JPH0323006B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a distributed parameter filter, and more particularly to an integrated distributed parameter filter in which a plurality of resonant elements are coupled together through coupling holes.

(Prior Art) FIG. 8 is a plan view showing a conventional example of this type of distributed constant filter. Figure 9 is the line in Figure 8 -
FIG. Distributed constant type filter 10
includes one rectangular dielectric block 12,
One surface 12a of the rectangular parallelepiped dielectric block 12 has a plurality of holes 14a, 14b, 14c and 14
d extends to the opposing end faces. On the inner peripheral surface of each of these holes 14a to 14d, an inner conductor 16 is provided, each forming a part of a resonant element.
a, 16b, 16c and 16d are formed.
Furthermore, an outer conductor 20 is formed on the outer peripheral surface of the dielectric block 12 to cooperate with these inner conductors 16a to 16d. Therefore, multiple holes or inner conductor 16
A plurality of TEM dielectric coaxial resonator elements are formed by each of a to 16d and a common outer conductor. And between each resonant element,
Square holes 18a, 18b and 18c for coupling are formed.

Further, in the vicinity of the inner conductors 16a and 16d, that is, the holes 14a and 14d constituting the first-stage and final-stage resonant elements, another hole 24a for external coupling is provided from the outer surface of the dielectric block 12, respectively.
and 24b are formed. And this hole 24
Connecting electrodes 26a and 26b are formed on the inner peripheral surfaces of a and 24b, respectively. Input terminals 30a and 30b are inserted into the connection electrodes 26a and 26b, respectively, and are electrically connected and mechanically fixed. Coupling cavities or slits 28a and 2 are provided between the other holes 24a and 24b and the holes 14a and 14d constituting the first and final stage resonant elements.
8b are formed respectively. These slits 28
a and 28b have the same structure and function as the square holes 18a to 18d described above.

Such an integrated distributed constant filter has 4
It is already well known that the stage has a combline-type structure and a Tievisiev-type damping characteristic, so its explanation will be omitted here.

(Problems to be Solved by the Invention) However, in the case of conventional distributed constant type filters, in order to steepen the attenuation characteristics of the filter,
It is necessary to increase the number of stages of resonant elements, which requires space, and it is difficult to miniaturize it.

Therefore, the main object of the present invention is to provide a distributed constant filter having a steep damping characteristic with fewer stages of resonant elements.

(Means for Solving the Problem) The present invention arranges a plurality of resonant elements in a plurality of rows and columns, and couples the resonant elements in each row with each other through coupling holes, and connects the resonant elements in each column with each other. This is a distributed constant type filter that combines the

(Function) Holes are formed in a dielectric block having an outer conductor on its outer circumferential surface in multiple rows and columns, and inner conductors are formed on the inner circumferential surface of the dielectric block, so that multiple resonant elements are arranged in multiple rows and multiple columns. On the other hand, the resonant elements in each row are coupled to each other and the resonant elements in each column are coupled to each other by coupling holes formed in the dielectric block.

(Effects of the Invention) According to the present invention, in the distributed constant filter, since the resonant elements in each row are coupled together and the resonant elements in each column are coupled together, the same number of resonant elements can be arranged in a row. Compared to the conventional example, the flow not only passes through these resonant elements in series, but also flows across them, so the filter characteristics become an elliptical type, and the number of stages of the same resonant element is lower than that of the conventional Tievisiev type. It is possible to construct a filter with steeper attenuation characteristics. Therefore, the number of stages of resonant elements can be reduced compared to the conventional method, and the size of the distributed constant filter can be reduced.

The above objects, other objects, features and advantages of the present invention will become more apparent from the following detailed description of embodiments with reference to the drawings.

(Embodiment) FIG. 1 is a plan view showing an embodiment of the present invention. The distributed constant filter 10 includes one dielectric block 12. 1 side 1 of dielectric block 12
2a has a hole 14a extending to its opposite end surface,
14b, 14c and 14d are formed in parallel with each other and arranged in two rows and two columns. Inner conductors 16a, 1 are provided on the inner peripheral surfaces of these holes 14a to 14d.
6b, 16c and 16d are formed respectively,
An outer conductor 20 is formed on the outer peripheral surface of the dielectric block 12. In this embodiment, the surface facing the open end surface 12a is covered with an outer conductor, so that a plurality of TEM dielectric coaxial resonant elements are arranged in two rows and two columns as λ/4 elements. Coupling holes 18a to 18d are formed between each of the resonant elements, that is, the inner conductors 16a to 16d, and in the resonant elements formed in a plurality of rows and columns, the resonant elements in each row are coupled to each other. and the resonant elements in each column are coupled together.

Further, in the vicinity of the inner conductors 16a and 16d, that is, the holes 14a and 14d constituting the first-stage and final-stage resonant elements, another hole 24a for external coupling is provided from the outer surface of the dielectric block 12, respectively.
and 24b are formed. And this hole 24a
Connection electrodes 26a and 26b are formed on the inner peripheral surfaces of and 24b, respectively. and,
Each of the connection electrodes 26a and 26b includes
Input terminals 30a and 30b are inserted, electrically connected, and mechanically fixed. Further, coupling holes 28a and 28 are provided between the other holes 24a and 24b and the holes 14a and 14d constituting the first-stage and final-stage resonant elements, respectively.
b is formed. These holes 28a and 28b
have the same structure and function as the previous holes 18a to 18d. With such a coupling structure, the input terminal 30a and the resonant element constituted by the inner conductor 16a are inductively coupled, that is, magnetically coupled.
Similarly, the input terminal 30b and the inner conductor 16
It is also inductively coupled, that is, magnetically coupled, to the resonant element constituted by b.

Note that the input terminals 30a and 30b and the inner conductor 1
Capacitive coupling, that is, electric field coupling may be performed between each of the resonant elements constituted by 6a and 16b.

The integrated distributed parameter filter 10 thus completed is formed in a plurality of rows and columns, and the resonant elements in each row are coupled together, and the resonant elements in each column are coupled together. The filter characteristics are steep as shown by the solid line in FIG. On the other hand, the characteristics of a conventional Tievishiev type filter are shown by the dotted line in FIG. In other words, even if the distributed constant filter is composed of the same number of stages (four stages) of resonant elements as the conventional one, according to the embodiment shown in FIG.
A continuous flow flows through these resonant elements in a U-shape, for example, and a flow crosses the resonant elements, thereby making it possible to obtain a steeper damping characteristic of an elliptical filter.

FIGS. 3 and 4 are plan views showing other embodiments of the invention, respectively. These distributed constant type filters 10 differ from the embodiment shown in FIG. 1 in that only coupling holes 18b and 18d or coupling holes 18a and 18c are formed. As shown in FIG. 3, only the coupling holes 18b and 18d are formed, or as shown in FIG.
Only 8a and 18c may be formed,
In either case, the resonant elements in each row and the resonant elements in each column are coupled. Therefore,
These distributed constant filters 10 also have elliptical filter characteristics. In this way, the coupling holes may be formed only between the rows or columns of the array of resonant elements to couple the resonant elements. In this way, the number of coupling holes can be reduced.

FIG. 5 and FIG. 6 are plan views showing still other embodiments of the present invention. These distributed constant type filters 10 especially have one coupling hole.
This embodiment differs from the above-mentioned embodiments in that In the distributed constant filter 10 shown in FIG. 5, the coupling slit 18e is formed as one substantially cross-shaped hole so that the end face of electromagnetic energy leakage is located between the arrays of each resonant element. In addition, in the distributed constant filter 10 shown in FIG.
is formed.

Slit 18e or hole 18 for these connections
It is clear that the resonant elements can be coupled to each other also by f.

These distributed constant filters 10 also have elliptical filter characteristics. In this way, the number of coupling holes may be one.

FIG. 7 is a sectional view showing a modification of the coupling hole. In this FIG. 7, the hole 18a is shown as a representative of the others, but the other holes 18b to 18d, 28a and 28
The same can be applied to b. For example, an electrode 22 electrically connected to the outer conductor 20 on the short-circuit end surface side of the dielectric block 12 is formed on the inner wall of the coupling hole 18a.

This electrode 22 is formed under the hole 18a, and by changing its length, thickness, etc., the degree of coupling due to the hole 18a can be adjusted.

[Brief explanation of drawings]

FIG. 1 is a plan view showing an embodiment of the present invention. FIG. 2 is a diagram showing the attenuation characteristics of the filter, where the dotted line shows the characteristics of the conventional example and the solid line shows the characteristics of the embodiment of the present invention. Figures 3 and 4 are
FIG. 7 is a plan view showing other embodiments of the present invention. FIG. 5 and FIG. 6 are plan views showing still other embodiments of the present invention. 7th
The figure is a sectional view showing a modification of the hole for connection. FIG. 8 is a plan view showing a conventional example of a distributed constant type filter. FIG. 9 is a sectional view taken along the line - in FIG. 8. In the figure, 10 is a distributed constant type filter, 12
is a dielectric block, 14a to 14d are holes, 16a
16d to 16d are inner conductors, 18a to 18f are coupling holes, and 20 is an outer conductor.

Claims (1)

[Scope of Claims] 1. An integrated distributed parameter filter in which a plurality of resonant elements are formed in one dielectric block, comprising: an outer conductor formed on the outer peripheral surface of the dielectric block; a plurality of holes formed in the block in an array of a plurality of rows and a plurality of columns; and a plurality of holes formed on the inner peripheral surface of each of the plurality of holes, each of which cooperates with the outer conductor to generate a resonant element in an arrangement of a plurality of rows and a plurality of columns. a distributed constant filter comprising a plurality of inner conductors, and coupling holes formed in the dielectric block for coupling between the resonance elements in each row and coupling between the resonance elements in each column; .