JPS58111408A - Dielectric loading type coaxial resonator - Google Patents

Abstract

PURPOSE:To decrease the deterioration of no-load Q, by providing a taper region for an outer circumference of a coaxial type capacitive element provided at the open end of a center conductor and an inner circumference of an outer conductor and contacting the taper regions. CONSTITUTION:A taper is provided at an inner circumference of an open end of the outer conductor 1 so that the thickness is made thin toward the open end. A part corresponding to the taper being a part of the outer circumference of a dielectric 3 of a coaxial type capacitive element 8 provided at the open end of a center conductor 2 is provided with the taper similarly. In this element 8, the dielectric 3 such as BaO-TiO2-Sm2O3 system porcelain is formed in annular shape, a part of the outer circumference is polished into taper and sintered, metallic conductor films 4, 4' made of silver are formed on the inner and outer circumference, and a metallic conductor in contact with the film 4 provided at the inner circumference and having a hole at the inside is inserted. The tip of the center conductor 2 is inserted to the hole provided at the metallic part 6 of the element 8 and screwed with a retainer 5.

Description

[Detailed Description of the Invention] The present invention relates to a dielectric mounted coaxial resonator,
The purpose is to make it possible to modify the resonant frequency without deteriorating the no-load Q of the resonator.

Conventionally, for the purpose of reducing size and weight, there have been rod-wavelength and four-wavelength TIEM coaxial resonators filled with a dielectric material having a high dielectric constant and low loss. Also known is a dielectric-mounted coaxial resonator that uses a cavity coaxial resonator and partially mounts a dielectric material thereon. In this case, conventionally, a dielectric 3 was processed and installed between the outer conductor 1 and the inner conductor 2 as shown in FIG. 1, but due to variations in the processing accuracy of the dielectric 3, Electric body 3 and internal conductor 2. A slight gap was created between the external conductor 1 and there were problems such as a shift in resonance frequency and deterioration of vibration resistance and temperature characteristics.

As shown in FIG. 2, the present applicant has attached a capacitive element 7, which has a metal conductor film 4.4' coated on the inner and outer peripheral surfaces of a dielectric 3, to the tip of the center conductor 2. We have proposed a dielectric-mounted resonator with a structure in which it is attached via a dielectric resonator. Although this structure solves the above problems to some extent, due to the processing precision of the material, a slight gap may occur between the inner circumferential surface of the outer conductor 1 and the outer circumferential metal conductor film 4' of the coaxial capacitive element 7, resulting in contact. The resistance increases and the no-load Q deteriorates. Also, when this gap is filled with solder or conductive paste, the electrical conductivity of the solder or conductive paste is much lower than that of the external conductor or metallized surface, so there is a drawback that the no-load Q deteriorates. .

The present invention has been made to overcome these drawbacks, and provides a dielectric-mounted coaxial resonator that is more stable and suitable for mass production.

FIG. 3 shows a first embodiment of the present invention. Although the cross-sectional shape is circular, it is not limited to this, and may be rectangular or other shapes. In this embodiment, a taper is provided on the inner peripheral surface of the open end side of the outer conductor 1 so that the wall thickness becomes thinner toward the open end, and - a coaxial type base provided at the open end of the male central conductor 2 is provided. Similarly, a taper is provided on a part of the outer periphery of the dielectric 3 of the quantum element 8 corresponding to the above-mentioned curves. The coaxial capacitive element 8 is made of, for example, Ba.
A dielectric material 3 such as O-TiO2-Sm2O3-based porcelain is formed into a ring shape, a part of its outer periphery is polished into a tenon shape, and then fired to form a metal conductor film 4, such as silver, on the dielectric material 3. It has a structure in which a metal conductor portion having a hole inside is inserted into the metal conductor film 4 formed on the inner peripheral surface and the outer peripheral surface of the metal conductor film 4 provided on the inner peripheral surface.

The tip of the center conductor 2 is inserted into a hole provided in the metal conductor portion 6 of the coaxial capacitive element 8, and screwed onto the holding plate 6. As in this embodiment, by providing a taper on the inner circumferential surface of the outer conductor 1 and a part of the dielectric 3 of the coaxial capacitive element 8, and making contact with this tapered surface, the metal of the coaxial capacitive element 8 is Adhesion between the conductor film 4 and the tapered surface of the external conductor 1 can be improved, contact resistance can be reduced, and deterioration of the no-load Q can be eliminated.

FIG. 4 shows a second embodiment of the present invention, which is the same as the first embodiment except that a coaxial capacitive element 9 is attached directly to the center conductor 2 by providing a groove in the metal conductor portion 6. It has a similar structure.

Table 1 shows the comparative values of no-load Q at a resonant frequency of 200M1fz for the conventional resonator shown in FIGS. 1 and 2 and the resonator of the present invention shown in FIGS. 3 and 4, both of which have the same shape. Shown below. It can be seen that the resonator according to the present invention is clearly superior. The outer circumferential surface of the type capacitive element and the inner circumferential surface of the outer conductor are provided with a wide area, and these areas are brought into contact with each other, which is extremely effective in reducing the deterioration of the no-load Q. In addition, compared to the conventional structure in which a dielectric material is processed and inserted, there is no electrical resonant frequency shift, and the design has good vibration resistance and temperature characteristics, and has good reproducibility. It has the advantage of being able to mass-produce resonators that are faithful to

Furthermore, it is highly anticipated that it will be applied to applied products such as filters that utilize this resonator.

[Brief explanation of drawings]

1 and 2 are cross-sectional views of a conventional dielectric-mounted coaxial resonator, and FIG. 3 (&) is a first embodiment of a dielectric-mounted coaxial resonator according to an embodiment of the present invention. A vertical cross-sectional view showing the same (
b) is a cross-sectional view of FIG. 4A, and FIG. 4 is a longitudinal cross-sectional view showing a second embodiment of the dielectric-mounted coaxial resonator of the present invention. 1...Outer conductor, 2...Center conductor, 3
...Dielectric material, 4.4 ...Metal conductor film, 6 ... Pressing plate, 6 ... Metal conductor part,
7,8.9... Coaxial type capacitive element.

Claims (2)

[Claims] (1) It has an outer conductor and a center conductor, and is configured so that one end is open-circuited and the other end is short-circuited. A coaxial capacitive element having a configuration in which the inner and outer peripheral surfaces of a dielectric material are coated with a metal conductor film is mounted on the open end of the center conductor, and the outer peripheral surface of the coaxial capacitive element is A dielectric body-mounted type, characterized in that a second tapered region is provided in a part of the outer conductor, and the inner circumferential surface of the outer conductor and the outer circumferential surface of the coaxial capacitive element are brought into contact with each other via a tapered region. Coaxial resonator. (2) A dielectric-mounted coaxial resonator according to claim 1, wherein the coaxial capacitive element is fixed to the center conductor with a screw.