JPH06237106A - Lamination type element for microwave - Google Patents

Abstract

PURPOSE:To obtain the small sized lamination type element manufactured by an easy baking condition and having an excellent microwave characteristic by employing a specific Ag/Pd alloy to part or all of a conductor. CONSTITUTION:The lamination type dielectric resonator has a structure that each of strip line conductors 2-4 is inserted between dielectric layers 1 to incorporate a shield conductor and a coupling capacitor as a lamination microwave element. The inner conductors 2-4 of the lamination type dielectric resonator are arranged at a prescribed interval via the dielectric layer 1 and they are connected respectively to an external electrode 5. All or part of the conductors 2-4 is made of an Ag/Pd alloy including 80wt.% or over of Ag. That is, the Ag/Pd alloy with a higher conductive rate comparatively except Ag,Cu,Au is employed for the conductors 2-4 of the microwave lamination type element, then a temperature at which simultaneous baking is attained is increased up to nearly 1050 deg.C, the environment control is not required, the selection of the dielectric layer 1 is extended and the dielectric body having a higher dielectric rate and a higher no load Q value is used for the dielectric layer 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microwave laminated element using an Ag / Pd alloy as a conductor and having excellent microwave characteristics.

[0002]

2. Description of the Related Art In recent years, there has been a demand for miniaturization of mobile communication devices such as car telephones, portable telephones, and the like, which utilize radio waves in the microwave band, or devices such as satellite broadcasting. For this purpose, it is necessary to reduce the size of individual parts that make up the equipment, and one of the means is to propose laminated elements such as bandpass filters, resonators, and duplexers that use dielectric materials. (Japanese Patent Laid-Open No. 3-254512).

In these small stacked elements, a dielectric layer using a dielectric material having a high dielectric constant in the microwave range, a large unloaded Q value and a small absolute value of the temperature change rate of the resonance frequency. It is required to be composed of a conductor having a high electric conductivity.

In this case, since the size of the element is inversely proportional to the square root of the permittivity of the dielectric, the larger the permittivity, the smaller the element can be, and the characteristics required for the element, as long as the same resonance mode is used. It is necessary that the loss of the dielectric material is small (the unloaded Q value is large) due to the low loss, and the loss of the electrode material is small (the conductivity is large), and the dielectric material is required for the temperature stability. This is because it is essential that the absolute value of the temperature change rate of the resonance frequency is small.

[0005]

However, metals such as Ag, Au, and Cu having a very high conductivity have a low melting point, and the dielectric material used at the same time must be able to be fired at a temperature lower than that temperature. For example, the melting point of Ag is extremely low at 961 ° C, and therefore, the only dielectric materials that can use Ag for conductors are very low-temperature sintered materials with a firing temperature of 961 ° C or less. The dielectric cannot be used as it is as a material for a laminated device.

Further, Cu and Au have melting points of 1083 ° C. and
Although 1063 ℃, which is higher than that of Ag, Au is an expensive noble metal, and there are some parts that are too expensive to be used as a conductor and are not practical, and since Cu oxidizes when fired in air, It is necessary to bake in an oxygen-free atmosphere, for example in nitrogen. However, in manufacturing a laminated device, it is essential to heat-treat an organic component contained in a dielectric sheet or a conductor paste in the presence of oxygen to burn out. Therefore, in order to use Cu as a conductor, organic components are scattered, but Cu is required to be controlled in a very difficult atmosphere without being oxidized.

For the above reasons, there is a problem that it is difficult to use a metal such as Ag, Au, or Cu as a conductor of a small-sized laminated type element for microwaves because of various restrictions. However, conventionally, conductors other than these metals have low electric conductivity and are considered to be unsuitable for use as conductors of microwave elements, and there has been no practical application.

The present invention solves the above-mentioned problems, and Ag / Au / Cu, which has a lower conductivity than Ag, Au, and Cu, is used.
An object of the present invention is to provide a small-sized laminated element for microwaves, which has excellent microwave characteristics while suppressing the loss of the laminated element itself by compensating for the drawbacks of the Pd alloy to some extent.

[0009]

To achieve this object, the present invention comprises at least a conductor and a dielectric layer,
All or part of the conductor is made of an Ag / Pd alloy containing 80% by weight or more of Ag.

[0010]

According to the present invention, by using an Ag / Pd alloy having a relatively high electric conductivity other than Ag, Cu, and Au for the conductor of the laminated element for microwaves, the temperature at which simultaneous firing is possible is about 1050 ° C. And eliminates the need for atmosphere control, which broadens the choice of dielectric layers and allows the use of dielectrics with higher dielectric constants and unloaded Q-values.

[0011]

EXAMPLE As a laminated microwave element, a laminated dielectric resonator having a structure in which a stripline conductor was sandwiched between dielectric layers and a shield conductor and a coupling capacitor were built in was produced.

FIG. 1 is a vertical cross-sectional view showing the structure of the laminated dielectric resonator according to one embodiment of the present invention manufactured as described above, and FIG. 2 is shown in FIG.
3 is a cross-sectional view of FIG. 3, and FIG. 3 is an external perspective view of FIG.

1 to 3, 1 is a dielectric layer,
2, 3, 4 are inner layer conductors, 5 is an outer electrode, and the inner layer conductors 2, 3, 4 are arranged at a predetermined interval via the dielectric layer 1 and are connected to the outer electrodes 5, respectively. Has become.

Next, the fabrication of the dielectric resonator will be described. High-purity PbO ₂ , SrO ₂ , and C are used as starting materials for the dielectric ceramic composition used for the dielectric layer 1 shown in FIGS.
aCO ₃ , Fe ₂ O ₃ , Nb ₂ O ₅ and WO ₃ were used. These are represented by the general formula (Pb _0.4625 Sr _0.05 Ca _0.4875 ) (Fe _1/2 Nb _1/2 ) _0.8.
After correcting the purity so as to be (Fe _2/3 W _1/3 ) _0.2 O ₃ , a predetermined amount was weighed and mixed with a stabilized zirconia boulder using pure water as a solvent in a ball mill for 17 hours. This was suction filtered to separate most of the water content, dried, put into an alumina crucible and calcined at 825 ° C. for 2 hours.

Next, the calcined product was roughly crushed in an alumina mortar and further crushed in a ball mill for 17 hours using a ball made of stabilized zirconia and pure water as a solvent, suction-filtered to separate most of water, and then dried.

A slurry obtained by adding an organic binder, a solvent, and a plasticizer to the calcined powder and mixing them was formed into a sheet by a doctor blade method. Also, the Ag / Pd alloy (Ag / Pd = 90/10) used as the conductor metal of the inner layer conductors 2, 3 and 4 is
It was kneaded with the vehicle to form a paste.

FIG. 4 shows a printed pattern of the conductor of one element. The length of the inner layer conductors 2, 3, 4 (strip line) in FIG. 4 was set to about 10 mm. After laminating a plurality of sheets, the conductor pattern of the inner layer conductor 2 of FIG. 4 is screen-printed, a plurality of sheets are laminated thereon, a conductor pattern of the inner layer conductor 3 is printed, and a plurality of sheets are laminated, After printing the conductor pattern of the inner layer conductor 4 and laminating a plurality of sheets, the sheets were pressure-bonded by a hot press. After cutting into individual elements, heat treatment was performed at 700 ° C. in air to scatter the binder. These devices were fired in air for 2 hours. The firing temperature was 1000 ° C.

Then, as the external electrode 5, a commercially available Ag paste was baked at 800 ° C. to obtain a laminated dielectric resonator. The length of the strip line after firing is about 8.8 mm to 9.2
It was mm. Ten elements were prepared for each conductor, and the average was used as the characteristic.

When another dielectric ceramic composition is used for the dielectric layer 1, the composition is blended so as to have each composition and formed into a sheet, and the lamination method is such that the size of the printing pattern is different for each dielectric. The manufacturing method is almost the same as the manufacturing method described above except that the size is set to a suitable size.

Table 1 shows the composition and firing temperature of the dielectric ceramic composition used for the dielectric layer of the laminated element, the dielectric constant ε and the unloaded Q value of each ceramic composition.

[0021]

[Table 1]

Table 2 shows the microwave dielectric characteristics of the laminated type element using these dielectric ceramic compositions in the dielectric layer, the length of the inner layer conductor (strip line), and the Ag / Pd alloy used. . Moreover, each dielectric layer number indicates that the dielectric ceramic composition of the number in Table 1 was used for the dielectric layer. The numbers marked with * in Table 1 are comparative examples of this example.

[0023]

[Table 2]

As is clear from Table 2, the firing temperature is 1050.
When a dielectric ceramic composition having a temperature of ℃ or below is used for the dielectric layer and an Ag / Pd alloy containing 80% by weight or more of Ag is used for the conductor layer, it can be fired in the air without controlling the atmosphere.
By firing at a temperature of up to 50 ° C, the Ag / Pd alloy of the conductor did not melt.

However, in the case of Nos. 9 and 13 which are comparative examples of this example, since the firing temperature was 1200 ° C., when the Ag / Pd alloy containing 80 wt% or more of Ag was used for the conductor layer, the dielectric layer At the temperature at which No. 1 sinters, the Ag / Pd alloy was melted and a good laminate could not be obtained. Therefore, in the case of Nos. 14 and 15 in which Ag / Pd alloy containing 70% by weight of Ag in this dielectric layer was used for the conductor, the conductor did not melt, but the conductor loss was too large, and Since the microwave characteristics were not sufficient, they were excluded from the scope of the present invention.

The resonance frequency of the laminated element of this embodiment is around 830 MHz, and the unloaded Q value is high and is 100 or more. Therefore, the laminated element for microwaves having excellent microwave dielectric characteristics under easy conditions is obtained. I was able to get Also,
Since it can be fired in air and the dielectric used for the dielectric layer can be selected to a certain extent, it has a very high dielectric constant and high unloaded Q.
Dielectrics having values can be stacked. As a result, it was possible to obtain a laminated element for microwaves, which is much smaller than the laminated element using the conventional low temperature sintered material in the same mode and the same resonance frequency.

Further, this laminated device has a dielectric unloaded Q
Since the value is high, the conductivity of the electrode is lower than that of Ag or Cu.
Even if the / Pd alloy is used, if the Ag content is 80% by weight or more, it has sufficient microwave dielectric properties. For example, since the dielectric constant of the conventional low temperature fired substrate material is about 8, in order to obtain the same resonance frequency with the same structure as the resonator of the present embodiment, the length of the inner layer conductor (strip line) of 31.9 mm is required. Is required. However, as an example of the dielectric used in this example, the dielectric constant ε is 100 and the unloaded Q value is 1230 (P
b _0.4625 Sr _0.05 Ca _0.4875 ) (Fe _1/2 Nb _1/2 ) _0.8 (Fe _2/3 W
_1/3 ) When _0.2 O ₃ is used, the inner layer conductor (stripline) length of the laminated element is very small, about 9.0 mm, and the element has excellent characteristics with an unloaded Q value of 114. A laminated device could be obtained.

It is also possible to obtain a smaller resonant device by forming the inner layer conductor (strip line) into a curved shape or a laminated shape. It is also possible to obtain a bandpass filter or the like by combining a plurality of these with a capacitor or the like.

[0029]

As described above, in the microwave laminated element of the present invention, by using an Ag / Pd alloy having an Ag content of 80% by weight or more as an electrode, the temperature at which simultaneous firing can be performed can be performed.
Raising the temperature to 1050 ° C eliminates the need for difficult atmosphere control during firing, and as a result, the selection of dielectrics that can be used for the dielectric layer can be broadened. As a result, a dielectric material having a high dielectric constant and a large unloaded Q value, which could not be used conventionally, can be used for the dielectric layer of the laminated element, which is much higher than that of a microwave device using a conventional dielectric material. It is possible to obtain a small stacked element.

Since various small-sized resonator systems usable in the microwave region can be formed by the present invention, it is considered that it greatly contributes to downsizing of microwave devices such as car phones and portable phones. To be Further, the dielectric porcelain of the present invention can be used for a microwave circuit board and the like.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view showing the structure of a built-in capacitor type dielectric resonator according to an embodiment of the present invention.

2 is a cross-sectional view of FIG.

3 is an external perspective view of FIG. 1. FIG.

FIG. 4 is a diagram showing a printed pattern of the inner conductor of FIG.

[Explanation of symbols]

1 ... Dielectric layer, 2, 3, 4 ... Inner layer conductor, 5 ... External electrode.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Junichi Kato 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (1)

[Claims] 1. At least a conductor and a dielectric layer,
A laminated element for microwaves, wherein all or part of the conductor is made of an Ag / Pd alloy containing 80% by weight or more of Ag.