JPH04347902A - Dielectric resonator - Google Patents

Abstract

PURPOSE:To obtain an excellent temperature characteristic or the like and to easily constitute a dielectric filter or the like by arranging a dielectric column in a ceramic case and providing a conductive film forming an actual current path on the surface of the ceramic case. CONSTITUTION:One dielectric column 12 which is independent of a ceramic case 14 and is made of ceramics is arranged in this ceramic case 14 like a cubical box which has upper and lower faces and two side faces and has a conductive film 16 formed on all of the surface. The actual current path is formed by the conductive film 16 of the ceramic case 14. Since a dielectric resonator 10 has the dielectric column 12 arranged in the ceramic case 14 in this manner, the temperature characteristic is good in distinction from the use of a metallic case. Since the conductive film 16 forming the actual current path is provided on the surface of the ceramic case 14, the loss is small and Q is high.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dielectric resonator of TM010 mode or a modified mode thereof, which is used for example in dielectric filters.

0002

2. Description of the Related Art In a conventional dielectric filter, as shown in FIG. 7, for example, a cavity case 4 is used to prevent a decrease in temperature characteristics by matching the coefficient of linear expansion with a dielectric column 2 made of ceramic. The entire structure was made of ceramic having the same or substantially the same coefficient of linear expansion as the dielectric column 2, and was housed in a metal case (not shown). 4a is a partition for coupling adjustment, and 6 is a conductive film for forming an actual current path.

By the way, if the cavity case is made of metal and the dielectric pillar 2 is soldered to it, in addition to the above-mentioned problem of deterioration of temperature characteristics, due to Joule loss etc. at the soldered part,
Another problem arises in that the Q of the resonator is significantly reduced.

0004

[Problems to be Solved by the Invention] However, in the dielectric filter in which the entire cavity case 4 as described above is made of ceramic and has multiple stages of dielectric resonators, the cavity case 4 has a size corresponding to the number of stages of the resonators. However, since the ceramic plate warps and the case becomes larger, it becomes difficult to join, making assembly work difficult.Also, since a large ceramic plate is required to make the cavity case 4, the material is difficult to assemble. There is a problem in that the cost increases, resulting in high costs.

The main object of the present invention is therefore to provide a dielectric resonator which has excellent temperature characteristics and can be easily constructed into a dielectric filter or the like.

[0006]

[Means for Solving the Problems] In order to achieve the above object, a dielectric resonator of the present invention is a ceramic case having upper and lower surfaces and at least one side surface, and a conductive film forming a real current path on the surface of the ceramic case. and one dielectric pillar disposed within the ceramic case between its upper and lower surfaces.

[0007]

[Function] According to the above structure, since the dielectric pillars are placed inside the ceramic case, the temperature characteristics are better than when using a metal case, and the surface of the ceramic case is conductive to form an actual current path. Since a membrane is provided, Q is also high. Furthermore, since this dielectric resonator is unitized, so to speak, by appropriately combining them, it is possible to easily construct a dielectric filter, etc., without using a large ceramic cavity case as in the past. can.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a perspective view showing an example of a dielectric resonator according to the present invention.

This dielectric resonator 10 is a square box-shaped ceramic case 14 made of ceramic and has an upper and lower surface and two side surfaces, and in this example, a conductive film 16 is formed on the entire surface by silver baking or the like. One cylindrical dielectric column 12, which was originally separate from the ceramic case 14 and is made of ceramic in this example, is arranged between the top and bottom surfaces of the case. , thereby forming a TM010 mode resonator. In this case, an actual current path is formed by the conductive film 16 on the surface of the ceramic case 14.

Ceramic case 14 of this dielectric column 12
Fixation to the ceramic case 14 is achieved by, for example, applying silver paste to the upper and lower end surfaces thereof and then baking this paste integrally with the conductive film 16 on the surface of the ceramic case 14.

Since the dielectric resonator 10 has the dielectric pillars 12 disposed within the ceramic case 14, it has better temperature characteristics than when a metal case is used. Dielectric pillar 12
If the material of the ceramic case 14 and the ceramic case 14 are made the same to eliminate the difference in linear expansion coefficient between the two, the temperature characteristics will be further improved. Furthermore, since the conductive film 16 forming the actual current path is provided on the surface of the ceramic case 14, there is little loss and the Q is high.

Moreover, since this dielectric resonator 10 is unitized, so to speak, by appropriately combining them, a dielectric filter can be easily constructed without using a large cavity case made of ceramic as in the past. can do. An example of this will be explained with reference to FIG. 2 and the like. Note that in FIG. 2, a portion corresponding to the lid of the metal case 24 is not shown.

The dielectric filter shown in FIG. 2 has a plurality of dielectric resonators 10 shown in FIG. (not shown in the figure) For example, by hanging a thin plate 20 such as a silver-plated metal foil and soldering it to each conductive film 16 with solder 22, electrical connection between adjacent dielectric resonators 10 is established. are connected to form a multi-stage dielectric filter.

Each dielectric resonator 10 is fixed to the metal case 24 by, for example, screwing using a screw 28 and a nut 30, as shown in FIG.

The electrical connection between the dielectric resonators 10 is achieved, for example, by sandwiching metal springs 26 above and below between the adjacent dielectric resonators 10 and the metal case 24, as shown in FIG. It's okay.

Further, the shape of the metal case 24 and the number of dielectric resonators 10 arranged in parallel (ie, the number of stages) are not limited to the illustrated example, but may be arbitrary.

According to the above structure, a predetermined electromagnetic coupling occurs between adjacent dielectric resonators 10, thereby obtaining a dielectric filter having predetermined characteristics.

Moreover, since the dielectric resonator 10 is unitized and housed in the metal case 24, the workability of assembly is improved and there is no need to use a large ceramic plate as a cavity case as in the past. Therefore, material costs will be lower, and as a result, significant cost reductions can be expected. Of course, the dielectric pillar 12 is not soldered to the metal cavity, and the actual current path is effectively formed by the conductive film 16 as described above, so the Q of the resonator is reduced. There is no problem.

Note that the number of side plates of the ceramic case 14 constituting the dielectric resonator 10 does not necessarily have to be two as in the above example, but may be one as shown in FIG. If it's something like that, 3 pieces is fine.

The dielectric resonator 10 is also provided with a partition plate 14a for coupling adjustment, as shown in FIG. 6, if necessary.
The partition plate 14a may be made of, for example, a silver-baked ceramic plate similar to the ceramic case 14, or a metal plate.

The conductive film 16 on the surface of the ceramic case 14 only needs to be able to form at least an actual current path;
It is not necessary to provide it on the entire surface of 4.

Further, the cross-sectional shape of the dielectric pillar 12 can be arbitrary. For example, the dielectric pillar 12 may be prismatic.

Further, the mode of the dielectric resonator 10 is TM
A modified mode of the 010 mode may also be used.

[0024]

[Effects of the Invention] As described above, in the dielectric resonator of the present invention, the dielectric pillars are arranged inside the ceramic case.
Unlike the case where a metal case is used, the temperature characteristics are good, and since the surface of the ceramic case is provided with a conductive film that forms an actual current path, the Q is also high.

Moreover, since this dielectric resonator is unitized, so to speak, by appropriately combining them, a dielectric filter etc. can be easily installed without using a large cavity case made of ceramic as in the past. Can be configured. In other words, using this dielectric resonator improves the workability of assembling dielectric filters, etc., and also reduces material costs because large ceramic plates are not required, resulting in a significant cost reduction for dielectric filters, etc. can be expected.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an example of a dielectric resonator according to the present invention.

2 is a partially cutaway perspective view showing an example of a dielectric filter using the dielectric resonator of FIG. 1; FIG.

FIG. 3 is a longitudinal cross-sectional view showing an example of means for fixing a dielectric resonator to a metal case.

FIG. 4 is a partially cutaway side view showing another example of electrical connection means between dielectric resonators.

FIG. 5 is a perspective view showing another example of the dielectric resonator according to the present invention.

FIG. 6 is a perspective view showing still another example of the dielectric resonator according to the present invention.

FIG. 7 is a cross-sectional view partially showing an example of a conventional dielectric filter.

[Explanation of symbols]

10 Dielectric resonator 12 Dielectric pillar 14 Ceramic case 16 Conductive film

Claims (1)

[Claims] [Claim 1] A ceramic case having upper and lower surfaces and at least one side surface, on which a conductive film is provided to form an actual current path, and a ceramic case disposed within the ceramic case between the upper and lower surfaces. A dielectric resonator comprising one dielectric column.