JPH0749844Y2 - TM mode dielectric resonator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Industrial Field of Application The present invention relates to a dielectric resonator utilizing a TM mode.

(B) Conventional Technology Generally, a TM mode dielectric resonator has a columnar core dielectric through which a displacement current flows, a cavity that holds this core dielectric and acts as a shield case through which an actual current flows, and this cavity. It is composed of a signal connector that inputs and outputs signals to and from the inside.

As the above-mentioned cavity, a ceramic having an electrode film formed thereon or a metal is used. However, in the case of a metal cavity, the coefficient of linear expansion of the metal cavity is significantly larger than the coefficient of linear expansion of the core dielectric. There is a problem that temperature characteristics cannot be obtained. The applicant of the present invention is Japanese Patent Laid-Open No. 59
No. 63802 and Japanese Unexamined Patent Publication No. 59-63801 propose a dielectric resonator having a good temperature characteristic in which a cavity is integrally formed with a core dielectric material.

The structure of a conventional TM mode dielectric resonator in which such a core dielectric and a cavity dielectric are integrated is shown in FIGS.

5 is an exploded perspective view of the dielectric resonator, and FIG. 6 is a dielectric resonator main body 8 excluding the upper lid 9 and the lower lid 13 of FIG. 5 for convenience.
FIG. 7 is a side sectional view taken along the line BB in FIG.

As shown in FIGS. 5 to 7, the dielectric resonator comprises a resonator body 8, an upper lid 9 and a lower lid 13. The main body 8 comprises a cavity dielectric 6 and a core dielectric 1 arranged in the center of the cavity dielectric 6,
They are connected and integrated by four connecting plates 2-5. Further, an electrode film 7 is provided on the entire outer peripheral surface of the cavity dielectric body 6 of the main body portion 8. Further, electrode films 12 and 14 are provided on the lower surface of the upper lid 9 and the upper surface of the lower lid 13, respectively. The upper lid 9 and the lower lid 13 are baked on the two openings of the resonator body 8 with an electrode paste.

The holes 10 and 11 of the upper lid 9 shown in FIG. 5 are holes for mounting the coaxial connectors 15 and 17 as shown in FIG.

(C) Problems to be Solved by the Invention As shown in FIGS. 5 to 7, the cavity dielectric and the core dielectric are manufactured by integral molding, which simplifies the assembly process. In addition, since the core dielectric and the cavity dielectric have the same linear expansion coefficient, distortion due to heat generation of the core dielectric hardly occurs and good temperature characteristics can be obtained.

However, in the case where the cavity dielectric and the core dielectric are integrally molded, the electric field leaks from the core dielectric to the connecting plate portion for connecting the core dielectric to the cavity dielectric. Therefore, the unloaded Q of the resonator
There was a problem that (Qo) decreased. Of course, if the thickness of the connecting plate is made thinner, the electric field leakage to the connecting plate part will be reduced and the Qo deterioration of the resonator can be suppressed. The cracks are likely to occur in the thin portion.

The purpose of this invention is to suppress the electric field leakage due to the connecting plate,
It is to provide a TM mode dielectric resonator that maintains a high Qo.

(D) Means for Solving the Problem The present invention is to integrally mold a cavity dielectric and a core dielectric by making the axial direction of the core dielectric substantially coincide with the direction between two opposing openings of the cavity dielectric. In the TM mode dielectric resonator in which the openings of the cavity dielectric are each closed with a plate material, a gap is formed between the connecting plate connecting the cavity dielectric and the core dielectric and the plate material. And

(E) Action In the TM mode dielectric resonator of the present invention, a gap is formed between the plate material that closes the opening of the cavity dielectric and the connecting plate that connects the cavity dielectric and the core dielectric. Since an air layer having a significantly lower dielectric constant than the connecting plate is provided at a constant distance in this manner, a high electric field is not applied to the connecting plate, and the electric field of the core dielectric hardly leaks. As a result, a TM mode dielectric resonator with high Qo is constructed.

(F) Embodiment The structure of the TM mode dielectric resonator which is an embodiment of the present invention is shown in FIGS. 1 to 3. 1 is an exploded perspective view of the TM mode dielectric resonator, and FIG. 2 is a top cover 9 and a bottom cover of FIG. 1 for convenience.
14 is a plan view of the dielectric resonator main body 8 excluding 14, and FIG. 3 is a side sectional view taken along the line AA in FIG.

As shown in FIG. 1, the dielectric resonator comprises a resonator body 8, an upper lid 9 and a lower lid 13. The main body 8 is provided with a rectangular tube-shaped cavity dielectric 6 and a cylindrical core dielectric 1 having the same height as the cavity at the center of the cavity 6, which are four connecting plates 2, 3, 4, Connected via 5 and integrated. As shown in FIGS. 1 and 3, the four connecting plates 2 to 5 are used to form the cavity dielectric 6
Alternatively, the height of the core dielectric 1 is not reached, and the core dielectric 1 is disposed inside the cavity dielectric 6 at a constant distance from the two opening surfaces.
An electrode film 7 is formed on the entire outer peripheral surface of the cavity dielectric body 6 of the main body portion 8. Further, electrode films 12 and 14 are formed on the lower surface of the upper lid 9 and the upper surface of the lower lid 13, respectively. The upper lid 9 and the lower lid 13 are baked and bonded to the two opening surfaces of the resonator body 8 by the electrode paste, respectively, so that the electrode film on the outer peripheral surface of the cavity dielectric is formed as shown in FIGS. 2 and 3. 7 and the electrode films 12 and 14 of the upper lid 9 and the lower lid 13 form a shield and an actual current path. Since the height of the connecting plates 2 to 5 is less than the height of the cavity dielectric 6 or the core dielectric 1, a gap G is formed between the upper lid 9 and the lower lid 13 and the electrode films 12 and 14.
Occurs.

In addition, the two holes 10, 1 formed in the upper lid 9 shown in FIG.
1 is a coaxial connector for signal input / output 1 as shown in FIG.
It is a hole for attaching 5,17. Signal connectors 16 and 18 are formed on the two coaxial connectors 15 and 17, respectively, to couple the core dielectric 1 with the electric field or the magnetic field in the cavity. At that time, the lines of electric force spill in the axial direction of the core dielectric 1 and an actual current flows through the electrode films 12, 7 and 14, but the lines of electric force of the core dielectric 1 hardly penetrate into the connecting plates 2-5. The electric field is concentrated only on the core dielectric 1.

Next, FIG. 4 shows the structure of the TM mode multistage dielectric filter according to the second embodiment. The figure is an exploded perspective view of a three-stage integrated TM mode dielectric filter. This dielectric filter is composed of a filter body 31, an upper lid 32 and a lower lid 36. The filter body 31 includes a cavity dielectric 23 and three cylindrical core dielectrics 20, 21, 22 arranged inside the cavity 23, and each core dielectric has two connecting plates 24. , 25, 26, 27, 28, 29 are connected to and integrated with the cavity dielectric 23. The height dimension of these connecting plates 24 to 29 does not reach the height dimension of the three core dielectrics 20 to 22 or the cavity dielectric 23, and each connecting plate is arranged inside the two opening surfaces of the filter body 31. Has been done. Further, an electrode film 30 is formed on the entire outer peripheral surface of the cavity dielectric 23 of the main body 31. Furthermore, the upper lid 32
Electrode films 35 and 37 are formed on the lower surface of the and the upper surface of the lower lid 36. The upper lid 32 and the lower lid 36 are baked and bonded to the two opening surfaces of the main body 31 with an electrode paste to form an integrated dielectric filter including three-stage TM mode dielectric resonators. The holes 33 and 34 formed in the upper lid 32 are mounting holes for the coaxial connector.

In each of the above embodiments, the core dielectrics are all cylindrical, but the core dielectrics are not limited to this, and may be prismatic core dielectrics such as a quadrangular prism.

Further, the electrode forming surfaces of the upper lid and the lower lid are not limited to the side facing the cavity dielectric, but may be the opposite sides.

(G) Effect of the Invention According to the present invention, the connecting plate for connecting the core dielectric to the cavity dielectric does not come into contact with the plate members (upper lid and lower lid) that close the opening of the cavity dielectric, but between them. Since the void is formed, the electric field of the core dielectric hardly leaks to the connecting plate, and a TM mode dielectric resonator with high Qo can be obtained.

[Brief description of drawings]

1 to 3 are views relating to a TM mode dielectric resonator which is a first embodiment of the present invention, and FIG. 1 is an exploded perspective view,
2 is a plan view of the resonator body, and FIG. 3 is a side sectional view taken along the line AA in FIG. FIG. 4 is an exploded perspective view of the dielectric filter according to the second embodiment of the present invention. 5 to 7 are views relating to a conventional TM mode dielectric resonator, FIG. 5 is an exploded perspective view, FIG. 6 is a plan view of a resonator main body portion, and FIG. 7 is in FIG. It is a sectional side view along BB. 1,20,21,22 …… Core dielectric, 2-5,24 ～ 29 …… Connecting plate,
6,23 …… Cavity dielectric, 9,32 …… Top lid, 13,36 ……
Lower lid, 7,12,14,30,35,37 ... Electrode membrane.

Front page continued (72) Inventor Masamichi Ando 2 26-10 Tenjin, Nagaokakyo, Kyoto Prefecture Murata Manufacturing Co., Ltd. (72) Inventor Sadao Yamashita 2 26-10 Tenjin, Nagaokakyo, Kyoto Murata Manufacturing Co., Ltd. (56) References JP-A-59-63801 (JP, A) JP-A-59-63802 (JP, A)

Claims (1)

[Scope of utility model registration request] 1. A cavity dielectric body and a core dielectric body are integrally molded with the axial direction of the core dielectric body substantially aligned with the direction between two facing openings of the cavity dielectric body. A TM mode dielectric resonator in which each of the above is closed by a plate member, wherein a gap is formed between the plate member and a connecting plate that connects a cavity dielectric and a core dielectric.