JPH0666566B2 - Dielectric resonator - Google Patents

Description

TECHNICAL FIELD The present invention relates to a dielectric resonator that can be used in communication devices such as car phones, personal radios, cordless phones, and the like.

[Prior Art] A rod-shaped lead terminal and a cylindrical resin dielectric surrounding the rod-shaped lead terminal in a through hole of a porcelain dielectric that constitutes a quarter-wavelength distributed constant dielectric resonator for use in communication equipment and the like. It is disclosed in, for example, Japanese Utility Model Application Laid-Open No. 58-54102, for example, to insert the unit to obtain an input coupling capacitance between the lead terminal and the inner conductor (inner peripheral electrode) on the wall surface of the through hole. According to this structure, the coupling capacitance can be obtained with a simple structure.

However, based on the target capacitance, -2.5% to +
Those with a tolerance of about 2.5% easily occurred, and the manufacturing yield was poor at about 70%, which was a factor of cost increase.
It is considered that the variation of the electrostatic capacitance is caused by the accumulation of the following (1) to (4).

(1) Due to variations in the diameter, wall thickness, and length of the cylindrical resin dielectric.

(2) Due to variations in the diameter of the through holes for resonance of the ceramic dielectric.

(3) Due to variations in the film thickness of the inner conductor film of the through-hole for resonance.

(4) Due to variations in adhesion of the cylindrical resin dielectric to the resonance through hole.

In order to solve the above-mentioned problems, the applicant of the present invention has proposed a structure in which an individual capacitor is used as a coupling capacitor in Japanese Patent Application Nos. 62-158425 and 63-6253.

[Problems to be Solved by the Invention] By the way, conventionally, when connecting the capacitor electrode to the inner conductor film of the through hole, a special connecting component was used, so that it was difficult to assemble easily. Further, it has been proposed to process the lead wire of the capacitor and solder it to the inner conductor film, but it is difficult to process the lead wire into a desired shape.

Therefore, an object of the present invention is to provide a dielectric resonator that is easy to assemble and that can reduce the cost.

[Means for Solving the Problem] The invention for achieving the above object is to provide a dielectric block having at least one through hole for resonance, an inner conductor film provided on a wall surface of the through hole, and the dielectric layer. It has an outer conductor film provided on the outer peripheral surface of the body block, and first and second terminals, and at least a part of the first terminals is arranged outside the through hole for resonance, and the second terminal is provided. The terminal can be inserted in the through hole in the dielectric resonator having a coupling capacitor inserted in the through hole for resonance and connected to the inner conductor film, with a margin with respect to the through hole. A metal plate having an outer dimension and having a through hole or a cutout portion is arranged in the through hole, and between the second terminal of the capacitor and the metal plate and between the metal plate and the inner conductor film. Is related to the dielectric resonator that is connected by solder between It is something.

[Function] The metal plate in the above invention has a function of bridging the second terminal and the inner conductor film and a function of blocking an unnecessary flow of solder. Therefore, even if the distance between the second terminal and the inner conductor film is relatively large, they are reliably connected. Also, since there are few restrictions on the size of the metal plate,
The cost of the metal plate can be significantly reduced compared to the conventional connecting parts.

[First Embodiment] Next, a 1/4 wavelength distributed constant dielectric resonator according to a first embodiment of the present invention will be described with reference to FIGS. 1 to 5.

This dielectric filter includes a cylindrical dielectric block 1 made of barium titanate porcelain. In the dielectric block 1, 1 from the one end face 2 to the other end face 3
Resonant through holes 4 are provided. Resonant through hole 4
Of the inner conductor film 5 is provided on the wall surface of the inner conductor film 5, the outer conductor film 7 is provided on the outer peripheral surface 6, that is, the side surface, and the inner conductor film 5 is formed on the other end surface 3.
An end face conductor film 8 is provided so as to connect the outer conductor film 7 with the outer conductor film 7. The inner conductor film 5, the outer conductor film 7 and the end face conductor film 8 are formed by applying a silver paste and baking it. The one end face 2 is an open end face.

As shown in FIG. 3, the coupling capacitor 9 arranged in the through-hole 4 for resonance is provided on a cylindrical capacitor porcelain dielectric 10 and a part of the inner peripheral surface, one end surface and the outer peripheral surface of the dielectric material 10. First electrode 11 provided and a second electrode provided on the outer peripheral surface
12 and a first metal cap 13 coupled to the first electrode 11
And a second metal cap 14 coupled to the second electrode 12.
And first and second lead wires 15 and 16 connected to the first and second metal caps 13 and 14, respectively.
The metal cap 13 and the first lead wire 15 function as the first terminal, and the second metal cap 14 and the second lead wire 16 function as the second terminal. In this embodiment, an insulating coating 17 made of synthetic resin is provided to stably mount the capacitor 9 in the through hole 4. Hereinafter, the combination of the capacitor 9 and the insulating coating 17 will be referred to as a capacitor assembly 18.

Since the capacitor 9 is an inexpensive general-purpose axial lead type cylindrical ceramic capacitor, it is possible to obtain a capacitor having a desired capacity extremely easily. In addition, even if a capacitor having a desired capacity is not available, the first and / or second electrode 1
The capacity can be adjusted by partially polishing 1 and 12.

The cover 17 has a collar portion 19 and a protruding portion 20 extending therefrom. The protrusion 20 is formed in a cylindrical shape and is fitted in the resonance through hole 4. The collar portion 19 contacts the one end surface 2 of the dielectric block 1 and determines the insertion depth of the protrusion portion 20.

When manufacturing this dielectric resonator, the dielectric block 1 having the inner conductor film 5, the outer conductor film 7 and the end face conductor film 8 is prepared, and the capacitor assembly 18 shown in FIG. 3 is prepared.

Next, part of the capacitor assembly 18 is inserted so that the second lead wire 16 side is inserted into the through hole 4. That is, the protrusion 20 is fitted into the through hole 4. As a result, one entrance of the through hole 4 is closed.

At this time, the assembly 18 is arranged such that the first lead wire 15 is on the lower side and the second lead wire 16 is on the upper side.
4 is inserted into the doughnut-shaped metal plate 21a shown in FIG. 4, and in this state, it is assembled in the through hole 4 of the dielectric block 1.
Insert part of 18. Since the outer dimension of the metal plate 21 has a margin with respect to the through hole 4, the metal plate 21 can be inserted very easily.

Next, cream solder (paste-like solder) is injected into the resonance through-hole 4 and heated in a constant temperature bath. As a result, the cream solder is melted and the solder penetrates between the metal plate 21 and the metal cap 14 and the lead wire 16 and between the metal plate 21 and the inner conductor film 5, so that the solder 22 and the metal plate 21 cause The second terminal composed of the metal cap 14 and the lead wire 16 is electrically and mechanically coupled to the inner conductor film 5.

When the dielectric resonator shown in FIG. 1 is mounted on a circuit board, the outer conductor film 7 is connected to the ground and the lead wire 15 is connected to the signal transmission line. Therefore, this dielectric resonator can be represented by an equivalent circuit composed of the capacitor C1, the inductance L1, and the coupling capacitor Ca shown in FIG.

[Second Embodiment] Next, a dielectric filter according to a second embodiment of the present invention will be described with reference to FIGS. 6 to 9. However, in FIGS. 6 to 9, substantially the same parts as those in FIGS. 1 to 5 are designated by the same reference numerals, and the description thereof will be omitted. This dielectric filter is a combination of two dielectric resonators.
Therefore, two resonance through holes 4 extending from one end face 2 to the other end face 3 of the dielectric block 1 are provided, and one coupling through hole 23 is provided between them. An inner conductor film 5 is provided on the wall surface of each resonance through hole 4, and an outer conductor film 7 is provided on the outer peripheral surface 6 between the pair of end faces 2 and 3, that is, four side faces.
Is provided on the other end face 3 of the inner conductor film 5 and the outer conductor film 7.
An end face conductor film 8 is provided so as to connect with. The inner conductor film 5, the outer conductor film 7 and the end face conductor film 8 are formed by applying a silver paste and baking it. The one end face 2 is an open end face.

A coupling capacitor 9 is inserted into each of the two resonance through holes 4. The structure of the coupling capacitor 9 is shown in FIG.
As in FIG. 3, a metal plate 21 is arranged between the second terminal composed of the lower metal cap 14 and the lead wire 16 and the inner conductor film 5 as in FIG. Connections between each other have been achieved.

The pair of capacitors 9 are connected to each other by an insulating coating 17a. A metal shield member 24 is further integrated with the insulating cover 17a.

When manufacturing this dielectric filter, the dielectric block 1 having the conductor films 5, 7 and 8 shown in FIG. 8 is prepared, and the pair of capacitors 9 and the shield member 24 are made of synthetic resin insulation coating 17a. Prepare the integrated assembly 25, 2
A single capacitor 9 is inserted into the two through-holes 4 for resonance at the same time, and electrical connection to the inner conductor film 5 is achieved by the metal plate 21 and the solder 22 as in the first embodiment.

The shield member 24 is a portion 24a that covers the upper portion of the coupling hole 23.
And a portion 24b, 24c that covers the pair of side walls, and is formed to have a U-shaped cross section as a whole.

When connecting the completed dielectric filter to the electric circuit,
One of the pair of lead wires 15 is used as an input lead terminal and the other is used as an output lead terminal, and the shield member 24 is connected to the ground.

FIG. 9 shows an equivalent circuit of the dielectric filter. Capacitor
The first resonance circuit composed of C1 and the inductance L1 is formed based on the inner conductor film 5 of one of the pair of through holes 4, the outer conductor film 7 and the end face conductor film 8 which are grounded, and
The second resonance circuit composed of C2 and the inductance L2 is formed based on the other inner conductor film 5 of the pair of through holes 4, the outer conductor film 7 and the end face conductor film 8 which are grounded, and has two resonances. The circuit is coupled by a dielectric impedance Z1. The input coupling capacitance Ca corresponds to one of the pair of capacitors 9, and the output coupling capacitance Cb corresponds to the other of the pair of capacitors 9.

Also in this embodiment, it is possible to obtain the same effect as that of the first embodiment.

[Modification] The present invention is not limited to the above-described embodiments, and the following modifications are possible, for example.

(1) Instead of cream solder, solder particles or solder pieces may be put into the through hole 4 for resonance, and this may be melted and soldered. Alternatively, cream solder may be applied to the metal plate 21 in advance and inserted into the through hole 4.

(2) Alternatively, the metal plate 21 may be inserted into the through hole 4 after the assembly 18 is mounted in the through hole 4.

(3) As shown in FIG. 10, the metal plate 21 is provided with a notch 21b having a notch extending to the through hole 21a, and the solder 22 and the metal cap 1 are provided.
The contact area with 4 may be increased.

(4) The capacitor 9 may have a pair of electrodes 11a and 12a provided on a cylindrical dielectric 10a as shown in FIG. 11, and metal caps 13 and 14 and lead wires 15 and 16 as terminal members. Good. Further, the capacitor 9 is a cylindrical dielectric of FIG.
The first electrode 11 is not provided on the inner peripheral surface of 10 and the first electrode 11 is provided only on the outer peripheral surface.
The electrode 11 may be provided.

(5) The cover 17 can be omitted. If a large gap is created between the inner conductor film 5 and the metal cap 14 by this, a detachable jig corresponding to the covering 17 is inserted into the resonance through hole 4 or the resonance through hole 4 is inserted. Open end face 2
It suffices to close the side inlet and add solder. Inner conductor film 5
When the gap between the metal cap 14 and the metal cap 14 is narrow, the solder 22 stays at a desired position without using a jig.

(6) The lead wire 16 may be removed below the capacitor 9 as necessary.

(7) Three or more resonance through holes 4 in the dielectric block 1
It is also applicable to the case of providing. In this case, the capacitors 9 are mounted in the resonance through holes 4 of the input stage and the output stage.

(8) It is also applicable to the case where the end face conductor film 8 is omitted and a 1/2 wavelength distributed constant dielectric resonator is formed.

EFFECTS OF THE INVENTION As is apparent from the above, according to the present invention, the cost of the dielectric resonator is reduced because the end of the capacitor is connected to the inner conductor film by using the low-cost metal plate. You can Further, since the metal plate having a large degree of freedom is used for the resonance through hole, the connection of the capacitor terminal to the resonance through hole can be easily achieved.

[Brief description of drawings]

1 is a sectional view of the dielectric resonator according to the first embodiment of the present invention taken along the line I-I of FIG. 2, FIG. 2 is a plan view of the dielectric resonator of FIG. 1, and FIG. 1 is an enlarged sectional view showing the capacitor of FIG. 1, FIG. 4 is a perspective view of the metal plate of FIG. 1, FIG. 5 is an equivalent circuit diagram of the dielectric resonator of FIG. 1, and FIG. A seventh embodiment of the dielectric filter according to the second embodiment of the invention
FIG. 7 is a sectional view taken along line VI-VI in FIG. 7, FIG. 7 is a plan view of the dielectric filter of FIG. 6, and FIG. 8 is a perspective view of a dielectric block including the conductor films of FIG. 6 is an equivalent circuit diagram of the dielectric filter of FIG. 6, FIG. 10 is a sectional view showing a modified metal plate, and FIG. 11 is a sectional view showing a modified capacitor. 1 ... Dielectric block, 4 ... Through hole for resonance, 5 ... Inner conductor film, 7 ... Outer conductor film, 9 ... Capacitor, 13, 14 ...
… Metal caps, 15,16 …… Lead wire, 21 …… Metal plate,
22 ... Solder.

Claims (1)

[Claims] 1. A dielectric block having at least one through hole for resonance, an inner conductor film provided on a wall surface of the through hole, and an outer conductor film provided on an outer peripheral surface of the dielectric block. It has a 1st and 2nd terminal, At least one copy of the said 1st terminal is arrange | positioned outside the said through-hole for resonance, The said 2nd terminal is inserted in the said through-hole for resonance, and the said inner conductor. A dielectric resonator including a coupling capacitor connected to a film, having an outer dimension that allows insertion with a margin to the through hole, and having a through hole or a notch A metal plate is disposed in the through hole, and the second plate of the capacitor is provided.
2. The dielectric resonator, wherein the terminal and the metal plate and the metal plate and the inner conductor film are connected by solder.