KR19990009996A - Dielectric filter and manufacturing method thereof - Google Patents

Abstract

The present invention relates to a dielectric filter and a method of manufacturing the same, and more particularly, in the method of manufacturing a dielectric filter for use in the construction of an RF stage circuit of a communication device, the shape of the interdigital capacitor 30 or the cap capacitor 32. When forming the dielectric resonator 10, the electrode 40 is formed by using silver or copper after forming the sintered dielectric resonator 10 after forming into an uneven shape, and then the input / output capacitors 17 and 19 are formed by chemical etching. And a method for manufacturing a dielectric filter, wherein the dielectric filter is manufactured by polishing a required surface, and the input terminal 12 and the output terminal 14 are formed outside the dielectric resonator 10. 10) to provide a dielectric filter characterized in that the shape of the interdigital capacitor 30 or the cap capacitor 32 is formed in an uneven form, reducing the manufacturing cost, excellent filter characteristics and variable Possible dielectric filter and to a method of manufacturing the same.

Description

Dielectric filter and manufacturing method thereof

The present invention relates to a dielectric filter and a method of manufacturing the same, and more particularly, to form an interdigital capacitor or a cap capacitor when forming a dielectric resonator made of ceramic material using a metal mold. The present invention relates to a dielectric filter and a method of manufacturing the same, which reduce manufacturing cost, have excellent filter characteristics, and can be manufactured by molding and sintering an accommodating part and a conductor line into which a chip capacitor is to be inserted or molded by using a metal mold.

The dielectric filter is a filter used when constructing an RF stage circuit of a communication device. In particular, a dielectric filter is used to move a cordless telephone, a cellular telephone, a global positioning system, a personal communication service, and the like. Used for communication.

The dielectric filter is generally grounded between a series of input capacitors 17, coupling capacitors 18, and output capacitors 19 connected to output terminals 14, generally connected to input terminals 12, as shown in FIG. It is configured by connecting a dielectric resonator 10 of ceramic material.

In such a dielectric filter, it is very important that the characteristics and economics of the dielectric filter depend on how the coupling capacitor 18 is formed.

Conventionally, a coupling capacitor 18 is formed by using a dielectric substrate or by attaching a polymer on an input / output pin.

Recently, in response to the miniaturization of telephones and the surface mounting of components, caseless type filters, which are small in size and low in cost, have become mainstream, and input / output capacitors have been formed in the resonator itself.

The conventional dielectric filter will be described in detail with reference to FIGS. 2A to 2F as follows.

2A to 2F are internal structural diagrams of a conventional dielectric filter.

FIG. 2A illustrates that a coupling capacitor 18 is formed on a dielectric substrate 20 such as epoxy or aluminum, and then the dielectric resonator 10 is combined to fix the dielectric resonator 10 and the coupling capacitor 18 with a metal case 16. will be.

FIG. 2B illustrates a coupling hole 24 serving as a coupling capacitor 18 using the shape of the dielectric coated terminal 22 and the dielectric resonator 10 coated with a dielectric material, and then coupled to each other using an inductance M, followed by a dielectric resonator ( 10) and the coupling holes 24 are fixed as the metal case 16.

The dielectric filter of FIGS. 2A and 2B has a disadvantage in that the size of the dielectric filter has to be increased due to the metal case 16.

Therefore, in recent years, in order to reduce the size of the dielectric filter and reduce the cost, a dielectric filter having no type of metal case 16 has been manufactured.

2C shows a recently developed dielectric filter in which the input and output terminals 12 and 14 are formed in the dielectric resonator 10 itself, and the coupling capacitor 18 between the input and output terminals 12 and 14 is connected to the dielectric resonator 10. It is possible to reduce the size and cost of the dielectric filter by forming using the

The method of forming the coupling capacitor 18 between the input and output terminals 12 and 14 when fabricating the dielectric filter, that is, the method of forming the coupling between the input and output terminals 12 and 14 is illustrated in FIG. 2D. A method of forming mutual inductance M and a parasitic capacitor with the coupling electrode 26 from which some electrodes 40 in the dielectric resonator 10 are removed, or by modifying the upper shape of the dielectric resonator 10 as shown in FIG. As the coupling capacitor 18 used, only the mutual inductance M is used, or as shown in FIG. 2F, the coupling electrodes 26 are formed on the dielectric resonators 10 and 10a, respectively, and then bonded.

The method of forming the coupling capacitor 18 when manufacturing the dielectric filter of the type shown in FIG. 2C becomes an important factor influencing the characteristics and economics of the dielectric filter.

The method of forming the coupling capacitor 18 when manufacturing the dielectric filter of the type shown in FIG. 2D becomes an important factor influencing the characteristics and economics of the dielectric filter.

When the coupling electrode 26 is formed by processing the inside of the dielectric resonator 10 as illustrated in FIG. 2d, the filter characteristics may be improved by using mutual inductance M and a parasitic capacitor, but the dielectric resonator 10 of ceramic material may be used during the manufacturing process. ) Because the inside should be finely processed using a diamond tip or the like, the manufacturing cost is increased and may cause fine breakage of the dielectric resonator 10.

In the case of Fig. 2E, by using only mutual inductance M, in a miniaturized form, characteristics such as asymmetrical bandwidth, insertion loss, etc. of the filter characteristics are reduced.

In the case of FIG. 2F, the filter characteristics are excellent, but the manufacturing cost of the dielectric resonators 10 and 10a is caused by the process of attaching the respective dielectric resonators 10 and 10a. There was a problem that the thermal durability and mechanical strength due to the coupling between 10a) falls.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object thereof is to provide excellent filter characteristics by using mutual inductance M and a parasitic capacitor as a coupling element of a coupling capacitor, thereby reducing manufacturing process and reducing manufacturing costs. In addition, the chip capacitor can be mounted on the dielectric resonator itself to provide structural stability. Also, the interdigital capacitor or the cap capacitor can be adjusted to change the dielectric characteristics and filter specifications of the dielectric resonator. The present invention provides a dielectric filter capable of using a mold and a method of manufacturing the same.

In order to achieve the above object, the present invention provides a method of manufacturing a dielectric filter, an interdigital capacitor or a cap. After the formation of the capacitor in the form of unevenness when forming the dielectric resonator, the sintered dielectric resonator is formed of electrodes using silver or copper, and then the input and output capacitors are formed by chemical nicking and polished the required surface. To provide a method for producing a dielectric filter.

In order to achieve the above object, the present invention provides a dielectric filter in which an input terminal and an output terminal are formed outside the dielectric resonator, wherein the dielectric resonator has a shape of an interdigital capacitor or a cap capacitor in an uneven shape. We want to provide a filter.

1 is a circuit diagram of a dielectric filter,

2A to 2F are internal structural diagrams of a conventional dielectric filter,

3A, 3B are a perspective view and a line A-A cross sectional view of a dielectric filter according to the present invention;

3c is a perspective view according to an embodiment of the present invention,

4A and 4B are perspective and partial front views of a dielectric filter in accordance with another embodiment of the present invention.

Explanation of symbols for main parts of the drawings

10, 10a: dielectric resonator 12: input terminal

14 output terminal 16 metal case

17: input capacitor 18: coupling capacitor

19: output capacitor 20: substrate

22 dielectric covering terminal 24 coupling hole

26: bonding electrode 28: junction

30: interdigital capacitor 32: cap capacitor

34: chip capacitor 36: conductor track

38: receiving portion 40: electrode

Hereinafter, the present invention will be described with reference to the accompanying drawings, FIGS. 3A to 4B. Referring to FIG.

3A and 3B are a perspective view and a line AA cross-sectional view of a dielectric filter according to the present invention, and FIG. 3C is a perspective view according to an embodiment of the present invention, and 4A and 4B are perspective views of a dielectric filter according to another embodiment of the present invention. And some front views.

First, when the present invention looks at the basic configuration, in the dielectric filter manufacturing method, the shape of the interdigital capacitor 30 or the cap capacitor 32 is formed into a concave-convex shape when forming the dielectric resonator 10 and then sintered dielectric resonator 10 ) And the electrode 40 is formed by using silver or copper, and then the input / output capacitors 17 and 19 are formed by chemical etching and are manufactured by polishing the necessary surface.

In detail, the coupling capacitor 18 is used as the interdigital capacitor 30 or the cap capacitor 32, and the shape of the interdigital capacitor 30 or the cap capacitor 32 is formed in a metal mold. After the surface is manufactured in the form of unevenness, the dielectric resonator 10 is formed and sintered using the metal mold.

Then, the shape of the interdigital capacitor 30 or the cap capacitor 32 is formed in the uneven shape on one surface of the dielectric resonator 10.

After the sintered dielectric resonator 10 is formed of silver or copper, the electrodes 40 are formed, and then the input / output capacitors 17 and 19 are formed by conventional chemical etching, and the necessary surfaces are polished. do.

For example, one side is polished to form a λ / 4 dielectric filter.

The dielectric filter is completed by adjusting the resonant frequency and coupling capacitor 18 according to the amount of polishing during polishing.

In addition, when the difference in the dielectric properties and shrinkage of the dielectric resonator 10 varies depending on the manufacturing process, the resonant frequency and the coupling capacitor 18 are changed so that the fine adjustment of the coupling capacitor 18 is prepared in case that the specification of the dielectric filter is not satisfied. To make this possible the shape of the unevenness as shown in Figure 3b

By manufacturing in a shape, the desired filter characteristics can be obtained by adjusting the distance between the electrodes 40 according to the polishing length.

The dielectric chiller manufactured by the above-described method exhibits better filter characteristics than the case of the filter using only the mutual inductance M by using the mutual capacitance M and the parasitic capacitor according to the shape of the dielectric resonator 10 as coupling elements.

By manufacturing the coupling capacitor 18 to obtain excellent filter characteristics in the molding process, it is possible to obtain an economical benefit from processing the dielectric resonator 10 after sintering, and to adjust the frequency by adjusting the dielectric resonator 10 to the uneven shape. Since the desired capacitor can be obtained only by polishing, the manufacturing process can be reduced rather than polishing the required surface of the conventional dielectric resonator, printing the electrode, and then sintering to obtain the desired capacitor.

In addition, the shape of the irregularities when forming the electrode 40 By the shape, the interdigital capacitor 30 or the cap capacitor 32 can be adjusted according to the polishing amount, so that the same metal mold or the same mold can be used even when the dielectric characteristics of the dielectric resonator 10 and the size of the filter are changed. It is.

The dielectric filter manufactured by the above-described process is a dielectric filter in which the input terminal 12 and the output terminal 14 are formed outside the dielectric resonator 10, wherein the interdigital capacitor 30 or the cap is connected to the dielectric resonator 10. The shape of the capacitor 32 is characterized in that formed in the uneven shape.

At this time, the unevenness is It is preferable that the filter characteristics to be obtained by adjusting the distance between the electrodes 40 in accordance with the polishing length should be made in the shape.

In another embodiment of the present invention, the conductive resonator 10 formed in the shape of the concave-convex shape of the conductor line 36 having the accommodating part 38 in the dielectric resonator 10 is copper plated, and the accommodating part 34 is a polymer. I / O capacitors 17 and 19 are formed by chemical nicking in the state in which the electrode 40 is not formed by using the metal chip, and the chip capacitor 34 and the conductor line which are mounted on the receiving portion 38 after polishing necessary surfaces are polished. A dielectric filter may be manufactured by joining (36).

In detail, the coupling capacitor 18 is used as the chip capacitor 34, and the accommodating part 38 and the conductor line 36 on which the chip capacitor 34 is to be seated are manufactured in a concave-convex shape on one side of the metal mold. After molding, the dielectric resonator 10 of ceramic material is molded and sintered.

The sintered dielectric resonator 10 is copper-plated, but the accommodating part 38 on which the chip capacitor 34 is to be seated does not form the electrode 40 using a polymer.

The input and output capacitors 17 and 19 are formed by ordinary chemical etching, and the necessary surface is polished.

For example, one side may be polished to form a λ / 4 dielectric filter.

In the polishing, the resonance frequency is adjusted according to the polishing amount, and the dielectric filter is completed by combining the chip capacitor 34 and the conductor line 36 seated on the receiving portion 38 using solder.

In the dielectric filter manufactured by the above-described method, the receiving portion 38 and the conductor line 36 on which the chip capacitor 34 is mounted are formed in the dielectric resonator 10 and the chip capacitor 34 and the conductor line ( 36) is bonded.

This can provide structural stability by forming an accommodating part 38 for mounting the chip capacitor 34 in the dielectric resonator 10 itself, and the coupling between the chip capacitor 34 and the dielectric resonator 10 has a concave-convex shape. The conductor line 36 eliminates the need for the metal terminal pin for coupling between the chip capacitor 34 and the dielectric resonator 10, thereby simplifying the manufacturing process and reducing the manufacturing cost.

As described above, the present invention uses the mutual inductance M and the parasitic capacitor as the coupling element of the coupling capacitor, and thus has excellent filter characteristics and can reduce the manufacturing process, thereby reducing the manufacturing cost and installing the chip capacitor on the dielectric resonator itself. It is possible to achieve structural stability as well as to control the interdigital capacitor or the cap capacitor, which is a useful invention that can use the same metal mold even when the dielectric characteristics and filter specifications of the dielectric resonator are changed.

Claims (5)

In the dielectric filter manufacturing method, After forming the shape of the interdigital capacitor 30 or the tab capacitor 32 into the uneven shape when forming the dielectric resonator 10, the sintered dielectric resonator 10 is formed of silver or copper to form the electrode 40. And the input / output capacitors (17, 19) are formed by chemical etching and manufactured by polishing the required surface. The method of claim 1, wherein the dielectric resonator (10) and the receiving portion 38 and the conductor line 36 in the form of concave-convex shape and sintered dielectric resonator (10) is copper plated, but the receiving portion (34) is a plymer In the state in which the electrode 40 is not formed, the input / output capacitors 17 and 19 are formed by chemical etching, and the necessary surface is polished, and then the chip capacitor 34 and the conductor line mounted on the receiving portion 38 are formed. A method for producing a dielectric filter, characterized in that it is produced by bonding (36). In the dielectric filter in which the input terminal 12 and the output terminal 14 are formed outside the dielectric resonator 10, Dielectric filter, characterized in that the shape of the interdigital capacitor (30) or the cap capacitor (32) is formed in the irregular shape in the dielectric resonator (10). The method of claim 3, wherein the irregularities Dielectric filter, characterized in that formed in the shape. 4. The conductor part 36 and the conductor line 36 on which the chip capacitor 34 is seated are formed in the dielectric resonator 10 itself, and the chip capacitor 34 and the conductor line 36 are bonded to each other. Dielectric filter characterized in that.