenna that realizes adjustment of the resonance frequency of a chip antenna including a conductor and at least one power supply terminal for applying a voltage to the conductor, by adjusting the total length of the conductor. Wherein the resonance frequency of the chip antenna is f0, the adjustment amount of the resonance frequency of the chip antenna is Δf, the total length of the conductor is L, and the adjustment amount of the total length of the conductor is ΔL,
The adjustment amount Δf of the resonance frequency is Δf = f0 × (ΔL /
L) is satisfied.

Further, the adjustment amount ΔL of the total length of the conductor is obtained by cutting the conductor.

Thus, according to the frequency adjusting method of the chip antenna of the first aspect, the adjustment amount of the total length of the conductor required for the adjustment amount of the resonance frequency is calculated from Δf = f0 × (ΔL / L).
Easy to find.

According to the frequency adjusting method of the chip antenna of the second aspect, the conductor is trimmed to adjust the total length of the conductor, thereby changing the inductance and the capacitance of the conductor and adjusting the resonance frequency of the chip antenna. can do.

[0012]

1 and 2 are a perspective view and an exploded perspective view of an embodiment of a frequency adjusting method for a chip antenna according to the present invention. The chip antenna 10 is provided with a conductor 12 spirally wound in the longitudinal direction of the dielectric substrate 11 inside a rectangular parallelepiped dielectric substrate 11. Here, the dielectric substrate 11 is a rectangular dielectric made of ceramic such as a mixture containing barium oxide, aluminum oxide or silica as a main component, resin such as Teflon resin, or a mixture of ceramic and resin. The sheets 13a to 13c are laminated. Of these, the dielectric sheets 13b and 13c
On the surface of, the conductive patterns 14a to 14h, which are made of copper or a copper alloy and have a linear shape, are provided by printing, vapor deposition, laminating, or plating, and the dielectric sheets 13b and 13c are formed in the thickness direction. The formed via hole 15 is provided. Then, the dielectric sheets 13a to 13c are laminated to form the conductive patterns 14a to 14h.
Are connected by via holes 15 to form a spirally wound conductor 12 having a rectangular winding cross section.

Further, one end of the conductor 12 (the conductive pattern 14
One end of e is formed on the surface of the dielectric substrate 11 to form a feeding end 17 connected to a feeding terminal 16 for applying a voltage to the conductor 12, and the other end (one end of the conductive pattern 14d) is formed. , The free end 18 is formed inside the dielectric substrate 11.

Then, the vicinity of the free end 18 of the conductor 12 is cut by a cutting line 19. In this way, the conductor 12 is trimmed together with the dielectric substrate 11 by laser or the like,
The resonance frequency of the chip antenna 10 is adjusted by changing the inductance and the capacitance of the conductor 12 by adjusting the total length of the.

Here, the resonance frequency of the chip antenna 10 is f 0, and the adjustment amount of the resonance frequency of the chip antenna 10 is Δ.
f, the total length of the conductor 12 is L and the adjustment amount of the total length of the conductor 12 is ΔL, the calculated value of Δf obtained from Δf = f0 × (ΔL / L) and the Δf obtained from measurement of reflection loss characteristics and the like. Table 1 shows the relationship between the measured values of

[0016]

[Table 1]

From Table 1 above, it can be seen that the calculated value of Δf and the measured value are substantially in agreement.

As a specific example, the shape is 5 mm × 8 mm ×
FIG. 3 shows changes in the resonance frequency of the chip antenna 10 having a dielectric constant of 6.1 on the dielectric substrate 11 of 2.5 mm, depending on whether trimming is performed. FIG. 3 shows the reflection loss characteristics. The solid line is trimmed and the broken line is not trimmed.

From FIG. 3, the resonance frequency of the untrimmed product is 1.887 GHz, whereas the resonance frequency of the trimmed product is 1.915 GHz, which is 28 MHz.
You can see that it is changing.

At this time, in the trimmed product, the conductor 12 having a total length of 44.45 mm is 0.7 mm from the free end 19.
Is cut off. These values are Δf = f0 × (Δ
Substituting for L / L, 1.887 GHz x (0.7 m
m / 44.45 mm) = 29.7 MHz, and the calculated value and the measured value are almost the same.

As described above, in the above embodiment, Δf =
The adjustment amount of the total length of the conductor required for the adjustment amount of the resonance frequency can be easily obtained from f0 × (ΔL / L).

By cutting the conductor and adjusting the total length of the conductor, the inductance and capacitance of the conductor can be changed and the resonance frequency of the chip antenna can be adjusted to a predetermined value.

In the above embodiments, the case where the substrate is made of a dielectric material has been described. However, the substrate is not limited to the dielectric substrate, and a magnetic substrate or a dielectric substrate and a magnetic substrate. A combination of body substrates may be used.

In the above embodiment, the number of conductors is 1.
Although the case of a book has been described, two or more may be formed.

Further, in the above-mentioned embodiment, the case where the conductor is formed inside the substrate has been described, but the conductor may be formed by winding a conductor pattern on at least one of the surface and the inside of the substrate. Alternatively, a spiral groove may be provided on the surface of the substrate, and a wire such as a plated wire or an enameled wire may be wound along the groove to form a conductor. Furthermore, the conductor may be formed in a meandering shape on at least one of the surface and the inside of the base.

Further, in the above-mentioned embodiment, the case where the conductor formed inside the dielectric substrate is cut together with the dielectric substrate has been described, but when the conductor is formed on the surface of the dielectric substrate, Only the conductor needs to be cut.

Further, the position of the power supply terminal is not an essential condition for carrying out the present invention.

[0028]

According to the frequency adjusting method of the first aspect, when the resonance frequency of the chip antenna moves in the manufacturing process, the adjustment amount of the total length of the conductor required for the adjustment amount of the resonance frequency is Δf = f0 × ( It can be easily calculated from ΔL / L). Thereby, it is possible to prevent the gain of the antenna from decreasing.

According to the frequency adjusting method of the second aspect, since the entire length of the conductor is adjusted by cutting, the inductance and the capacitance of the conductor can be changed and the resonance frequency of the chip antenna can be adjusted to a predetermined value. .

[Brief description of drawings]

FIG. 1 is a perspective view of an embodiment of a frequency adjusting method for a chip antenna according to the present invention.

FIG. 2 is an exploded perspective view of FIG.

FIG. 3 is a reflection loss characteristic of FIG.

FIG. 4 is a sectional view of a conventional chip antenna.

5 is a schematic plan view illustrating a method of manufacturing the chip antenna of FIG.

[Explanation of symbols]

 10 chip antenna 11 substrate 12 conductor 16 power supply terminal

Front page continuation (72) Kenji Asakura Inventor Kenji Asakura 2-10-10 Tenjin, Nagaokakyo-shi Kyoto Prefecture Murata Manufacturing Co., Ltd.

Claims (2)

[Claims] 1. A base 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 base, and a voltage applied to the conductor provided on the surface of the base. A resonance frequency adjusting method for a chip antenna, comprising: adjusting the resonance frequency of a chip antenna having at least one feeding terminal for adjusting the resonance frequency of the chip antenna by adjusting the total length of the conductor. f0, Δf is the adjustment amount of the resonance frequency of the chip antenna, L is the total length of the conductor, and ΔL is the adjustment amount of the total length of the conductor, the adjustment amount Δf of the resonance frequency is Δf = f0 × (ΔL / A method for adjusting a resonance frequency of a chip antenna, characterized in that L) is satisfied. 2. The adjustment amount ΔL of the total length of the conductor is obtained by cutting the conductor.
The method for adjusting the resonance frequency of the chip antenna according to [4].