JPH0635521Y2 - Dielectric resonator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a dielectric resonator using a TM mode.

[Prior art and its problems]

Conventionally, a dielectric resonator utilizing TM mode system resonance has a structure in which a columnar dielectric is fixed in a metal case.
However, when the case is made of metal in this way, the linear expansion coefficient of the case and the columnar dielectric differ, so cracks may occur at the joint between the case and the columnar dielectric due to temperature changes around the resonator. However, there is a problem that the minute gap at the joint changes and the temperature characteristic of the resonance frequency deteriorates.

In order to solve such a problem, a dielectric resonator having a good temperature characteristic has been proposed as described in JP-A-59-139704. This dielectric resonator has a structure in which the case is made of a material having the same linear expansion coefficient as that of the columnar dielectric, that is, the case is made of a dielectric, and a conductive film is provided on the inner surface or the outer surface of the case.

However, in the case of the above dielectric resonator, there is a problem in that the weight is increased because the case is made of a thick dielectric substrate. Further, even if the case and the columnar dielectric are made of materials having the same linear expansion coefficient, if there is a temperature difference between them, the respective expansion amounts will be different and the minute gap at the joint may change. In particular, when the expansion amount of the case is larger than the expansion amount of the columnar dielectric, cracks are likely to occur at the joint between the case and the columnar dielectric.

[Purpose of device]

The present invention has been made in view of the above problems, and an object thereof is to provide a lightweight dielectric resonator having excellent temperature characteristics.

[Constitution of device]

In order to achieve the above-mentioned object, the present invention provides a dielectric resonator using a TM mode, in which a columnar dielectric body and a substantially non-deformable structure in which a conductive portion is formed on an inner surface or an outer surface is fixed to both end surfaces of the columnar dielectric material. The upper and lower plates, and the easily deformable conductive material installed between the upper and lower plates so that the upper and lower ends are electrically connected to the conductive parts of the upper and lower plates, respectively. And a film body.

[Action]

That is, since the upper and lower plates are fixed to the upper and lower surfaces of the columnar dielectric and the conductive film body is provided between these plates, the columnar dielectric functions as a pillar of the upper and lower plates, and mechanical strength can be maintained. The weight of the portion corresponding to the side plate can be reduced. Further, even if there is a temperature difference between the columnar dielectric and the conductive film, the conductive film easily expands and contracts due to the temperature expansion of the columnar dielectric, so that the upper and lower plates are joined to the columnar dielectric. Almost no stress acts on the part. Therefore, the joint between the upper and lower plates and the columnar dielectric is not cracked or the gap at the joint does not change, and the change in temperature characteristics can be suppressed to the minimum.

The resonance mode of the present invention uses the TM mode.
The mode is TM ₀₁₀ mode. The TM ₁₁₀ mode or these approximation modes are included.

〔Example〕

FIG. 1 shows an example of a dielectric resonator using the TM ₀₁₀ mode, which includes a cylindrical dielectric 1, a rectangular upper plate 2 and a lower plate 3.
And two conductive film bodies 4 and 5. In this embodiment, the front and rear two surfaces of the dielectric resonator facing each other are open, and a multistage filter can be configured by connecting a plurality of resonators to each other at the open portions.

The upper and lower plates 2 and 3 are made of, for example, the same material as the cylindrical dielectric 1, that is, a thick dielectric substrate, and silver paste is applied to the inner surfaces 2a and 3a and both side surfaces 2b and 3b of the dielectric board and baked. The conductive film is thus formed. The inner surfaces 2a, 3a having the conductive film formed thereon are bonded and fixed to the upper and lower end surfaces of the cylindrical dielectric 1 by a conductive bonding material. It should be noted that the bonding material may be one that serves both mechanical fixation and electrical connection, and for example, silver paste, solder or the like can be used.

The conductive film bodies 4 and 5 are made of, for example, a metal foil having excellent conductivity such as silver and copper, and are installed between the upper and lower plates 2 and 3. That is, the upper and lower end portions of the conductive film bodies 4 and 5 are bonded to both side surfaces 2b and 3b of the upper and lower plates 2 and 3 on which the conductive film is formed by a bonding material 6 such as solder. Upper plate 2 and lower plate 3 are electrically connected via 5.

In this way, the columnar dielectric 1 functions as a pillar of the upper and lower plates 2 and 3, and the mechanical strength of the resonator can be maintained even if the side plates are omitted, and the conductive film body is provided between the upper and lower plates 2 and 3. Since it is electrically connected by 4 and 5, the weight of the part corresponding to the conventional side plate can be reduced, and the weight can be greatly reduced. In addition, even if the columnar dielectric 1 expands and contracts due to temperature change, the conductive film members 4, 5
Is easily deformed according to the expansion and contraction of the columnar dielectric 1, and the upper and lower plates 2,
Almost no stress is generated at the joint between 3 and the columnar dielectric 1.
Therefore, the joint between the upper and lower plates 2 and 3 and the columnar dielectric 1 is not cracked or the gap at the joint does not change, and the deterioration of the temperature characteristics can be prevented.

Further, although the conductive film is formed on the inner surfaces 2a and 3a of the upper and lower plates 2 and 3 in the above embodiment, the conductive film may be formed on the outer surface, or the conductive film may be formed on the entire inner and outer surfaces. In any case, it suffices that the conductive film and the conductive film bodies 4 and 5 surround the columnar dielectric body 1 to have a function as a conductive path and a shield function. Also,
A conductive film body having a large area by dispersing the current flowing out from the junction with the columnar dielectric 1 by the conductive film of one plate
Since it flows to the conductive film of the other plate through 4,5, it is possible to prevent the Q of the resonator from being lowered due to the resistance of the conductive film bodies 4,5.

FIG. 2 shows a second embodiment of the present invention, in which an upper plate 7 and a lower plate 8 made of a disk-shaped dielectric material are fixed to the upper and lower surfaces of the cylindrical dielectric material 1, and The circumference is covered with a conductive film body 9. Also in this case, as in the first embodiment, conductive films are formed on the inner surfaces and the peripheral portions of the upper and lower plates 7 and 8, and the upper and lower ends of the conductive film body 9 are the peripheral portions of the upper and lower plates 7 and 8. It is electrically connected to the conductive film by soldering, a conductive paste, or the like.
Two holes 10 for inserting a connector are formed in the upper plate 7 in the case of using this dielectric resonator as a filter.

In both of the above embodiments, the dielectric substrates were used as the upper and lower plates, but they may be formed of metal plates. In the case of a metal plate, since the plates themselves have conductivity, it is not necessary to form a conductive film. .

Further, as the conductive film body, in addition to a metal foil, a flexible resin sheet on which a conductive film is printed can be used.

Further, although the cylindrical dielectric 1 is used in the above-mentioned embodiment, a rectangular pillar-shaped dielectric may be used, and the resonance mode in this case is TM ₁₁₀ mode.

[Effect of device]

As is clear from the above description, according to the present invention, the upper plate and the lower plate are fixed to the upper and lower surfaces of the columnar dielectric, and the conductive film body is installed between these upper and lower plates, which corresponds to the conventional side plate. It is possible to reduce the weight of the portion to be covered, and the columnar dielectric body functions as the pillars of the upper and lower plates to maintain the mechanical strength of the resonator.

Further, even if there is a temperature difference between the columnar dielectric and the conductive film, the conductive film easily expands and contracts due to the temperature expansion of the columnar dielectric, so that the upper and lower plates are joined to the columnar dielectric. Almost no stress acts on the part. Therefore, the joint between the upper and lower plates and the columnar dielectric is not cracked or the gap at the joint does not change, and the change in temperature characteristics can be suppressed to the minimum.

Further, since the conductive film body functions as a conductive path for electrically connecting the upper and lower plates, and a current flows through the conductive film body having a wide passage area, the Q of the resonator due to the resistance of the conductive film body. Can be prevented.

[Brief description of drawings]

FIG. 1 is a perspective view of a first embodiment of a dielectric resonator according to the present invention, and FIG. 2 is a perspective view of a second embodiment. 1 …… Column dielectric, 2,7 …… Upper plate, 3,8 …… Lower plate, 4,5,9
...... Conductive film body, 6 ... Solder.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Creator Takashi Takagaki 26-10 Tenjin, Nagaokakyo-shi, Kyoto Murata Manufacturing Co., Ltd. (56) References JP 63-266902 (JP, A) -127309 (JP, U)

Claims (1)

[Scope of utility model registration request] 1. A dielectric resonator using a TM mode,
A columnar dielectric, a substantially non-deformed upper plate and a lower plate fixed to both end faces of the columnar dielectric, and having conductive portions formed on the inner surface or the outer surface thereof, and upper and lower end portions on the conductive portions of the upper plate and the lower plate, respectively. A dielectric resonator comprising: an electrically deformable conductive film body provided between an upper plate and a lower plate so as to be electrically joined.