JPH11177305A - Dielectric filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a mounting area while maintaining the characteristic of a filter by forming a pair of input/output terminal holes positioned on both ends on the side the dielectric block in the direction of. SOLUTION: A dielectric block 11 is made of ceramic power with a high dielectric constant for microwave use which is formed into a given shape by hermetically molding using a metal mold and then sintered. Three through holes for forming resonator holes 12a-12c are formed after sintering and a pair of through holes for forming the input/output terminal holes 13a and 13b are formed on the side parts of the resonator holes 12a and 12c at both end parts so that they are overlapped in the thickness direction of the dielectric block 11. One end part of each input/output terminal 14 is inserted into the input/output terminal holes 13a and 13b, and the outer part is positioned so that it protrudes to an outer part by prescribed length from the dielectric block 11. Then, the input/output terminals 14 are soldered to conductor layers in the input/output terminal holes 13a and 13b.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dielectric filter used in a microwave radio, a mobile phone, a GPS, and the like.

[0002]

2. Description of the Related Art Hitherto, as a dielectric filter used in a microwave radio, a mobile phone, a GPS, or the like, a dielectric filter having a structure indicated by reference numeral 1 in FIGS. 4 and 5 is known.

In this dielectric filter 1, a plurality of resonator holes 3 are formed in a rectangular parallelepiped dielectric block 2 at predetermined intervals in the length direction and penetrate in the width direction. Input / output terminal holes 4 are formed at both ends of the dielectric hole 2 in the length direction of the dielectric block 2. A layer is formed, and a conductor layer on the inner surface of each of the resonator holes 3 is electrically connected to a conductor layer of the dielectric block 2 at one end of the resonator hole 3. In addition, the conductor layers of the input / output terminal holes 4 are insulated from the conductor layers of the dielectric block 2 at both ends of the input / output terminal holes 4. In the conductor layer of
The input / output terminals 5 are electrically connected, and these available terminals 5 are drawn out of the dielectric block 2.

[0004]

In order to mount such a conventional dielectric filter 1 on a device, as shown in FIG. 4, one side of a dielectric block 2 is brought into surface contact with a substrate 6. The input / output terminal 5 is fixed to the substrate 6 by connecting the input / output terminal 5 to a conductor formed on the substrate 6 by soldering or the like. Since the dimension L in the longitudinal direction is large, when the above-described mounting is performed, the area occupied by the dielectric filter 1 on the substrate 6 is large, that is, a large mounting area is required, and the size of the device is reduced. Has become an obstacle.

The present invention has been made in view of such conventional problems, and has as its object to provide a dielectric filter capable of reducing the mounting area while maintaining the characteristics of the filter.

[0006]

According to the present invention, in order to achieve the above object, a plurality of resonators are provided on a rectangular parallelepiped dielectric block at predetermined intervals in the length direction and penetrating in the width direction. A hole is formed, and an input / output terminal hole is formed on a side of the pair of resonator holes located at both ends of the dielectric block in a thickness direction of the dielectric block.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below.

In FIGS. 1 and 2, reference numeral 10 denotes a dielectric filter according to the present embodiment.
No. 0 forms a plurality of resonator holes 12a to 12b at predetermined intervals in the length direction and penetrates in the width direction in the rectangular parallelepiped dielectric block 11;
Of a pair of resonator holes 12a and 12c located at both ends of
The input / output terminal holes 13a and 13b are formed on the side of the dielectric block 11 in the thickness direction.

Next, the details will be described. The dielectric block 11 is formed by compacting a powder of a high dielectric constant ceramic material for microwave into a predetermined shape by using a mold or the like and then sintering. After sintering, three through-holes for forming the resonator holes 12a to 12c are formed, and the input / output terminals are provided on both sides of the resonator holes 12a and 12c at both ends. A pair of through holes for forming the holes 13a and 13b are formed so as to overlap in the thickness direction of the dielectric block 11 (up and down direction in FIG. 1). The formed dielectric block 11 is, for example,
It is immersed in a silver paste bath to apply a silver paste to the inner surface of each through hole and the entire outer surface of the dielectric block 11, and then baked this silver paste to form a surface of the dielectric block 11 and an inner surface of each through hole. A conductor layer is formed integrally with the end portions of the resonator holes 12a to 12c on the side to be insulated and the input / output terminal holes 13a and 13b.
By removing the conductor layer by cutting or the like at both ends of the above, the resonator holes 12a to 12c and the input / output terminal holes 13a and 13b are formed.

The input / output terminal holes 13a, 13a
b, one end of the input / output terminal 14 is inserted, and the other end is positioned so as to protrude from the dielectric block 11 to the outside by a predetermined length. By connecting to the conductor layer on the inner surface of the output terminal hole 14 by soldering or the like, the dielectric filter 11 according to the present embodiment can be obtained. In the present embodiment, the insulating portions of the resonator holes 12a to 12c are removed. A so-called comb line type, which is located on the same surface side of the dielectric block 11, is shown.

On the other hand, the portions of the input / output terminals 14 protruding from the dielectric block 11 are temporarily extended in the longitudinal direction of the input / output terminal holes 13a and 13b,
The dielectric block 11 is bent toward a side portion on the side to be a mounting surface, and further has a shape in which the front end portion is again in contact with the mounting surface so as to be substantially flush with the mounting surface.

The thus configured dielectric filter 10 according to the present embodiment has one side surface (that is, a mounting surface) on a substrate 15 (see FIG. 1) of a device on which the dielectric block 11 is to be mounted. It is attached to the substrate 15 by being installed so as to be in contact with each other and by connecting the input / output terminal 14 to a conductor formed on the substrate 15 by soldering or the like.

In the dielectric filter 10 mounted on the substrate 15 in this manner, the input / output terminal holes 13a and 13b formed in the dielectric block 11 have the resonator holes 12a and 12c located at both ends. On the other hand, since the dielectric block 11 is superposed in the thickness direction of the dielectric block 11, the length S of the dielectric block 11 is correspondingly shortened. As a result, in a state where the dielectric block 11 is mounted on the substrate 15,
The mounting area can be greatly reduced.

Here, when the filter characteristics of the dielectric filter 10 according to the present embodiment were measured,
The result shown in FIG. 3 was obtained.

As is apparent from the results, in the frequency band other than the target frequency F1, a substantially smooth attenuation characteristic is obtained, and a decrease in the filter characteristic due to the configuration according to the present embodiment is observed. Absent.

As described above, in this embodiment, the dielectric filter 10 having a small mounting area can be obtained while maintaining the filter characteristics.

Note that the shapes, dimensions, and the like of the respective parts shown in the above embodiment are merely examples, and can be variously changed based on design requirements and the like.

For example, the spacing between the resonator holes 12a to 12c and the spacing between the resonator holes 12a and 12c at both ends and the input / output terminal holes 13a and 13b are determined in consideration of the mounting area to be strengthened. It can be changed as appropriate, and these resonator holes 12a to 12c and both input / output terminal holes 13a and 13c are provided.
The inner diameter of b and the like can be changed as appropriate.

In the above-described embodiment, the comb line type is described. However, an interdigital structure in which insulating portions of the resonator holes 12a to 12c are alternately formed on a pair of parallel surfaces of the dielectric block 11 is provided. Application to types is also possible.

[0020]

As described above, in the dielectric filter according to the present invention, a plurality of resonator holes are provided in a rectangular parallelepiped dielectric block at predetermined intervals in the length direction and penetrate in the width direction. Forming a pair of resonator holes located at both ends of the dielectric block, on the side in the thickness direction of the dielectric block, an input / output terminal hole is formed. It has the following excellent effects.

The input / output terminal holes are overlapped with the resonator holes located at both ends in the thickness direction of the dielectric block, so that the length of the dielectric block can be shortened accordingly. As a result, when mounting on a substrate, the mounting area can be significantly reduced.

Further, even if the position of the input / output terminal hole is changed as described above, no change in filter characteristics is caused.

[Brief description of the drawings]

FIG. 1 is a side view of a dielectric filter according to an embodiment of the present invention.

FIG. 2 is a plan view of a dielectric filter according to one embodiment of the present invention.

FIG. 3 is a filter characteristic diagram of the dielectric filter according to the embodiment of the present invention.

FIG. 4 is a side view showing an example of a conventional dielectric filter.

FIG. 5 is a plan view showing an example of a conventional dielectric filter.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Dielectric filter 11 Dielectric block 12a-12c Resonator hole 13a / 13b I / O terminal hole 14 I / O terminal

Claims (1)

[Claims] 1. A rectangular parallelepiped dielectric block (11),
A plurality of resonator holes (12a to 12c) are formed at predetermined intervals in the length direction and penetrate in the width direction, and a pair of resonator holes (12a to 12c) located at both ends of the dielectric block (11) are formed. 12a, 12c), said dielectric block (11)
Input / output terminal holes (13a, 13b)
Forming a dielectric filter (1).
0).