JPS61214801A - Coaxial dielectric resonator - Google Patents

Abstract

PURPOSE:To raise the unloaded Q and to reduce the variance by forming corner parts of a bottom surface covered with a conductive film to a circular arcuate shape in a coaxial dielectric resonator where the inside peripheral surface, the outside peripheral surface and one bottom surface of a hollow cylindrical dielectric are covered with the conductive film. CONSTITUTION:An inside peripheral surface 1a, an outside peripheral surface 1b, and a bottom surface 1c of a hollow cylindrical dielectric 1 formed with dielectric materials of a high dielectric constant of high Q are covered with a conductive film 2. Corner parts 1d and 1e of the bottom surface 1c are formed into a circular arcuate shape. Thus, the adhesive strength of the conductive film is improved uniformly, and the conductive film sticking state of conductors 2d and 2e in corner parts having an influence upon raising of Q is smooth especially. The unloaded Q is raised and the variance is reduced thereby.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a coaxial dielectric resonator in which a dielectric material is interposed between an inner conductor and an outer conductor.

2. Description of the Related Art In recent years, in the high frequency field of general communication equipment, active element I
Although the use of C is progressing, one of the challenges is miniaturization of passive elements that are difficult to make into ICs. Recently, coaxial dielectric resonators using dielectric materials with high Q and high permittivity have been developed mainly in the U.
It is often used as an HF band filter.

FIG. 2 shows the structure of a conventional common coaxial dielectric resonator. This is a so-called λ/4 structure in which a conductive film 2 is closely covered with the inner circumferential surface 1&, outer circumferential surface 1b, and bottom surface 1C of a hollow cylindrical dielectric material 1 made of a dielectric material with high Q and high permittivity. It is a type resonator. The conductive film 2 is generally covered with a method such as silver baking or copper electroless plating. This is a λ/4 wavelength type resonator in which the conductive film 2 on the inner circumferential surface 1a serves as a so-called resonant line, one side is short-circuited and the other side is open, and the area around the resonant line is filled with a dielectric material with a high permittivity. Therefore, if the relative dielectric constant is ε, then 1/rr
Since the resonant line length is shortened at the rate of γ, it is advantageous in terms of miniaturization of the coaxial resonator.

Problems to be Solved by the Invention In recent years, the realization of a low-loss bandpass filter using this coaxial dielectric resonator has become an issue. To achieve this, the question is how high should the unloaded Q of the coaxial dielectric resonator be. The present invention mainly provides solutions to the second and third problems.

To explain the conventional coaxial dielectric resonator in Fig. 2, in a resonant state at a frequency of λ/4 wavelength, the length of the inner conductor is the resonant line length, and at the open end face, the high frequency voltage is The high-frequency current is small, and the short-circuited end face is in a state where the high-frequency voltage is small and the high-frequency current is large. Therefore, the parts that have the most influence on increasing the Q are the shapes of the corner parts 1d and 10 of the short-circuit side end face and the state of adhesion of the conductive film 2. In this conventional example, since the corners are at right angles, the dielectric surface is rougher than other parts, and the state of adhesion of the conductive film 2 is not uniform, or sometimes only a part of it comes off. This caused a decrease in the no-load Q. Particularly during mass production, this caused variations in no-load Q and resulted in extremely poor quality.

The present invention solves these problems and reduces the no-load Q.
This is to increase the value and reduce the variation.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention provides a coaxial dielectric resonator in which the inner peripheral surface, outer peripheral surface, and one bottom surface of a hollow cylindrical dielectric material are covered with conductive films. In the container, the corner portion on the bottom side covered with the conductive film was formed into an arc shape.

By making the corners of the bottom side (short circuit side) covered with the conductive film into an arc shape, the adhesion of the conductive film is uniformly improved.
This increases the no-load Q of the resonator and reduces variations.

Embodiment FIG. 1 shows a structural diagram of an embodiment of the present invention. The same parts as in the conventional example are given the same reference numerals. High Q.

Hollow cylindrical dielectric body 1 made of dielectric material with high dielectric constant
The conductive film 2 is closely covered with the inner circumferential surface 1a, outer circumferential surface 1b, and bottom surface 1C, but the difference from the conventional example is that the corner portions 1d and 10 on the bottom surface 1C side are shaped like an arc. That's what I did. With this structure, the conductivity of the inner circumferential surface conductor 2a, corner conductor 2d, short-circuit side bottom conductor 2c, corner conductor 2e, and outer circumferential surface conductor 2b, which form a λ/4 resonant line and a shielding effect, is improved. The adhesion of the film 2 to the hollow cylindrical dielectric 1 is uniformly improved. In particular, since the state of conductive film adhesion on the corner conductors 2d and 2e, which affects the increase in Q, becomes smoother, the no-load Q becomes higher and its variation becomes smaller.

Effects of the Invention As is clear from the above explanation, the present invention has the following excellent effects. That is, in a coaxial dielectric resonator in which the inner peripheral surface, outer peripheral surface, and one bottom surface of a hollow cylindrical dielectric body are covered with a conductive film, by making the corner portion on the bottom surface side covered with the conductive film into an arc shape. , the no-load Q of a coaxial dielectric resonator made of a dielectric material with a high no-load Q can be increased without deterioration, and the variation can be reduced, so it is very effective especially in mass production. In addition, when manufacturing bandpass filters and the like using this coaxial dielectric resonator, the corners are arcuate and smooth, so there are problems such as scratches on the conductive film during manufacturing, resulting in Q deterioration. It disappears.

[Brief explanation of the drawing]

1A and 1B are a top view and a sectional view of a coaxial dielectric resonator according to an embodiment of the present invention, and FIGS. 2A and 2B are a top view and a sectional view of a conventional general coaxial dielectric resonator. be. 1...Hollow cylindrical dielectric, 1a...Inner peripheral surface, 1b...Outer peripheral surface, 1c...Bottom surface, 1d, 1e... ... Corner part, 2... Conductive film. Name of agent: Patent attorney Toshio Nakao and 1 other person
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Claims (1)

[Claims] A coaxial dielectric resonator characterized in that the inner peripheral surface, outer peripheral surface, and one bottom surface of a hollow cylindrical dielectric material are covered with a conductive film, and the corner portion on the bottom surface side covered with the conductive film is formed into an arc shape. .