JPH11122012A - Dielectric resonator and resonance frequency temperature coefficient compensating method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To compensate the temperature coefficient of a resonance frequency over a wide range by composing a support base for a dielectric by using a material including a high polymer material having a lower dielectric constant than the dielectric and selecting the kind and content of the high polymer material in consideration of a thermal expansion coefficient, etc. SOLUTION: A housing 11 is constituted of metal such as aluminum or an alloy and a base 13 for a dielectric 12 is formed of a composite material of a high polymer material with a low dielectric constant and low-dielectric constant ceramic and low-dielectric constant glass cloth, or >=2 kinds of low- dielectric constant high polymer material. The thermal expansion coefficient is freely controlled by using a composite material such as this to give satisfactory heat conductivity. Even if the ambient temperature of the dielectric resonator varies, the support base 13 can be constituted so as not to vary the electromagnetic coupling between the dielectric 12 and electrodes 14 and 15, the variations in the resonance frequency of the dielectric resonator due to the difference in thermal expansion between the dielectric 12 and housing 11 can be compensated over a wide range.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dielectric resonator used in a high frequency band and a method for compensating a temperature coefficient of the resonance frequency. Preferred application examples of the present invention are a satellite broadcast device, a mobile communication device, a high-frequency communication device, a transmitter and a filter used for a base station thereof and the like.

[0002]

2. Description of the Related Art In high-frequency communication from the UHF band to the microwave band and the millimeter wave band, a resonator is used as a device constituting an oscillator, a filter or the like. Dielectric resonators are widely used because of their advantages such as temperature stability, high Q value, and downsizing.

A conventional dielectric resonator is provided with a housing made of a metal case or a metal-plated plastic case, a dielectric, and electrodes for inputting and outputting high-frequency signals. In this type of dielectric resonator, resonance electromagnetic field energy is stored inside and near the dielectric. When a housing made of a metal conductor is present near the dielectric, a high-frequency current flows on the surface of the housing, causing a loss of electromagnetic field energy due to the high-frequency resistance, thereby deteriorating the resonator characteristics. Therefore, a support base is arranged in the housing, a dielectric is mounted on the support base, the dielectric is separated from the housing, and the loss of electromagnetic field energy is reduced. The support also has a function of radiating heat generated due to dielectric loss of the dielectric from the dielectric to the housing.

[0004] For these reasons, the support base requires a material having a low dielectric constant and a low dielectric loss. Conventionally, low dielectric constant ceramics such as quartz and forsterite have been used as materials meeting this demand.
No. 3 discloses an embodiment using a quartz tube as a support.

[0005]

In this type of dielectric resonator, electromagnetic coupling is performed between the dielectric and an electrode for inputting and outputting a high-frequency signal. Normally, the optimum electromagnetic coupling between the dielectric and the electrode is adjusted by selecting the height of the support.

However, since the housing, the dielectric, and the support to which the electrodes are fixed are made of different materials, they have different coefficients of thermal expansion. Therefore, when the ambient temperature of the dielectric resonator changes, the distance between the dielectric and the electrode changes. For this reason, the electromagnetic coupling between the dielectric and the electrode changes due to a change in the ambient temperature, and the resonance frequency of the dielectric resonator fluctuates, deteriorating the characteristics.

Further, in the case of industrial mass-produced products, it is necessary to change the material of the housing and the dielectric according to various requirements such as weight, strength and characteristics. Therefore, the thermal expansion coefficients of the housing and the dielectric each have various values. Correspondingly, various coefficients of thermal expansion must be selected for the support.

However, since the conventional support base is made of low dielectric constant ceramics, the range of selectable thermal expansion coefficient is narrow, which naturally results in a restriction on the product development of the dielectric resonator. Was.

SUMMARY OF THE INVENTION An object of the present invention is to provide a dielectric resonator capable of compensating a temperature coefficient of a resonance frequency in a wide range, and a method of compensating the temperature.

[0010]

In order to solve the above-mentioned problems, a dielectric resonator according to the present invention includes a housing, a support, and a dielectric. The support base includes a polymer material component having a dielectric constant lower than the dielectric constant of the dielectric, and is disposed in the housing. The dielectric is mounted on the support.

[0011] As described above, in the dielectric resonator according to the present invention, the support is disposed in the housing, and the dielectric is mounted on the support. Away from the body, the loss of electromagnetic field energy can be reduced.

The support base has a dielectric constant lower than that of the dielectric so as not to greatly affect the electromagnetic field distributed around the dielectric. Further, heat generated due to dielectric loss of the dielectric can be radiated to the housing through the support base.

A characteristic feature of the present invention is that the support base contains a polymer material component. The support base containing the polymer material component controls the content of the polymer material component,
Alternatively, the temperature coefficient of the resonance frequency of the dielectric resonator can be compensated by selecting the type of the polymer material component in consideration of the thermal expansion coefficient and the like.

It is easy to control the content of the polymer material component. Further, it is easy to select a polymer material having a lower dielectric constant than a dielectric material and a thermal expansion coefficient suitable for required resonance frequency temperature compensation from a large number of polymer materials.

For this reason, even when the ambient temperature of the dielectric resonator changes, a coefficient of thermal expansion of the support is selected so as not to change the electromagnetic coupling between the dielectric and the electrode, and the coefficient of thermal expansion between the dielectric and the housing is selected. Variations in the resonance frequency of the dielectric resonator due to the difference in thermal expansion can be compensated over a wide range.

Furthermore, for a wide variety of requirements such as weight reduction, strength improvement, and high performance, a polymer material meeting various requirements is selected from polymer materials having various thermal expansion coefficients. Therefore, the degree of freedom in designing the housing and the dielectric is significantly increased, and the degree of freedom in industrial product development can be greatly expanded.

In one embodiment, the support may include a glass cloth. Further, ceramics having a lower dielectric constant than the dielectric may be contained. In the present invention,
Preferred polymer material components include those obtained by polymerizing a monomer composition containing at least a fumaric acid diester as a monomer. Other preferred examples of the polymer material component include homopolypropylene and (styrene /
Examples thereof include those obtained by graft polymerization of a divinylbenzene) polymer. The polymer material component is
It may be a composite composition containing two or more polymer material components.

Other objects, configurations and advantages of the present invention will be described in more detail with reference to the accompanying drawings. However,
It goes without saying that the technical scope of the present invention is not limited to these illustrated embodiments.

[0019]

FIG. 1 is a perspective view, partially cut away, showing an example of a dielectric resonator according to the present invention, and FIG. 2 is a sectional view of the dielectric resonator shown in FIG. Referring to the drawings, a dielectric resonator according to the present invention includes a housing 11 and a dielectric 12.
And a support 13. The housing 11 has an electromagnetic field shielding effect and a function as a protective case. This housing 11
Is made of a conductive material such as copper, silver, aluminum or an alloy. Alternatively, the housing may be made of a metal-plated plastic or the like.

The support 13 is arranged inside the housing 11. In the drawing, the support base 13 has a columnar shape, and has a lower end attached to a substantially central portion of the bottom plate 110 of the housing 11 by mechanical coupling means such as bonding or screwing.

The dielectric 12 is mounted on the other end of the support 13. The illustrated dielectric 12 has a columnar shape made of microwave dielectric ceramics, and is joined to the upper end surface of the support base 13. In connecting the dielectric 12 to the support 13, means such as adhesion is employed.

Opposite side plates 111, 11 of the housing 11
2, a pair of electrodes 14 for inputting / outputting a high-frequency signal
15 are provided. The illustrated electrodes 14 and 15 are loop-shaped and face the dielectric 12 via a space.

The support 13 is made of a low dielectric constant material having a dielectric constant lower than that of the dielectric 12. Thus, the electromagnetic field distributed around the dielectric 12 is not significantly affected.

As described above, in the dielectric resonator according to the present invention, since the support 13 is disposed inside the housing 11 and the dielectric 12 is mounted on the support 13,
The support 12 separates the dielectric 12 from the housing 11,
Electromagnetic energy loss can be reduced.

Since the support 13 has a dielectric constant lower than the dielectric constant of the dielectric 12, the support 13 is
2 does not significantly affect the electromagnetic field distributed around 2. Further, heat generated due to dielectric loss of the dielectric 12 can be radiated to the housing 11 through the support 13.

A feature of the present invention is that, in the above-described basic structure, the support 13 contains a polymer material having a low dielectric constant. The support 13 including the polymer material component is
The temperature coefficient of the resonance frequency of the dielectric resonator can be compensated by controlling the content of the polymer material component or selecting the type of the polymer material component in consideration of the thermal expansion coefficient and the like. . It is easy to control the content of the polymer material component. Further, it is easy to select a polymer material having a lower dielectric constant than the dielectric 12 and having a thermal expansion coefficient suitable for required resonance frequency temperature compensation from a large number of polymer materials.

For this reason, even if the ambient temperature of the dielectric resonator changes, the support base 13 having a thermal expansion coefficient that does not change the electromagnetic coupling between the dielectric 12 and the electrodes 14 and 15 is formed. Variations in the resonance frequency of the dielectric resonator due to the difference in thermal expansion between the body 12 and the housing 11 can be compensated over a wide range.

Further, for a wide variety of requirements such as weight reduction, strength improvement, and high performance, a polymer material meeting various requirements is selected from polymer materials having various thermal expansion coefficients. The housing 11 and the dielectric 12
This greatly increases the degree of freedom in the design of products, and greatly expands the degree of freedom in industrial product development.

As the low dielectric constant polymer material to be included in the support 13, a polymer material obtained by polymerizing a monomer composition containing a fumaric acid diester, homopolypropylene, and (styrene / divinylbenzene) A polymer material obtained by graft polymerization of a polymer, a low dielectric constant polymer material such as polystyrene, polycarbonate, polyphenylene ether, or polyphenylene oxide can be used, and the material is selected according to a desired coefficient of thermal expansion.

Among these, a polymer material obtained by polymerizing a monomer composition containing a fumaric acid diester or a polymer material obtained by graft-polymerizing a homopolypropylene and a (styrene / divinylbenzene) polymer Is particularly preferable in that it exhibits high heat resistance and a low dielectric constant of about 1.8 to 3.0.

The support 13 of the present invention comprises a composite material of a low dielectric constant polymer material and a low dielectric constant ceramic as described above, a low dielectric constant polymer material, a low dielectric constant glass cloth, and a low dielectric constant ceramic. Or a composite material composed of two or more types of low dielectric constant polymer materials. By using such a composite material,
The thermal conductivity can be further improved, and the coefficient of thermal expansion can be freely controlled. When a composite material of a low dielectric constant polymer material and a low dielectric constant ceramic, for example, as shown in Japanese Patent Publication No. 5-59062, Ba-Co-Mg-Ta-Nb-O microwave dielectric ceramics, Al ₂ O ₃ and SiO ₂ are preferred in view of low dielectric loss and high thermal conductivity.

The low dielectric constant glass cloth constituting the support 13 of the present invention exhibits low dielectric loss.
R glass cloth, D glass cloth, E glass cloth, T
Preferably, glass cloth is used.

Next, an embodiment will be described. Support table 1
As a material of No. 3, a material obtained by impregnating a polymer material obtained by polymerizing dicyclohexyl fumarate (di-cHF), which is a low dielectric constant polymer material, into E glass cloth, which is a low dielectric constant glass cloth, was used. FIG. 3 shows a support 13 using the above-mentioned material.
Thermal expansion coefficient (linear expansion coefficient) and E glass cloth
FIG. 3 is a diagram showing the relationship between the amount of impregnation of a polymer material obtained by polymerizing di-cHF.

As can be seen from FIG. 3, the thermal expansion coefficient tends to increase as the impregnation amount increases, and it is apparent that the thermal expansion coefficient can be freely controlled.

Next, another embodiment of the present invention will be described. As a material of the support 13, a composite material of a polymer material obtained by polymerizing di-cHF, which is a low dielectric constant polymer material, and SiO _{2 of} low dielectric constant ceramic was used. Support 13 using this composite material
FIG. 4 shows the relationship between the thermal expansion coefficient of the composite material and the content of the polymer material obtained by polymerizing di-cHF in the composite material.

As is clear from FIG. 4, the thermal expansion coefficient tends to increase as the content of the polymer material increases, and the thermal expansion coefficient can be freely controlled over a wide range.

Next, the thermal expansion coefficient of the support obtained by the embodiment of the present invention is shown in Table 1 in comparison with the thermal expansion coefficient of the conventional support. In Table 1, Sample Nos. 1 to 3 are Examples and Samples Nos. 4 and 5 are Comparative Examples. In sample No. 1, as a material for the support 13, a low dielectric constant glass cloth E glass cloth was impregnated with a polymer material obtained by polymerizing dicyclohexyl fumarate (di-cHF), which is a low dielectric constant polymer material. Material used.

In sample No. 2, a composite material of a polymer material obtained by polymerizing di-cHF as a low dielectric constant polymer material and SiO ₂ as a low dielectric constant ceramic was used as the material of the support 13. .

In sample No. 3, as the material of the support 13, a polymer material (PP-gP (St) obtained by graft polymerization of a homopolymer of a low dielectric constant polymer and a (styrene / divinylbenzene) polymer was used. / DVB)) and a low dielectric constant ceramic Al ₂ O ₃ composite material was used.

In sample No. 4, quartz, which is a low dielectric constant ceramic, which is a conventional support base material, was used. Sample No.5
Then, forsterite, which is also a conventional support base material, was used. As is clear from Table 1, Samples Nos. 1 to 3 using the support base material of the present invention have a wider range of heat values than Samples Nos. 4 and 5 using the conventional low dielectric constant ceramics. It can be seen that the expansion coefficient can be controlled. Therefore, by controlling the content of the low dielectric constant polymer material constituting the support, even when the ambient temperature of the dielectric resonator changes, the electromagnetic coupling between the dielectric and the loop electrode is not changed. The thermal expansion coefficient of the dielectric resonator due to the thermal expansion difference between the dielectric and the housing
It is possible to manufacture a dielectric resonator that compensates for the dielectric resonator.

The dielectric resonator of the present invention can have various shapes and structures. An example is shown in FIG. In the example shown in FIG. 5, a substrate 17 is disposed on the surface of the bottom plate 110 of the housing 11, and electrodes 18 and 19 formed of strip transmission lines are provided on the surface of the substrate 17. Output. In this example as well, by selecting the thermal expansion coefficient of the support 13 so as not to change the electromagnetic coupling between the dielectric 12 and the electrodes 18 and 19 formed of strip transmission lines, fluctuations in the resonance frequency due to temperature can be reduced. A compensating dielectric resonator can be obtained.

[0042]

As described above, according to the present invention,
A dielectric resonator capable of compensating a temperature coefficient of a resonance frequency in a wide range and a temperature compensation method thereof can be provided.

[Brief description of the drawings]

FIG. 1 is a partially cutaway perspective view showing an example of a dielectric resonator according to the present invention.

FIG. 2 is a sectional view of the dielectric resonator shown in FIG.

FIG. 3 is a diagram showing the relationship between the impregnation amount of a polymer material obtained by polymerizing di-cHF into E glass cloth and the coefficient of thermal expansion.

FIG. 4 is a diagram showing the relationship between the content of a polymer material obtained by polymerizing di-cHF with respect to SiO ₂ and the coefficient of thermal expansion.

FIG. 5 is a partially cutaway perspective view showing another example of the dielectric resonator according to the present invention.

[Explanation of symbols]

 Reference Signs List 11 housing 12 dielectric 13 support base 14, 15, 18, 19 electrode

Claims (12)

[Claims] 1. A dielectric resonator including a housing, a support, and a dielectric, wherein the support includes a polymer material component having a dielectric constant lower than that of the dielectric. The dielectric resonator is disposed in the housing, and the dielectric is mounted on the support base. 2. The dielectric resonator according to claim 1, wherein the support base includes a glass cloth. 3. The dielectric resonator according to claim 1, wherein the support base contains a ceramic having a dielectric constant lower than that of the dielectric. 4. The dielectric resonator according to claim 1, wherein the polymer material component is a monomer composition containing at least a fumaric acid diester as a monomer. A dielectric resonator obtained by polymerization. 5. The dielectric resonator according to claim 1, wherein the polymer material component is obtained by graft-polymerizing a homopolypropylene and a (styrene / divinylbenzene) polymer. Dielectric resonator obtained. 6. The dielectric resonator according to claim 1, wherein the polymer material component is a composite composition including two or more polymer material components. Body resonator. 7. A method for compensating a temperature coefficient of a resonance frequency of a dielectric resonator, wherein the dielectric resonator includes a housing, a support, and a dielectric, wherein the support is A polymer material component having a dielectric constant lower than the dielectric constant of the dielectric, disposed in the housing, wherein the dielectric is mounted on the support, A resonance frequency temperature coefficient compensation method for compensating a temperature coefficient of a resonance frequency of a dielectric resonator by controlling a content or selecting a type of a polymer material component in consideration of a thermal expansion coefficient. 8. The method according to claim 7, wherein the support includes a glass cloth. 9. The resonance frequency temperature coefficient compensation method according to claim 7, wherein the support base includes a ceramic having a dielectric constant lower than that of the dielectric. Coefficient compensation method. 10. The resonance frequency temperature coefficient compensation method according to claim 7, wherein the polymer material component contains at least a fumaric acid diester as a monomer. A method for compensating a resonance frequency temperature coefficient obtained by polymerizing a product. 11. The resonance frequency temperature coefficient compensation method according to claim 7, wherein the polymer material component is obtained by graft polymerization of a homopolypropylene and a (styrene / divinylbenzene) polymer. The method of compensating the resonance frequency temperature coefficient obtained by the above method. 12. The resonance frequency temperature coefficient compensation method according to claim 7, wherein the polymer material component is a composite composition containing two or more polymer material components. Resonance frequency temperature coefficient compensation method.