JPH1168426A - Dielectric filter and electronic instrument using the filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dielectric filter capable of surely forming an electric path with a conductive box body, a dielectric block and a conductor plate and obtaining a prescribed stable electric characteristic; and an electronic instrument using the dielectric filter. SOLUTION: This dielectric filter includes a box body 1 consisting of a conductive material and having an aperture on its upper part, a cylindrical dielectric block 3 arranged so that a lower end electrode 3b is electrically brought into contact with its inner bottom and a flexible conductor plate 2 arranged in press-contact with an upper end electrode 3a and capable of forming an electric path in cooperation with the box body 1 and the block 3. The press- contact of the conductor plate 2 is executed by projecting the upper end electrode 3a of the block 3 upward from the upper aperture of the box body 1, holding the center part of the plate 2 by the electrode 3a and a large diameter screw 6 on a cover body 5, and depressing the periperal edge part of the plate 2 to the peripheral part of the aperture of the box body 1 by the cover body 5 itself.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dielectric filter suitable for use in an electronic device such as a duplexer for transmitting and receiving signals for a cellular base station, and an electronic device using the same.

[0002]

2. Description of the Related Art As shown in FIGS. 8 and 9, a conventional dielectric filter C used for a transmission signal / reception signal duplexer (Duplexer) has a bottomed box made of a conductive material such as die cast. It comprises a body 30, a dielectric block 31 housed therein, and a lid 33. Box 30
4 is provided at a predetermined position in the peripheral portion 30a of the upper opening.
A plurality of screw holes are provided, and the lid 33 is fixed by screws 34. The lid 33 made of an insulating material is a rectangular flat plate, and a conductor 33a is formed on the entire lower surface of the lid 33 by electroless plating or the like. The ceramic dielectric block 31 made of a dielectric material is a column, and the electrodes 31a and 31b are respectively formed by applying and baking a conductive paste on the upper surface and the lower surface, or by an electroless plating method or the like. . The dielectric block 31 has a lower electrode 31.
It is fixed to the inner bottom 30b of the box 30 by soldering with b facing downward. The height of the dielectric block 31 and the box 30
The height from the inner bottom 30b to the peripheral portion 30a of the upper opening is set to be equal.

In assembling the dielectric filter C having such a configuration, first, cream solder is applied to the inner bottom of the box 30 at a position where the dielectric block is mounted, and the lower end electrode 31b of the dielectric block 31 is attached. Place it face down on the applied cream solder. When the box 30 is passed through a heating furnace (not shown) in this state, the cream solder is melted and the dielectric block 3 is melted.
One lower electrode 31b is fixed to the inner bottom 30b of the box 30 by soldering. Next, the lid 33 is arranged on the periphery 30a of the opening of the box 30 so that the conductor 33a on the lower surface of the lid 33 is in contact with the lid 33, and is fixed with screws 34. Thereby, the lid 33
Is in contact with the upper electrode 31a of the dielectric block 31, and the conductor 33a of the lid 33 and the upper electrode 31a of the dielectric block 31 are electrically connected.
Therefore, the path through which the current flows in the dielectric filter C is determined by the dielectric block 31 and the upper electrode 31 of the dielectric block 31.
a, the conductor 33a on the lower surface of the lid 33, the box 30, the lower electrode 31b of the dielectric block 31, and the dielectric block 31. The current circulates in this order.

[0004]

However, in the conventional dielectric filter, since the dielectric block 31 disposed in the path through which current flows is made of ceramic, the dielectric block 31 after firing of the dielectric block 31 is manufactured at the time of manufacture. The height dimension varies. Due to this variation, the height of the dielectric block may not be formed equal to the height of the side wall from the inner bottom of the box 30. In such cases,
The upper end electrode 31a of the dielectric block does not contact the conductor 33a on the lower surface of the lid 33, and there is a possibility that predetermined stable electrical characteristics cannot be obtained. SUMMARY OF THE INVENTION An object of the present invention is to provide a dielectric filter capable of reliably forming an electric path in a dielectric filter and obtaining stable predetermined electrical characteristics, and an electronic device using the same.

[0005]

A dielectric filter according to the present invention is mounted on a box body made of a conductive material and having an open top, and a lower electrode electrically connected to the inner bottom of the box body. And a flexible conductive plate that is disposed in pressure contact with the upper end electrode of the dielectric block and forms an electric path in cooperation with the box and the dielectric block. . According to such a dielectric filter, an electric path through which a current flows reliably is formed by the box, the dielectric block, and the conductor plate. The dielectric block may have a columnar shape or a rectangular parallelepiped shape, or may have a columnar shape having an elliptical cross section.

In the dielectric filter according to the present invention, the upper end of the dielectric block protrudes upward from the opening of the box, and the conductor plate is pressed against the upper electrode of the dielectric block while being pressed around the opening of the box. It may have a biasing means for pressing down, or the upper end electrode of the dielectric block is located below the opening of the box, and the upper end of the dielectric block is supported while the conductor plate is supported around the opening of the box. You may have the urging | biasing means which presses down on an electrode. By these urging means, the dielectric block and the conductor plate can be reliably pressed into contact with each other, and the conductor plate can also be pressed against the box body to reliably form an electric path through which the current flows.

Further, the present invention is a multi-stage dielectric filter having a plurality of the above-described dielectric filters, and can be formed in a form suitable for the purpose of electronic equipment using the multi-stage dielectric filter. .

According to still another aspect of the present invention, there is provided an electronic apparatus having the above-described dielectric filter, and an electronic apparatus having a desired bandwidth can be easily obtained.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the dielectric filter according to the present invention will be described below with reference to the drawings. Figure 1
As shown in FIG. 3, the dielectric filter A is rectangular,
Box 1 made of conductive material such as die cast
have. The box 1 includes a rectangular bottom wall 1a and a bottom wall 1a.
, A rectangular hole 1d formed at the center of a pair of opposed side walls 1b, and four screws provided at predetermined positions on an upper end surface 1c of the side wall 1b. And a hole 1e. The pair of rectangular holes 1d have a function of performing electrical coupling with an adjacent dielectric filter A when a plurality of dielectric filters A are connected and used. The conductor plate 2 made of a flexible metal plate such as phosphor bronze is rectangular and has a thickness of 0.05 mm to 0.5 mm.
1 mm, and four elliptical holes (not shown) for screw insertion are formed at positions corresponding to the screw holes 1 e of the box 1. The conductor plate 2 is arranged on the upper end surface 1 c of the box 1 so as to close the upper opening of the box 1.

For example, a ceramic dielectric block 3 made of a dielectric material such as BaO-TiO2-Nd2O3 has a columnar shape, and an upper surface and a lower surface thereof are coated with a conductive paste and baked. Electrodes 3a and 3b formed by a method such as electrolytic plating are formed. Also,
The height L1 of the dielectric block 3 is equal to the side wall 1b of the box 1.
Is set to be smaller than the height L2 from the inner bottom. In the dielectric block 3, the lower electrode 3b of the dielectric block 3 is fixed to the bottom wall 1a of the box 1 by soldering or the like. At this time, the upper surface of the dielectric block 3 is located below the upper end surface 1c of the box 1.

The lid 5 serving as an urging means for pressing the conductor plate 2 against the upper electrode 3a of the dielectric block 3 has a main body of a flat plate and a small diameter 4 at a position corresponding to the screw hole 1e of the box 1. Each hole is formed, and a large-diameter screw hole is formed at the center. A small-diameter screw 4 is screwed into each of the four small-diameter holes of the lid 5, and a large-diameter screw 6 with a flat tip is screwed into the large-diameter screw hole. The lid 5 is superimposed on the conductor plate 2, and the screw 4 is further screwed into the screw hole 1 e of the box 1, and the box 1 and the conductor plate 2 are fastened by the screw 4. At this time, the conductor plate 2 is composed of the lid 5 and the upper end surface 1 of the box 1.
c, so that the upper end opening of the box 1 is closed. Further, by screwing the screw 6 downward, the central portion of the conductor plate 2 is pressed against the upper end electrode 3a of the dielectric block 3, thereby forming a current path by the box 1, the conductor plate 2 and the conductor block 3. Will be done.

Next, the assembly of the dielectric filter A will be described. First, the dielectric block 3 is placed on the inner bottom of the bottom wall 1a of the box 1 with the lower electrode 3b facing downward.
At this time, cream solder (not shown) is applied in advance to the position where the dielectric block 3 is placed on the bottom wall 1a. Then, when the box 1 is passed through a heating furnace (not shown) in this state,
The cream solder is melted and the lower electrode 3 of the dielectric block 3 is melted.
b is fixed to the bottom wall 1a of the box 1 by soldering. Then, the conductive plate 2 is placed on the upper end surface 1c of the box 1 so as to cover the upper opening of the box 1, and the lid 4 is held together with the box 1 to hold the conductive plate 2. And place it.

Then, the screws 4 are screwed into the small diameter holes of the lid 5 and the corresponding screw holes 1e of the box 1, and the lid 5, the conductor plate 2 and the box 1 are fastened. Further, the screw 6 screwed into the large-diameter hole of the lid 5 is screwed downward, and the conductor plate 2 is pressed against the upper end electrode 3 a of the dielectric block 3 while pushing down the center of the conductor plate 2. By this pressure contact, the conductive plate 2 and the upper end electrode 3a of the dielectric block 3 are electrically connected. Further, since the central portion of the conductive plate 2 is pushed down by the screw 6 and is inclined from the central portion of the conductive plate 2 to the peripheral edge, the inner side of the upper end surface 1c of the box 1 and the conductive plate 2 maintains a stable contact state. As a result, the path through which the current flows in the dielectric filter A includes the dielectric block 3, the upper electrode 3a of the dielectric block 3, the conductor plate 2, the upper end face 1c of the box 1, the side wall 1b of the box 1, the box 1 The bottom wall 1a, the lower electrode 3b of the dielectric block 3, and the dielectric block 3 are arranged in this order, and the current circulates in this order.

Next, another embodiment of the dielectric filter of the present invention will be described. As shown in FIGS. 4 to 6, the dielectric filter B is rectangular and has a bottomed box 10 made of a conductive material such as die-cast. The box 10 includes a rectangular bottom wall 10a, a side wall 10b extending upward from the periphery of the bottom wall 10a, and four screw holes 10e provided at predetermined positions on an upper end surface 10c of the side wall 10b. I have. Further, similarly to the above-described embodiment, a pair of rectangular holes 10d are formed in the side wall 10b. The conductor plate 11 made of a flexible metal plate such as phosphor bronze is rectangular and has a thickness of 0.05 mm to 0.1 mm,
The box 10 has four oval holes (not shown) for screw insertion at positions corresponding to the screw holes 10e, and overlaps the upper end surface 10c of the box 10 to cover the opening of the box 10. It is shaped.

The ceramic dielectric block 12 made of a dielectric material such as BaO-TiO2-Nd2O3 is cylindrical and has a columnar shape. A conductive paste is applied to the upper and lower surfaces and baked, or a method such as electroless plating is used. Are formed, respectively. The height dimension L3 of the dielectric block 12 is
The height b is set higher than the height L4 from the inner bottom. The dielectric block 12 is formed on the bottom wall 10 a of the box 10.
Is fixed by soldering or the like with the lower electrode 12b facing downward. At this time, the surface of the upper electrode 12a of the dielectric block 12 is disposed so as to protrude upward from the side wall 10b of the box 10, and is pressed against the central portion of the conductive plate 11 so as to be pushed up.

The cover 14 made of an insulating material serves as an urging means for pressing the conductor plate 11 against the upper electrode 12b of the dielectric block 12, and its main body is in the shape of a rectangular tube with a ceiling, and corresponds to the ceiling. A rectangular upper wall 14a and an upper wall 14
A side wall 14b extending downward from the periphery of a is provided with four small-diameter holes (not shown) provided in the upper wall 14a at positions corresponding to the screw holes 10e of the box body 10. Further, similarly to the above-described embodiment, the lid body 14 has a large-diameter screw hole formed at the center, and a large-diameter screw 15 having a flat tip is screwed into the large-diameter screw hole. The lid 14 is superimposed on the conductor plate 11, and a small-diameter screw 16 screwed into a small-diameter hole (not shown) is further screwed into a screw hole 10 e of the box body 10. Are fastened together with the box 10. At this time, the conductor plate 11 is
4 and the box 11 are sandwiched so as to close the upper end opening of the box 10. Further, by screwing the large-diameter screw 15 downward, the central portion of the conductor plate 11 pushed up by the upper electrode 12a of the dielectric block 12 is sandwiched by the tip of the large-diameter screw 15 and the upper electrode 12a. Box 1, conductor plate 2, and conductor block 3
Is formed.

Next, the assembly of the above-mentioned dielectric filter B will be described. First, the lower electrode 12b of the dielectric block 12 is placed on the bottom wall 10a of the box 10 with the lower electrode 12b facing downward. At this time, cream solder (not shown) is previously applied to the position on the bottom wall 10a where the dielectric block 12 is to be placed. When the box 10 is passed through a heating furnace (not shown) in this state, the cream solder melts, and the lower electrode 12b of the dielectric block 12 is soldered to the bottom wall 10a of the box 10.
The upper end of the soldered dielectric block 12 projects upward from the upper end surface 10c of the box 10. Next, the lower surface of the conductor plate 11 is pressed against the upper electrode 12 a of the dielectric block 12, and the conductor plate 11 is arranged on the box 10 so as to cover the upper end opening of the box 10. The lid 14 is arranged so that the lower end surface of the side wall 14b of the body 14 comes into contact with the lid 14.

In this state, the screw 16 is screwed into each small-diameter hole of the lid 14 and the corresponding screw hole 1 of the box 10 is screwed.
Then, the conductor plate 11 is fastened by being sandwiched between the lid 14 and the box 10. Furthermore, the lid 14
The large-diameter screw 15 is screwed downward, so that the conductor plate 11 is pushed up from the dielectric block 12 from below.
Is sandwiched between the large-diameter screw 15 and the upper end electrode 12a. Thus, the dielectric filter shown in FIGS. 3 and 4 is formed. The path through which the current flows in the dielectric filter B includes the dielectric block 12, the upper electrode 12a of the dielectric block 12, the conductor plate 11, the upper surface 10c of the box 10,
The side wall 10b, the bottom wall 10a, and the lower end electrode 12b of the dielectric block 12 are arranged in this order, and the current circulates in this order.

Next, an embodiment of the electronic apparatus according to the present invention will be described. As shown in FIG. 7, an electronic device in which the above-described dielectric filter A is applied to a transmission signal / reception signal sharing device (Duplexer) for a cellular base station includes an antenna 50,
The dielectric filter A is formed by coupling three dielectric filters A such that the rectangular hole 1d of the dielectric filter A is connected to the rectangular hole 1d of the adjacent dielectric filter A.
A transmission band-pass filter 51 composed of: a transmission band-pass filter 51; and a reception band-pass filter 52 composed of three dielectric filters A on the lower side in FIG.
Shared circuit 5 arranged at a connection portion with these band-pass filters 51 and 52 and connected to antenna 50
3, an input terminal 54 for inputting a transmission signal to the transmission bandpass filter 51, and an output terminal 55 for outputting a reception signal from the reception bandpass filter 52. The shared circuit 53 has a connector (not shown) fitted in the rectangular hole 1d of the connecting dielectric filter A unit of each of the bandpass filters 51 and 52, and is electrically coupled to each of these bandpass filters. I have. Similarly, the input terminal 54 and the output terminal 55 are electrically connected to the band-pass filters 51 and 52 by connectors fitted in the rectangular holes 1d of the dielectric filter A.

In the transmission / reception signal duplexer having the above-described configuration, the signal received by the antenna 50 is input to the shared circuit 53, and the received signal from the shared circuit 53 is input to the received signal band-pass filter 52. Then, only a signal of, for example, 880 to 915 MHz is passed through the bandpass filter 52 for the received signal and supplied from the output terminal 55 to a receiving circuit (not shown). When a transmission signal from a transmission circuit (not shown) is input to an input terminal 54, the input transmission signal is transmitted to a bandpass filter 51 for the transmission signal.
The transmission signal band-pass filter 51 passes only a transmission signal of, for example, 925 to 960 MHz, supplies the transmission signal to the antenna 50 via the shared circuit 53, and transmits the signal from the antenna 50. It is configured to be.

In this embodiment, it goes without saying that the above-described dielectric filter B may be used in place of the dielectric filter A in FIG. Further, instead of simply connecting the dielectric filters A or B, a large box having a shape like that of the boxes 1 or 10 of these dielectric filters is produced, and each room of the large box, that is, Each chamber corresponding to the above-mentioned box 1 or 10 has a dielectric filter A
Or the dielectric block 3 or 12 of B is installed, respectively.
On these blocks, the conductor plate 2 or 11 and the lid 5 or 1
4 may be a multi-stage type dielectric filter in which a plurality of dielectric filters A or B formed by closing each room from above are connected.

[0022]

According to the present invention, there is provided a dielectric filter as described above, wherein a flexible conductive plate is pressed against an upper electrode of a columnar dielectric block placed on the inner bottom of a conductive box. Since they are arranged in a state, the box, the dielectric block, and the conductor plate cooperate to form an electric path through which a current flows reliably.

[Brief description of the drawings]

FIG. 1 is an overall perspective view showing an embodiment of a dielectric filter according to the present invention.

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

FIG. 3 is a plan view showing a box and a dielectric filter shown in FIG. 1;

FIG. 4 is an overall perspective view showing another embodiment of the dielectric filter of the present invention. .

FIG. 5 is a cross-sectional view showing another embodiment of the dielectric filter of the present invention.

FIG. 6 is a plan view showing the box and the dielectric filter shown in FIG.

FIG. 7 is a schematic configuration diagram showing an electronic device using the dielectric filter shown in FIG.

FIG. 8 is an overall perspective view showing a conventional dielectric filter.

FIG. 9 is a sectional view showing a conventional dielectric filter.

[Explanation of symbols]

 A, B Dielectric filter 1, 10 Box 2, 11 Conductor plate 3, 12 Dielectric block 3a, 12a Upper electrode 3b, 12b Lower electrode 5, 14, Lid (biasing means) 6, 15 Large diameter screw (with Force means)

Claims (5)

[Claims] 1. A box made of a conductive material and having an open top, a columnar dielectric block placed on the inner bottom of the box with a lower end electrode in electrical contact therewith, and the dielectric block And a flexible conductive plate which is disposed in pressure contact with the upper end electrode and forms an electric path in cooperation with the box and the dielectric block. 2. An upper end electrode of the dielectric block protrudes upward from an opening of the box, and presses the conductor plate against the upper end electrode of the dielectric block and presses the conductor plate around an opening of the box. 2. The dielectric filter according to claim 1, further comprising a biasing means. 3. An upper end electrode of the dielectric block is positioned below an opening of the box, and the conductor plate is pressed against the upper end electrode of the dielectric block while being supported by a periphery of the opening of the box. 2. The dielectric filter according to claim 1, further comprising a biasing unit. 4. A multi-stage dielectric filter comprising a plurality of the dielectric filters according to claim 1. 5. An electronic device comprising the dielectric filter according to claim 1. Description: