JPH0569321B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention mainly relates to a dielectric resonator device using a TM dielectric resonator for a bandpass filter.

[Prior Art] In a conventional dielectric resonator device, one dielectric resonator 2 is installed in a cylindrical case 1, as shown in FIG. A disk-shaped plate 3 is fixed to the inner peripheral surface of the cylindrical case 1. The dielectric resonator 2 passes through a hole formed in the plate 3, and a coupling gap 4 is formed between the dielectric resonator 2 and the plate 3.

Input/output connectors 5 are fixed to both ends of the cylindrical case 1. The internal conductor 6 of the connector 5 passes through the hole 7 of the cylindrical case 1 and is firmly fitted into the hole 8 formed at both ends of the dielectric resonator 2, thereby connecting the connector 5 and the dielectric resonator 2. has been done.

[Problems to be Solved by the Invention] In the conventional configuration, the internal conductor 6 is hidden in the hole 8, so once the internal conductor 6 and the hole 8 are fitted and fixed, there is no connection between the external circuit and the first or final stage. It becomes difficult to adjust the degree of coupling with the stage resonator.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and provide a dielectric resonator device in which the coupling coefficient can be easily matched.

[Means for Solving the Problems] A dielectric resonator device according to the present invention includes: a conductive case, a rod-shaped dielectric resonator disposed within the case, and a rod-shaped dielectric resonator fixed to both ends of the dielectric resonator. A dielectric resonator device having a flat electrode and an input/output connector fixed to the electrode, characterized in that the electrode has a flat plate shape and a gap is formed between the electrode and the case.

[Function] When a voltage in a certain frequency band is applied from the input connector, the dielectric resonator is excited and an output is obtained from the output connector, but this depends on the size of the gap formed between the electrode and the case. This determines the degree of coupling between the external circuit and the first or final stage resonator.

The degree of coupling is set by appropriately determining the shape and size of the electrode and varying the size of the gap between the electrode and the case. When changing the connection, even after the electrodes and input/output connectors are connected, the degree of coupling can be easily fine-tuned by scraping the flat electrodes or applying silver paste to the electrodes. It is possible to do so.

[Example] In Fig. 1 showing the case where the dielectric resonator device according to the present invention is used in a bandpass filter, TM _p10
The mode dielectric resonator device includes a case 10 formed in a cylindrical shape, a cylindrical dielectric resonator 11 made of a high-frequency ceramic material arranged concentrically within the case 10, an external coupling means 12, and a coupling means 12. It mainly has a plate 13.

The case 10 is made of a cylindrical body made of a material having a linear expansion coefficient equivalent to that of the resonator 11, and has a metal film formed on all surfaces thereof, or is made of metal. Resonator 1
It is closed by a disk made of a material having a linear expansion coefficient equal to 1, with a metal film formed on all surfaces, or by an end plate 14 made of metal. Both end plates 1
A hole 15 is formed in the center of each of the holes 4 and 14.
The dimensions of the hole 15 are determined so that it is in a cut-off condition for the mode of use.

The external coupling means 12 includes an electrode 16 fixed to the end face of the resonator 11 and having a larger diameter than the resonator 11, a coaxial connector 17 attached to the end plate 14, and a center pin of the coaxial connector 17. It includes an antenna conductor portion 18 connected to or integrally formed with the center pin. The antenna conductor portion 18 extends into the case 10 through the hole 15, and its tip is electrically and mechanically fixed to the center of the electrode 16. Thereby, the dielectric resonator 11 is arranged within the case 10 and concentrically with the case 10.

In this way, the dielectric resonator 11 is a cylindrical member, and electrodes 16 having a larger diameter than the dielectric resonator 11 are fixed to both ends by silver bonding. Second
As shown in the figure, the electrode 16 is a disc-shaped member made of ceramics with silver baked onto it, and the dielectric resonator 1
It is placed concentrically with 1. As shown in FIG. 1, a gap 21 is formed between the electrode 16 and the case 10, and by changing the state of this gap 21, the degree of coupling between the external circuit and the first or final stage resonator can be changed. is starting to change.

The plate 13 is a disc-shaped member, and has a hole in the center into which the dielectric resonator 11 is fitted.
In the embodiment shown in FIG. 1, three plates 13 are fitted over the dielectric resonator 11 at equal intervals and fixed by silver bonding. The plate 13 has a structure in which silver is baked onto ceramic. The outer diameter of the plate 13 is set to be somewhat smaller than the inner diameter of the case 10, so that a coupling gap 20 is formed between the case 10 and the plate 13.

Note that the ceramic constituting the electrode 16 and the plate 13 has the same coefficient of linear expansion as the dielectric resonator 11 (including substantially the same range). A gap 21 is also formed between the electrode 16 and the case 10, and the degree of coupling between the external circuit and the first or final stage resonator is determined by the size of this gap 21.

Next, the operation of this embodiment will be explained.

When an input signal is applied to one coaxial connector 17, a constant bandwidth output can be obtained through the other coaxial connector 17.

The external circuit and the first-stage or final-stage resonator are considered to be electrically coupled between the electrode 16 and the resonator, and magnetically coupled between the antenna conductor rod 18 and the resonator.

The coupling coefficient between the resonators can be set or changed as desired by changing the thickness of the plate 13 and the dimensions of the gap 20 between the plate 13 and the case. At this time, since the gap 20 is placed on the side of the case 10 where the electric field strength is weak, the plate 1
It is not necessary to finish the gap 20 between the case 10 and the case 10 with high precision. Also, case 10 and plate 1
Since the change in the coupling coefficient with respect to the change in the gap 20 between the case 10 and the dielectric resonator 1 is small, the case 10 is
It becomes unnecessary to use a material having the same coefficient of linear expansion as that of 1 and plate 13. For example, any metal that is easy to process can be used, leading to cost reductions. Since the electrode 16 is floating from the case 10 through the gap 21, it is stable against temperature changes. On the other hand, the gap 21 between the electrode 16 and the case 10 can be easily changed by changing the shape of the electrode 16. By changing this gap, the degree of bonding can be changed.

In addition, when changing the bonding between the gaps 20 and 21, it is possible not only to change the design of the plates 13 and electrodes 16, but also by simply scraping the surfaces of the plates 13 and electrodes 16 slightly or attaching silver paste. Fine adjustments can be made as appropriate.

[Another Embodiment] (a) Instead of the electrode 16, an electrode made of a simple metal plate may be used. Further, the size of this electrode is not limited to a case where the diameter is larger than the dielectric resonator 11, but it may be made of, for example, an electrode film 22 and a smaller diameter than the dielectric resonator 11, as shown in FIG. It may be hot.

(b) In the above embodiments, a cylindrical dielectric resonator device has been described, but the present invention can be implemented in the same manner even if the dielectric resonator device is prismatic.

[Effects of the Invention] According to the dielectric resonator device according to the present invention, the electrodes fixed to both ends of the dielectric resonator are plate-shaped,
Because a gap was formed between the electrode and the case,
The gap can be easily finely adjusted.

By finely adjusting the gap, the strength of the bond can be easily finely adjusted.

[Brief explanation of drawings]

FIG. 1 is a vertical sectional view of an embodiment according to the present invention, and FIG.
The figure is an enlarged partial view, and Figure 3 is a second example of another embodiment.
4 is a diagram corresponding to FIG. 1 of the conventional example. 10 is a case, 11 is a dielectric resonator, 12 is an external coupling means, 16 is an electrode, and 21 is a gap.

Claims (1)

[Scope of Claims] 1. A conductive case, a rod-shaped dielectric resonator disposed within the case, electrodes fixed to both ends of the dielectric resonator, and an input/output connector fixed to the electrodes. A dielectric resonator device having: the electrode having a flat plate shape, and a gap being formed between the electrode and the case.