JPH06140805A - Dielectric filter and manufacture of the same - Google Patents

Abstract

PURPOSE:To miniaturize an entire dielectric filter in comparison in the case of changing a pitch between inner conductor forming holes, to fix the pitch between the inner conductor forming holes, and to make parts common. CONSTITUTION:An outer conductor 4 is formed on the outer surface of a dielectric, plural inner conductor forming holes 5 and 6 and a non-forming part 8 of an inner conductor is provided in the vicinity of the opening faces of the inner conductor forming holes 5 and 6 so as to enable comb-line coupling. Then, the degree of coupling resonators is decided corresponding to a distance between the central axes of the inner conductor forming holes 5 and 6 and the outer surface of the dielectric without changing the pitch between the inner conductor forming holes 5 and 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dielectric filter in which a plurality of inner conductors are formed in a dielectric body and outer conductors are formed on the outer surface of the dielectric body, and a method for manufacturing the same.

[0002]

2. Description of the Related Art A dielectric resonator having an inner conductor forming hole formed inside a dielectric block and an outer conductor formed on the outer surface of the dielectric block, and two or more dielectric plates provided with various electrodes in advance. A dielectric resonator having an inner conductor provided inside and an outer conductor provided on the outer surface is used as, for example, a band-pass filter in the microwave band.

The applicant of the present application is, for example, Japanese Patent Application No. 4-920.
No. 7 or Japanese Patent Application No. 4-10009 filed an invention relating to a multi-stage dielectric filter in which an inner conductor non-formation region is provided in an inner conductor formation hole and comb line coupling is performed.

[0004]

In such a dielectric filter, conventionally, the degree of coupling between adjacent resonators has been determined by determining the pitch between inner conductor forming holes.

However, especially when the degree of coupling is weakened, it is necessary to increase the pitch between the inner conductor forming holes, which causes a problem that the entire dielectric filter becomes large. Further, if the pitch between the inner conductor forming holes is the same, only the degree of coupling corresponding to the pitch can be obtained. Therefore, in order to manufacture a filter having a different degree of coupling, another pitch having a different pitch between the inner conductor forming holes is produced. I had to design and manufacture a dielectric filter.

An object of the present invention is to make it possible to change the coupling degree between the resonators without changing the pitch between the inner conductor forming holes, so that even if the coupling degree between the resonators is weakened, the size can be easily reduced. It is to provide a dielectric filter that can do the above.

Another object of the present invention is to make it possible to adjust the degree of coupling between resonators without changing the pitch between inner conductor forming holes, so that the same component (dielectric unit) can be used in many cases with different degrees of coupling. So that you can get different types of dielectric filters,
An object of the present invention is to provide a dielectric filter having common parts.

[0008]

According to a first aspect of the present invention, there is provided a dielectric filter in which a plurality of inner conductor forming holes are arranged in a dielectric body, and an outer conductor is formed on an outer surface of the dielectric body. In the dielectric filter, the non-formation portion of the inner conductor is provided near at least one opening surface of the formation hole, and a signal input / output electrode capacitively coupled to the inner conductor is provided in a part of the outer conductor. The degree of coupling between the resonators is adjusted without changing the pitch between the inner conductor forming holes by adjusting the distance between the central axis and the outer surface.

According to a second aspect of the present invention, there is provided a method of manufacturing a dielectric filter in which a plurality of inner conductor forming holes are arranged in a dielectric body, an outer conductor is formed on an outer surface of the dielectric body, and at least one of the inner conductor forming holes is formed. A method for manufacturing a dielectric filter, comprising a non-formed portion of an inner conductor provided in the vicinity of an opening surface, and a signal input / output electrode capacitively coupled to the inner conductor in a part of the outer conductor, wherein It is characterized in that the distance between the central axis of the inner conductor forming hole and the outer surface is adjusted by cutting to adjust the coupling degree between the resonators without changing the pitch between the inner conductor forming holes.

[0010]

In the dielectric filter according to the present invention, a plurality of inner conductor forming holes are provided in the dielectric body, an outer conductor is formed on the outer surface of the dielectric body, and at least one opening surface of the inner conductor forming hole is provided in the vicinity of the opening surface. A non-formed portion of the inner conductor is provided, and a signal input / output electrode capacitively coupled to the inner conductor is provided in a part of the outer conductor. The distance between the central axis of the inner conductor forming holes and the outer surface is adjusted, and the degree of coupling between the resonators is adjusted without changing the pitch between the inner conductor forming holes.

Now, the relationship between the capacitance and the coupling coefficient generated in each part in the dielectric filter will be described with reference to FIG. FIG. 4 is a view seen from the opening surface of the inner conductor forming hole. In FIG. 4, 5 and 6 are inner conductor forming holes having inner conductors formed on their inner surfaces, and 4 is an outer conductor formed on the outer surface of the dielectric. The inner conductor forming hole 5 provided in the dielectric body forms the resonator R _i , and the inner conductor forming hole 6 forms the resonator R _{i + 1} .
The capacitance between the inner conductor and the outer conductor 4 in the inner conductor forming hole 5 is C _i ,
The capacitance between the inner conductor and the outer conductor 4 in the inner conductor forming hole 6 is C _{i + 1.}
And the capacitance between the inner conductors in the inner conductor forming holes 5 and 6 is C _{i, i + 1} , the coupling coefficient k _{i, i + 1} is expressed by (Equation 1).

[0012]

[Equation 1]

Where θ _i, θ _{i + 1} : electrical angle of the resonator Za _i, Za _{i + 1} : characteristic impedance of the resonator Zodd: characteristic impedance of the resonator in the odd mode Zeven: characteristic of the resonator in the even mode Impedance.

Also, the characteristic impedance Zodd _i of the odd mode and the characteristic impedance Zeven of the even mode.
_i is represented by (Equation 2) and (Equation 3), respectively.

[0015]

[Equation 2]

[0016]

[Equation 3]

Here, εr: relative permittivity Vc: speed of light.

Therefore, the coupling coefficient k is C _i shown in FIG.
And C _{i, i + 1} .

In the dielectric filter according to the first aspect, the distance between the central axis of the inner conductor forming hole and the outer surface is adjusted.
C _i and / or C _{i + 1} shown in ( ₁₎ can be changed, whereby the degree of coupling between the resonators can be determined without changing the pitch between the inner conductor forming holes.

In the method of manufacturing the dielectric filter according to the second aspect, the outer surface of the dielectric is cut to adjust the distance between the central axis of the inner conductor forming holes and the outer surface, whereby the pitch between the inner conductor forming holes is adjusted. A dielectric filter in which the degree of coupling between the resonators is adjusted can be manufactured without changing Therefore, when manufacturing a dielectric filter having a different degree of coupling between resonators, another component (dielectric unit) having a different pitch between inner conductor forming holes is formed.
It is not necessary to design and manufacture the parts, and it is possible to reduce costs as a whole by using common parts.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The construction of a dielectric filter according to an embodiment of the present invention is shown in FIGS.

FIG. 1 is an external perspective view of a dielectric filter. The dielectric block has a substantially hexahedral shape as shown in FIG. 1. Two dielectric conductor forming holes 5 and 6 are provided in this dielectric block, and inner conductors are formed on the respective inner surfaces. Further, the signal input / output electrodes 9 are provided on the outer surface of the dielectric block.
10 is formed, and the outer conductor 4 is formed on substantially the entire six surfaces except the portions where the signal input / output electrodes 9 and 10 are formed. The positions of the central axes of the inner conductor forming holes 5 and 6 are determined by molding or adjusted by grinding the outer surface of the dielectric block after molding and sintering. As will be described later, the degree of coupling between the resonators is determined by the distance between the central axes of the inner conductor forming holes 5 and 6 and the outer surface of the dielectric block.

FIG. 2 is a sectional view through the central axis of the inner conductor forming hole 6 in FIG. In this way, the inner conductor 3 is provided inside the inner conductor forming hole 6 provided in the dielectric block 1, and the inner conductor non-forming portion 8 is provided in the vicinity of one opening surface, and the tip capacitance is formed at this portion. is doing. Such a non-formed portion of the inner conductor can be provided by cutting using a rotary grindstone, as described in the example of Japanese Patent Application No. 4-9207.

FIG. 3 is an external perspective view showing the structure of a dielectric filter according to another embodiment. The difference from the previous embodiment shown in FIGS. 1 and 2 is that, instead of using a single dielectric block, two dielectric plates 11 and 12 are used, and they are joined and integrated, A dielectric filter similar to that shown in FIG. 1 is obtained.

Next, FIG. 5 shows three examples of adjusting the coupling degree.
Shown in. 5A, 5B, and 5C are views respectively viewed from the opening surface side of the inner conductor forming hole, in which a is a width dimension and b and b ′ are thickness dimensions. As shown in (A), one surface of the dielectric block is cut or the position of the inner conductor forming hole is decentered in advance to reduce the thickness dimension b to b '. As a result, the capacitances C _i and C _{i + 1} between the inner conductor forming hole and the outer conductor shown in FIG. 4 are increased. As a result, the degree of coupling between the resonators can be increased. Also,
As shown in (B), without changing the thickness dimension b, one surface of the dielectric block is cut or the position of the inner conductor forming hole is eccentric in advance to reduce the dimension a in the lateral width direction to a '. There is. As a result, C _i shown in FIG. 4 can be increased to weaken the degree of coupling between the resonators. Furthermore, (C)
As shown in (4), the degree of coupling can be adjusted by cutting the four faces of the dielectric block or by molding so that the inner conductor forming holes are at predetermined positions in advance.

In the embodiment, the dielectric filter including the two-stage dielectric resonator is taken as an example, but the present invention can be similarly applied to three or more stages.

[0027]

According to the dielectric filter of the present invention, since the degree of coupling between the resonators can be reduced without increasing the pitch between the inner conductor forming holes, a compact dielectric filter can be obtained as a whole. be able to.

Further, according to the method of manufacturing the dielectric filter of the present invention, the pitch between the inner conductor forming holes is not changed,
By cutting the outer surface of the dielectric material, the degree of coupling between the resonators can be adjusted, so by using parts with the same pitch between inner conductor formation holes, various types of dielectric filters with different characteristics can be manufactured at low cost. Be able to manufacture.

[Brief description of drawings]

FIG. 1 is an external perspective view showing the configuration of a dielectric filter that is an embodiment of the present invention.

FIG. 2 is a cross-sectional view passing through a central axis of an inner conductor forming hole 6 in FIG.

FIG. 3 is an external perspective view of a dielectric filter according to another embodiment.

FIG. 4 is a diagram for explaining a relationship between a capacitance generated in each part in a dielectric filter and a coupling coefficient between resonators.

FIG. 5 is a diagram showing an example of adjusting the degree of coupling.

[Explanation of symbols]

 1-Dielectric Block 3-Inner Conductor 4-Outer Conductor 5,6-Inner Conductor Forming Hole 8-Inner Conductor Non-Forming Area 9,10-Signal Input / Output Electrode 11,12-Dielectric Plate

Front page continuation (72) Inventor Tadahiro Yorita 26-10 Tenjin Tenjin, Nagaokakyo-shi, Kyoto Murata Manufacturing Co., Ltd.

Claims (2)

[Claims] 1. A plurality of inner conductor forming holes are arranged in a dielectric body,
An outer conductor is formed on the outer surface of the dielectric, an inner conductor non-formation portion is provided in the vicinity of at least one opening surface of the inner conductor forming hole, and a signal input for capacitively coupling the inner conductor to a part of the outer conductor. In a dielectric filter with output electrodes, adjust the distance between the central axis between inner conductor formation holes and the outer surface to adjust the degree of coupling between resonators without changing the pitch between inner conductor formation holes. Dielectric filter made by. 2. A plurality of inner conductor forming holes are arranged in a dielectric body,
An outer conductor is formed on the outer surface of the dielectric, an inner conductor non-formation portion is provided in the vicinity of at least one opening surface of the inner conductor forming hole, and a signal input for capacitively coupling the inner conductor to a part of the outer conductor. A method for manufacturing a dielectric filter having an output electrode, wherein the outer surface of the dielectric is cut to adjust the distance between the central axis of the inner conductor forming holes and the outer surface, and to adjust the pitch between the inner conductor forming holes. A method of manufacturing a dielectric filter, characterized in that the degree of coupling between resonators is adjusted without changing.