JPS62252202A - Dielectric filter - Google Patents

Abstract

PURPOSE:To eliminate the need for a base, or a case made of a metal, by constituting a device so that an input/output pin terminal piercing through the protruding wall of a dielectric block is provided, and an opened surface is covered with a metallic plate utilizing the protruding wall. CONSTITUTION:A dielectric block 32 is constituted so that a protruding wall 40 is formed at least at a part of the edge of the opened surface, and an input/ ouput pin terminal 42 is provided by piercing the protruding wall 40, and also, the opened surface is covered with a metallic plate 44 utilizing the protruding wall 40. In this way, the need for the base, or the case made of the metal is eliminated. and a structure is simplified, and remarkable miniaturization can be obtained.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a multi-stage dielectric filter with an integral structure used in high frequency bands such as microwaves, and more specifically, to A wall is formed, and the input/output terminals are arranged so as to pass through the protruding wall, and the protruding wall is used to cover the open surface with a metal plate, so there is no need for a metal base or metal case for installation. The present invention relates to a dielectric filter.

[Prior Art] Multi-stage resonant filters using dielectric ceramics such as barium titanate have the characteristics of low loss, high Q, and high dielectric constant, allowing for miniaturization, and are used in automobile telephones, satellite communications, etc. Widely used for microwave bands.

As a prior art related to dielectric filters, for example, the first
As shown in Figure 0, a rectangular parallelepiped dielectric block lO
A plurality of resonator holes 12 and coupler holes 14 are provided alternately at predetermined intervals in the longitudinal direction of the The outer surface of the resonator hole 12 and the inner surface of the resonator hole 12 are metallized to form a conductor layer 16.
An integrated multi-stage structure is known in which a large number of resonant elements having a resonant frequency four times the length of the resonator hole 12 are formed by forming the resonator hole 12.

In such a filter, each resonator hole 12 corresponds to a single resonant element. For connection with external circuit,
For example, this is done by using a coupling capacitor attached to the open end of a resonator hole formed at both ends of a dielectric block.

In the case of a filter with pin terminals, a metal base 20 is used for fixing the input/output terminals and for grounding. While inserting and fixing the input/output pin terminal 22 on the metal base 2o, the dielectric filter body is placed horizontally, the conductor layer on the side surface is brought into close contact with the base 20, and the coupling capacitor 18 and the pin terminal 22 are connected with the lead wire 24. After connection, a structure is adopted in which the base 20 is covered with a lid 26 made of a metal plate.

Here, as the pin terminal 22, a glass terminal or a terminal made of special synthetic resin (polytritetrafluoroethylene, etc.) is used so as not to impair high frequency characteristics. Further, the dielectric filter main body and the base 20 are fixed by adhesion using a conductive adhesive, soldering, or pressure bonding using a spring.

[Problems to be Solved by the Invention] In the above-mentioned conventional technology, the dielectric filter body needs to be completely surrounded by a metal base and cover, which makes the structure complicated, expensive, and large. There were drawbacks such as. Further, the electrical connection between the conductor layer 16 formed on the side surface of the dielectric filter body and the metal base 2o tends to be unstable, which causes problems such as deterioration of filter characteristics.

An object of the present invention is to provide a dielectric filter with an improved structure that eliminates the drawbacks of the prior art as described above, has a simple structure, is inexpensive to manufacture, and can improve filter characteristics. It is about providing.

[Means for Solving the Problems] The present invention, which can achieve the above objects, has a plurality of resonator holes disposed in the longitudinal direction of a dielectric block having a substantially rectangular parallelepiped shape, and A dielectric filter having an integral structure in which one of the surfaces where the hole is open is an open surface and a conductor layer is formed on the other outer surface and the inner surface of the resonator hole,
The dielectric block has a structure in which a protruding wall is present on at least a part of the edge of the open surface, and input/output pin terminals are provided through the protruding wall, and the open surface is covered with a metal plate using the protruding wall. It is designed to cover.

The protruding wall formed on the open surface of the dielectric block is preferably formed on all four edges so as to surround the open surface, but it is sufficient that it is provided at least in part, that is, in the part from which the input/output terminals are drawn out.

Also effective are a configuration in which the ground terminal is embedded in the dielectric block in the vicinity of the input/output pin terminal, or a configuration in which a hole for attachment is provided at the end of the dielectric block.

[Effect]

Connection with external circuits is achieved by inserting and fixing input/output pin terminals that penetrate through the protruding wall of the dielectric block into holes in the printed circuit board, etc. and soldering them.
In the present invention, the dielectric block itself holds the pin terminals, and since the dielectric block itself becomes a case structure and can be attached to the printed board, it is only necessary to cover the open surface with a metal plate of a simple structure, and This eliminates the need for a case, base, etc., simplifying the structure and making it possible to achieve significant downsizing.

[Example] FIG. 1 is a perspective view showing an example of a dielectric filter according to the present invention, and FIG. 2 is a longitudinal sectional view thereof. This embodiment is a four-stage integrated filter.

The dielectric filter body 3o has four resonator holes 34 formed at intervals in the longitudinal direction of a substantially rectangular parallelepiped dielectric block 32 made of a sintered body of a high dielectric constant ceramic material such as barium titanate. At the same time, a connector hole 36 is provided between the resonator holes 34, and a conductor layer 3B is formed by metallization on all sides and bottom surfaces of the dielectric block 32 and on the inner surface of the resonator hole 34. Therefore, in this case, the upper surface of the dielectric block 32 becomes an open surface.

Note that in the drawings, portions where the dielectric base is exposed without being metallized are shown with fine dots. Further, although the conductor layer 38 is depicted as having a considerable thickness for ease of understanding, it is actually quite thin and is formed by baking silver paste or the like.

As is clear from FIGS. 1 and 2, the present invention is significantly different from the prior art in that the dielectric block 32 has a structure in which a protruding wall 40 is formed on at least a part of the edge of the open surface. An input/output pin terminal 42 is provided through the protruding wall 40, and the open surface is connected to the metal plate 4 using the protruding wall 40.
Fake the point configured to be covered by 4. Such a dielectric block 32 can be easily produced by simply powder molding using a mold suitable for the shape of the dielectric block 32.

In this embodiment, the protruding wall 40 is provided in a frame shape so as to surround the open surface, and the conductor layer 38 is formed by metallization up to the upper surface of the protruding wall. Connection with an external circuit is performed by mounting and fixing a coupling capacitor 46 on the open ends of resonator holes located at both ends of the dielectric block 32, and connecting the input/output pin terminals 42 to it.

FIG. 3 is a plan sectional view of the main part showing the connection state of the pin terminals, and FIG. 4 is a side view thereof.

A through hole 50 is formed in the protruding wall 40 formed on the dielectric block 32.
is provided, and a non-metallized ring-shaped non-conductive portion 51 is formed around it.

Further, a hole 52 for a ground terminal is formed in line with the through hole 50. In the case of the hole 52 for the ground terminal, the input/output pin terminal 42, which does not need to be passed through, is press-fitted and fixed into the through hole 50, and its inner end is soldered to the coupling capacitor 46.

In addition, the 7-ss terminal 52 is inserted into the hole 54 and the conductor layer 3 on the surface is inserted.
Fix it by soldering or conductive adhesive.

Furthermore, in this embodiment, through holes 56 for attachment are provided on both sides of the dielectric block 32.

The through hole 50 and hole 54 as described above are installed through the river hole 56.
etc. can be easily formed by scraping the dielectric block when it is unsintered.

After adjusting the resonance frequency for each resonator hole 34,
A metal plate 44 is placed and fixed so as to cover the open surface. This fixation can be done by soldering or conductive adhesive.
The dielectric filter assembled in this way has a fifth
As shown in the figure, the input/output pin terminals 42 and the ground terminal 52 are inserted into holes 60 formed in the printed circuit board 60 and connected to the conductive patterns of the printed circuit board 60 by soldering. Further, in order to strengthen the mechanical connection with the printed circuit board 60, screws 66 are inserted into the holes 56 for fixation (see FIG. 6).

In the above embodiment, a simple and inexpensive rod-shaped pin terminal is used as the input/output pin terminal 42. Of course, conventional glass terminals or terminals made of synthetic resin may be used. In that case, a through hole sized to accommodate the outer conductor surrounding the glass or resin is formed in the protruding wall, and the outer conductor is connected to the dielectric. It may be bonded to the conductor layer of the body block by soldering or with a conductive adhesive.

The input/output pin terminals can be drawn out in any direction.

For example, as shown in FIG. 7, it may be drawn out from two sides perpendicular to each other, or, although not shown, it may be drawn out from two opposing sides in opposite directions.

The shape of the protruding wall formed on the open surface of the dielectric block is also arbitrary. In order to simplify the shape of the metal plate 11, it is desirable to have it protrude on all four sides like a picture frame as in the above embodiment, but in some cases, as shown in FIG. It may be formed in a U-shape on the sides, or it may be formed in an L-shape on the long and short sides as shown in FIG.

Further, depending on the case, they may be provided only on the two opposing long sides.

In order to ensure ground continuity and improve filter characteristics, it is desirable to embed the ground terminal in the protruding wall close to the human output bin, but in some cases it may be possible to embed the ground terminal using the conductor layer 38 formed on the dielectric block 32. The structure may be such that it is directly brought into surface contact with the printed circuit board.

Mechanical coupling between the dielectric filter and the printed circuit board or the like may be achieved by attaching the dielectric filter to the dielectric block by using metal fittings or the like to attach the dielectric filter to the dielectric block without providing a hole.

The structure of the input/output coupling section is also arbitrary. In each of the above embodiments, coupling capacitors are placed on the open ends of the resonator holes located at both ends to couple with an external circuit, but the input/output coupling holes are provided at the ends of the dielectric block. A metal rod called an antenna rod may be inserted into the dielectric filter to connect it to an external circuit.Furthermore, the number of resonator holes formed in the dielectric filter is also arbitrary.

[Effects of the Invention] As described above, the present invention provides a dielectric block with a structure in which the edge of the open side protrudes, and an input/output pin terminal is provided by penetrating the protruding wall, and the dielectric block is opened using the protruding wall. Since the surface is covered with a metal plate, the input/output pin terminals are attached to the dielectric block itself, which also serves as a case, eliminating the need for a metal base or case, simplifying the structure, making it cheaper and more compact. There is an effect that can be done.

Furthermore, it becomes possible to use inexpensive spring pins or the like as input/output pin terminals, which also reduces costs.

Furthermore, in the present invention, since the conductor layer formed on the outer surface of the dielectric block is directly connected to the ground, it is possible to securely connect the ground at the shortest distance, and the attenuation characteristics can be improved. The mounting with the dielectric block is simple and reliable, and has excellent effects such as preventing leakage of radio waves and suppressing the generation of spurious waves.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing an embodiment of a dielectric filter according to the present invention, FIG. 2 is a vertical cross-sectional view thereof, FIG. 3 is a plan cross-sectional view of main parts showing the connection state of pin terminals, and FIG. is its side view,
FIG. 5 is a sectional view showing how the dielectric filter is attached to the substrate, FIG. 6 is a perspective view thereof, and FIGS. 7, 8, and 9 each show other embodiments of the present invention. A perspective view, FIG. 10 is a perspective view showing an example of the prior art. 30... Dielectric filter body, 32... Dielectric block, 34... Resonator hole, 36... Coupler hole, 3B
...Conductor layer, 40...Protruding wall, 42...Input/output pin terminal, 44...Metal plate, 46...Coupling capacitor, 50...Through hole, 52...Earth terminal , 60・
··Printed board. Patent Applicant: Fuji Electrochemical Co., Ltd. Agent: Dan Shigeru Figure 2 Figure 3 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10

Claims (1)

[Claims] 1. A plurality of resonator holes are arranged in the longitudinal direction of a dielectric block having a substantially rectangular parallelepiped shape, and one of the surfaces of the dielectric block where the resonator holes are open is set as an open surface and the other outer surface is In the monolithic dielectric filter in which a conductor layer is formed on the inner surface of the resonator hole, the dielectric block has a structure in which a protruding wall is provided on at least a part of the edge of the open surface, and the dielectric block is inserted through the protruding wall. A dielectric filter characterized in that an output pin terminal is provided and the open surface is covered with a metal plate using the protruding wall.