JPH0946108A - Dielectric resonator and dielectric filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid increase in the processing man-hours and the characteristics fluctuation by forming a metallic layer to an outer face of a dielectric block and an inner face of a non-throughhole to configure a resonance section and eliminating part of the resonance section to form an input output coupling section having an external connection electrode. SOLUTION: A cylindrical non-throughhole 2 is provided to a rectangular parallelepiped dielectric block 1, and a semi-coaxial resonator section of 1/4 wavelength type is formed by coating a metallic layer 3 made of a material such as silver or copper whose thickness is 3 to 10μm to the outer side of the dielectric block and the inner side of the non-throughhole 2 by the chemical plating or the like. Then an external connection electrode 5 surrounded by a metallic layer elimination section 4 of a hook shape is formed at the outer side of the dielectric block and at the side adjacent to a bottom side of the non-throughhole 2 to form the input output coupling section. The part around the bottom side of the non-throughhole 2 acts like an open end face and the resonance wavelength reduction effect is obtained by providing a capacitance component between the part equivalent to the open end and the metallic layer 3 on the outer face of the dielectric block 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dielectric resonator and a dielectric filter used in mobile communication equipment and the like.

[0002]

2. Description of the Related Art As an example of a dielectric filter used in a frequency band of several hundred MHz to several GHz, FIG. 9 (a perspective view) and FIG. 10 (a sectional view taken along a broken line CC 'in FIG. 9). ) There is a configuration as shown in. In this dielectric filter, a through hole 20 is provided in a dielectric block 10, a metal layer 30 is formed on an outer surface of the dielectric block and an inner surface of the through hole, and one of the through hole opening end faces of the dielectric block is formed. The metal layer on the end face 100 is removed, and the metal pin 9 held by the insulating member 8 is inserted and mounted in the opening of the through hole on the metal layer removal end face (open end face) side.

[0003]

In the manufacturing process of the above-mentioned conventional dielectric filter, the metal layer on one end surface of the dielectric block needs to be removed by a polishing method or the like, so that the processing cost of the polishing process is increased. In addition to being expensive, the loss of a metal layer made of an expensive material such as silver contributes to an increase in material cost.

There is also a problem that the filter characteristics change when the metal pin is inserted and mounted in the opening of the through hole.

The present invention solves problems such as an increase in processing man-hours, material loss, and characteristic fluctuations by simplifying the structure of a dielectric resonator or a dielectric filter.

[0006]

In a dielectric resonator and a dielectric filter according to the present invention, a non-through hole is provided in a dielectric block, and a metal layer is formed on an outer surface of the dielectric block and an inner surface of the non-through hole. By doing so, a resonance portion is formed, and by removing a part of the metal layer formed on the outer surface of the dielectric block, an input / output coupling portion having an external connection electrode is formed.

[0007]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a perspective view of a dielectric resonator according to an embodiment of the present invention, and FIG. 2 is a sectional view taken along the plane indicated by the broken line AA 'in FIG. In this dielectric resonator, a cylindrical non-through hole 2 is provided in a rectangular parallelepiped dielectric block 1, and silver, copper, etc. having a thickness of 3 to 10 μm are formed on the outer surface of the dielectric block and the inner surface of the non-through hole. A quarter-wave type semi-coaxial resonance portion is formed by depositing a metal layer 3 made of a non-through hole on the bottom surface of the non-through hole on the outer surface of the dielectric block. An external connection electrode 5 surrounded by the metal layer removing portion 4 having a circular shape is formed in a portion located on the side to form an input / output coupling portion. An equivalent circuit of the dielectric resonator is shown in FIG.

The cross-sectional shape of the non-through hole is shown in FIG.
If the shape is such that the diameter becomes smaller toward the bottom surface of the hole, such as the stepped shape shown in Fig. 5 or the tapered shape shown in Fig. 5, the press formability of the dielectric block is improved and the inner surface of the hole is The adhesion of the metal layer is improved.

In the resonance part of the dielectric resonator according to the above embodiment, the vicinity of the bottom surface of the non-through hole has a function corresponding to the open end surface 100 of the conventional dielectric filter shown in FIGS. 9 and 10. However, the resonance wavelength shortening effect is obtained due to the presence of the capacitance component between the portion corresponding to the open end and the conductor layer on the outer surface of the dielectric block.

On the other hand, as an application of the dielectric resonator according to the above embodiment, as shown in FIGS. 6 (perspective view) and 7 (backside perspective view of FIG. 6), a plurality of non-through holes 2 are formed in the dielectric block.
And a metal layer 3 is formed on the outer surface of the dielectric block and the inner surface of the non-through hole, and the outer surface of the dielectric block is formed in a circular shape at a portion located laterally of the bottom surface of the non-through hole. A dielectric filter is formed by forming the external connection electrode 5 surrounded by the metal layer removal portion 4.

Also in the dielectric filter, the cross section shown by the broken line BB 'in FIG. 6 has the same structure as the cross section shown in FIG. 2 or FIGS. 4 and 5.

In the dielectric filters shown in FIGS. 6 and 7, the groove 6 extending parallel to the depth direction of the non-through hole is provided outside the dielectric block.
This groove is for adjusting the coupling between the plurality of resonance parts corresponding to the plurality of non-through holes, and various filter characteristics can be obtained by appropriately designing the length, width, depth, etc. of the groove. It is possible to provide a dielectric filter having the same.

The external connection electrode 5 for forming the input / output coupling portion of the dielectric filter shown in FIGS. 6 and 7 is provided on the side of the bottom surface of the non-through hole, but is shown in FIG. As described above, the external connection electrode 51 partially connected to the conductor layer on the outer surface of the dielectric block may be provided in the vicinity of the opening of the non-through hole.

The input / output coupling in the example shown in FIGS. 6 and 7 is performed by the metal layer removing portion having a circular shape, which is insulated from the conductor layer 4 on the outer surface of the dielectric block and the metal layer near the bottom surface of the through hole. In contrast to the capacitive coupling between the external connection electrode 51 and the external connection electrode 51 in the example of FIG. 8, the external connection electrode 51 is partially separated from the conductor layer on the outer surface of the dielectric block by the metal layer removing portions 41 that are separated from each other. There is magnetic field coupling between the metal layer near the opening of the through hole and the metal layer.

[0016]

According to the present invention, variations in characteristics are reduced and the manufacturing cost is reduced by simplifying the structure of the dielectric resonator and the dielectric filter.

[Brief description of drawings]

FIG. 1 is a perspective view of a dielectric resonator according to a first embodiment of the present invention.

FIG. 2 is a sectional view of a dielectric resonator according to the first embodiment of the present invention.

FIG. 3 is an equivalent circuit diagram of the dielectric resonator according to the first embodiment of the present invention.

FIG. 4 is a sectional view of a dielectric resonator according to a second embodiment of the present invention.

FIG. 5 is a sectional view of a dielectric resonator according to a third embodiment of the present invention.

FIG. 6 is a perspective view of a dielectric filter according to a fourth embodiment of the present invention.

FIG. 7 is a perspective view of a dielectric filter according to a fourth embodiment of the present invention.

FIG. 8 is a perspective view of a dielectric filter according to a fifth embodiment of the present invention.

FIG. 9 is a perspective view of a dielectric filter according to a conventional example.

FIG. 10 is a cross-sectional view of a conventional dielectric filter.

[Explanation of symbols]

 1 Dielectric Block 2 Non-Through Hole 3 Metal Layer 4 Metal Layer Removal Section 5 External Connection Electrode

Claims (5)

[Claims] 1. A resonator block is formed by forming a non-through hole in a dielectric block, and forming a metal layer on an outer surface of the dielectric block and an inner surface of the non-through hole to form a resonator portion on the outer surface of the dielectric block. A dielectric resonator, wherein an input / output coupling portion including an external connection electrode is formed by removing a part of the metal layer. 2. The dielectric resonator according to claim 1, wherein the non-through hole provided in the dielectric block has a shape in which a diameter becomes smaller toward a bottom surface of the hole. 3. A dielectric block is provided with a plurality of non-through holes, and a plurality of resonance parts are formed by forming a metal layer on an outer surface of the dielectric block and an inner surface of the non-through hole. A dielectric filter comprising an input / output coupling section including an external connection electrode by removing a part of a metal layer formed on the outer surface of the dielectric filter. 4. The dielectric filter according to claim 3, wherein the non-through hole provided in the dielectric block has a shape in which the diameter becomes smaller toward the bottom surface of the hole. 5. The dielectric filter according to claim 3, wherein the coupling degree between the plurality of resonance parts is adjusted by providing a groove on the outer surface of the dielectric block.