JPH03292006A - Manufacture of tm-mode dielectric resonator - Google Patents

Abstract

PURPOSE:To easily manufacture a resonator having a requested resonance frequency characteristic by integrating a core dielectric to part of a cavity, forming a recessed part to the outer face of the cavity corresponding to the end face of the core dielectric, and revising the resonance frequency depending on the size of the recessed part. CONSTITUTION:A core dielectric 1 is integrated to part of a cavity 2 and a recessed part 8 is formed to the outer face of the cavity 2 corresponding to the end face of the core dielectric 1. Then an electrode film 5 is formed to the outer face of the cavity 2 and the inner face of the recessed part 8. Then the ceramic cavity is formed by bonding ceramic plates 3, 4 with the electrode film formed to the side facing the cavity dielectric 2 to the cavity dielectric 2. The electrode film 5 decides the size of the core dielectric 1 in the axial direction. Since the C of an LC resonance circuit is changed mainly in the equivalent circuit of the resonator depending on the change in the size of the core dielectric 1 in the axial direction, the position of a metallic die of the recessed part forming part so as to make the depth of the recessed part 8 to be a prescribed value or the recessed part is polished after forming to realize the TM mode dielectric resonator having a prescribed resonance frequency.

Description

DETAILED DESCRIPTION OF THE INVENTION (Al Industrial Field of Application) This invention relates to a method of manufacturing a dielectric resonator using the 7M mode.

(b) Prior art In general, a 7M mode dielectric resonator consists of 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 core dielectric. It consists of signal connectors that connect to the body and input and output signals.

The above-mentioned cavity is made of ceramic with an electrode film formed thereon, or metal is used. In the case of a ceramic cavity, a core dielectric is placed in a cavity made of a ceramic material having approximately the same coefficient of linear expansion as the core dielectric. There is a method of joining, and a method of integrally molding the core dielectric and the cavity using the same dielectric ceramic material.

(C) Problem to be solved by the invention When using a TM mode dielectric resonator in a filter etc.
The resonant frequency of the resonator must be determined according to the characteristics of the filter. The resonant frequency of a TM mode dielectric resonator is generally determined by the width or radial dimensions of the core dielectric, but in the case where the core dielectric is integrally molded with the cavity, the molding die is adjusted for each resonant frequency. There was a problem in that a large amount of mold cost and time were required to manufacture a new filter with different characteristics. Of course, there is a problem in that resonance adjustment work is required by forming a notch in a part of the core dielectric and adjusting the amount of dielectric inserted into the notch, which also increases manufacturing costs. It is not suitable for determining the resonant frequency without adjustment due to accuracy.

An object of the present invention is to enable manufacturing of a plurality of types of TM mode dielectric resonators having close and different resonance frequencies using the same mold.

(d) Means for Solving the Problems The method for manufacturing a TM mode dielectric resonator of the present invention includes integrating a core dielectric into a part of a cavity, and forming a recess on the outer surface of the cavity corresponding to an end surface of the core dielectric. The method is characterized in that an electrode film is further formed on the outer surface of the cavity and the inner surface of the recess.

(e) Function In the method for manufacturing a TM mode dielectric resonator of the present invention, the core dielectric is integrated into a part of the cavity, and a recess is formed on the outer surface of the cavity corresponding to the end surface of the core dielectric. Thereafter, an electrode film is formed on the outer surface of the cavity and the inner surface of the recess.

Electrode films formed on the outer surface of the cavity and the inner surface of the recess define the axial dimensions of the core dielectric. Since the value of C of the LC resonant circuit in the equivalent circuit of the resonator changes mainly due to a change in the axial dimension of the core dielectric, the relationship between the depth of the recess and the resonant frequency is uniquely determined. Therefore, a TM mode dielectric resonator having a predetermined resonance frequency can be obtained by determining the mold position of the recess forming part so that the depth dimension of the recess becomes a predetermined value, or by grinding after molding. be able to.

Note that this invention is not limited to the case in which the cavity and the core dielectric are integrally molded, but as long as an electrode film is formed outside the cavity, a separate core dielectric is bonded inside the cavity to form a resonator. It can also be applied to things that

(f) Embodiment The structure of a TM mode dielectric resonator to which this invention is applied is shown in FIGS. 1 and 2.

FIG. 1 is an exploded perspective view. In the same figure, 2 is a cavity dielectric with round holes 6 and 7 formed on the top surface for inserting a signal input connector and a signal output connector, and a recess 8 formed in the center, and an electrode film is applied on the outer surface. ing. Reference numeral 1 denotes a core dielectric having a rectangular column shape as a whole, which is integrated into the center of the cavity dielectric 2 by integral molding.

Therefore, the recess 8 is located at a location corresponding to the upper end surface of the core dielectric 1. In addition, 3 and 4 are cavity dielectric bodies 2, respectively.
It is a ceramic plate on which an electrode film is formed on the side facing the cavity dielectric 2, and forms a ceramic cavity by joining it to the cavity dielectric 2.

FIG. 2 is a central vertical cross-sectional view of the integrated product of the core dielectric 1 and the cavity dielectric 2 shown in FIG. As shown in the figure, a cavity dielectric 2 and a core dielectric 1 are integrally molded, and an electrode film 5 is formed on the outer surface of the cavity dielectric 2. At this time, a continuous electrode film is also formed on the inner surface of the recess.

By joining two ceramic plates 3 and 4, each of which has an electrode film formed on the side facing the cavity dielectric, to the two opening surfaces of the cavity dielectric which has such an electrode film formed thereon, one TM mode dielectric is formed. Configure a resonator.

Therefore, the axial dimension of the core dielectric 1, that is, the distance between the electrodes at both ends of the core dielectric 1 changes depending on the depth of the recess. As the depth of this recess is increased, the value of C of the LC resonant circuit in the equivalent circuit of the resonator increases, and the resonant frequency decreases. The relationship between the depth of the recess and the resonant frequency can be determined in advance, and the recess may be formed in accordance with the desired resonant frequency.

Next, as another embodiment to which the present invention is applied, the structure of a TM mode multistage dielectric filter is shown in FIG. This figure is an exploded perspective view of a three-stage integrated TM mode dielectric filter. This dielectric filter consists of a filter main body 31, an upper cover 32, and a lower cover 39. It's intimidating. The filter main body 31 includes a cavity dielectric 23 and three cylindrical core dielectrics 20 disposed inside the cavity dielectric 23.
, 21.22, and each core dielectric has two connecting plates 23, 24. 25, 26, 27° 28.2, respectively.
It is connected to the cavity dielectric 23 via 9 and is integrated therewith. Furthermore, an electrode 1I30 is formed on the outer peripheral surface of the cavity dielectric 23 of the main body portion 31. The upper lid 32 is provided with through holes 33 and 34 into which signal input/output connectors are inserted,
Furthermore, recesses 35, 36, and 37 are formed on the upper surface at positions facing the three core dielectrics 20, 21, and 22, respectively, when joined to the filter main body 31. Furthermore, continuous electrode films 38 are formed on the upper surface of the upper lid 32, the inner surfaces of each of the recesses 35, 36, 37, the inner surfaces of the through holes 33, 34, and the four side surfaces of the upper lid 32, respectively. On the other hand, electrodes 40 are formed on the bottom and four side surfaces of the lower lid 39.

In this way, the bottom of the filter body 31 is placed on both opening surfaces. 3 by joining 32 and lower 139
fi! is an integrated dielectric filter consisting of stages of TM mode dielectric resonators. It is fied. At this time, the axial dimensions of the three core dielectrics 20, 21, 22 are determined by the depth of the recesses 35, 36, 37 formed in the top cover, which determine the resonant frequency of each resonator.

In each of the above embodiments, the depth of the recess is shallower than the wall thickness of the cavity, but it may be made deeper to reach the inside of the core dielectric. Further, in each of the above embodiments, the recess formed on the outer surface of the cavity is a round hole,
If the inner diameter is smaller than the width direction or outer diameter of the core dielectric, but the depth of the recess is shallower than the wall thickness of the cavity, the recess should be made in a wider range than the width direction or outer diameter of the core dielectric. It's okay.

(0 Effects of the Invention According to this invention, the resonant frequency can be changed by changing the dimensions of the recess formed on the outer surface of the cavity.
A TM mode dielectric resonator having the required resonance frequency characteristics can be easily manufactured. Furthermore, since there is no need to change the entire mold or the main parts, the cost required for the mold can be reduced, and manufacturing costs can be significantly lowered.

[Brief explanation of drawings]

FIG. 1 is an exploded perspective view of a TM mode dielectric resonator according to a first embodiment of the present invention, and FIG. 2 is a central vertical sectional view of the main part of the resonator. FIG. 3 is an exploded perspective view of a TM mode multistage dielectric filter according to a second embodiment of the present invention. 1.20, 21.22 - Core dielectric, 2.23 - Cavity dielectric, 3.4 - Ceramic plate, 5.30.38.40 - Electrode film, 8.35, 36.37 - Recess.

Claims (1)

[Claims] (1) The core dielectric is integrated into a part of the cavity, a recess is formed on the outer surface of the cavity corresponding to the end face of the core dielectric, and an electrode film is further formed on the outer surface of the cavity and the inner surface of the recess. A method for manufacturing a featured TM mode dielectric resonator.