KR101016745B1 - Method for fabricating resonator of high frequency filter and resonator - Google Patents

Abstract

PURPOSE: A high frequency resonator manufacturing method and a resonance thereof are provided to offer a communication system of high reliability by having small frequency deviation of a resonator according to the temperature variation. CONSTITUTION: The metal base and the carbon group powder are prepared in the step(S10, S20). The metal base and the carbon group power are dry mixed and shattered in the step(S30). The base metal is formed by heat-melting and cooling the mixed powder in the step(S40). The base material is cut in the resonator in the step(S50).

Description

Method for fabricating resonator of high frequency filter and resonator

The present invention relates to a resonator for a high frequency filter, and more particularly, has a low coefficient of thermal expansion and high electrical conductivity, so that the frequency shift of the resonator according to the temperature change of the high frequency (microwave) filter is small and the processing is also easy. It relates to a manufacturing method and a resonator.

A filter is a device for passing only a signal of a specific frequency band among input frequency signals, and has been implemented in various forms. A base station of a mobile communication system generally includes a cavity filter for filtering high frequency signals, and the cavity filter is a filter having a structure in which a resonator is provided in a plurality of cavities. As the resonator used in such a cavity filter, a dielectric resonator or a metal rod is used.

Here, the parameters for determining the quality of the resonator can be largely divided into Q (quality coefficient), ε r (relative dielectric constant), τ i (resonant frequency temperature coefficient), and the like.

The cavity filter is composed of a housing forming an inner space, an upper and lower cover, a resonator, and a tuning bolt. In addition, each of these components is plated with a low resistance material (eg, silver) to minimize signal loss. In the case of such a small resistor, the effect of temperature when applied to an electric circuit can be considered fatal to the characteristics of the dielectric resonator. In particular, when the variation of the resonance frequency fo is brought about by the influence of temperature, the insertion loss and the frequency characteristic of the filter may be changed, which may cause oscillation frequency variation of the oscillator.

On the other hand, the material of the metal resonator and filter is mainly used aluminum, brass, pure copper and iron to match the temperature characteristics. However, the coefficient of thermal expansion of these materials is relatively large to be applied to the filter, so the frequency shifts with temperature. Therefore, Invar (alloy of Ni and iron) having a very small coefficient of thermal expansion is used for the manufacture of filters having a high standard. However, Invar is difficult to machine due to its high strength, and the price is relatively expensive compared to conventional materials such as aluminum, brass, pure copper and iron.

The thermal expansion coefficients of aluminum, pure copper, and iron are as shown in [Table 1].

material Thermal expansion coefficient (ppm / ℃) aluminum 23.9 Pure copper 17 iron 11.7

On the other hand, in the case of a resonator using a dielectric in the metal cavity, the dielectric resonator has a relatively low temperature due to the temperature difference between the dielectric resonator and the metal frame when the temperature changes abruptly. In this case, moisture tends to form on the surface of the dielectric resonator, and when moisture forms, the quality factor Q of the dielectric resonator drops significantly and a change in the resonance frequency fo occurs. Therefore, there is a problem in that the performance of the filter using the actual dielectric resonator is significantly reduced.

On the other hand, Korean Patent Laid-Open No. 1999-0074403 discloses a dielectric resonator having a low loss low dielectric constant dielectric Teflon, polyethylene, and polystyrene shielding film on the surface of the dielectric resonator main body to prevent characteristics deterioration due to temperature and humidity. It completely removes moisture, but adds a resonator manufacturing process.

In addition, Korean Patent Publication No. 10-2005-0077232 shows that by replacing each metal resonator with a ceramic filter, it is possible to improve the temperature characteristics of the metal cavity filter, and to reduce the weight. However, in the case of a filter composed of a ceramic resonator, the characteristics deteriorate when the temperature is increased, and when the voltage applied to the dielectric is changed, the dielectric constant value is changed to change the resonance frequency.

In addition, Utility Model Registration No. 20-0417739 proposes a filter for preventing frequency shift due to temperature change by providing a bimetal and a short circuit means at a predetermined position of the housing or cover to suppress the shift of resonance frequency due to temperature change. Since additional parts are required, there is a problem of increasing manufacturing cost and time.

Accordingly, the present invention is to solve all the disadvantages and problems of the prior art as described above, the present invention has a low coefficient of thermal expansion and high electrical conductivity has a low frequency shift of the resonator according to the temperature change of the high frequency (microwave) filter It is also an object of the present invention to provide a resonator method of manufacturing a resonator for a high frequency filter that is easy to process.

In order to achieve the above object, the present invention comprises the steps of preparing a metal base and a carbon-based powder; Dry mixing and pulverizing the metal base and the carbon-based powder to form a mixed powder; Heating and melting the mixed powder to form a base material of the resonator for a high frequency filter; Cutting the base material into a predetermined resonator shape; And metal-plating the surface of the cut resonator to complete the high frequency filter resonator.

Here, the metal base is at least one metal of aluminum (Al), iron (Fe), copper (Cu), and silver (Ag) having a particle size of about 0.3 to 10um, and the carbon-based powder has a particle size of about 0.1 to 5um. It is preferable that it is graphite or carbon powder which has a.

The metal base and the carbon-based powder are preferably 20 to 80% by weight of the metal base and 20 to 80% by weight of the carbon-based powder.

In addition, to achieve the above object, the present invention comprises the steps of preparing a metal base and carbon-based powder and carbon fiber; Dry mixing and pulverizing the metal base, carbon-based powder, and carbon fiber to form a mixed powder; Heating and melting the mixed powder to form a base material of the resonator for a high frequency filter; Cutting the base material into a predetermined resonator shape; And forming a metal plate on the cut surface of the resonator to complete the high frequency filter resonator.

Here, the metal base is at least one metal of aluminum (Al), iron (Fe), copper (Cu), and silver (Ag) having a particle size of about 0.3 to 10um, and the carbon-based powder has a particle size of about 0.1 to 5um. It is preferably a graphite or carbon powder having a carbon fiber of at least one of 0.5 to 5mm carbon fiber, single-walled carbon nanotubes and multi-walled carbon nanotubes.

The metal base, the carbon-based powder, and the carbon fiber are preferably 20-90 wt% of the metal base, and 10-80 wt% of the carbon-based powder and the carbon fiber.

Meanwhile, the step of forming the base material of the high frequency filter resonator by heating and melting the mixed powder and then cooling it is performed using HP (Hot Press) at 10 ^-1 to 10 ^-3 torr in a vacuum or inert gas atmosphere at 200 to 300 kg / cm It is preferable to carry out heat treatment at a pressure of ² .

In addition, the step of heating and melting the mixed powder to form the base material of the resonator for a high frequency filter may include heat treatment at a temperature of 500 to 600 ° C. for 0.5 to 1 hour when aluminum is used as the metal base, and iron as the metal base. In the 1100 to 1300 ℃ temperature is preferably 0.5 to 1 hour heat treatment.

In addition, the present invention, in order to achieve the above object, the metal base of any one of aluminum (Al), iron (Fe), copper (Cu) and silver (Ag) having a particle size of 0.3 to 10um; And at least one carbon-based powder of graphite or carbon powder having a particle size of 0.1 to 5 μm.

On the other hand, the present invention in order to achieve the above object is any one or more of the metal base of aluminum (Al), iron (Fe), copper (Cu) and silver (Ag) having a particle size of 0.3 to 10um; Carbon-based powder of any one or more of graphite or carbon powder having a particle size of 0.1 to 5um; And 0.5 to 5 mm of carbon fiber, single-wall carbon nanotubes and multi-walled carbon nanotubes of at least one carbon fiber; and provides a resonator for a high frequency filter.

Here, the thermal expansion coefficient of the resonator for high frequency filter is preferably 4.5 ppm / ^o C or less, and the bending strength is preferably 10 MPa or more.

The present invention has the following effects.

First, the frequency shift of the resonator according to the temperature change of the high frequency (microwave) filter is small, thereby minimizing the insertion loss or the change in the frequency characteristic, thereby providing a reliable communication system.

Second, as a resonator element for a high frequency filter, a metal element that is easy to process and a composite material in which graphite powder or fibers are uniformly dispersed may be easily processed, and a resonator for a high frequency filter using a low cost element may be provided.

1 is a flowchart illustrating a method of manufacturing a resonator for a high frequency filter according to a first embodiment of the present invention;
2 is a flowchart illustrating a method of manufacturing a resonator for a high frequency filter according to a second embodiment of the present invention;
3 is a scanning electron microscope (SEM) photograph of a resonator for a high frequency filter according to the present invention.

Hereinafter, with reference to the accompanying drawings, the present invention will be described in detail through a preferred embodiment.

In addition, the terminology used in the present invention was selected as a general term that is widely used at present, but in certain cases, the term is arbitrarily selected by the applicant, and in this case, since the meaning is described in detail in the corresponding part of the present invention, a simple term It is to be understood that the present invention is to be understood as a meaning of terms rather than names. In addition, in describing the embodiments, descriptions of technical contents which are well known in the technical field to which the present invention belongs and are not directly related to the present invention will be omitted. This is to more clearly communicate without obscure the subject matter of the present invention by omitting unnecessary description.

1 is a flowchart for explaining a method of manufacturing a resonator for a high frequency filter according to a first embodiment of the present invention. In the method of manufacturing the resonator for a high frequency filter according to the first embodiment of the present invention, as shown in FIG. 1, a metal base and a carbon-based powder are prepared (S10) (S20). Here, the metal base is prepared from one or more metals of aluminum (Al), iron (Fe), copper (Cu), and silver (Ag) having a particle size of about 0.3 to 10 μm. As the carbon-based powder, graphite or carbon powder having a particle size of about 0.1 to 5 μm is prepared. At this time, when the content of the metal base and the carbon-based powder is 100, the content of the carbon-based powder is 20wt% to 80wt%.

Subsequently, the metal base and the carbon-based powder are dry mixed and ground for about 1 hour in a ball mill (grinding) to obtain a uniform mixed powder (S30).

Then, these mixed powders are melted by heating at a pressure of 200 to 300 kg / cm ^{2 in} a vacuum of 10 ^-1 to 10 ^-3 torr using HP (Hot Press), and then cooled to form a resonator for a high frequency filter (S40). . At this time, in the first embodiment of the present invention, when aluminum is used as the metal base, it is heated and melted at 500 to 600 ° C., and when the iron is used as the metal base, it is heated and molten at about 1100 to 1300 ° C. for about 0.5 to 1 hour.

Next, the base material is cut into a predetermined resonator shape (S50). At this time, not only the resonator for high frequency filters but also a housing shape, a cavity shape, a cover shape, etc. can be processed.

Subsequently, metal plating is performed on the cut resonator surface to complete the high frequency filter resonator (S60). In this case, the metal is preferably plated with a material having high electrical conductivity, for example, silver (Ag).

2 is a flowchart for explaining a method of manufacturing a high frequency filter resonator according to a second embodiment of the present invention. In the method of manufacturing the resonator for a high frequency filter according to the second embodiment of the present invention, as shown in FIG. 2, a metal base, carbon powder, and carbon fiber are prepared (S110) (S120) and S130. Here, as the metal base, at least one metal of aluminum (Al), iron (Fe), copper (Cu), and silver (Ag) having a particle size of about 0.3 to 10 μm is prepared. And as a carbon-based powder, graphite or carbon powder having a particle size of about 0.1 to 5um is prepared. In addition, as the carbon fiber is prepared one or more of 0.5 to 5mm carbon fiber, single-walled carbon nanotubes and multi-walled carbon nanotubes. At this time, when the content of the metal base and the carbon-based powder and carbon fiber is 100, the content of the carbon-based powder and carbon fiber is 10 to 80wt%.

Subsequently, the metal base, carbon-based powder, and carbon fiber are dry mixed and ground for about 1 hour in a ball mill (grinding) to obtain a uniform mixed powder (S140).

Then, these mixed powders are melted by heating at a pressure of 200 to 300 kg / cm ^{2 in} a vacuum of 10 ^-1 to 10 ^-3 torr using HP (Hot Press) and cooled to form a base material of the high frequency filter resonator (S150). ). In the second embodiment of the present invention, in the case of using iron as a metal base, it is heated and melted at 500 to 600 ° C., and in the case of iron, it is heated and melted at a temperature of 1100 to 1300 ° C. for about 0.5 to 1 hour to form the base material of the high frequency filter resonator. It can manufacture. At this time, the thermal expansion coefficient of the base material of the resonator is 4.5 ppm / ^o C or less, it is preferable that the bending strength is 10 MPa or more.

Next, the resonator base material is cut into a predetermined shape (S160). At this time, not only the resonator for high frequency filters but also a housing shape, a cavity shape, a cover shape, etc. can be processed.

Subsequently, the surface of the processed resonator is plated with metal (S170). In this case, the metal is preferably plated with a material having high electrical conductivity, for example, silver (Ag).

On the other hand, the thermal expansion coefficient and the bending strength in the case of using aluminum as a metal base, using graphite as a carbon-based powder, and selectively adding carbon fiber to constitute the composition are shown in Table 2 below.

sample black smoke
Content (wt%) aluminum
Content (wt%) Carbon fiber
Content (wt%) Sintering Temperature
(℃) Coefficient of thermal expansion
(ppm / ℃) Bending strength
(MPa) One 20 80 0 600 18.4 25 2 30 70 0 600 17.6 45 3 40 60 0 600 17.3 60 4 40 60 0 550 19.6 24 5 40 60 0 500 20.0 12 6 50 50 0 600 12.1 64 7 60 40 0 600 11.2 65 8 50 40 10 600 10.5 76 9 80 20 0 600 9.3 112 10 70 20 10 600 8.4 124

In addition, the coefficient of thermal expansion and the bending strength in the case of using iron as a metal base, graphite as a carbon-based powder, and selectively adding carbon fiber to form a composition are shown in Table 3 below.

sample black smoke
Content (wt%) iron
Content (wt%) Carbon fiber
Content (wt%) Sintering Temperature
(℃) Coefficient of thermal expansion
(ppm / ℃) Bending strength
(MPa) One 40 60 0 1100 8.9 287 2 50 50 0 1100 7.6 151 3 60 40 0 1100 6.4 77 4 70 30 0 1100 5.5 35 5 60 30 10 1100 4.8 39 6 80 20 0 1100 4.9 12 7 80 20 0 1200 4.4 15 8 80 20 0 1300 4.1 17 9 70 20 10 1100 3.9 19

On the other hand, the coefficient of thermal expansion of the composition consisting of the composite material shown in Table 2 and Table 3 measured the specimen of width * length * height = 5 * 5 * 25mm from room temperature to 200 ℃ using a dilatometer One case. In addition, the bending strength is the result of measuring the specimen of width * length * height = 5 * 5 * 12.5mm using an Instron equipment. In particular, looking at the results in Table 3, it can be seen that excellent results in the coefficient of thermal expansion compared to aluminum, pure copper and iron materials as shown in Table 1. At this time, the thermal expansion coefficient is low, the more, the bending strength is high, more so to maintain the resonator characteristics are designed to suppress the frequency deviation due to temperature changes, and as much as possible the thermal expansion coefficient is 4.5ppm / ^o C or less, the bending strength is 10MPa or greater using the composition It is desirable to form a resonant element.

In addition, in forming the composite material, it may be treated in an inert gas atmosphere as well as in a vacuum state. At this time, when the heat treatment in a vacuum or inert gas atmosphere can be obtained a relatively high sintered density compared to the non-vacuum state, it is advantageous for the low thermal expansion coefficient.

3 is a scanning electron microscope (SEM) photograph of a resonator for a high frequency filter according to the present invention. The resonator device for a high frequency filter of the present invention is a surface SEM photograph of a composite material in which graphite and aluminum are mixed in a weight ratio of 50: 50, respectively, indicating that graphite 10 and aluminum 20 are formed.

As described above, the present invention has been described as a preferred embodiment, which is intended to help the understanding of the present invention but is not intended to limit the technical scope thereto. Therefore, those skilled in the art to which the present invention pertains that various modifications and variations are possible without departing from the technical spirit of the present invention.

10: graphite 20: aluminum

Claims (11)

Preparing a metal base and a carbon-based powder, respectively;
Dry mixing and pulverizing the metal base and the carbon-based powder to form a mixed powder;
Forming a base material of the resonator for a high frequency filter by heating and melting the mixed powder;
Cutting the base material into a predetermined resonator shape; And
Metal plating a surface of the cut resonator to complete a high frequency filter resonator; Method of manufacturing a resonator for a high frequency filter comprising a. The method of claim 1,
The metal base is at least one metal of aluminum (Al), iron (Fe), copper (Cu) and silver (Ag) having a particle size of 0.3 to 10um,
The carbon-based powder is a graphite or carbon powder having a particle size of 0.1 to 5um of manufacturing method for a high frequency filter resonator, characterized in that. The method of claim 1,
The metal base and the carbon-based powder,
20 to 80% by weight of the metal base and 20 to 80% by weight of the carbon-based powder. Preparing a metal base, carbon-based powder, and carbon fiber, respectively;
Dry mixing and pulverizing the metal base, carbon-based powder, and carbon fiber to form a mixed powder;
Forming a base material of the resonator for a high frequency filter by heating and melting the mixed powder;
Cutting the base material into a predetermined resonator shape; And
And metal-plating the cut resonator surface to complete the high frequency filter resonator. The method of claim 4, wherein
The metal base is at least one metal of aluminum (Al), iron (Fe), copper (Cu) and silver (Ag) having a particle size of 0.3 to 10um,
The carbon-based powder is graphite or carbon powder having a particle size of 0.1 to 5um,
The carbon fiber is a method of manufacturing a resonator for a high frequency filter, characterized in that at least one of 0.5 to 5mm carbon fiber, single-walled carbon nanotubes and multi-walled carbon nanotubes. delete The method according to claim 1 or 4,
Forming the base material of the resonator for high frequency filter by heating and melting the mixed powder after cooling,
A method of manufacturing a resonator for a high frequency filter using HP (Hot Press) for heating and melting at a pressure of 200 to 300kg / cm ² in a vacuum or inert gas atmosphere 10 ^-1 to 10 ^-3 torr. The method according to claim 1 or 4,
Forming the base material of the resonator for high frequency filter by heating and melting the mixed powder after cooling,
In case of using aluminum as the metal base, heat treatment is performed at 500 to 600 ° C. for 0.5 to 1 hour, and when iron is used as the metal base, heating and melting is performed at 1100 to 1300 ° C. for 0.5 to 1 hour. Manufacturing method. A metal base of at least one of aluminum (Al), iron (Fe), copper (Cu), and silver (Ag) having a particle size of 0.3 to 10 μm; And
Resonator for high frequency filters, characterized in that consisting of; carbon-based powder of any one or more of graphite or carbon powder having a particle size of 0.1 to 5um. At least one metal base of aluminum (Al), iron (Fe), copper (Cu), and silver (Ag) having a particle size of 0.3 to 10 μm;
Carbon-based powder of any one or more of graphite or carbon powder having a particle size of 0.1 to 5um; And
Resonator for high frequency filters, characterized in that consisting of; carbon fiber of 0.5 to 5mm, at least one carbon fiber of single-walled carbon nanotubes and multi-walled carbon nanotubes. The method of claim 9 or 10,
The thermal expansion coefficient of the high frequency filter resonator is 4.5ppm / ^o C or less, the bending strength is characterized in that 10MPa or more.

Images