JP2005200269A - Dielectric porcelain composition for high frequency, dielectric resonator and dielectric filter, dielectric duplexer and communication equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dielectric porcelain composition for high frequency that has a high ε<SB>r</SB>and a high Q value and indicates excellent dielectric characteristics with a small absolute value of τ<SB>f</SB>. <P>SOLUTION: The dielectric porcelain composition for high frequency has a composition represented by a compositional formula (Ag<SB>1/2</SB>Re<SB>1/2</SB>)TiO<SB>3</SB>(wherein, Re is at least one metal element selected from La, Nd, Sm and Pr). <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a high-frequency dielectric ceramic composition used in a high-frequency region such as a microwave and a millimeter wave, and a dielectric resonator, a dielectric filter, a dielectric duplexer, and a communication device configured using the same About.

  In high frequency regions such as microwaves and millimeter waves, dielectric ceramics are widely used as materials constituting dielectric resonators and circuit boards.

When such a high-frequency dielectric ceramic is particularly intended for applications such as dielectric resonators and dielectric filters, the required dielectric characteristics are as follows: (1) the wavelength of electromagnetic waves in the dielectric is 1 / (ε _r ^1/2 ), the dielectric constant (ε _r ) is high as a response to the demand for miniaturization, (2) the dielectric loss is small, that is, the Q value is high, and (3) the resonance frequency. Is excellent in temperature stability, that is, the absolute value of the temperature coefficient (τ _f ) of the resonance frequency is small.

Here, τ _f is a slope (first derivative) when the resonance frequency temperature curve is linearly approximated using the resonance frequency (f ₂₀ ) at 20 ° C. and the value of the resonance frequency (f ₇₀ ) at 70 ° C. The value is obtained by the following formula: τ _f = (f ₇₀ −f ₂₀ ) / (f ₂₀ · (70 ° C.−20 ° C.)).

Conventionally, as a dielectric ceramic composition for high frequency that can satisfy the above-described requirements, for example, BaO—Nd ₂ O ₃ —TiO ₂ —Bi ₂ O ₃ (see Patent Document 1), (A _1/2 B _{1 / 2} ) A porcelain composition such as TiO ₃ (where A is Li and / or Na, B is at least one metal element selected from Nd, Sm, Co, and Pr) (see Patent Document 2) Has already been proposed.
Japanese Patent Publication No. 5-68044 Japanese Patent No. 2654299

In recent years, there has been an increasing demand for low loss and downsizing of electronic devices, and more excellent dielectric properties required for high frequency dielectric ceramics for applications such as dielectric resonators and dielectric filters are required. It is supposed to be. In particular, even when used in a high frequency region, there is an increasing demand for materials having both a high ε _r , a high Q value, and a high temperature stability (the absolute value of τ _f is small).

However, the dielectric properties of the dielectric ceramic composition having the composition system described in Patent Document 1 are as follows: ε _r is 52 to 100, Q × f value is 2200 to 8000 GHz, and absolute value of τ _f is 1 to 115 ppm / The temperature was ℃, and ε _r remained at 100 or less, and it could not be said to be sufficiently high.

The dielectric properties of the dielectric ceramic composition having the composition system described in Patent Document 2 are as follows: ε _r is 31 to 92, Q × f value is 1000 to 6600 GHz, and absolute value of τ _f is 58 to 405 ppm / Similarly, it cannot be said that ε _r is sufficiently high, and when ε _r is increased, the absolute value of τ _f increases.

Therefore, in order to further reduce the size of dielectric resonators and dielectric filters, a dielectric ceramic composition having a higher ε _r and a smaller absolute value of τ _f has been demanded.

Therefore, an object of the present invention is to solve the above-described problem, that is, even when used in a high frequency region such as a microwave or a millimeter wave, it has a high ε _r and a high Q value, and the absolute value of τ _f An object of the present invention is to provide a high frequency dielectric ceramic composition having a small value and exhibiting excellent dielectric properties.

In order to solve the above technical problem, the high frequency dielectric ceramic composition of the present invention has a composition formula: (Ag _1/2 Re _1/2 ) TiO ₃ (where Re is La, Nd, Sm, and Pr) At least one metal element selected from among the above.

  The dielectric resonator according to the present invention is a dielectric resonator in which a dielectric ceramic is operated by electromagnetic coupling to an input / output terminal, and the dielectric ceramic is used for the high frequency of the present invention described above. It consists of a dielectric ceramic composition.

  The dielectric filter of the present invention includes the above-described dielectric resonator and external coupling means connected to the input / output terminal of the dielectric resonator.

  The dielectric duplexer of the present invention includes at least two dielectric filters, input / output connection means connected to each of the dielectric filters, and antenna connection means commonly connected to the dielectric filter. A dielectric duplexer, wherein at least one of the dielectric filters is the above-described dielectric filter according to the present invention.

  Furthermore, the communication device of the present invention includes the above-described dielectric duplexer, a transmission circuit connected to at least one input / output connection means of the dielectric duplexer, and the input / output described above connected to the transmission circuit. A receiving circuit connected to at least one input / output connection means different from the means; and an antenna connected to the antenna connection means of the dielectric duplexer.

According to this invention, the composition represented by the composition formula: (Ag _1/2 Re _1/2 ) TiO ₃ (where Re is at least one metal element selected from La, Nd, Sm, and Pr). Ε _r is as high as 120 to 170, Q × f value is as high as 1050 to 1500 GHz, and the absolute value of τ _f is as small as 140 to 230 ppm / ° C. A high frequency dielectric ceramic composition exhibiting characteristics can be obtained.

  Therefore, for example, a dielectric resonator mounted in a base station, a mobile phone, a personal radio, a satellite broadcast receiver, etc. is downsized, the dielectric loss is reduced, and the temperature stability of the resonance frequency is excellent. be able to. As a result, if such a dielectric resonator is used, a dielectric filter, a dielectric duplexer, and a communication device that are downsized and have excellent characteristics can be advantageously configured.

  First, a dielectric resonator, a dielectric filter, a dielectric duplexer, and a communication device to which the high frequency dielectric ceramic composition of the present invention is applied will be described.

  FIG. 1 is a cross-sectional view schematically showing the basic structure of a dielectric resonator 1 constructed using the high frequency dielectric ceramic composition of the present invention.

  Referring to FIG. 1, a dielectric resonator 1 includes a metal case 2, and a columnar dielectric ceramic 4 supported by a support base 3 is disposed in a space inside the metal case 2. A coupling loop 5 is formed between the center conductor and the outer conductor of the coaxial cable 7 to serve as an input terminal. Further, a coupling loop 6 is formed between the central conductor and the outer conductor of the coaxial cable 8 to serve as an output terminal. Each terminal is held by the metal case 2 in a state where the outer conductor and the metal case 2 are electrically joined.

  The dielectric porcelain 4 operates by electromagnetic coupling to the input terminal and the output terminal, and only a signal having a predetermined frequency input from the input terminal is output from the output terminal.

  The dielectric ceramic 4 provided in such a dielectric resonator 1 is composed of the high frequency dielectric ceramic composition of the present invention.

  The dielectric resonator 1 shown in FIG. 1 is a TE01δ mode resonator used in a base station or the like, but the high-frequency dielectric ceramic composition of the present invention has other TE modes, TM modes, and TEMs. The same can be applied to a dielectric resonator using a mode or the like.

  FIG. 2 is a block diagram illustrating an example of a communication device configured using the dielectric resonator 1 described above.

  The communication device 10 shown in FIG. 2 includes a dielectric duplexer 12, a transmission circuit 14, a reception circuit 16, and an antenna 18.

  The transmission circuit 14 is connected to the input connection means 20 of the dielectric duplexer 12, and the reception circuit 16 is connected to the output connection means 22 of the dielectric duplexer 12.

  The antenna 18 is connected to the antenna connection means 24 of the dielectric duplexer 12.

  The dielectric duplexer 12 includes two dielectric filters 26 and 28. The dielectric filters 26 and 28 are configured by connecting an external coupling means to the dielectric resonator of the present invention. In the illustrated embodiment, for example, each of the dielectric filters 26 and 28 is configured by connecting external coupling means 30 to the input / output terminals of the dielectric resonator 1 shown in FIG. One dielectric filter 26 is connected between the input connection means 20 and the other dielectric filter 28, and the other dielectric filter 28 is connected between the one dielectric filter 26 and the output connection means 22. Connected to.

  Next, the dielectric ceramic composition for high frequency of the present invention that is advantageously used in the high frequency region, such as the dielectric ceramic 4 provided in the dielectric resonator 1 shown in FIG. 1, will be described.

The dielectric ceramic composition for high frequency of the present invention has a composition formula: (Ag _1/2 Re _1/2 ) TiO ₃ (where Re is at least one metal selected from La, Nd, Sm, and Pr) Element).

  In the present invention, examples that serve as the basis for selecting the specific composition and firing conditions as described above will be described below.

As starting materials, high-purity Ag ₂ O, Re ₂ O ₃ (where Re is at least one metal element selected from La, Nd, Sm, Pr, Ce, Gd, Dy, and Er), and Each powder of TiO ₂ was prepared.

Next, each starting material powder was prepared so that the composition represented by the composition formula: (Ag _1/2 Re _1/2 ) TiO ₃ was obtained using Re as the metal element shown in Table 1.

  Next, the blended powder was wet-mixed for 16 hours using a ball mill and dispersed uniformly, and then subjected to dehydration and drying treatment to obtain an adjusted powder.

  Next, this adjusted powder is calcined at a temperature of 900 to 1000 ° C. for 5 hours, an appropriate amount of binder is added to the obtained calcined powder, and then wet pulverized again using a ball mill for 16 hours to obtain a powder for firing. Obtained.

  The powder for firing was press-molded into a disk shape at a pressure of 200 MPa, and then fired at a temperature of 1300 ° C. for 5 hours in an atmosphere having an oxygen content shown in Table 1, with a diameter of 10 mm and a thickness of 5 mm. A disk-shaped sintered body was obtained.

With respect to the obtained sintered body of each sample, the measurement frequency (f) is set to around 3 GHz, the resonance point peak is measured by the double-end short-circuited dielectric resonator method, and the resonance point peak height and the sample size in the TE011 mode are measured. ε _r was determined. Further, the Q value was obtained from the resonance point peak shape, and converted to a Q × f value by the resonance frequency at that time. Further, the resonance frequency was measured by a cavity method using the TE01δ mode, and τ _f in a temperature range of 20 to 70 ° C. was measured.

Table 2 shows ε _r , Q × f value, and τ _f corresponding to the sample composition, measured as described above.

  In Tables 1 and 2, the sample number with * is a sample outside the scope of the present invention.

As shown in Tables 1 and 2, according to the high frequency dielectric ceramic composition according to Samples 1 to 7 within the scope of the present invention, ε _r is as large as 120 to 170, and the Q × f value is 1050 to 1500 GHz. The absolute value of τ _f can be reduced to 140 to 230 ppm / ° C., and excellent microwave dielectric characteristics can be obtained.

  In contrast, samples that are outside the scope of this invention are considered.

When Re is other than La, Nd, Sm, and Pr, as shown in sample numbers 8 to 11, the dielectric loss is too large, that is, the Q value is too small, so that Re is La, Nd, Sm, and Pr. In some cases, the resonance point peak that was clearly confirmed could not be identified, and specific values of ε _r and Q value could not be obtained based on the peak height and peak shape. Further, since the resonance point peak could not be identified, the temperature characteristic of the resonance frequency could not be measured.

  The high frequency dielectric ceramic composition of the present invention is a chemical amount represented by the above composition formula based on the purity of the starting materials, the preparation method, the firing conditions, etc., in the range of not detracting from the object of the present invention. Deviation from the theoretical composition may occur.

In addition, the high frequency dielectric ceramic composition of the present invention may contain a slight amount of impurities as long as the object of the present invention is not impaired. For _{example, MnO 2, NiO, Fe 2} O 3, Cr 2 O 3, SiO 2, B 2 O 3, Al 2 O 3, a _{ZrO 2, Nb 2 O 5,} Ta 2 O 5 or the like from 0.01 to 0. Even if the content is about 50% by weight, the characteristics of the dielectric ceramic are not greatly affected.

It is sectional drawing which shows the basic structure of the dielectric resonator 1 comprised using the dielectric ceramic composition for high frequencies of this invention schematically. It is a block diagram which shows an example of the communication apparatus comprised using the dielectric resonator 1 shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Dielectric resonator 2 Metal case 3 Support stand 4 Dielectric porcelain 5, 6 Coupling loop 7, 8 Coaxial cable 10 Communication apparatus 12 Dielectric duplexer 14 Transmission circuit 16 Reception circuit 18 Antenna 20 Input connection means 22 Output connection Means 24 Antenna connection means 26, 28 Dielectric filter 30 External coupling means

Claims (5)

It has a composition represented by a composition formula: (Ag _1/2 Re _1/2 ) TiO ₃ (where Re is at least one metal element selected from La, Nd, Sm, and Pr). A high frequency dielectric ceramic composition.   2. A dielectric resonator in which a dielectric ceramic is operated by electromagnetic coupling to an input / output terminal, wherein the dielectric ceramic is a dielectric comprising the dielectric ceramic composition for high frequency according to claim 1. Resonator.   A dielectric filter comprising: the dielectric resonator according to claim 2; and an external coupling unit connected to an input / output terminal of the dielectric resonator.   A dielectric duplexer comprising at least two dielectric filters, input / output connection means connected to each of the dielectric filters, and antenna connection means commonly connected to the dielectric filter, wherein the dielectric A dielectric duplexer, wherein at least one of the filters is a dielectric filter according to claim 3.   5. The dielectric duplexer according to claim 4, a transmission circuit connected to at least one input / output connection means of the dielectric duplexer, and at least one different from the input / output means connected to the transmission circuit A communication apparatus comprising: a receiving circuit connected to an input / output connection means; and an antenna connected to an antenna connection means of the dielectric duplexer.

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