JPH1127006A - Dielectric filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compact dielectric filter which has high mechanical strength and also can easily set a circuit constant. SOLUTION: A circuit layered product 10a consisting of dielectric layers 11a to 11f placed on an open end face 8 of a dielectric ceramic block 2 is disposed. A coupled circuit L of the product 10a is connected to the necessary resonators 3A to 3C of a resonator circuit X. In such a constitution, a compact dielectric filter is obtained in a simple and even shape. As a result, the circuit designing is facilitated and also an optional circuit constant can be easily set since an LC coupled circuit consists of the product 10a.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dielectric filter having a plurality of resonators arranged side by side, which is used for mobile communication devices such as a mobile phone and a mobile phone.

[0002]

2. Description of the Related Art As shown in FIG. 11, a plurality of resonators b formed by coating an inner conductor on an inner peripheral surface of a through hole are arranged in a dielectric ceramic block a in one direction. Ground conductor c on the required outer peripheral surface except the open end surface where the through hole opens
And an input terminal pad P ₁ to be coupled to the resonator t on one end is formed on a side surface by dividing the input terminal pad P ₁ from the ground conductor c.
Obtained by forming the side surface of the output terminal pad P _2, which binds to the other end of the resonator t and divides the grounding conductor c dielectric filter have been proposed. In this configuration, as shown in the figure, the surface of the counterbore d formed at the opening end of each through-hole is coated with a conductive coating on the open end surface, or a pattern conductor is printed on the open surface to form each resonance. A conductive layer e connected to the inner conductor of the container is formed, and the respective conductive layers e are connected to each other to form a band-pass filter.

[0003]

However, as described above, when a coupling circuit for coupling resonators is formed by forming a counterbore or a pattern, the circuit constant obtained is limited, and the design is limited. Causes restrictions. In order to solve this problem, a device using lumped constant components such as a coil and a capacitor has been proposed. However, in such a configuration, although the degree of freedom is given to the design, the number of assembling steps is increased, and the form is not a uniform shape like a rectangular parallelepiped, the dimensions are large, and a cluttered circuit arrangement is required. As a result, the circuit design becomes complicated, and the mechanical strength also decreases. An object of the present invention is to eliminate such a problem.

[0004]

According to the present invention, a plurality of resonators each formed by coating an inner conductor on an inner peripheral surface of a through-hole are arranged in a dielectric ceramic block in one direction, and a plurality of resonators are provided. On the open end face of the dielectric porcelain block in which the required outer peripheral surface except the open end face where the hole opens is covered with a ground conductor,
A circuit laminate formed by laminating a plurality of dielectric layers is provided, a coupling circuit is configured by the circuit laminate, and a required filtering circuit is configured by coupling the coupling circuit to a required resonator. A dielectric filter characterized in that:

In such a configuration, a coupling circuit is formed by a simple configuration in which a dielectric layer is disposed on an opening end surface of a dielectric ceramic block, and a dielectric filter having a uniform shape is formed. At the same time, by selecting the structure of the circuit laminate, an arbitrary circuit constant can be formed.

In the above structure, a circuit laminate having a one-chip structure formed by laminating a plurality of dielectric layers and sintering them on the open end face of the dielectric ceramic block is proposed. . Thus, by forming the circuit laminate into a one-chip structure, a dielectric filter can be easily formed only by bonding the chip to the opening end face of the dielectric ceramic block.

The coupling circuit formed by the circuit laminate is coupled to each resonator to form a low-pass filter coupling circuit forming a low-pass filter, a band-pass filter coupling circuit forming a band-pass filter, or a high-pass filter. A high-pass filter coupling circuit can be applied.

[0008]

1 to 3 show a first embodiment of the present invention, in which a flat rectangular parallelepiped dielectric ceramic made by sintering a dielectric ceramic material such as titanium oxide or barium oxide. Block 2 shows a dielectric filter 1a which is disposed in parallel with one direction of the three resonators 3A to 3C and has a circuit laminate 10a joined to the open end face 8 thereof. This dielectric filter 1a constitutes the low-pass filter shown in FIG.

As shown in FIG. 3, each of the resonators 3A to 3C is formed by coating an inner conductor 6 on a cylindrical through-hole 5 and further forming an open end face 8 through which the through-hole 5 opens. The ground conductor 7 is coated on the required outer peripheral surface except for that. The resonators 3A to 3C are made to substantially match the resonance length dimension corresponding to λ / 4 of the resonance frequency. Then, the resonators 3A to 3A
C constitutes the resonator circuit X shown in FIG.

A circuit laminate 10a constituting a low-pass filter coupling circuit L is joined to the open end face 8. The circuit laminate 10a is made of a dielectric material such as glass ceramic, a composite material of glass and a dielectric ceramic material, or a low-melting oxide, and has a rectangular shape that matches the shape of the open end face 8 of the dielectric ceramic block 2. It is formed by laminating a plurality of dielectric layers 11a to 11f in a shape and sintering them integrally to form a one-chip structure. The circuit laminate 10a includes dielectric layers 11a to 11f.
, The low-pass filter coupling circuit L is coupled to the required resonators 3A to 3C of the resonator circuit X to form a low-pass filter. Thus, the circuit laminate 10
Since a is integrated into one chip by integrally sintering the dielectric layers 11a to 11f, it is easy to form a uniform dielectric filter 1a having a uniform rectangular parallelepiped by bonding on the open end face 8. Can be configured as follows.

Each of the dielectric layers 11a to 11f is formed by printing a required pattern conductor on the surface thereof and further forming a through hole. The specific configuration will be described.

On the surface of the dielectric layer 11a, the resonators 3A to 3A
The electrode layers 12a, 12b, 12c
Is formed, and through holes are formed in a penetrating manner,
Connected to the inner conductor of each resonator.

Further, on the surface of the dielectric layer 11b, the electrode layers 13a, 13b,
13c is formed, whereby the capacitance between the resonators 3A to 3B and the electrode layers 13a, 13b, 13c is determined by the thickness of the dielectric layer 11b and the electrode area of the electrode layers 12a to 12e, 13a to 13e. The capacitors C _{1 to} C ₃ (see FIG. 4) of the coupling circuit L are configured.

Further, through holes h are formed in the dielectric layer 11c so as to be connected to the electrode layers 13a, 13b and 13c, and an inductor L formed of a meandering conductive path is formed between the through holes h on the surface thereof. ₁ and L ₂ are formed.

The electrode layer 1 is provided on the surface of the dielectric layer 11d.
I / O extension path 1 connected to 3a via through hole h
5a and an input / output extension path 15b also connected to the electrode layer 13c via the through hole h.

An electrode layer 20 is formed on the surface of the dielectric layer 11e.
a, 20b, and 20c are formed, and the dielectric layers 11
The electrodes are connected to the electrode layers 13a, 13b, and 13c through through holes h passing through the holes c, 11d, and 11e.

Furthermore dielectric layer 11f is the grounding conductor 21 is formed on the surface, this grounding conductor 21, the electrode layer 20a, 20b, a capacitor C ₄ 20c is opposed with the dielectric layer 11f -C ₆ Is composed.

After the dielectric layers 11a to 11f are stacked, the input / output extension path 1
Input / output terminal pad 18a connected to input / output terminal 5a, input / output terminal pad 18b connected to input / output extension path 15b, and ground conductor 21 and dielectric block 2 of circuit laminate 10a.
And an earth conductor 19 for connecting the earth conductor 7 of FIG. Incidentally, a conductive layer which is formed by laminating the input / output terminal pads 18a, 18b and the ground conductor 19 on the dielectric layers 11a to 11f may be formed in advance.

Thus, a circuit laminate 10 comprising a plurality of dielectric layers 11a to 11f is provided on the open end of the dielectric ceramic block 2.
a, the capacitors C _{1 to} C ₃ and C _{4 to} C
_6, the low-pass filter coupling circuit L comprised of the inductor L ₁ ~L ₃ is formed, the low-pass filter coupling circuit L are linked with the desired resonator 3A~3C resonator circuit X, FIG. 6
Thus, a low-pass filter circuit indicated by.

FIGS. 5 and 6 show a dielectric filter 1b according to a second embodiment of the present invention, in which a plurality of dielectric layers 21a to 21e are provided.
A bandpass filter coupling circuit B is realized by a circuit laminated body 10b formed by laminating the resonators, and the circuit laminated body 10b is joined to the dielectric ceramic block 2 to couple with the required resonators 3A to 3C of the resonator circuit X. Thus, the band pass filter shown in FIG. 7 is configured. The structure of the dielectric porcelain block 2 is the same as that of the first embodiment.

Here, the resonators 3A to 3A are provided on the dielectric layer 21a.
Through holes h are formed in the portions facing 3C, respectively.

In the dielectric layer 21b, through holes h are formed at portions facing the resonators 3A to 3C, and U-shaped electrodes connected to the through holes h are formed between the through holes h on the surface thereof. Thus, capacitors C ₁₂ and C ₁₃ are formed.

Each of the dielectric layers 2c has
Electrode layers 22a and 22b connected to resonators 3A and 3C via through holes h formed through holes 1a and 21b are formed.

Furthermore, the surface of the dielectric layer 21d, the electrode layer 22a, and 22b and the counter electrode layer 23a, 23 constituting the capacitor C _11, C ₁₄ by the thickness of the electrode layer 21d
b is formed, and the input / output extension path 26a is formed in the electrode layer 23a.
The input / output extension path 26b is also extended to the electrode layer 23b.

An earth conductor 25 is formed on the surface of the dielectric layer 21e.

After the dielectric layers 21a to 21e are stacked, the input / output extension path 2
An input / output terminal pad 27a connected to the input / output terminal 6a, an input / output terminal pad 27b connected to the input / output extension path 26b, an earth conductor 28 connected to the earth conductor 25 of the circuit laminate 10b and the earth conductor 7 of the dielectric block 2, Is formed.
Note that the input / output terminal pads 27 are provided on the dielectric layers 21a to 21e.
a, 27b and the ground conductor 28 may be formed in advance with a conductive layer to be formed by lamination.

Thus, the circuit laminate 10 composed of a plurality of dielectric layers 21a to 21e is provided on the open end of the dielectric ceramic block 2.
simply joining b, it is possible to constitute a band-pass filter coupling circuit B comprising a capacitor C ₁₁ -C _14, which is coupled to the resonator 3A-3C, configured band pass filter having the configuration shown in FIG. 7 Will be done.

FIGS. 8 to 10 show a dielectric filter 1c according to a third embodiment of the present invention.
A high-pass filter coupling circuit H is realized by a circuit laminate 10c formed by laminating f, and the circuit laminate 10c is joined to the dielectric ceramic block 2 to couple with the required resonators 3A to 3C of the resonator circuit X. Thus, a high-pass filter shown in FIG. 10 is configured. The structure of the dielectric porcelain block 2 is the same as that of the first embodiment.

Here, the dielectric layers 31a have resonators 3A to 3A.
A through hole h connected to the 3C inner conductor is formed in a penetrating shape, and the ground conductor 32 is formed on the surface thereof so as to be insulated from each through hole h.

The resonators 3A to 3A are provided on the surface of the dielectric layer 31b.
The electrode layers 33a, 33b, 33c
Is formed.

The electrode layers 34a, 34b, and 34c are also provided on the surface of the dielectric layer 31c and at the portions facing the resonators 3A to 3C.
34c are formed, thereby forming the electrode layers 33a to 33c.
And between the electrode layer 34 a - 34 c, and the thickness of the dielectric layer 31c, and the capacitor C ₂₁ -C ₂₃ of the high-pass filter coupling circuit L capacity is determined by the electrode area of each electrode layer (see FIG. 10) is configured Become. The electrode layers 34a, 3
4c are joined interstage spaced electrode layer 34b and the spacing therebetween to form a capacitor C _24, C _25.

Further, a through hole h connected to the electrode layers 34a, 34b, 34c is formed in the dielectric layer 31d in a penetrating manner, and the surface of the through hole h is electrically connected to the electrode layers 34a, 34c through the through holes h on both sides. The inductors L ₂₁ and L ₂₃ are formed of meandering conductive paths that are electrically connected. Then, one end thereof is connected to an electrode layer constituting the ground conductor 37 formed on the lower edge of the dielectric layer 31d, and the other end is formed on the input / output terminal pads 38a and 38b formed on the upper edge of the dielectric layer 31d (FIG. 10)).

The inductor L ₂₂ in the dielectric layer 31e made of meandering conductive path is formed, one end of the dielectric layer 31
d, 31e through the through hole h formed in the electrode layer 3
4b, and the other end is connected to a conductive layer constituting a ground conductor 37 formed on the lower edge of the dielectric layer 31e.

Further, a ground conductor 39 is formed on the surface of the dielectric layer 31f.

[0035] In the state according dielectric layer 31a~31f are stacked, as shown in Figure 9, on both sides of the upper surface of the circuit laminate 10c, and output terminal pads 38a to be connected to the inductor L _21, inductor output terminal pads 38b to be connected to L ₂₃ are formed, and more circuits central portion and the lower surface of the upper surface of the laminate 10c, the ground conductor 37 is formed over the stacking direction, the ground conductor 39 and the dielectric block 2
Are connected. The grounding conductor 37, as described above, one end of the inductor L _21, L _22, L ₂₃ are respectively connected.

Thus, the circuit laminate 10 composed of a plurality of dielectric layers 31a to 31f is provided at the open end of the dielectric ceramic block 2.
By simply joining the capacitor c, a high-pass filter coupling circuit H composed of capacitors C _{21 to} C ₂₅ and inductors L _{21 to} L ₂₃ is formed.
Are combined with the required resonators 3A to 3C to form the high-pass filter circuit shown in FIG.

[0037]

As described above, according to the present invention, a plurality of dielectric layers 11a to 11a are provided on the open end face 8 of the dielectric porcelain block 2.
f, 21a to 21e and 31a to 31f are laminated, and the circuit laminates 10a, 10b, and 10c are arranged, and the coupling circuits L, B, and H are connected to the required resonators 3A to 3C of the resonator circuit X.
To form a low-pass filter, a band-pass filter or a high-pass filter. 1) The entire structure can be formed into a simple and uniform shape. Space can be used. 2) The mechanical strength is improved because it is based only on the dielectric porcelain block and the dielectric layer. 3) The coupling circuits L, B, and H are the circuit laminates 10a, 10b,
Since the structure is confined within 10c, it is cut off from the external atmosphere, is less susceptible to external influences such as humidity and mechanical shock, and is stable in characteristics. 4) Since the circuit laminates 10a, 10b, and 10c form a coupling circuit, those having arbitrary circuit constants can be easily configured, and the degree of freedom in designing a filter is given. 5) When the circuit laminates 10a, 10b, and 10c are formed into one chip by laminating and sintering a plurality of dielectric layers 11a to 11f, 21a to 21e, and 31a to 31f,
A circuit laminate 10 is provided on the open end face 8 of the dielectric ceramic block 2.
a, 10b, and 10c can be assembled simply by joining them, and are easy to manufacture and excellent in mass productivity.

[Brief description of the drawings]

FIG. 1 shows a dielectric filter 1a according to a first embodiment of the present invention.
FIG.

FIG. 2 shows a dielectric filter 1a according to a first embodiment of the present invention.
It is a perspective view of.

FIG. 3 is a vertical sectional side view of a part of the dielectric porcelain block 2;

FIG. 4 is an equivalent circuit diagram of the low-pass filter according to the first embodiment.

FIG. 5 shows a dielectric filter 1b according to a second embodiment of the present invention.
FIG.

FIG. 6 shows a dielectric filter 1b according to a second embodiment of the present invention.
It is a perspective view of.

FIG. 7 is an equivalent circuit diagram of a bandpass filter according to a second embodiment.

FIG. 8 shows a dielectric filter 1c according to a third embodiment of the present invention.
FIG.

FIG. 9 shows a dielectric filter 1c according to a third embodiment of the present invention.
It is a perspective view of.

FIG. 10 is an equivalent circuit diagram of a high-pass filter according to a third embodiment.

FIG. 11 is a perspective view of a dielectric filter D having a conventional configuration.

[Explanation of symbols]

 1a, 1b, 1c Dielectric filter 2 Dielectric ceramic block 3A to 3C Resonator 7 Ground conductor 8 Open end face 10a, 10b, 10c Circuit laminate 11a to 11f Dielectric layer 21a to 21e Dielectric layer 31a to 31f Dielectric layer 18a, 18b I / O terminal pad 27a, 27b I / O terminal pad 38a, 38b I / O terminal pad L Low-pass filter coupling circuit B Band-pass filter coupling circuit H High-pass filter coupling circuit

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[Procedure amendment]

[Submission date] December 26, 1997

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0019

[Correction method] Change

[Correction contents]

Thus, a circuit laminate 10 comprising a plurality of dielectric layers 11a to 11f is provided on the open end of the dielectric ceramic block 2.
a, the capacitors C _{1 to} C ₃ , C _{4 to} C
_6, the low-pass filter coupling circuit L comprised of the inductor _L 1 ~L ₃ is formed, the low-pass filter coupling circuit L are linked with the desired resonator 3A~3C resonator circuit X, FIG. 4
Thus, a low-pass filter circuit indicated by.

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0031

[Correction method] Change

[Correction contents]

The electrode layers 34a, 34b, and 34c are also provided on the surface of the dielectric layer 31c and at the portions facing the resonators 3A to 3C.
34c are formed, thereby forming the electrode layers 33a to 33c.
An electrode layer between 34 a - 34 c, and the thickness of the dielectric layer 31c, the capacitor _C 21 _{-C 23} of the high-pass filter coupling circuit H capacity is determined by the electrode area of each electrode layer (FIG. 10
Reference). Further, the electrode layers 34a,
34c is inter-stage coupled to the electrode layer 34b with a space therebetween, forming capacitors C ₂₄ and C ₂₅ therebetween.

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0032

[Correction method] Change

[Correction contents]

Further, a through hole h connected to the electrode layers 34a, 34b, 34c is formed in the dielectric layer 31d in a penetrating manner, and the surface of the through hole h is electrically connected to the electrode layers 34a, 34c through the through holes h on both sides. The inductors L ₂₁ and L ₂₃ are formed of meandering conductive paths that are electrically connected. An input / output terminal pad 38 having one end connected to the electrode layer forming the ground conductor 37 on the lower edge of the dielectric layer 31d and the other end formed on the upper edge of the dielectric layer 31d.
a, 38b (see FIG. 10).

[Procedure amendment 4]

[Document name to be amended] Drawing

[Correction target item name] Fig. 9

[Correction method] Change

[Correction contents]

FIG. 9

Claims (3)

[Claims] 1. A plurality of resonators formed by coating an inner conductor on an inner peripheral surface of a through hole in a dielectric ceramic block in one direction and excluding an open end face in which the through hole is opened. A circuit laminate comprising a plurality of dielectric layers laminated on an open end face of a dielectric porcelain block having a required outer peripheral surface covered with a ground conductor is disposed, and a coupling circuit is formed by the circuit laminate. A dielectric filter having a required filtering circuit formed by coupling the coupling circuit to a required resonator. 2. The circuit laminate according to claim 1, wherein a plurality of dielectric layers are laminated and sintered on the open end face of said dielectric porcelain block to form a one-chip circuit laminate. Dielectric filter. 3. A coupling circuit formed by the circuit laminate is a low-pass filter coupling circuit, a band-pass filter coupling circuit, or a high-pass filter coupling circuit coupled to each resonator. Item 3. The dielectric filter according to Item 2.