JPH09219603A - Dielectric filter and manufacture therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dielectric filter which can be inexpensively and simply manufactured and a manufacturing method therefor. SOLUTION: In this dielectric filter, the main part is composed of a box unit shaped filter case 1 composed of a bottom surface member 10 made of a steel plate and a cover member 20 obtained by performing bending and working a steel plate, and dielectric resonators 3, input side and output side connectors 4 and 6, input side and output side microstrip antennas 5 and 7 and a frequency adjusting machine screw which are mounted, respectively, within this case. Because the filter case obtained by bending a steel plate is applied in place of a conventional filter case obtained by machining a metal body such as duralumin, etc., in this filter, the working cost can be remarkably reduced and dielectric filters can be inexpensively and simply mass-produced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dielectric filter used in microwave and quasi-microwave communication devices and the like, and more particularly to a dielectric filter which is lightweight, inexpensive and easy to manufacture, and a manufacturing method thereof. is there.

[0002]

2. Description of the Related Art A dielectric filter of this type is shown in FIG.
As shown in FIGS. 2 to 13, a metal filter case a such as duralumin, and one or a plurality of pieces which are arranged in a row in the longitudinal direction of the filter case a and which are attached via a supporting portion b ′ made of quartz or the like. Columnar or prismatic dielectric resonator b (in this example, a plurality of dielectric resonators are applied), an input side connector c and an input side antenna attached to the input side of the filter case a. d, an output-side connector e and an output-side antenna f respectively attached to the output side of the filter case a, and a metallic cover g made of duralumin or the like for closing the open part of the filter case a. Things are known.

The dielectric filter has the following functions. That is, the input side connector c
The inputted high frequency wave is transmitted through the input side antenna d to the dielectric resonator b closest to the input side antenna d via the magnetic field, and then sequentially transmitted to the adjacent dielectric resonator b, and finally. A high frequency wave is transmitted to the output side connector e through the output side antenna f. Then, in the frequency corresponding to the resonance frequency of the dielectric resonator b, finally the degree of coupling between the dielectric resonators b (if one dielectric resonator is applied, It is possible to pass only high frequency waves having a bandwidth determined by the characteristics of the body resonator itself). In this case, FIG.
The adjustment of the degree of coupling in the dielectric filter shown in FIG. 13 is performed by fixing the dielectric resonator b to the filter case a and the distance between the filter case a and the dielectric resonator b and the dielectric resonators. After adjusting the interval L1 between them, the adjustment is performed by adjusting the insertion dimension of the coupling degree adjusting screw h provided between the dielectric resonator b and the input-side antenna d and the output-side antenna f. The adjustment is performed by adjusting the protrusion size of the frequency adjusting screw i arranged above or below each dielectric resonator b in the filter case a.

On the other hand, as a dielectric filter capable of adjusting the coupling degree and the frequency without using the coupling degree adjusting screw and the frequency adjusting screw, the dielectrics arranged in the filter case a as shown in FIGS. There is also known a structure in which a conductive rod-shaped body j is provided in a gap between the body resonators b in a direction perpendicular to the direction in which the dielectric resonator b is arranged via a support base j ′. That is, this dielectric filter utilizes that the coupling degree between the dielectric resonators b is adjusted when the conductive rod-shaped body j is inserted into the space placed between the dielectric resonators b. Therefore, if the degree of coupling between the dielectric resonators b is large, the bandwidth of the high-frequency frequency that passes through this filter becomes wide, and conversely, if the degree of coupling between the dielectric resonators b is small, the high frequency that passes through the filter When the conductive rod-shaped body j is lengthened, the bandwidth of the high frequency passing through the filter is widened and the length of the conductive rod-shaped body j is shortened. Then, due to the phenomenon that the bandwidth of the high frequency frequency passing through the filter becomes narrow, the bandwidth of the high frequency frequency passing through the filter is adjusted appropriately.

Further, in place of the cylinder or prism type dielectric resonator, one or a plurality of cylinder type coaxial dielectric resonators (however, in this example, a plurality of) are applied as a dielectric filter. A structure shown in 16 is also known.
In this coaxial type dielectric filter, the amount of insertion when the rod-shaped input side antenna d provided in the input side connector c is inserted into the inner conductor of the coaxial type dielectric resonator b, and the insertion amount is provided in the output side connector e. The insertion amount when inserting the rod-shaped output-side antenna f into the inner conductor of the coaxial dielectric resonator b, and
The coupling degree and frequency can be adjusted by appropriately setting the distance between the coaxial dielectric resonators.

[0006]

By the way, as a filter case a in which one or a plurality of dielectric resonators b and the like are housed in these dielectric filters, a housing having a concave shape formed by cutting is conventionally used. A thick metal body such as duralumin having a portion a ′ was applied (see FIG. 17).

The reason why such a cut metal body is used is that, when the processing accuracy of the inner wall surface of the housing portion a'is not good, the dielectric resonance housed in the inner wall surface of the housing portion a'is accommodated. This is because it was thought that there is a slight variation in the spacing between the vessels, which is likely to adversely affect the degree of coupling and frequency adjustment described above, making it difficult to manufacture a dielectric filter that passes only high frequencies of the required bandwidth. It was

Since nearly half of the manufacturing cost of the dielectric filter is spent on cutting the metal body, there is a problem that the dielectric filter cannot be supplied at a low cost.

Further, when an attempt is made to obtain a small-sized dielectric filter, it becomes difficult to cut the metal body, and one or a plurality of dielectric resonances are provided at a predetermined portion in the small-sized accommodating portion a '. Since it is extremely difficult to install a container or the like, there has been a problem that it is difficult to mass-produce dielectric filters.

Further, since a thick metal body such as duralumin is used as the filter case, there is a problem that the obtained dielectric filter is heavy.

The present invention has been made by paying attention to such problems, and its problems are light weight and low cost.
An object of the present invention is to provide a dielectric filter that can be easily manufactured and a manufacturing method thereof.

Therefore, in order to solve the above problems, the present inventor uses a box body obtained by bending a metal plate in place of the conventional filter case obtained by cutting a metal body, and uses the same dielectric A prototype body filter was examined and its function was investigated, and it was found that the coupling degree and frequency could be sufficiently adjusted contrary to conventional expectations, and it was not sufficient depending on the application field of this type of dielectric filter. It turned out to work. The present invention has been completed based on such knowledge.

[0013]

That is, the invention according to claim 1 provides a dielectric filter which comprises one or a plurality of dielectric resonators in a covered filter case and allows only a predetermined frequency to pass therethrough. As a premise, the filter case covered with the lid is constituted by a box body formed by bending a metal plate.

According to the dielectric filter of the present invention, a box body obtained by bending a metal plate is used instead of the conventional filter case obtained by cutting a metal body. Since it is applied, it is possible to significantly reduce the processing cost of the filter case as compared with the conventional one, so that it has the advantage that this type of dielectric filter can be manufactured at low cost, and a lightweight metal plate is used. By applying it, there is an advantage that the weight of the dielectric filter can be significantly reduced.

In such a technical means, as the metal plate constituting the filter case, any metal can be applied as long as it is a material which is formed into a predetermined shape by an appropriate means such as punching and can be bent. Examples thereof include a steel plate having a thickness of about 8 mm and a steel plate having a surface plated with silver or the like.

Further, the structure of the dielectric filter is also arbitrary, and as shown in FIGS. 12 to 13, a cylindrical or prismatic dielectric resonator is incorporated and a coupling degree adjusting screw and a frequency adjusting screw are provided. Structures and Figures 14 to 1
Any of the structure shown in FIG. 5 provided with a conductive rod-shaped body or the structure shown in FIG. 16 in which a coaxial resonator such as a cylindrical type is incorporated. Further, the number of the above-mentioned dielectric resonators is also arbitrary, and in the dielectric filters of FIGS. 12 and 16 mentioned in the conventional example, one dielectric resonator may be used to configure this. Also, as illustrated in FIG. 16, a dielectric filter may be composed of a plurality of dielectric resonators. Further, the antennas provided on the input side and the output side are also optional, for example, as shown in FIG.
~ A linear or rod-shaped antenna as shown in Fig. 16 may be applied, or a plate-shaped antenna (not shown) may be applied. Further, the microstrip line antenna and the like exemplified in the section of the embodiment of the invention described below may be applied.

Next, when manufacturing the dielectric filter according to the present invention, the metal plate is bent as shown in FIG. 9 and the bottom member 10 having the recess 15 corresponding to the conventional storage portion and the lid member 20 are first formed. Then, the dielectric resonator 3, an antenna such as a microstrip line, and other members are appropriately placed at predetermined positions in the recess 15 of the bottom member 10, and these members are fixed. Thus, by closing the upper surface and both side surfaces of the recess 15 to form a box-shaped filter case, the main part of the dielectric filter can be completed. However, in this filter case, it is necessary to dispose the dielectric resonator 3 and the like in the recess 15 that is a small-sized space that is formed in advance.
Since the arrangement work becomes complicated, the filter case shown in FIGS. 4 and 6 in which the recess side is the lid member is more advantageous. That is, in the filter case shown in FIG. 4, the portion corresponding to the conventional storage portion is formed by the flat bottom member 10, and the recess 21 is provided toward the lid member 20. Therefore, compared to the structure shown in FIG. 9, the work of arranging the dielectric resonator 3 and the like in a narrow space becomes unnecessary, which has an advantage that the arranging work can be simplified. Incidentally, in the filter case shown in FIG. 4, the filter case shown in FIGS.
As shown in, the bottom member 10 and the lid member 20 are composed of separate metal plates. On the other hand, when the filter case member shown in FIG. 6 is used, the bottom member 10 and the lid member 20
Is composed of one metal plate, and like the filter case shown in FIG. 4, the dielectric resonator 3 and the like can be arranged easily and easily.
Since the box body is formed by the bending process once to complete the main part of the dielectric filter, the workability is extremely excellent. The invention according to claim 2 is made for such a technical reason.

That is, the invention according to claim 2 is premised on the method for manufacturing a dielectric filter according to claim 1, and is provided at a predetermined portion of a metal plate before bending, which has a predetermined shape.
One or more dielectric resonators and necessary members are arranged, after fixing these resonators and members, the metal plate is bent into a box shape to manufacture the dielectric filter. To do.

According to the dielectric filter manufacturing method of the present invention, the troublesome process of arranging the dielectric resonator and the like in the recess, which is a narrow space, is simplified, and is performed once. Since the box body is formed by the bending process of (1) and the main part of the dielectric filter can be completed, the workability is excellent, and there is an advantage that the dielectric filter can be mass-produced inexpensively and easily.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

This dielectric filter comprises a box-shaped filter case 1 obtained by bending as shown in FIGS. 1 and 2, and a quartz support stand arranged in the filter case 1 in the longitudinal direction. Two cylindrical dielectric resonators 3 attached via 2, input side connector 4 and input side microstrip antenna 5 attached to the input side of filter case 1, and output side of filter case 1. The output-side connector 6 and the output-side microstrip antenna 7 form a main part, and two frequency adjusting screws are provided on the upper surface of the filter case 1 located above each dielectric resonator 3. 8 are provided.

First, as shown in FIG. 3, the filter case 1 is made of a flat plate-shaped bottom member 10 formed of a steel plate 12 with silver plating 11 on both surfaces, and the same material as the bottom member 10. The bottom member 1 formed by bending
The cover member 20 has a rectangular concave portion 21 that covers the central portion of 0 and is open on the lower side. The bottom member 10 and the lid member 20 are joined to each other via a conductive adhesive (not shown), and the lid member 20 has a rectangular recess 21.
Has an outer diameter of 60 mm × 18.4 mm × 10 mm and an inner diameter of 45 mm × 15 mm × 8 mm.

The cylindrical dielectric resonator 3 mounted in the filter case 1 is made of cylindrical ceramic having a relative permittivity of 80, a diameter of 9.0 mm and a thickness of 4.2 mm.

The input side microstrip antenna 5 and the output side microstrip antenna 7 are shown in FIG.
As shown in FIG. 2, a 0.8 mm-thick fluorine-based glass substrate (having a relative dielectric constant of 2.5) 32 soldered to the bottom surface member 10 via a Cu conductor 31 and a fluorine-based glass substrate 32 are provided. And a rod-shaped input-side connector 4 and an output-side connector 6 are attached to one end of each substantially U-shaped waveguide line 33. .

In this dielectric filter,
Instead of a conventional filter case obtained by cutting duralumin (see FIGS. 10 to 11), a flat plate-shaped bottom member 10 made of a steel plate 12 with silver plating 11 on both sides and the above steel plate are bent. Since the box-shaped filter case composed of the lid member 20 having the rectangular recess 21 obtained by processing is applied, the processing cost is higher than that of the conventional filter case (see FIGS. 10 to 11). The processing cost is about 1/30, and the manufacturing cost can be significantly reduced.
Moreover, the weight of the filter case has been reduced, and the weight of the dielectric filter has been significantly reduced.

Further, in the conventional filter case,
As shown in FIG. 17, a screw hole portion for attaching a metal lid g (see FIG. 11) for closing the open portion of the housing portion a ′ to the filter case having the housing portion a ′ formed by cutting. Since it is necessary to provide p along the opening edge of the accommodating portion a ′, it is necessary to set the widthwise dimension of the filter case to that extent. On the other hand, since the filter case of the dielectric filter according to this embodiment does not have such a need, it has an advantage that the dimension of the dielectric filter in the width direction can be set smaller.

Regarding the characteristics of the dielectric filter according to the present embodiment, the conventional dielectric filter shown in FIGS. 10 to 11 (except for the filter case and the metal lid, is the same as the dielectric filter according to the present embodiment). The same dielectric resonator applied, the input side connector and the input side microstrip antenna, the output side connector and the output side microstrip antenna, and the frequency adjustment screw are mounted). It was possible to obtain almost the same characteristics depending on the adjustment condition.

Here, the bottom member 10 and the rectangular recess 2 are provided.
1 is applied to the lid member 20 having the structure shown in FIG. 4, and the bottom member 10 and the lid member 20 are joined with a conductive adhesive. ) And (B), the bottom member 10 and the lid member 20 having the structure shown in FIG.
Alternatively, the bottom member 10 and the lid member 20 may be joined by fitting the bottom member 10.

[0029]

According to the dielectric filter of the first aspect of the present invention, a box body obtained by bending a metal plate is applied instead of the conventional filter case obtained by cutting a metal body. Therefore, it becomes possible to significantly reduce the processing cost of the filter case as compared with the conventional one, and it is possible to inexpensively manufacture this type of dielectric filter, and
The use of a lightweight metal plate has the effect of significantly reducing the weight of the dielectric filter.

Further, when a metal plate for a filter case, in which the concave side forming the main part of the above box body serves as a lid, is applied,
Since it becomes possible to dispose the constituent members such as the dielectric resonator on the flat bottom member, and the conventional cumbersome process of disposing the constituent members in the recess which is a narrow space is simplified, the dielectric filter It has an effect that it can be manufactured easily and it can correspond to miniaturization of the dielectric filter.

On the other hand, according to the method of manufacturing a dielectric filter according to the second aspect of the present invention, one or a plurality of dielectric resonators are provided at a predetermined portion of the metal plate, which is formed into a predetermined shape and before bending. Since the dielectric filter is obtained by arranging the necessary members and fixing these resonators and members, the metal plate is bent into a box shape to obtain the dielectric filter. The conventional cumbersome process of arranging etc. is simplified, and the box body is formed by one bending process, and the main part of the dielectric filter can be completed, so its workability is extremely excellent, It has an effect that the dielectric filter can be mass-produced inexpensively and easily.

[Brief description of drawings]

FIG. 1 is a schematic plan view in which a part of a dielectric filter showing an embodiment of the present invention is cut away.

FIG. 2 is a schematic sectional view of a dielectric filter showing an embodiment of the present invention.

3 is a schematic sectional view taken along the line III-III in FIG.

FIG. 4 is an assembly explanatory view of a filter case of the dielectric filter according to the present invention.

5 (A) and 5 (B) are plan views showing a lid member and a bottom member before bending which are constituent members of the filter case of FIG.

FIG. 6 is a plan view showing a metal plate before bending of a filter case according to another embodiment.

FIG. 7 is an assembly explanatory diagram of a filter case according to another embodiment.

8 (A) and 8 (B) are plan views showing a lid member and a bottom member before bending which are constituent members of the filter case of FIG. 7.

FIG. 9 is an assembly explanatory diagram of a filter case according to another embodiment.

FIG. 10 is a schematic plan view of a comparative dielectric filter according to a conventional example with a lid removed.

11 is a schematic sectional view of the dielectric filter of FIG.

FIG. 12 is a schematic plan view of a conventional dielectric filter with a lid removed.

13 is a schematic sectional view of the dielectric filter of FIG.

FIG. 14 is a schematic plan view of a dielectric filter according to another conventional example with a lid removed.

15 is a schematic sectional view of the dielectric filter of FIG.

FIG. 16 is a schematic plan view of a dielectric filter according to another conventional example with a lid removed.

FIG. 17 is a schematic perspective view of a filter case according to a conventional example with a lid removed.

[Explanation of symbols]

 1 Filter Case 3 Dielectric Resonator 4 Input Connector 5 Input Microstrip Antenna 6 Output Connector 7 Output Microstrip Antenna 8 Frequency Adjustment Screw 10 Bottom Member 20 Lid

Claims (2)

[Claims] 1. A dielectric filter having one or a plurality of dielectric resonators in a covered filter case, which allows passage of only a predetermined frequency, and a box formed by bending a metal plate. A dielectric filter comprising the capped filter case. 2. The method of manufacturing a dielectric filter according to claim 1, wherein one or more dielectric resonators and necessary members are arranged at a predetermined portion of a metal plate formed into a predetermined shape and before bending. Then, after fixing these resonators and members, the metal plate is bent into a box shape to manufacture the dielectric filter.