JPH05102706A - Coupling structure of dielectric filter - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] To provide a coupling structure capable of sufficiently miniaturizing a dielectric filter while maintaining desired characteristics and easily electrically connecting to a wiring pattern of a circuit board. [Structure] A plurality of coaxial dielectric resonators 1A and 1B in which a dielectric 5 is filled are arranged between an inner conductor 4 and an outer conductor 3, and between the resonators and between the resonators and the input / output terminals. Is provided with a coupling dielectric block 2 for capacitor coupling between the two, and the coupling dielectric block has holes 6A and 6B facing the inner conductor 4 of each dielectric resonator. Electrodes 7A, 7B are formed on the inner surface of each of the electrodes, and the conductive spacers 9 are used to form the electrodes 7A, 7B of the coupling dielectric block.
B and the corresponding inner conductor 4 of the resonator are connected to each other, and the input terminal electrode 8 is provided on the side surface of the coupling block 2.
A and the output terminal electrode 8B are formed, and a part of the input terminal electrode and a part of the output terminal electrode exist on the same plane.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dielectric filter coupling structure in which a plurality of coaxial dielectric resonators are combined, and in particular, a dielectric filter in which coupling between dielectric resonators is realized by a capacitor capacitance. Regarding the bond structure of.

[0002]

2. Description of the Related Art As a structure for electrically coupling between resonators and electrical coupling between a resonator and an input / output terminal in a dielectric filter of this type, a conventional structure is disclosed in, for example, Japanese Patent Laid-Open No.
As described in JP-A-57302 or JP-A-55-35560, a dielectric is filled between an inner conductor and an outer conductor to form a coaxial dielectric resonator. A dielectric filter is formed by arranging a plurality of the resonators or arranging a plurality of the resonators integrally with each other with the outer conductor being common, and between the resonators of the dielectric filter and between the resonators and the input / output terminals. It has a dielectric block for capacitor coupling with and. This coupling dielectric block has a flat plate shape and is arranged so as to face a plurality of resonator arrays of the dielectric filter, and its surface electrically corresponds to the inner conductor of each dielectric resonator. An electrode pattern is formed which is coupled to. Then, by appropriately selecting the material of the coupling dielectric block and setting the coupling capacitor capacitance between the electrode patterns to a proper value,
The capacitance between the resonators is adjusted to each set value.

[0003]

However, in the process of promoting miniaturization of the dielectric resonator, the following problems have been raised. That is, when a plurality of coaxial dielectric resonators are used to form a dielectric filter, the distance between adjacent inner conductors becomes shorter as the resonator becomes smaller,
There is no choice but to reduce the electrode pattern in the coupling dielectric block. For this reason, as the size of the resonator is reduced, a desired electrode pattern area cannot be obtained, and a necessary coupling capacitor capacitance cannot be obtained. In other words, in order to obtain a desired coupling capacitor capacity by forming a flat electrode pattern on the surface of the flat plate-shaped coupling dielectric block, the distance between the inner conductors of the dielectric resonator should be a certain value or more. This must be ensured, which hinders miniaturization of the dielectric filter.

The present invention has been made in view of the above circumstances, and a sufficient coupling capacitor capacitance is obtained even if the dielectric block is downsized by three-dimensionalizing the electrode pattern of the coupling dielectric block. Therefore, it is an object of the present invention to provide a coupling structure that enables miniaturization of a dielectric filter while maintaining desired characteristics in response to miniaturization of each dielectric resonator.

[0005]

According to the present invention, in order to achieve the above object, a plurality of coaxial dielectric resonators having a dielectric filled between an inner conductor and an outer conductor are arranged. Alternatively, a dielectric filter is configured by arranging a plurality of the resonators integrally with each other with the outer conductor being common, and between the resonators of the dielectric filter and between the resonator and the input / output terminal. Is a coupling structure for a dielectric filter, the coupling structure including a coupling dielectric block for capacitor coupling, wherein the coupling dielectric block has a hole portion facing an inner conductor of each of the dielectric resonators. An electrode is formed on the inner surface of the hole, and a conductive spacer is interposed between the coupling dielectric block and each of the resonators, and the coupling spacer is formed by these conductive spacers. Each electrode of the block and the corresponding An inner conductor of the resonator is connected, and an input terminal electrode and an output terminal electrode are formed on a side surface of the coupling block. A part or all of the input terminal electrode and one of the output terminal electrodes are connected to each other. Provided is a coupling structure for a dielectric filter, characterized in that all or all of them are coplanar.

In the present invention, the holes of the coupling dielectric block are predetermined to determine a desired coupling capacitor capacitance between each electrode formed on the inner surface of the coupling dielectric block and the electrode of the adjacent hole or the adjacent input / output terminal electrode. Is formed with the shape, size and relative position of. Further, in the present invention, there is an aspect in which a slit is formed on the side surface of the coupling dielectric block to determine the capacitance of the coupling capacitor between the electrodes of the holes. Further, in the present invention, the coupling capacitor capacitance between the resonators is on the same plane where some or all of the input terminal electrodes and some or all of the output terminal electrodes are present on the side surface of the coupling dielectric block. In some embodiments, a ground electrode that determines

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Specific embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 and FIG. 2 show a dielectric filter having two coaxial dielectric resonators 1A and 1B and a coupling dielectric block 2 as constituent elements as a first embodiment of the present invention. The bond structure is shown. Here, each of the coaxial dielectric resonators 1A and 1B is a rectangular tube-shaped outer conductor 3
And the cylindrical inner conductor 4 is filled with a dielectric material 5 and has a known structure. The coupling dielectric block 2 is a plate having a predetermined thickness and is provided with holes 6A and 6B corresponding to the two inner conductors 4 of the dielectric resonators 1A and 1B. And film-shaped electrodes 7A and 7B are formed on their inner surfaces. In addition, one side surface of the coupling dielectric block 2 (see FIG.
Both the film-shaped input terminal electrode 8A and the film-shaped output terminal electrode 8B are formed on the front surface of the film. This side surface is substantially flush with the side surface (front surface in FIG. 1) of the dielectric resonators 1A and 1B. As shown in FIG. 1, the input terminal electrode 8A and the output terminal electrode 8B extend to the end surface (the left surface or the right surface in FIG. 1) of the coupling dielectric block 2 respectively. (This also applies to the embodiments described below).

In this embodiment, the inner conductor 4 and the electrodes 7A,
Electrical conduction with 7B is performed using a conductive spacer 9 made of metal. The conductive spacer 9 is provided with a conductive flange 9A having a predetermined thickness in the middle, and the shaft portion 9B protruding vertically is inserted into the inner conductor 4 and the holes 6A, 6B and joined by soldering. There is. Thus, the resonators 1A and 1B and the coupling dielectric block 2 are structurally and electrically coupled.

The thus-coupled dielectric filter electrically has a structure as shown in the equivalent circuit of FIG. Here, a material having a relative dielectric constant of, for example, 93 is used for the coupling dielectric block 2, and equivalently, a coupling capacitor capacitance C ₂ is interposed between the electrodes 7A and 7B. And input / output terminal electrodes 8A, 8B
Coupling capacitor capacities C ₁ and C ₃ are interposed between the electrodes and the electrodes 7A and 7B, respectively. Further, the capacitance C _C is interposed between the input / output terminal electrodes 8A and 8B, whereby an attenuation pole can be provided on the low frequency side in the filter characteristic of the dielectric filter, and the frequency characteristic can be improved by the capacitor coupling. You can measure.

The above dielectric filter can be mounted as shown in FIGS. 4 is a sectional view and FIG. 5 is a perspective view. 4 and 5, reference numeral 12 is a circuit board, a wiring pattern is formed on the surface of the board, and 13A is an input line.
3B is an output line and 14 is an earth line.
The side surface of the coupling dielectric block 2 on which both the input terminal electrode 8A and the output terminal electrode 8B are formed and the side surface of the resonator corresponding thereto are appropriately positioned and joined to the wiring pattern of the substrate 12. Specifically, the input line 13A is soldered to the input terminal electrode 8A, the output line 13B is soldered to the output terminal electrode 8B,
The ground line 14 and the outer conductor 3 of the resonators 1A and 1B are joined by solder. Reference numeral 15 is a metal cover, and the cover is attached by sandwiching the resonator from the outside by the tabs 16A and 16B.

As described above, in this embodiment, electrical connection can be made extremely easily by simply aligning and joining the wiring pattern formed on the circuit board 12. No special connecting line is required for the connection.

In the second embodiment shown in FIG. 6, the outer conductor 3 is common to the two dielectric resonators 1A and 1B, and thus the two resonators are integrated. The other structure is similar to that of the first embodiment.

In the third embodiment shown in FIG. 7, four dielectric resonators are combined and the coupling dielectric block 2 corresponding to the inner conductors 4 of the second and third resonators.
The capacitance of the coupling capacitor between the electrodes 7B and 7C in each hole is adjusted by forming the slit 11 having the width W and the length L in the dielectric block 2. The other structure is similar to that of the first embodiment.

FIG. 8 shows a modification of the coupling dielectric block used in the third embodiment. In this example, the dielectric block 2 has laterally projecting portions 17A and 17B at both ends, and side surfaces of these projecting portions (see FIG. 8).
(The surface on the front side of) is on the same plane, and the input terminal electrode 8A and the output terminal electrode 8B are formed here.
In this example, the input terminal electrode 8A and the output terminal electrode 8B
Respectively extend to the end surface of the dielectric block 2. With such a configuration, it is possible to reduce the placement accuracy required on the circuit board during mounting. That is, as shown in FIG. 9, the dielectric block 2 for the input line 13A and the output line 13B formed on the circuit board 12 is formed.
Even if the position of is slightly shifted in the direction of the arrow, input line 1
Since one of the 3A and the output line 13B is separated from the portion of the dielectric block 2 where the terminal electrode is not formed, the capacitance change is small, and therefore the positioning accuracy does not have to be so precise. is there.

In the fourth embodiment shown in FIGS. 10 and 11, the holes 6A to 6A formed in the coupling dielectric block 2 are formed.
D is the longitudinal direction of the dielectric block (that is, the resonators 1A to 1A).
The elongated holes are formed in the direction of the arrangement of D), and the intervals between the adjacent hole portions are set to desired values such as d _{1 to} d ₃ . By this, the capacitance of the coupling capacitor between the electrodes 7A to 7D can be determined.

In the fifth embodiment shown in FIG. 12, the diameters of the holes 6A to 6D formed in the coupling dielectric block 2 are appropriately set, and by this setting, the holes 6A to 6D are formed on the inner peripheral surface of the hole. The capacitance of the coupling capacitor between the electrodes 7A to 7D is adjusted.

In the sixth embodiment shown in FIG. 13, the ground electrode 10 is formed on the side surface of the coupling dielectric block 2 on which both the input / output terminal electrodes 8A and 8B are formed.
The ground electrode is joined to the ground line of the wiring pattern on the circuit board. As a result, the capacitance of the coupling capacitor between the resonators 1B and 1C is reduced between the resonators 1A and 1B and between the resonators 1C and 1D.
It can be smaller than the capacitance of the coupling capacitor between them.

[0019]

As described above in detail, according to the coupling structure of the dielectric filter of the present invention, a hole is formed in the coupling dielectric block, an electrode is formed on the inner surface of the hole, and the electrode is formed. Since the inner conductor of the resonator and the corresponding inner conductor are connected by the conductive spacer, even if the coupling dielectric block is downsized, the coupling and coupling between the resonators can be performed without forming a complicated planar electrode pattern. The capacitance of the coupling capacitor required for output coupling can be obtained. Therefore, in response to the miniaturization of each dielectric resonator, it is possible to sufficiently miniaturize the dielectric filter while maintaining desired characteristics.

Further, according to the present invention, the input terminal electrode and the output terminal electrode are formed on the side surface of the coupling block, and a part or all of the input terminal electrode and a part or all of the output terminal electrode are formed. Since they are on the same plane, electrical connection can be made extremely easily by simply aligning and joining the wiring patterns formed on the circuit board.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of the present invention.

FIG. 2 is a vertical sectional view of FIG.

FIG. 3 is an equivalent circuit diagram of the embodiment of FIG.

FIG. 4 is a sectional view of the mounting state of the embodiment of FIG.

5 is a perspective view of the mounting state of the embodiment of FIG. 1. FIG.

FIG. 6 is a perspective view showing an embodiment of the present invention.

FIG. 7 is a perspective view showing an embodiment of the present invention.

FIG. 8 is a perspective view showing an example of a coupling dielectric block used in the present invention.

FIG. 9 is a diagram showing how the coupling dielectric block of FIG. 8 is attached to a circuit board.

FIG. 10 is a perspective view showing an embodiment of the present invention.

11 is a partial vertical cross-sectional view of FIG.

FIG. 12 is a perspective view showing an embodiment of the present invention.

FIG. 13 is a perspective view showing an embodiment of the present invention.

[Explanation of symbols]

 1A, 1B Dielectric resonator 2 Coupling dielectric block 3 Outer conductor 4 Inner conductor 5 Dielectric material 6A to 6D Holes 7A to 7D Electrode 8A Input terminal electrode 8B Output terminal electrode 9 Conductive spacer 10 Earth electrode 11 Slit 12 Circuit board 13A Input line 13B Output line 14 Ground line 15 Metal cover 16A, 16B Tab 17A, 17B Projection

Claims (4)

[Claims] 1. A plurality of coaxial dielectric resonators in which a dielectric material is filled between an inner conductor and an outer conductor are arranged, or a plurality of the resonators are integrated by using a common outer conductor. A dielectric filter is formed by arranging the dielectric filters, and the dielectric filter includes coupling dielectric blocks for capacitor coupling between the resonators of the dielectric filter and between the resonator and the input / output terminals. A coupling structure of a filter, wherein the coupling dielectric block has a hole portion facing an inner conductor of each of the dielectric resonators, and an electrode is formed on an inner surface of the hole portion. Conductive spacers are interposed between the dielectric block and the resonators, and the conductive spacers connect the electrodes of the coupling dielectric block and the corresponding inner conductors of the resonators. In addition, the above connecting block An input terminal electrode and an output terminal electrode are formed on a side surface of the input terminal electrode, and a part or all of the input terminal electrode and a part or all of the output terminal electrode are present on the same plane, Dielectric filter coupling structure. 2. The hole of the coupling dielectric block has a predetermined shape for determining a desired coupling capacitor capacity between each electrode formed on the inner surface of the hole and an electrode of an adjacent hole or an adjacent input / output terminal electrode, The coupling structure for a dielectric filter according to claim 1, wherein the coupling structure has a size and a relative position. 3. The dielectric filter according to claim 1, wherein a slit is formed on a side surface of the coupling dielectric block to determine a capacitance of a coupling capacitor between electrodes of the holes. Coupling structure. 4. The coupling capacitor capacitance between the resonators is determined on the same plane where some or all of the input terminal electrodes and some or all of the output terminal electrodes are present on the side surface of the coupling dielectric block. 2. The dielectric filter coupling structure according to claim 1, wherein a grounding electrode is formed.