JPH11112205A - Dielectric filter and filter device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To narrow spaces between filters and to miniaturize a device by forming shielding electrodes in the stacking direction of dielectric layers between resonance lines. SOLUTION: The shielding electrodes 41-43 are formed in the stacking direction between four resonance lines 13A-13D formed on the surface of the second dielectric layer 2. Namely, the lower ends of the shielding electrodes 41-43 are connected to the ground electrode 11 formed on the first dielectric layer 1 and the upper ends are extended to positions which are not exposed to the upper face of the third dielectric layer 3. Namely, the upper ends of the shielding electrodes 41-43 are formed in a state where they are not connected to input/output electrodes 15A and 15B and floating capacity electrodes 16A-16C. Thus, electric connection between the resonance lines 13A-13D can be reduced and the spaces between the resonance lines 13A-13D can be narrowed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dielectric filter and a filter device, and more particularly to a laminated dielectric filter and a dielectric filter used in a filter or a duplexer incorporated in a radio section of a high-frequency circuit such as a portable communication telephone. The present invention relates to a filter device including a plurality of body filters.

[0002]

2. Description of the Related Art With the miniaturization of portable telephones, the demand for miniaturization of electronic components has become stronger. Along with this, various laminated dielectric filters have hitherto been devised. Many conventional laminated dielectric filters use a plurality of resonance lines (strip lines). However, electromagnetic coupling exists between the resonance lines (these couplings are actively used). ), It is necessary to increase the interval between the resonance lines so that the coupling does not affect the characteristics.

[0003] In addition, a dual mobile phone (for example, 9
(Can transmit and receive both 00MHz band and 1800MHz band)
, There are simply two RF filters for reception and L for transmission.
Two PFs are required.

[0004]

However, when a plurality of resonance lines are formed by widening the interval between the resonance lines, there is a problem that the size of the laminated dielectric filter and the filter device increases.

In the future, as the number of filters increases as the number of filters increases, the number of filters increases. However, the size of mobile phones is not allowed to increase, and further downsizing is required. Therefore, a laminated dielectric filter which can reduce the coupling between the resonance lines and between the filters and can cope with dualization is required.

[0006]

A dielectric filter according to the present invention comprises a plurality of dielectric layers laminated on each other, and a plurality of resonance lines formed on at least one of the dielectric layers. A shield electrode is formed between the resonance lines in a direction in which the dielectric layers are stacked.

Further, at least first to fifth dielectric layers are sequentially laminated, ground electrodes are respectively formed on the first dielectric layer and the fifth dielectric layer, and a plurality of ground electrodes are formed on the second dielectric layer. Are formed substantially in parallel, input / output electrodes are formed on a third dielectric layer, and a plurality of capacitance forming electrodes are formed on a fourth dielectric layer. And the capacitance forming electrodes on the fourth dielectric layer are connected by via-hole conductors, respectively.
A shield electrode is formed on the second dielectric layer and the third dielectric layer in a stacking direction, and one end of the shield electrode is connected to a ground electrode on the first dielectric layer.

[0008] In the filter device of the present invention, a plurality of dielectric filters are built in a substrate formed by laminating a plurality of dielectric layers, and at least one of the dielectric filters is at least one of them. And a shield electrode is formed between the dielectric filters in the stacking direction of the dielectric layers.

[0009]

According to the dielectric filter of the present invention, since the shield electrode is formed between the plurality of resonance lines (strip line and microstrip line) in the direction in which the dielectric layers are stacked, the interval between the resonance lines can be reduced. , Thereby enabling miniaturization. Further, by controlling the size and shape of the shield electrode between the resonance lines, the electromagnetic coupling state of the pair of resonance lines formed on both sides of the shield electrode can be controlled, and various filter characteristics can be obtained. be able to.

Further, in the filter device of the present invention, since the shield electrode is formed between the filters in the direction of lamination of the dielectric layers, the interval between the filters can be narrowed, and the miniaturization can be promoted.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1 An embodiment of a laminated dielectric filter having a shield electrode formed in the laminating direction will be described below.

FIG. 1 is a schematic development view of a laminated dielectric filter (hereinafter sometimes referred to as a filter) of the present invention, and FIG.
Is a perspective view showing the external appearance of the filter, in which the internal structure is omitted, FIG. 3 is a sectional view of the filter, and FIG. 4 is an equivalent circuit diagram of the filter.

In FIG. 1, reference numerals 1 to 6 are first to sixth dielectric layers. Reference numerals 11 and 12 denote ground electrodes formed on the surfaces of the first dielectric layer 1 and the fifth dielectric layer 5, respectively. Reference numerals 13A to 13D denote four ground electrodes formed on the surface of the second dielectric layer 2. It is a resonance line.

Reference numerals 14A to 14D denote four capacitance forming electrodes formed on the surface of the fourth dielectric layer 4, which are connected to the resonance lines 13A to 13D by via holes 31 to 34, respectively. These capacitance forming electrodes 14A to 14A
A resonance capacitance is formed between D and the ground electrode 12 of the fifth dielectric layer 5. These earth electrodes 11 and 12, the resonance lines 13A to 13D, the capacitance forming electrodes 14A to 14D,
The via holes 31 to 34 constitute a four-stage 波長 wavelength strip line resonator.

Reference numerals 15A and 15B denote input / output electrodes formed on the surface of the third dielectric layer 3. The input / output electrodes are mainly opposed to the capacitance forming electrodes 14A and 14D to form input / output capacitance. Reference numerals 16A, 16B, and 16C denote floating capacitance electrodes formed on the surface of the third dielectric layer 3 between the input / output electrodes 15A and 15B.
A capacitance is formed between -3 stages and 3-4 stages. That is,
The resonance lines 13A and 13B and the floating capacitance electrode 16A, the resonance lines 13B and 13C and the floating capacitance electrode 16B, the resonance line 13
A capacitance is formed between C, 13D and the floating capacitance electrode 16C.

In the laminated dielectric filter of the present invention, the shield electrodes 41 to 43 are formed between the resonance lines 13A to 13D in the laminating direction. That is, the lower ends of the shield electrodes 41 to 43 are connected to the ground electrode 11 formed on the first dielectric layer 1, and the upper ends extend to positions not exposed on the upper surface of the third dielectric layer 3. That is, the upper ends of the shield electrodes 41 to 43 are
A, 15B and the floating capacitance electrodes 16A, 16B, 16C are not connected.

Hereinafter, a method of manufacturing the present filter will be described. First, the dielectric layers 1 to 6 are made of a dielectric material made of ceramic or glass ceramic, a photocurable monomer,
It is formed by thinning a slip material containing an organic binder to produce a molded insulating layer, laminating and firing.

The slip material used as the insulating layer molded body is a slip material obtained by homogeneously kneading a ceramic raw material powder, a photocurable monomer, an organic binder, and an organic solvent or water. In addition, although ceramic raw material powder is mentioned as an insulating layer molded body material, glass ceramic is also included.

In a low-temperature fired substrate fired at 850 to 1050 ° C., the ceramic raw material powder is a composite oxide containing at least Mg, Ti, and Ca as metal elements, and the composition of the metal oxide is Expression (1
-X) MgTiO ₃ -xCaTiO ₃ (where x represents a weight ratio and 0.01 ≦ x ≦ 0.15), and 100 parts by weight of the main component represented by B ₂ O _Three
It is preferable to add 3 to 30 parts by weight in terms of conversion and 1 to 25 parts by weight of an alkali metal-containing compound in terms of alkali metal carbonate.

In addition to the above-mentioned ceramic raw material powder, the constituent materials of the slip material include a photocurable monomer and an organic binder which are eliminated by sintering, and further, an organic solvent or water. A slip material containing an organic solvent is called a solvent-based slip material, and a slip material containing water is called a water-based slip material.In the solvent-based slip material and the water-based slip material, a photocurable monomer and an organic binder are slightly mixed. different.

Incidentally, the organic solvent or water mainly adjusts the viscosity of the slip and the like, and is completely lost during the binder removal process in the firing step.

The photocurable monomer of the solvent-based slip material must have excellent thermal decomposability in order to cope with a low-temperature and short-time baking process. As a photocurable monomer, a monomer having a secondary or tertiary carbon, which needs to be photopolymerized by exposure after application of a slip material and drying, capable of forming free radicals and chain growth addition polymerization. For example, alkyl acrylates such as butyl acrylate having at least one polymerizable ethylenic group and the corresponding alkyl methacrylates are effective. Further, polyethyne glycol diacrylates such as tetraethylene glycol diacrylate and methacrylates corresponding thereto are also effective. The photo-curable monomer is added in such a range that it can be cured by exposure and a portion other than the exposure can be easily removed by development.

The organic binder of the solvent-based slip material must have good thermal decomposability like the photocurable monomer. At the same time, because it determines the viscosity of the slip, wettability with solids must also be emphasized. According to studies by the present inventors, carboxyl groups such as acrylic acid or methacrylic acid-based polymers, alcoholic hydroxyl groups Preferred are ethylenically unsaturated compounds with The addition amount is preferably 25% by weight or less based on the solid content.

The photocurable monomer and the organic binder of the water-based slip material must be water-soluble,
A hydrophilic functional group such as a carboxyl group is added to the monomer and the binder. The amount of addition is 2 to 300, and preferably 5 to 100 in terms of acid value.
If the added amount is small, the solubility in water and the dispersibility of the solid component powder become poor, and if the added amount is large, the thermal decomposability becomes poor. In consideration of the above, it is appropriately added within the above range.

As described above, the photocurable monomer and the organic binder in any of the slip materials must have good thermal decomposability.
Thermal decomposition must be possible below 0 ° C. More preferably, the temperature is 500 ° C. or lower.

If the thermal decomposition temperature exceeds 600 ° C., it remains in the dielectric layer, is trapped as carbon, changes the color of the substrate to gray, and lowers the insulation resistance of the dielectric layer. In addition, it may become a void and cause delamination.

As a slip material, a sensitizer, a photoinitiating material or the like may be added as required. For example,
Examples of the photoinitiating material include benzophenones and acyloin ester compounds.

As described above, the solvent-based slip material or the water-based slip material serving as the insulating layer is formed by mixing and kneading with the ceramic raw material powder, the photocurable monomer, the organic binder, and the organic solvent or water. The method of mixing and kneading may be a conventionally used method, for example, a method using a ball mill. Examples of the method for thinning the slip material include a doctor blade method (knife coat method),
A doctor blade method or the like, which is formed by a roll coating method, a printing method, or the like, and in which the surface of the insulating film after application is easy to flatten, is particularly preferable. The viscosity is adjusted to a predetermined value according to the method of thinning.

Further, the conductive paste of a conductive material to be various electrodes is made of a powder of at least one metal material of gold, silver, copper or an alloy thereof, a low melting point glass component, an organic binder, and an organic solvent. A homogeneously kneaded mixture is used. In particular, since the firing temperature is 850 to 1050 ° C., a material having a relatively low melting point and a low resistance is selected as the metal material.

The laminated dielectric filter of the present invention firstly
The slip material is repeatedly thinned (hereinafter, simply referred to as coating) and dried on the supporting substrate to form an insulating layer molded body to be the dielectric layer 1.

As a coating method, it is formed by a doctor blade method, a roll coating method, a printing method using a screen having a coating area approximately the same as that of the supporting substrate, or the like. The drying method is performed using a batch-type drying furnace or an inline-type drying furnace, and the drying condition is desirably 120 ° C. or lower. Also, rapid drying may cause cracks on the surface, so it is important to avoid rapid heating.

Here, a glass substrate,
Examples thereof include an organic film and an alumina ceramic.
This support substrate is removed before the firing step, but in the case of alumina ceramics and the like, firing is performed simultaneously,
A part of the completed laminated dielectric filter may be constituted. Therefore, an internal wiring or a surface wiring may be formed on this alumina support substrate.

Next, a conductor serving as the ground electrode 11 is formed on the insulating layer formed body serving as the dielectric layer 1 formed on the support substrate by using the above-mentioned conductive paste. Thereafter, on the upper surface of the conductor serving as the ground electrode 11, the slip material is repeatedly thinned (hereinafter simply referred to as coating) and dried to form an insulating layer molded body serving as the dielectric layer 2.

The dielectric layer 2 includes shield electrodes 41 to 43
Are formed in the direction of lamination of the dielectric layers, and the shield electrodes 41 to 43 are formed on a film formed by applying and drying a slip material or by repeatedly applying and drying the film. On the other hand, exposure and development are performed to form through grooves in the direction of lamination of the dielectric layers. Actually, the lower part of the through groove is closed by the insulating layer molded body of the dielectric layer 1, but is referred to as a through groove for convenience.

In the exposure treatment, for example, a photo target is brought close to or placed on the insulating layer molded body, and a region other than the through groove is irradiated with low-pressure, high-pressure, or ultra-high-pressure mercury lamp exposure light.

As a result, in the region other than the through groove, the photocurable monomer causes a photopolymerization reaction. Therefore, only the through-groove portion becomes a fusible portion that can be removed by the developing process.

In practice, the exposure accuracy is improved when the photo target is brought into contact with the insulating layer molded body and exposed.
The optimal exposure time is determined by the thickness of the molded insulating layer, the width of the through groove, and the like. The exposure apparatus may be a general one used for a so-called photoengraving technique.

In the developing treatment, a solvent such as chlorocene is brought into contact with the exposed and solubilized portion, which is a through groove, by, for example, a spray developing method or a paddle developing method to perform development. Thereafter, washing and drying are performed as necessary.

Next, a conductor member to be the shield electrodes 41 to 43 is formed by filling and drying the conductive paste into the through-groove. The filling method is performed by, for example, a screen printing method. In addition, it is also possible to form a via hole together when the shield electrode is formed.

Thereafter, conductors serving as the resonance lines 13A to 13D are formed on the upper surface of the insulating layer formed body serving as the dielectric layer 2. The application and drying of the slip material is repeated on this upper surface to form an insulating layer molded body that will become the dielectric layer 3. Thereafter, the above steps are repeated to produce a laminated molded body having a pattern structure as shown in FIG.

When the dielectric layer is formed, it may be formed by one application, or may be formed in two or more steps.
In particular, when the dielectric layer 3 is manufactured, first, a slip material is applied, dried, exposed, and developed, and a conductive paste is filled into the through-hole of the shield electrode and the through-hole of the via-hole conductors 31 to 34 of the insulating layer molded body. And the shield electrodes 41 to 43,
After preparing conductor members to be the via-hole conductors 31 to 34, application, drying, exposure, and development of a slip material are performed again,
It can be manufactured by forming a through-hole for a via-hole conductor in an insulating layer molded body and filling it with a conductive paste.

Finally, firing is performed. The firing step includes a binder removal step and a firing step.
° C), the organic components of the insulating layer molded body and various electrodes disappear.
Thereafter, the laminated dielectric filter of the present invention can be obtained by firing the insulating layer molded body to be the dielectric layer and the conductor members to be various electrodes at a predetermined atmosphere and at a predetermined temperature.

The laminated dielectric filter of the present invention has a shape as shown in FIG. 2 when used alone. Input / output electrodes 15A, 1
External input / output electrodes 21 and 22 are formed at positions corresponding to 5B, and external ground electrodes 23 and 24 are formed on the remaining two side surfaces. The external ground electrode 23 has a ground electrode 11, 1
2 are connected, and the external ground electrode 24 is further connected to the resonance electrodes 13A to 13D.

The laminated dielectric filter of the present invention can be built in a circuit board (made integrally). In this case, the external ground electrodes 23 and 24 and the external input / output electrode 2
It is preferable to use a via-hole conductor, a vertical electrode, or the like instead of 1 and 22 because a laminated dielectric filter can be built in an arbitrary portion of the circuit board.

FIG. 4 shows an equivalent circuit of the laminated dielectric filter of the present invention, which will be described below. The resonance lines 13A to 13D and the via-hole conductors 31 and 34 form resonance inductors 51 to 54, and the capacitance between the capacitance forming electrodes 14A to 14D and the ground electrode 12 form resonance capacitors 55 to 58. Input / output electrode 1
5A and the capacitance forming electrode 14A between the input / output capacitor 6
1. Similarly, an input / output capacitor 65 is formed between the input / output electrode 15B and the capacitance forming electrode 14D.

The capacitors (interstage capacitance) 62 between adjacent resonance lines are formed by the floating capacitance electrodes 16A to 16C.
~ 64.

When there is no shield electrode formed in the stacking direction between adjacent lines of the resonance lines 13A to 13D, electromagnetic coupling occurs, which is represented by a mutual inductance M in an equivalent circuit. However, in the multilayer dielectric filter of the present invention, the shield electrode 4 is provided between the resonance lines.
1 to 43, the coupling between the lines is weakened, and the capacitors (inter-stage capacitances) 62 to 64 are smaller than M in the equivalent circuit.
Becomes dominant.

In such a laminated dielectric filter, since the shield electrodes 41 to 43 are formed between the resonance lines 13A to 13D in the direction in which the dielectric layers are laminated, the resonance lines 13A to 13D are formed by the shield electrodes 41 to 43. Electromagnetic coupling between the resonant lines 13
The interval between A to 13D can be reduced, and downsizing can be achieved.

Further, by controlling the size and shape of the shield electrode between the resonance lines, that is, FIG. 5 is a side view showing a state where the shield electrode 41 is formed between the two resonance lines 13A and 13B. It is an explanatory view, but by changing the height h of the shield electrode 41 protruding upward from the resonance lines 13A and 13B, electromagnetic coupling of the pair of resonance lines 13A and 13B formed on both sides of the shield electrode 41 is performed. The state can be controlled, and various filter characteristics can be obtained. FIG. 6 shows two resonance lines 1.
FIG. 5 is an explanatory plan view showing a state in which a shield electrode 41 is formed between 3A and 13B. The resonance line 13A can also be formed by adjusting the size (length, thickness) and formation position of the shield electrode 41. , 13B can be controlled.

Embodiment 2 Hereinafter, a filter device in which two laminated dielectric filters of the present invention are combined and a shield electrode is formed therebetween in the laminating direction will be described.

FIG. 7 is a schematic development view of the filter device of the present invention, and FIG. 8 shows the appearance of the filter device. This filter device contains two dielectric filters.

In FIG. 7, reference numerals 1 to 6 denote dielectric layers. Reference numerals 13E to 13J denote resonance lines formed on one main surface of the dielectric layer 2, and reference numerals 11 and 12 denote ground electrodes.

Reference numerals 14E to 14J denote capacitance forming electrodes formed on one main surface of the dielectric layer 4, each of which is a resonance line 13E.
To 13J and via-hole conductors 31 to 37. A resonance capacitance is formed between these capacitance forming electrodes 14E to 14J and the ground electrode 12. Reference numerals 15C to 15F are input / output electrodes formed on one main surface of the dielectric layer 3, and reference numerals 16D to 16G are floating capacitance electrodes.

Reference numeral 44 denotes a shield electrode formed in the stacking direction. The shield electrode reduces the coupling between the two stacked dielectric filters, thereby contributing to the composite filter. The upper part of the shield electrode 44 is the ground electrode 12.
The lower end is connected to the ground electrode 11. Note that FIG.
Although not shown, a shield electrode is formed between the resonance lines 13E to 13J in the same manner as in FIG.

FIG. 8 is an external perspective view of such a filter device. External input / output electrodes 25A, 25B, 26A, 26B are formed at positions corresponding to the input / output electrodes 15C to 15F. Further, external input / output electrodes 25A, 25B,
On the side different from 26A and 26B, an external earth electrode 27 is provided.
A and 27B are formed, and the ground electrodes 11 and 12 are connected. Further, resonance lines 13E to 13G are connected to the external earth electrode 27A, and resonance lines 13H to 13J are connected to the external earth electrode 27B. External ground electrodes 28 and 29 are formed on the same side surface as the external input / output electrodes 25A, 25B, 26A and 26B.
Is connected to

In such a filter device, the coupling between the resonance lines can be reduced, and the two laminated dielectric filters can be provided close to each other.

In FIG. 7, a shield electrode may be formed only between the resonance lines of one of the two dielectric filters. A shield wall may be formed between dielectric filters in which no shield electrode is formed between the resonance lines.

Incidentally, the pattern structure of the laminated dielectric filter is not limited to the above embodiment, but may be any other pattern structure as long as it has at least a plurality of resonance lines.

In the filter device of the present invention, for example, a combination of a band-pass filter (BPF) and a low-pass filter (LPF), a combination of an LPF and an LPF, and the like are possible. In addition, it goes without saying that not only a combination of two filters but also three or more, for example, two BPFs and two LPFs may be combined and a shield electrode may be provided between each.

[0060]

According to the dielectric filter of the present invention, since the shield electrode is formed between the plurality of resonance lines in the direction in which the dielectric layers are stacked, the interval between the resonance lines can be reduced, and the size can be reduced. . Further, by controlling the size, shape, and the like of the shield electrode between the resonance lines, the electromagnetic coupling state of a pair of resonance lines formed on both sides of the shield electrode can be controlled, and various filter characteristics can be obtained. be able to.

Further, in the filter device of the present invention, since the shield electrode is formed between the filters in the direction of lamination of the dielectric layers, the interval between the filters can be reduced, and the miniaturization can be promoted.

[Brief description of the drawings]

FIG. 1 is a schematic view of a conductor portion of a dielectric filter according to the present invention.

FIG. 2 is an external perspective view of the dielectric filter of the present invention.

FIG. 3 is a sectional view of the dielectric filter of the present invention.

FIG. 4 is an equivalent circuit diagram of the dielectric filter of the present invention.

FIG. 5 is an explanatory view seen from a side direction for explaining a protruding height of a shield electrode of the dielectric filter of the present invention.

FIG. 6 is an explanatory view seen from a plane direction for explaining a formation position of a shield electrode of the dielectric filter of the present invention.

FIG. 7 is a schematic view of a conductor portion of the filter device of the present invention.

FIG. 8 is an external perspective view of the filter device of the present invention.

[Explanation of symbols]

1 to 6: Dielectric layer 11, 12: Earth electrode 13A to 13J: Resonant line 14A to 14J: Capacitance forming electrode 15A to 15F: Input / output electrode 16A to 16G: Floating Capacitance electrodes 21, 22, 25A, 25B, 26A, 26B ... external input / output electrodes 23, 24, 27A, 27B, 28, 29 ... external earth electrodes 31 to 37 ... via hole conductors 41 to 44 ...・ Shield electrodes 51-54 ・ ・ ・ Resonant inductors 55-58 ・ ・ ・ Resonant capacitors 61,65 ・ ・ ・ Input / output capacitors 62-64 ・ ・ ・ Interstage capacitors

Claims (3)

[Claims] 1. A dielectric filter comprising a plurality of stacked dielectric layers, wherein a plurality of resonance lines are formed on at least one of said dielectric layers, wherein said resonance layer includes a plurality of resonance lines formed between said resonance lines. A dielectric filter, wherein a shield electrode is formed in a stacking direction. 2. The method according to claim 1, wherein at least first to fifth dielectric layers are sequentially laminated, ground electrodes are respectively formed on the first dielectric layer and the fifth dielectric layer, and a plurality of ground electrodes are formed on the second dielectric layer. Are formed substantially in parallel, input / output electrodes are formed on a third dielectric layer, and a plurality of capacitance forming electrodes are formed on a fourth dielectric layer. And a capacitance forming electrode on the fourth dielectric layer are connected by via-hole conductors, and a shield electrode is provided between the resonance lines on the second dielectric layer and the third dielectric layer in the stacking direction. 2. The dielectric filter according to claim 1, wherein one end of the shield electrode is connected to a ground electrode on the first dielectric layer. 3. A dielectric filter according to claim 1, wherein a plurality of dielectric filters are built in a substrate formed by laminating a plurality of dielectric layers, and at least one of the dielectric filters is the dielectric filter according to claim 1 or 2. And a shield electrode is formed between the dielectric filters in the direction in which the dielectric layers are stacked.