JPH0573281B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an improvement in a dielectric resonator device having a structure in which one or more dielectric resonator units are passed between the inner walls of a shielded case.

[Prior Art] Japanese Patent Laid-Open No. 121502/1983 discloses a dielectric filter shown in FIG. 2. Here, a plurality of dielectric resonance units 2, 2, . . . are housed in a metal case 1 shown by imaginary lines. Electrodes 3, 3... are formed on both end faces of each dielectric resonance unit 2, and the electrodes 3, 3... are bonded to the inner wall of the metal case 1 by soldering or using a conductive adhesive. .

[Problems to be Solved by the Invention] In the conventional configuration described above, the metal shield case 1 having different coefficients of thermal expansion and the dielectric resonant unit 2 are joined. Therefore, when the ambient temperature changes, the coefficient of thermal expansion of the two will be different, so
In some cases, the end of the dielectric resonant unit 2 may be separated from the inner wall of the shield case 1, creating a slight clearance between the two. As a result, the resonant frequency of each resonant unit 2 changes, making it difficult to accurately set the coupling coefficient.

In the dielectric filter shown in FIG. 2, in order to eliminate such problems even to some extent, the electrode 3 is formed on the end face of the dielectric resonance unit 2, and the electrode 3 is soldered to the inner wall of the shield case 1. By bonding using a conductive adhesive, the ends of the dielectric resonance unit 2 are prevented from coming off the inner wall of the shield case 1. However, in reality, even if the electrodes 3 are used to bond, the bond is broken due to temperature changes, and the above-mentioned problems often occur.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a dielectric resonator device that can accurately set the resonant frequency or center frequency and coupling coefficient, and exhibits stable characteristics against temperature fluctuations.

[Means for Solving the Problems] The dielectric resonator device of the present invention utilizes a cylindrical dielectric ceramic in which at least one resonant portion extending between inner walls is integrally formed. Closing means are provided at both ends of the cylindrical dielectric ceramic so as to close the openings at both ends, and the entire outer peripheral portion of the dielectric ceramic provided with the closing means is shielded. A shield layer is formed as shown in FIG.

[Operations and Effects of the Invention] According to the present invention, one or more resonant portions are formed integrally with a cylindrical dielectric ceramic and extend between the inner walls of the dielectric ceramic. Therefore, since the case is made of ceramic, which is the same material as the resonant part, no clearance will be created between the resonant part and the cylindrical body even if the ambient temperature changes. That is, in the present invention, the case is constructed using dielectric ceramics, which is the same material as the resonant portion. On the other hand, in this type of dielectric resonator device, the resonant portion made of ceramic must be covered with a shield case. Therefore, in the present invention, a closing means is provided to close the openings at both ends of the cylindrical dielectric ceramic, and a closing means is provided to cover the outer peripheral surface of the cylindrical dielectric ceramic provided with the closing means. A shield layer is formed.

Therefore, in this invention, even if the ambient temperature changes, no clearance is created between the resonant part and the shield case, so the resonant frequency (center frequency in the case of a dielectric filter) and coupling coefficient can be accurately controlled. Therefore, it is possible to realize a dielectric resonator device with stable characteristics.

Further, by changing the thickness of the cylindrical portion of the cylindrical dielectric ceramic, the distance between one or more resonant portions, etc., the frequency characteristics and the coupling coefficient can be easily changed. Therefore, a dielectric resonator device with arbitrary characteristics can be easily obtained.

[Description of Embodiments] FIG. 1 is a sectional view showing a dielectric resonator device according to an embodiment of the present invention applied to a dielectric filter.

Although it is not necessarily clear from FIG. 1, the dielectric filter 10 is constructed using a cylindrical dielectric ceramic 11 having a plurality of resonant parts 12 to 15 extending between its inner walls. A closing member 1 made of the same material as the cylindrical dielectric ceramic 11 is provided at both end openings of the cylindrical dielectric ceramic 11.
6 and 17 are fixed using a conductive adhesive or the like, thereby closing the openings at both ends.

By the way, the cylindrical dielectric ceramic 11 is
As shown in FIG. 3, a plurality of divided dielectric ceramic bodies 21 to 29 are prepared, laminated in the order shown, and bonded to each other using, for example, a conductive adhesive. Among the plurality of divided bodies 21 to 29, divided bodies 22, 24, 26, 2
8 are constructed of the same material and each have a resonant portion 12, 13, 14 and 15 extending between the inner walls. The resonant parts 12 to 15 are integrally formed with the divided bodies 22, 24, 26, and 28.

The reason why the resonant parts 13 and 15 are arranged in different directions with respect to the resonant parts 12 and 14 in FIG. 3 is to adjust the degree of coupling between the resonant units composed of the resonant parts 12 to 15. and
It can be arranged in various orientations depending on the desired degree of coupling.

Note that in this case, the resonant portion 12 and the resonant portion 14, and the resonant portion 13 and the resonant portion 15 are not coupled to each other, so that they are arranged in a perpendicular positional relationship.

Moreover, the cylindrical dielectric ceramic divided bodies 21, 23, 2 in which the resonant parts 12 to 15 are not formed
5, 27, and 29 are provided to similarly adjust the degree of coupling between the respective resonance units.

In the dielectric filter of this embodiment, the cylindrical dielectric ceramic 11 (Fig. 1) is formed by laminating the divided bodies 21 to 29 and bonding them together with a conductive adhesive as shown in Fig. 3. can get. and,
As described above, the closing members 16 and 17 are attached to close the openings at both ends of the cylindrical dielectric ceramic 11. Furthermore, as shown in FIG. 1, a shield layer 31 is formed over the entire outer peripheral surface of the cylindrical dielectric ceramic 11 to which the closing members 16 and 17 are fixed. Shield layer 31
is formed by applying and baking a suitable conductive material such as copper paste or silver paste, or by any other suitable method. This shield layer 31 cooperates with the cylindrical dielectric ceramic 11 and the closing members 16 and 17 to form a shield layer 31.
Functions as a case.

In addition, each of the divided bodies 21 to 29 and the closing member 1
6 and 17 may be bonded to each other by forming the above-described shield layer 31 without using a conductive adhesive.

As described above, in the embodiments shown in FIGS. 1 and 3, the shield case is constructed using the cylindrical dielectric material 11, and the resonant portions 12 to 1
5 is formed integrally with the cylindrical dielectric ceramic 11. Therefore, even if the ambient temperature changes, the resonant parts 12 to 15 will never come off the cylindrical dielectric ceramic 11. Therefore, a dielectric filter that is stable against fluctuations in ambient temperature can be easily constructed.

In the embodiment shown in FIG. 1, the shield layer 31 is formed by baking a conductive paste on the outer peripheral surface, and each of the divided bodies 21 to 29 is electrically connected by the conductive paste, so that the Q value is This has the advantage that the decrease in

In the embodiment shown in FIG. 1, the divided bodies 21, 23, 25, 27, and 29 having different thicknesses are interposed.
Depending on the desired degree of bonding, it is also possible to use cylindrical dielectric ceramic segments of equal thickness.

Note that a plurality of cylindrical dielectric ceramic division bodies 33 having a resonant portion 32 as shown in FIG. 4 and a cylindrical dielectric ceramic division body 35 having no resonance portion as shown in FIG. Filters can also be configured.

In addition, in the embodiment of FIG. 1, the closing members 16, 17
1 are constructed of separate dielectric ceramics, however, in the embodiment of FIG. 1, closing portions may be integrally formed on the outer surfaces of the divided bodies 21 and 29 located at both ends.

Furthermore, as shown in FIG.
4, 26, and 28, a cylindrical dielectric ceramic divided body 4 having a resonant portion 41 drawn inward in the axial direction of the cylindrical body relative to the thickness of the cylindrical body.
It is also possible to use 2. Similarly, as the divided bodies located at both ends, a cylindrical dielectric ceramic divided body 51 in which a resonant portion 53 and a closing portion 52 are integrally formed as shown in FIG. 7 may be used. In this case, the resonant part 53 needs to be formed separately from the closing part 52.

In the embodiment of FIG. 1, a plurality of resonant parts 12 to 1
5 was formed, but it is also possible to form only one resonant part and thus form a dielectric resonator.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of one embodiment of the present invention, and FIG.
The figure is a schematic perspective view for explaining an example of a conventional dielectric resonator device, FIG. 3 is a perspective view for explaining a plurality of divided dielectric ceramic bodies used in the embodiment of FIG. 1, and FIG. FIG. 5 is a perspective view showing a dielectric ceramic segmented body with an integrated resonant portion, FIG. 5 is a perspective view showing a dielectric ceramic segmented body without a resonant portion, and FIG. 6 is another example of the dielectric ceramic segmented body. FIG. 7 is a sectional view showing still another example of a dielectric ceramic segmented body in which a closed portion is integrally formed. In the figure, 10 is a dielectric filter as a dielectric resonator device, 11 is a cylindrical dielectric ceramic, 12 to 15 are resonance parts, 16 and 17 are closing members as closing means, and 21 to 29 are cylinders. 31 represents a shield layer.

Claims (1)

[Scope of Claims] 1. A cylindrical dielectric ceramic in which at least one resonant portion is integrally formed and extended between inner walls; A dielectric resonator device comprising: closing means provided at both ends of a dielectric ceramic; and a shield layer formed to shield an outer peripheral surface of the dielectric ceramic on which the closing means is provided. 2. The dielectric ceramic is made up of a plurality of cylindrical dielectric ceramic segments joined to each other, and at least one resonant portion is formed in at least one of the segments. The dielectric resonator device according to item 1. 3. The dielectric resonator device according to claim 1, wherein the closing means is integrally formed at an end portion of the dielectric ceramic. 4. The dielectric resonator device according to claim 1, wherein the closing means is a separate closing member fixed to an end of the dielectric ceramic.