JPH0648966Y2 - Dielectric resonator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a dielectric resonator for use in a VCO (voltage controlled oscillator) of a communication device such as a car phone, a personal radio, and a cordless phone.

[Prior Art] A rod-shaped lead terminal and a cylindrical resin dielectric surrounding it in a through hole of a porcelain dielectric that constitutes a quarter-wavelength distributed constant dielectric resonator for use in a VCO or the like. Inserting the unit to obtain the input coupling capacitance between the lead terminal and the inner conductor (inner peripheral electrode) on the wall surface of the through hole is described in, for example,
No. 62-8562. According to this structure, the coupling capacitance can be obtained with a simple structure.

[Problems to be solved by the invention] However, based on the target capacitance, -2.5% to +
Those with a tolerance of about 2.5% easily occurred, and the product yield was 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 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.

The above-mentioned problems are caused by Japanese Patent Application No. 62-1584 related to the applicant.
It can be solved by the dielectric resonator proposed in No. 25. In the dielectric resonator proposed here,
Since an individual capacitor is inserted in the through-hole for resonance, it is possible to achieve miniaturization, and it is also possible to easily obtain the target coupling capacitance by selecting and using the capacitor with the desired electrostatic capacity, and also to the feeding point. Can be moved. However, in the dielectric resonator according to the above application, there is a demand for a structure that allows the coupling capacitor to be mounted in the through-hole for resonance more easily.

Therefore, an object of the present invention is to provide a dielectric resonator having a structure capable of improving the manufacturing yield and easily mounting a coupling capacitor.

[Means for Solving Problems] The present invention for solving the above problems and achieving the above objects will be described with reference to the reference numerals of the drawings illustrating the embodiments. A dielectric block 1 having holes 2 and 2a, an inner conductor film 6a provided on the wall surface 3 of the through holes 2 and 2a, and an outer conductor film 6b provided on the outer peripheral surface 4 of the dielectric block 1. And a dielectric 8 having a groove 9 or a hole in the center, a first electrode 10 provided on the wall surface of the groove 9 or the hole, and at least a pair of outer peripheral surface regions symmetrical about the groove 9 or the hole. And second coupling electrodes 7 and 22 which are arranged in the through holes 2 and 2a.
A lead terminal 13 having one end electrically and mechanically coupled to the first electrode 10 and the other end led out from the through hole 2, the second electrodes 11 and 12, and the inner conductor film. The present invention relates to a dielectric resonator provided with connecting members 17 and 18 having a spring property, which are arranged between the connecting members 17 and 18 in order to connect 6a.

[Operation] The capacitance value of the coupling capacitors 7 and 22 in the above invention can be measured before the coupling capacitors 7 and 22 are arranged in the resonance through holes 2 and 2a. Therefore, the target coupling capacity can be easily obtained. Even if there is an error in the distance between the second electrodes 11 and 12 of the coupling capacitors 7 and 22 and the inner conductor film 6a, the connection members 17 and 18 are connected so as to absorb the above error because they have spring properties. The members 17, 18 are deformed and the second electrode
11 and 12 are securely connected to the inner conductor film 6a. Further, the position of the condenser 7 can be easily adjusted.

[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.

The dielectric resonator shown in FIGS. 1 and 2 includes a cylindrical dielectric block 1 made of barium titanate porcelain. Through hole 2 provided at the center of this dielectric block 1
A conductor film 6 made of silver paste applied and baked is provided on the wall surface 3, the outer peripheral surface 4 and the one end surface 5. The conductor film 6 is an inner conductor film 6a on the wall surface 3 of the through hole 2, an outer conductor film 6b on the outer peripheral surface 4, and an end face conductor film 6c for short-circuiting these.
It consists of and.

A coupling capacitor 7 for connecting the resonator to an external circuit is arranged in the through hole 2. This coupling capacitor 7
Is a rectangular parallelepiped dielectric body 8 made of magnesium titanate porcelain, a first electrode 10 provided on the wall surface of the central groove 9 of the dielectric body 8 and in the vicinity thereof, and on both side surfaces of the dielectric body 8. And two second electrodes 11 and 12. First electrode
The 10 and the second electrodes 11 and 12 are obtained by applying a silver paste and baking the same, and face each other with the dielectric 8 interposed therebetween.

The metallic lead terminal 13 with silver plating on brass is
It is composed of a lead wire portion 14 and a fitting portion 15, is arranged at the center of the through hole 2, and a part of this portion projects from the open end surface. The fitting portion 15 is a portion fitted into the groove 9 of the dielectric 8 of the capacitor 7.
15a and a pair of legs 15b and 15c separated by a groove 16 are fitted to the first electrode 10 as shown in FIG. 4 and electrically and mechanically coupled by solder (not shown). ing.

A pair of connecting members 17, 18 made of a copper plate is arranged between the pair of second electrodes 11, 12 of the capacitor 7 and the inner conductor film 6a, and the second electrode 11 is formed by the solder 19 as a conductive bonding material. , 12 and the connecting members 17, 18 are joined, and the connecting member 1 is connected by the solder 20.
7, 18 and the inner conductor film 6a are bonded.

The pair of connecting members 17, 18 are formed in a semi-cylindrical shape as shown in FIG. 4 and have a spring property. Therefore, before being joined to the inner conductor film 6a by the solder 20, the connecting members 17, 18 are
Can be moved up and down together with the capacitor 7 in the through hole 2.

At the time of assembling this dielectric resonator, the main body portion including the dielectric block 1 and the conductor film 6 is prepared, and the coupling capacitor 7 is also prepared. The coupling capacitor 7 is selected from a large number of capacitors whose characteristics have been measured in advance and used in close proximity to the target capacitance.

Next, the lead terminal 13 is fitted to the coupling capacitor 7, and the lead terminal 13 is electrically and mechanically coupled to the first electrode 10 with cream solder. Further, the connecting members 17 and 18 are joined to the second electrodes 11 and 12 by the solder 19.

Next, cream solder is applied to the connecting members 17 and 18, and the assembly shown in FIG. 4 is inserted into the through hole 2. Even if the size of the through hole 2 is slightly smaller than that of the assembly shown in FIG. 4, the connecting members 17 and 18 are elastically deformed and can be inserted. After that,
The cream solder is melted in a state of being temporarily fixed by the spring action of the connecting members 17 and 18 and the cream solder, and the connecting members 17 and 18 are fixed to the inner conductor film 6a with the solder 20. It should be noted that cream solder is applied to the inner conductor film 6a in advance, whereby the connecting members 17, 18 are
May be fixed. Alternatively, after the assembly of FIG. 4 is inserted into the through hole 2, cream solder may be supplied to achieve the connection by the solder 20.

In this distributed constant type 1/4 wavelength dielectric resonator, the dielectric block 1 having the through hole 2 and the conductor film 6 constitute a resonance circuit composed of L1 and C1 in FIG. The coupling capacitor 7 shown in FIG. 5 provides the coupling capacitance Ca shown in FIG. Note that the equivalent circuit of FIG. 5 is schematically illustrated by ignoring the action and effect between the open end and the feeding point (capacitor connection point).

The dielectric resonator of this embodiment has the following advantages.

(1) The capacitance of the coupling capacitor 7 can be known before mounting it in the through hole 2 of the dielectric block 1. Therefore, the coupling capacitor 7 can be selected so as to have a desired capacitance, the capacitance as designed can be easily obtained, and the manufacturing yield of the dielectric resonator can be improved to about 80%. It was

(2) Since the connecting members 17 and 18 having spring properties are used,
The second electrodes 11 and 12 of the coupling capacitor 7 can be easily and surely connected to the inner conductor film 6a.

(3) The position of the coupling capacitor 7 can be easily adjusted.

(4) By using the connecting members 17 and 18 having spring properties, the coupling capacitor 7 can be arranged at any position in the through hole 2. Therefore, the through hole 2 of the dielectric block 1 is used to determine the height position of the coupling capacitor 7.
Since it is unnecessary to provide the dielectric resonator outside, the miniaturization of the dielectric resonator can be achieved.

[Second Embodiment] Next, a dielectric resonator having a plurality of through holes for resonance, that is, a dielectric filter according to a second embodiment of the present invention will be described with reference to FIGS. 6 and 7. However, in FIGS. 6 and 7, parts common to those in FIGS. 1 to 4 are designated by the same reference numerals, and the description thereof will be omitted.

In the dielectric filter of FIGS. 6 and 7, the dielectric block 1 is provided with first and second through holes 2 and 2a for resonance and a coupling hole 21. Similar to FIG. 1, an inner conductor film 6a is provided in each of the two resonance through holes 2 and 2a, and is connected to the outer conductor film 6b by an end face conductor film 6c.

The internal structure of the first and second through holes 2 and 2a for resonance shown in FIG. 6 is exactly the same as the internal structure of the through hole 2 of the dielectric resonator shown in FIG. The lead terminal 13 of the first capacitor 7 in the first resonator through hole 2 functions as an input terminal or an output terminal of the filter, and the lead terminal 13 of the second capacitor 22 in the second resonator through hole 2a is a filter. Function as an output terminal or an input terminal of. The second capacitor 22 has the same structure as the first capacitor 7, and has the same structure as the connecting member.
It is connected to the inner conductor film 6a by 17 and 18.

FIG. 8 shows an equivalent circuit of the dielectric filter. Capacitor
The first resonant circuit consisting of C1 and the inductance L1 is the first
A second capacitor formed based on the inner conductor film 6a and the outer conductor film 6b of the through hole 2 of and including a capacitor C2 and an inductance L2.
The resonance circuit of is the inner conductor film 6a and the outer conductor film 6b of the second through hole 2a.
And the two resonant circuits are coupled by an inductive impedance Z1. The input coupling capacitance Ca corresponds to the first capacitor 7, and the output coupling capacitance Cb corresponds to the second capacitor 22.

Since the dielectric filters shown in FIGS. 6 and 7 have the same basic structure as the dielectric resonator shown in FIG. 1, the same effects can be obtained.

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

(1) As shown in FIG. 9, four resonance through holes 2, 2a, 2
It is also applicable to the case where a multistage filter is constructed by providing b and 2c and three coupling holes 21a, 21b and 21c, and inserting coupling capacitors into the through holes 2 and 2a at both ends as in FIGS. 1 and 6. It is possible.

(2) It is also applicable when the filters shown in FIG. 6 are connected in cascade.

(3) The dielectric 8 of the capacitor 7 is formed into a cylindrical shape, the first electrode 10 is provided on the inner wall of the through hole, and the lead terminal 13 is connected thereto, and the whole or a pair of surfaces on the outer peripheral side of the cylindrical dielectric are provided. A second electrode may be provided.

[Advantage of the Invention] As is apparent from the above, according to the present invention, the manufacturing yield can be improved, and the coupling capacitor can be easily and surely connected to the inner conductor film.

[Brief description of drawings]

1 is a sectional view showing a dielectric resonator according to a first embodiment of the present invention, FIG. 2 is a perspective view of the dielectric resonator shown in FIG. 1, and FIG. 3 is a coupling capacitor shown in FIG. FIG. 4 is an exploded perspective view of the lead terminal and the connecting member, FIG. 4 is a perspective view showing an assembly of respective parts of FIG. 3, FIG. 5 is a circuit diagram showing an equivalent circuit of the dielectric resonator of FIG. 7 is a sectional view showing a dielectric filter according to a second embodiment of the present invention, FIG. 7 is a plan view of the dielectric filter of FIG. 6, and FIG. 8 is an equivalent circuit diagram of the dielectric filter of FIG. FIG. 9 is a perspective view showing a modification of the dielectric filter. DESCRIPTION OF SYMBOLS 1 ... Dielectric block, 2 ... Through hole, 6 ... Conductor film, 6a ... Inner conductor film, 6b ... Outer conductor film, 6c ... End face conductor film, 7 ... Coupling capacitor, 8 ... Dielectric material, 9 ... Groove, 10 ... First electrode, 11, 12
... second electrode, 13 ... lead terminal, 17,18 ... connecting member, 19
…solder.

Claims (1)

[Scope of utility model registration request] 1. A through hole (2, 2a) for resonance, comprising one or more resonances.
A dielectric block (1) having an inner conductor film (6a) provided on the wall surface (3) of the through hole (2, 2a), and an outer peripheral surface (4) of the dielectric block (1). The outer conductor film (6b), the dielectric (8) having a groove (9) or a hole in the center, the first electrode (10) provided on the groove (9) or the wall surface of the hole, and the groove (9). 9) or the second electrode (11, 12) provided in at least a pair of outer peripheral surface regions symmetrical about the hole, and the coupling capacitor (2, 2a) arranged in the through hole (2, 2a). 7) (22), a lead terminal (13) having one end electrically and mechanically coupled to the first electrode (10) and the other end led out from the through hole (2), In order to connect the second electrode (11) (12) and the inner conductor film (6a), a connecting member (17) (18) having a spring property disposed between them is provided. For example a dielectric resonator are.