JPH03230602A - Manufacture of tm mode dielectric resonator - Google Patents

Abstract

PURPOSE:To manufacture plural kinds of dielectric resonators whose resonance frequencies are close to each other through the use of a same metallic mold by setting a prescribed resonance frequency by grinding of a cavity. CONSTITUTION:A cavity dielectric body 2 and a core dielectric body 1 are molded integrally, an opening of the cavity dielectric body 2 is ground and an electrode film 8 is formed to an outer surface. Moreover, electrode films 9, 10 are formed to the inner face of ceramic boards 6, 7 respectively and baked and bonded to the end face of the opening of the cavity dielectric body 2. The interval between the electrode films 9, 10 formed respectively to the ceramic boards 6, 7 is decided by changing the size A of the two openings of the cavity dielectric body 2 and the resonance frequency of the resonator is decided. Thus, when the resonance frequencies of resonators are close to each other, plural kinds of TM mode dielectric resonators with different resonance frequencies are manufactured by using a same metallic die.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Industrial Application Field The present invention relates to a method for manufacturing a 7M mode dielectric resonator having a predetermined resonant frequency.

(b) Prior Art Conventionally, cavity resonators, semi-coaxial cavity resonators, and the like have been mainly used as filters for high power applications, but these filters have been extremely large.

Therefore, in applications that require smaller size, 7M, which has a high no-load Q (Qo) and is small and has high heat dissipation efficiency
mode dielectric resonators have been put into practical use.

A 7M mode dielectric resonator has a columnar core dielectric through which a displacement current flows, a cavity that holds this core dielectric and acts as a shield case through which an actual current flows, and a signal input/output to and from the cavity. It consists of signal connectors etc.

A partially cutaway perspective view and a sectional view of a conventional TM mode dielectric resonator are shown in FIGS. 3 and 4. 3a in both figures
3 is a side plate, 3b is a bottom plate, and 3c is a top plate, and these constitute a cavity. A columnar core dielectric 1 is arranged between the bottom plate 3b and the top plate 30 of this cavity. Further, a coaxial connector provided with a coupling loop for inputting and outputting signals is attached to the top plate 3c. In both figures, one of the coaxial connectors 4 and the coupling loop 5 attached thereto are visible.

By connecting such 7M mode dielectric resonators in multiple stages, one
When one filter is configured, the resonant frequency of each dielectric resonator is set by the diameter (D in FIG. 4) of the columnar core dielectric of each dielectric resonator. If the core dielectric is a prism, the resonant frequency will be determined by its width. For example, when manufacturing multiple types of resonators with close resonance frequencies, the dimensions of each core dielectric are modified by grinding.

(C) Problems to be Solved by the Invention A TM mode dielectric resonator can be constructed by bonding a core dielectric inside a ceramic cavity as described above. There is also a method of molding. A TM mode dielectric resonator formed by integral molding not only simplifies the assembly process, but also reduces distortion due to heat generation in the core dielectric because the linear expansion coefficients of the core dielectric and the cavity dielectric are equal. This has the advantage of being less likely to occur.

However, in a TM mode dielectric resonator formed by integral molding, it is not possible to grind only the core dielectric.

Therefore, if we try to set the resonant frequency directly by the dimensions at the time of molding, in order to configure one filter consisting of multi-stage resonators, we need to use multiple metals to mold each of the multiple TM mode dielectric resonators. The purpose of this invention, which requires a mold, is to enable the manufacture of multiple types of TM mode dielectric resonators having different resonant frequencies using the same mold when the resonant frequencies are close to each other.

fd) Means for Solving the Problems The method for manufacturing a TM mode dielectric resonator according to the present invention involves grinding a cavity in which a core dielectric is provided to a predetermined external dimension, thereby forming the same structure as described above. The method is characterized in that the resonant frequency of a TM mode dielectric resonator having a core dielectric is set.

(e) Function In the method for manufacturing a TM mode dielectric resonator of the present invention, the external dimensions of the cavity are modified by grinding. By changing the external dimensions of the cavity, the resonant frequency of a resonator using this cavity changes. Since the relationship between the external dimensions of the cavity and the resonant frequency is uniquely determined, a TM mode dielectric resonator having a predetermined resonant frequency can be obtained by grinding until the external dimensions of the cavity reach a predetermined value. .

Note that the present invention is not limited to a structure in which the cavity is integrated with a core dielectric material, but can also be applied to a structure in which a core dielectric material is joined within a cavity to form a resonator.

(f) Embodiment The configuration of a TM mode dielectric resonator applied to the present invention is shown in FIGS. 1 and 2.

FIG. 1 is an exploded perspective view. In the same figure, 2 is a round hole Hi into which the signal input connector and signal output connector are inserted on the top surface.
and a cavity dielectric in which Ho is formed,
Reference numeral 1 has a core dielectric having a square columnar shape as a whole and has an electrode film on its outer surface. The cavity dielectric 2 and the core dielectric 1 are integrated by integral molding. Also, 6.7
are ceramic plates each having an electrode film formed on the side facing the cavity dielectric 2, and constitute a ceramic cavity by joining to the cavity dielectric 2.

In FIG. 1, the inter-opening dimension A of the cavity dielectric 2 is adjusted by lapping one or both opening end faces of the cavity dielectric 2. In FIG. Due to this, when the ceramic plates 6 and 7 are joined, the ceramic plates 6.
A resonance frequency characteristic determined according to the distance between the electrodes (ie, A) formed on the inner surface of each of the electrodes 7 is obtained. Note that the eight dimensions in the figure may be changed by grinding the side surface of the ceramic cavity 2, but the variable range of the resonant frequency is narrow due to the limitation of the wall thickness of the ceramic cavity.

FIG. 2 is a central vertical cross-sectional view after applying an electrode film to each component shown in FIG. 1 and bonding. As shown in the figure, a cavity dielectric 2 and a core dielectric 1 are integrally molded, and after the opening of the cavity dielectric 2 is ground, an electrode film 8 is formed on the outer surface. Furthermore, electrode films 9 and 10 are formed on the inner surfaces of the ceramic plates 6 and 7, respectively, and bonded to the end faces of the opening of the cavity dielectric 2 by baking with Ag paste or the like. By changing the dimension A between the two openings of the cavity dielectric 2 in this way, the ceramic plate 6
．． The spacing between the electrode films 9 and 10 formed on the electrodes 7 is determined, thereby determining the resonant frequency of the resonator. Therefore, for example, a plurality of ceramic cavities obtained from the same mold are ground, each set to a predetermined size, and the TM mode dielectric resonators thus formed are connected in multiple stages to form one filter. be able to.

(g) Effects of the Invention According to the present invention, a TM mode dielectric resonator having a predetermined resonance frequency can be manufactured by grinding a cavity. Therefore, it is possible to manufacture a plurality of types of dielectric resonators with similar resonator frequencies using the same mold, and it is also possible to configure one filter by combining them.

[Brief explanation of drawings]

1 and 2 are an exploded perspective view and a center vertical sectional view after assembly of a TM mode dielectric resonator to which the present invention is applied. 3 and 4 are a partially cutaway perspective view and a central vertical sectional view of a conventional TM mode dielectric resonator. ■-core dielectric, 2-cavity dielectric, 6.7-ceramic plate, 8.9.10-electrode film.

Claims (1)

[Claims] (1) By grinding a cavity in which a core dielectric is provided to a predetermined external dimension, the resonant frequency of a TM mode dielectric resonator having this cavity and the above-mentioned core dielectric can be set. A method for manufacturing a featured TM mode dielectric resonator.