JPH04168801A - Dielectric filter - Google Patents

Abstract

PURPOSE:To easily constitute a coupling capacitor with a specific value by arranging a dielectric plate, where a conductor pattern for coupling capacitor formation is formed, as a different body on a dielectric block where plural unit resonators are constituted and coupling the unit resonators with one another. CONSTITUTION:The dielectric plate 10 as the different body from the dielectric block 2 is arranged on the open surface 7 of the dielectric block 2 so as to constitute a capacity coupling means. The dielectric plate 10 has a proper dielectric constant and a resin plate is usable. On one surface of the dielectric plate 10, mutually insulated conductive layers 12a, 12b, and 12c which correspond to resonator holes 3a, 3b, and 3c of the dielectric block 2 are formed. Gaps 13a and 13b are formed between the adjacent conductive layers 12a and 12b, and 12b and 12c. Consequently, capacitors for coupling the unit resonators of the block 2 are formed. Consequently, the desired coupling capacitors can easily be constituted without being restrained by the size, etc., of the dielectric block 2.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides resonator holes that penetrate a dielectric block from its open surface to its short surface, and that the resonator holes are arranged in parallel at predetermined intervals. The present invention relates to a dielectric filter in which a plurality of unit resonators having a resonator hole at the center are formed by forming conductive layers that are electrically conductive to each other on the inner surface of the dielectric block and on the four side surfaces and short surfaces of the dielectric block.

[Conventional technology]

The dielectric filter having the above structure is known as a quarter-wavelength dielectric filter, and is used, for example, in terminal parts of car phones, cordless phones, and the like. Typical examples of this type of dielectric filter are shown in FIGS. 7 and 8.

The dielectric filter shown in FIG. 7 is constructed with a rectangular parallelepiped dielectric block 2 as its main component. Dielectric block 2
Resonator holes 8a, 8b, and 3c with circular cross sections pass through the resonator holes 8a, 8b, and 3c, and coupling holes 4a and 4b with appropriate cross sections (circular in the illustrated case) are formed between them.

the four sides and bottom surface of the dielectric block 2, and the resonator hole 3a;
Conductive layers 5 shown by hatching are formed on the inner surfaces of 8b and 3e, respectively.

With this configuration, the lower surface of the dielectric block 2 functions as a short surface 6, and the upper surface functions as an open surface 7.

In the dielectric filter configured as described above, three sets of unit resonators are configured around the resonator holes 3a, 3b, and 3c, and the coupling holes 4 are connected between these unit resonators.
A three-stage dielectric filter capacitively coupled by coupling capacitances formed around a and 4b is completed.

In the dielectric filter of FIG. 8, the coupling holes 4a and 4b in the dielectric filter of FIG. 7 are not provided, but instead, resonator holes sa and s are provided on the open surface 7.
Conductive patterns 8a and 8b that are electrically connected to the conductive layer 5 on the side surface are formed between B and Be, and a coupling capacitance is formed using these conductive patterns and the conductive layer on the inner surface of the resonator hole as electrodes.

In a dielectric filter configured as shown in FIG. 7 or 8, input/output terminals are used to connect a pair of outermost unit resonators to an external circuit via an input/output capacitance (not shown). is derived.

The equivalent circuit of the dielectric filter constructed as described above is shown in FIG. 9. In FIG. 9, three unit resonators configured around resonator holes 3a, 3b, and 3c are Q, , Q2 . Represented by Q3, the coupling hole 4a,
4b or the conductive layers 8a and 8b is represented by C12''23, and input/output capacitances (not shown) are each represented by Ctl''t2.

[The invention aims to solve a! Title]

As mentioned above, in a dielectric filter having a plurality of unit resonators, there are gaps between the stages, that is, unit resonators Q, , Q2 . Q
In order to configure coupling capacitances C1° and C23 between the three,
Conventionally, as shown in FIG. 7, resonator holes 3a, 3b, 3
c. Provide coupling holes 4a, 4b between each other, or resonator holes 3a, 3b, on the open surface 7 as shown in FIG.
Conductive patterns 8a and 8b are formed between Be.

However, as dielectric filters become smaller,
It has become spatially very difficult to obtain a coupling capacitance having a predetermined value by providing coupling holes or conductive patterns between the resonator holes.

The present invention has been made in consideration of the above circumstances, and an object of the present invention is to provide a dielectric filter that can more easily form a coupling capacitance having a predetermined value.

[Means to solve the problem]

In order to achieve the above object, the dielectric filter of the present invention has the following features:
By arranging resonator holes penetrating from the open surface to the short surface in parallel at a predetermined interval, and forming conductive layers that are electrically conductive to each other on the inner surface, four sides, and the short surface of the resonator hole, the resonator can be fabricated. A dielectric block configured with a plurality of unit resonators centered on a hole, and a dielectric block arranged on the open surface of the dielectric block and in contact with the conductive layer in the resonator hole of the dielectric block, so that adjacent unit resonators are mutually connected. A dielectric filter is constructed of a dielectric plate having a conductive pattern formed therebetween, which serves as an electrode for forming a coupling capacitance.

[For production]

According to the above configuration, a separate dielectric plate on which a conductive pattern for forming a coupling capacitance is formed is arranged on a dielectric block in which a plurality of unit resonators are formed, thereby coupling the unit resonators to each other. A coupling capacitance is formed for this purpose.

Therefore, a desired coupling capacitance can be configured without being greatly restricted by the dimensions of the dielectric block.

〔Example〕

FIG. 1 shows an embodiment of a dielectric filter according to the present invention. Resonator holes 3a, 3b and 3c pass through the dielectric block 2 of this dielectric filter. The west side, bottom surface and resonator hole 3a of the dielectric block 2,
A conductive layer 5 is formed on the inner surface of each of 3b and 3e. With the above configuration, the lower surface of the dielectric block 2 functions as the short surface 6, and the upper surface functions as the open surface 7. Three sets of unit resonators are constructed around the resonator holes 3a, 3b, and 3c. The dielectric block 2 itself is not provided with means for capacitively coupling unit resonators to each other.

A dielectric plate IO separate from the dielectric block 2 is arranged on the open surface 7 of the dielectric block 2 to constitute a capacitive coupling means. The structure of the dielectric plate 10 is shown in FIG. This dielectric plate 10 has a suitable dielectric constant, and in some cases, a resin plate known as a printed circuit board can be used. Unit resonators of the dielectric block 2, that is, resonator holes 3a, 3b, 3c are formed on one surface of the dielectric plate IO.
Conductive layers 12a and 12b insulated from each other corresponding to
, 12c are formed. Adjacent conductive layer 12a
, 12b and between the conductive layers 12b and 12c, slight gaps 13a and 13b are formed for insulation. With such a configuration, the dielectric plate I
Conductive layers 12a and 12b and conductive layer 12
Capacitors having conductive layers as electrodes are formed in b and 12c, respectively, and are used as coupling capacitors for coupling adjacent unit resonators of the dielectric block 2.

That is, the dielectric plate lO is established on the open surface 7 of the dielectric block 2 as shown in FIG.
, 12b and 12c are connected to the resonator holes 3a and 3, respectively.
b.

Connecting leads 14a, 14b, 1 to the conductive layer 3c
4c, and further conductive layers 12 at both ends.
a.

By leading input/output leads lea and 18b from chip capacitor 12c via chip capacitors 15a and 15b, a dielectric filter corresponding to the equivalent circuit shown in FIG. 9 is completed. Connection of each lead and fixation of the chip capacitor can be performed by soldering.

Depending on the value of the capacitance formed between the conductive layers of the dielectric plate 10, the pattern of the facing portions between the conductive layers 12a, 12b, 12c can be modified in various ways.

Fig. 3 shows a state in which the facing portions of the two conductive layers are intertwined with each other by forming jagged edges in a comb-tooth shape so as to increase the opposing length between a pair of adjacent conductive layers 12d and 12c in order to obtain a larger capacitance. This is what I did.

FIG. 4 is based on the one shown in FIG. 3, and shows an example in which comb-tooth-like serrations are formed only in a part of the facing portion in order to adjust the capacitance value to be slightly reduced.

In the dielectric filter shown in FIG. 1, the input and output capacitances are obtained by chip capacitors 15a and 15b, but FIGS. 5 and 6 show an example in which the input and output capacitances are also obtained by the dielectric plate 10. It is something.

In the dielectric plate 10 shown in FIG. 5, an input/output is provided at both edges of the back surface of the dielectric plate 10, which has a conductive layer as shown in FIG. By forming the terminal conductive layers 17a and 17b, input/output capacitance is formed between the conductive layers 12a and 17a and between the conductive layer 12c and the conductive layer 17b, respectively. In the dielectric plate IO of FIG. 6, the conductive layers 12a are located at both ends on the same surface side.

A conductive layer 12a is provided between 12c and the edge of the dielectric plate lO.

By forming conductive layers 19a and 19b for input/output terminals through slight gaps 18a and 18b from 12c, it is possible to create an input between conductive layers 12a and 19a and between conductive layer 12c and conductive layer 19b, respectively. Configure output capacity. In both embodiments, the chip capacitor as an independent component can be omitted.

As described above, by arranging a separate dielectric plate 10 on which a conductive pattern is formed on the dielectric block 2 that constitutes a plurality of unit resonators, the unit resonators of the dielectric block 2 can be A capacitance is formed to couple each other, so that a desired coupling capacitance can be constructed relatively easily without being greatly restricted by the dimensions of the dielectric block 2.

The dielectric plate described above can be formed into a large number of pieces in advance, and after screening, can be cut and used according to each individual product, and thus the dielectric plate of the present invention is suitable for mass production. It can be constructed at low cost.

In the embodiments described above, a dielectric filter having a three-stage configuration, that is, a dielectric filter equipped with three unit resonators, was illustrated, but the present invention clearly provides a dielectric filter with four or more resonator holes, or two resonator holes, that is, a dielectric filter with three unit resonators. It can also be applied to a dielectric filter having unit resonators of more than one stage or two stages.

〔Effect of the invention〕

As described above, according to the present invention, by arranging a dielectric plate separate from the dielectric block on which a plurality of unit resonators are configured, the distance between the unit resonators of the dielectric block is By forming a coupling capacitance, a desired coupling capacitance can be formed relatively easily without being greatly restricted by the dimensions of the dielectric block. Here, a dielectric filter suitable for mass production and miniaturization can be provided.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an embodiment of a dielectric filter according to the present invention, FIG. 2 is an enlarged perspective view of a dielectric plate in the dielectric filter of FIG. 1, and FIGS. 3 and 4 are dielectric plates. FIGS. 5 and 6 are plan views showing configuration examples of different patterns of conductive layers for forming input/output capacitances formed in the conductive layers for forming input/output capacitances, and FIGS. FIG. 8 is a perspective view showing a different configuration example of a conventional dielectric filter, and FIG. 9 is an equivalent circuit diagram of the dielectric filter shown in FIGS. 7 and 8. 2...Dielectric block, 3a, 3b, , 3c...
・Resonator hole, 5... Conductive layer, 6... Short surface, 7
...Open surface, IO...Dielectric plate, 12a,
12b, 12c... conductive layer for forming coupling capacitance, 13
a, 13b ・= gap, 14a, 14b,
14c... Connection lead, 15a, 15b...
Chip capacitor, lea, 16b--Input/output lead, 17a, 17b--Conductive layer for input/output terminal, 18a, 18b--Gap, 19a, 19b
- Conductive layer for input/output terminals. Applicant's agent Sato - Rotori 1 Fig. jp) 2 Fig. 3 Fig. 4 Fig. Atsushi 5 Fig. 6 Tori Fig. 7 Fig. 8 Fig. Tori 9

Claims (1)

[Claims] Resonator holes penetrating from the open surface to the short surface are arranged in parallel at predetermined intervals, and on the inner surface of the resonator hole, the four sides of the dielectric block, and the short surface, respectively. a dielectric block that constitutes a plurality of unit resonators with the resonator hole at the center by forming conductive layers that are electrically conductive to each other; A dielectric filter comprising a dielectric plate formed with a conductive pattern that contacts a conductive layer in a child hole and serves as an electrode for forming a coupling capacitance between adjacent unit resonators.