JPH0818329A - Production of small-sized antenna - Google Patents

Abstract

PURPOSE:To obtain the production for small-sized antenna suitable for mass production. CONSTITUTION:Conductors 12a and 12b are formed on the upper face and the lower face of a dielectric ceramic substrate 11 which has such shape that plural, for example, 16 smallsized antennas can be obtained. Thereafter, this dielectric ceramic substrate 11 is cut into plural, for example, 16 parts (as shown in a figure D).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a small antenna suitable for use in mobile communications such as mobile phones and GPS (satellite positioning system).

[0002]

2. Description of the Related Art Recently, as a mobile communication device such as a mobile phone and a GPS device is downsized, an antenna is downsized, and a dielectric ceramic substrate having a high dielectric constant (εr ≧ 10) is used as shown in FIG. Such a small antenna has been proposed.

To explain this FIG. 3, in FIG. 3, 1 is (Mg _1-X Ca _X ) TiO ₃ (X = 0.05)
A dielectric ceramic substrate having a relative dielectric constant of 20 is obtained by press-molding powder having a composition and firing at 1350 ° C. The dielectric ceramic substrate 1 has a shape of vertical a × horizontal b × thickness t of, for example, 12.5 mm × It is 12.5 mm × 6 mm.

The upper surface and the lower surface of the dielectric ceramic substrate 1 are formed with the upper surface conductor 2a and the lower surface conductor 2b by a conductor such as Cu, and the side surface conductor 3 which short-circuits the upper surface conductor 2a and the lower surface conductor 2b is formed. is there.

When using this small antenna, FIG.
As shown in, the lower surface conductor 2b of the small antenna is placed on the metal chassis 4 of the mobile phone, for example, and is used as a reception-only antenna. In this case, this small antenna constitutes a microstrip inverted F antenna.

In such a small antenna, as shown in FIG. 3, the vertical length is a, the horizontal length is b, the relative permittivity of this dielectric ceramic substrate 1 is εr, and the wavelength of the received radio wave is λ. When The relationship is established and, for example, a radio wave of 800 MHz is 12.5
It can be received by a small antenna having a size of mm × 12.5 mm × 6 mm.

[0007]

Conventionally, when a small antenna as shown in FIG. 3 is manufactured, as shown in FIG.
A dielectric ceramic substrate is formed from a ceramic material, and the dielectric ceramic substrate has a predetermined shape, for example, 12.5 mm.
After grinding and cutting to × 12.5 mm × 6 mm, the upper surface conductor 2a, the lower surface conductor 2b, and the side surface conductor 3 are formed by screen-printing a conductor paste and baking it. In the manufacturing method, since the upper surface conductor 2a, the lower surface conductor 2b, and the side surface conductor 3 are formed one by one, it takes time and labor, and there is a disadvantage that it is not suitable for mass production. In view of this point, the present invention proposes a manufacturing method suitable for mass production.

[0008]

A method of manufacturing a small antenna according to the present invention is, for example, as shown in FIG. 1, a dielectric ceramic substrate 1 having a shape capable of obtaining a plurality of small antennas, for example, 16 small antennas.
1. Conductors 12a and 12b are formed on the upper surface and the lower surface of 1, and then a plurality of dielectric ceramic substrates 11 are formed, for example, 16
It is designed to be cut into individual pieces (FIG. 1D).

The method of manufacturing the small antenna of the present invention is, for example, as shown in FIG. 1, in the method of manufacturing the small antenna described above, the dielectric ceramics are used to form the conductors 12a and 12b on the upper surface and the lower surface of the dielectric ceramic substrate 11. The conductor paste 13 is printed on the upper and lower surfaces of the substrate 11 and baked.

The method for manufacturing a small antenna of the present invention is the same as the method for manufacturing a small antenna described above, in which the conductors 12 are formed on the upper surface and the lower surface of the dielectric ceramic substrate 11 by plating.

[0011]

According to the present invention, the upper surface conductor 1 is formed on the dielectric ceramic substrate 11 from which a plurality of, for example, 16 small antennas can be obtained.
Since the dielectric ceramic substrate 11 is cut into a plurality of, for example, 16 pieces after forming the lower surface conductors 2a and the lower surface conductors 12b, a plurality of, for example, 16 pieces of the upper surface conductors 2a and the lower surface conductors 2 are formed.
b can be formed simultaneously and a small antenna can be manufactured with high productivity.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a method for manufacturing a small antenna according to the present invention will be described below with reference to FIGS. First, as shown in FIG. 1A, a dielectric ceramic substrate 11 having a shape capable of obtaining 16 small antennas is prepared.

This dielectric ceramic substrate 11 is a dielectric
As a ceramic material, for example (Mg _1-XCa_X) TiO
₃The composition of (X = 0.05) is used. This is Hara
MgO (magnesium oxide), CaCO₃(Charcoal
Calcium acid), TiO₂Weigh powder (titanium oxide)
Then, after mixing with a ball mill for 15 hours, 100 in the air
It is calcined at 0 ° C and crushed again in a ball mill for 15 hours.
As a binder, PVA (polyvinyl alcohol)
1) in an amount of 1350% by weight, and then granulated and molded in air 1350
Create a dielectric ceramic substrate by firing at ℃
It The dielectric constant of the dielectric ceramic substrate of this example is 20.
is there.

Next, the dielectric ceramic substrate is made to have a predetermined size, for example, a small antenna having a size of 12.5 mm × 12.5 mm.
When the size is 6 mm, for example, the size of 16 pieces is 55 mm 5
The dielectric ceramic substrate 11 shown in FIG. 1A is obtained by grinding to a size of 5 mm × 6 mm. The size of the shape of the dielectric ceramic substrate 11 is determined by the wavelength λ of the radio wave used and the dielectric constant εr of the dielectric ceramic substrate used.

Next, as shown in FIG. 1B, a conductor paste 13 is applied by printing on the upper and lower surfaces of this dielectric ceramic substrate 11. In this case, as the conductor paste 13, for example, NP-4501 manufactured by Noritake Co., Ltd.
Alternatively, H-9154 silver paste manufactured by Shoei Chemical Industry is used. As the conductor paste, Pt in addition to Ag,
A conductor paste made of Pd, Cu or a mixture thereof can be used.

After the conductor paste 13 is applied, it is dried at a predetermined temperature of 120 ° C to 200 ° C. Then, in an air atmosphere, it is baked at a temperature of 800 ° C. to 900 ° C. for 10 to 15 minutes, and this conductor paste is silver conductor 1 having a thickness of 40 μm
2a and 12b, and silver conductors 12a and 12b are formed on the upper and lower surfaces of the dielectric ceramic substrate 11 as shown in FIG. 1C.

Next, the dielectric ceramic substrate 11 as shown in FIG. 1C is cut into 16 pieces using a diamond grindstone. In this case, by using a multi-grinding machine, a large number of cuts can be made at the same time. The size of one piece after cutting at this time is 12.5 mm × 12.5 mm × 6 mm.

Thereafter, the blocks cut into 16 pieces are erected as shown in FIG. 1E, and a conductor paste is applied by screen printing to a portion corresponding to the side conductor 3. In this case, it is possible to print and coat a plurality of blocks at the same time by arranging a plurality of blocks upright.

The printed and applied conductor paste is heat-treated and baked to form the short-circuit side conductors 3 to obtain a small antenna.

According to this example, since the upper surface conductors 12a and the lower surface conductors 12b are formed on the conductor ceramic substrate 11 from which 16 small antennas can be obtained, this dielectric ceramic substrate 11 is cut into 16 pieces. 16 upper surface conductors 2a and lower surface conductors 2b can be formed at the same time, and there is an advantage that a small antenna can be manufactured with high productivity.

In the above-mentioned example, since the conductor paste 13 is applied by printing on the entire upper surface and lower surface of the dielectric ceramic substrate 11 from which 16 small antennas can be obtained, there is no defect due to printing misalignment, and the upper and lower conductors 2a. Since the dimensional accuracy of 2 and 2b is determined by the cutting processing accuracy of the dielectric ceramic substrate, there is an advantage that dimensional control becomes easy.

In the above embodiment, the conductor paste 13 is formed by printing and baking to form the conductors 12a and 12b on the upper surface and the lower surface of the dielectric ceramic substrate 11.
Instead, the conductors 12a and 1
2b may be formed. An example of the electroless copper plating step which is this plating step will be described below.

First, as shown in FIG. 1A, the dielectric ceramic substrate 11 having the shape of 16 small antennas is subjected to alkaline degreasing using Ascreen A-220 (manufactured by Okuno Chemical Industries Co., Ltd.) and then washed with water. .

Next, hydrofluoric acid 40 is used to make the surface of the dielectric ceramic substrate 11 uneven in order to increase the adhesion.
%, 60% nitric acid mixed solution is used for etching, followed by washing with water.

Next, the solution was pre-dipped using a solution of hydrochloric acid 35%, and then a mixture of OPC80 Catalyst (manufactured by Okuno Chemical Industry Co., Ltd.) and a solution of hydrochloric acid 35% was used to perform catalyzing for attaching palladium to the surface. To do. After this catalyzing, it is washed with water.

Next, an accelerator X was added to a solution of sulfuric acid 97%.
Acceleration is performed in order to activate the catalyst using a mixture of (Okuno Pharmaceutical Co., Ltd.). After accelerating, wash with water.

Next, as an electroless plating solution for copper, OPC copper T (manufactured by Okuno Chemical Industries Co., Ltd.) is used to perform electroless plating of copper. This copper is plated with a predetermined thickness, for example 20 μm, and then washed with water.

Next, anticorrosion treatment is performed using a glycoat, and then heat treatment is performed in an N ₂ atmosphere at 300 ° C. for 10 minutes to perform dielectric ceramic substrate 11 and conductors 12a and 1a.
The adhesion with the copper plating film which is 2b is increased. As the plating, Cu, Ag, Ni, or Au plating can be used.

In the above-mentioned embodiment, the example in which the dielectric ceramic substrate 11 capable of obtaining 16 small antennas is used is described. However, other dielectric ceramic substrates capable of obtaining a plurality of small antennas may be used. It is easy to understand that in this case as well, the same effects as the above can be obtained.

Further, the present invention is not limited to the above-mentioned embodiments, and it goes without saying that various other configurations can be adopted without departing from the gist of the present invention.

[0031]

According to the present invention, the upper surface conductor 12a and the lower surface conductor 12b are formed on the dielectric ceramic substrate 11 from which a plurality of small antennas can be obtained, and then the dielectric ceramic substrate 11 is cut into a plurality of pieces. Therefore, there is an advantage that a plurality of upper surface conductors 12a and lower surface conductors 12b can be simultaneously formed and a small antenna can be manufactured with high productivity.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of a method for manufacturing a small antenna of the present invention.

FIG. 2 is a diagram used for explaining a method for manufacturing a small antenna of the present invention.

FIG. 3 is a perspective view showing an example of a small antenna.

FIG. 4 is a diagram used for explaining an example of a conventional method for manufacturing a small antenna.

[Explanation of symbols]

 1, 11 Dielectric ceramic substrate 2a, 2b, 3, 12a, 12b Conductor 13 Conductor paste

Claims (3)

[Claims] 1. A conductor is formed on an upper surface and a lower surface of a dielectric ceramic substrate having a shape capable of obtaining a plurality of small antennas,
After that, the dielectric ceramic substrate is cut into a plurality of pieces, which is a method for manufacturing a small antenna. 2. The method for manufacturing a small antenna according to claim 1, wherein a conductor paste is printed on the upper and lower surfaces of the dielectric ceramic substrate to form conductors on the upper and lower surfaces of the dielectric ceramic substrate, and then baked. A method for manufacturing a small antenna characterized by the above. 3. The method for manufacturing a small antenna according to claim 1, wherein conductors are formed on the upper surface and the lower surface of the dielectric ceramic substrate by plating.