JPH05335806A - Dielectric microwave filter - Google Patents

Abstract

PURPOSE:To obtain a small-sized dielectric microwave filter easily manufactured and having a narrow band characteristic. CONSTITUTION:Through-holes 13 of dielectric coaxial resonators 12, 12 arranged side by side are made orthogonal in a dielectric block 11, and electromagnetic fields generated by the adjacent dielectric coaxial resonators 12, 12 are made orthogonal to each other. Coupling holes 17 are arranged between the adjacent dielectric coaxial resonators 12, 12 to disturbance the orthogonal linking of the said electromagnetic fields to couple electromagnetically the adjacent dielectric coaxial resonators 12, 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dielectric microwave filter using a plurality of dielectric coaxial resonators formed in a dielectric block.

[0002]

2. Description of the Related Art Generally, a dielectric coaxial resonator includes an antenna duplexer, a diplexer, a duplexer, and a multiplexer.
It is used to construct a filter in what is called an Iplexer, a demultiplexer, a multiplexer, a combiner or a transmission duplexer. An example of a conventional dielectric microwave filter of this type using a dielectric coaxial resonator is shown in FIGS. 3 and 4.

The above-mentioned dielectric microwave filter comprises a dielectric block 1 having a rectangular parallelepiped shape made of, for example, a titanium oxide ceramic dielectric, and three sets of dielectric coaxial resonators 2, 2 and 2. . Each dielectric coaxial resonator 2 has a resonator electrode 4 formed on the inner wall surface of a through hole 3 penetrating from one end surface 1a of the dielectric block 1 to another end surface 1b opposite to the end surface 1a, and the through hole 3 described above. Electrode 5 formed on the outer surface of the dielectric block 1 surrounding the
Then, the resonator electrode 4 and the ground electrode 5 are short-circuited by using the other end face 1b of the dielectric block 1 as a short-circuit end so that each of the dielectric coaxial resonators 2 becomes a quarter wavelength resonator. It is composed of a short-circuit electrode 6. A coupling hole 7 for coupling the dielectric coaxial resonators 2 and 2 is provided between the adjacent dielectric coaxial resonators 2 and 2.

Signals from an external circuit (not shown) are input to the dielectric microwave filter through the through holes 3 of the dielectric coaxial resonators 2 located at both ends of the dielectric block 1, and the dielectric microwave filter is also provided. In order to extract a signal from the body microwave filter, a coupling rod 9 formed by coating a dielectric material 8 such as resin on the outer peripheral portion is inserted (see FIG. 4). A signal is supplied to the one of the coupling rods 9 from the external circuit, and the signal filtered by the dielectric microwave filter is extracted from the other coupling rod 9. Necessary coupling between the adjacent dielectric coaxial resonators 2 and 2 is adjusted by adjusting the distance between the dielectric coaxial resonators 2 and 2 or changing the size and shape of the coupling hole 7. .

[0005]

By the way, in the above-mentioned conventional dielectric microwave filter, in order to obtain a narrow band characteristic, the size of the coupling hole 7 should be reduced, or the dielectric coaxial resonators 2 and 2 should be separated from each other. Either structure that widens the intervals is adopted. However, it is difficult to reduce the size of the coupling hole 7 as described above from the viewpoint of the molding of the dielectric block 1. Further, if the distance between the dielectric coaxial resonators 2 and 2 is increased, the dielectric material is reduced. There is a problem that the shape of the microwave filter becomes large.

It is an object of the present invention to provide a dielectric microwave filter which is easy to manufacture and has a small band characteristic.

[0007]

Therefore, according to the present invention, a dielectric block, a plurality of through holes penetrating from one of the surfaces facing each other to the other, and a resonator formed on the inner wall surface of each through hole. An electrode and an earth electrode formed on the outer surface of the dielectric block, and a plurality of dielectric electrodes are formed on the dielectric block by the dielectric constituting the resonator electrode, the earth electrode, and the dielectric block existing therebetween. A dielectric microwave filter comprising dielectric coaxial resonators, wherein adjacent dielectric coaxial resonators are electromagnetically coupled to each other. Electromagnetic fields generated by adjacent dielectric coaxial resonators that are orthogonal to each other in the body block are orthogonal to each other, and are arranged between adjacent dielectric coaxial resonators so that It is characterized in that it comprises a coupling means for electromagnetically coupling with each other the dielectric coaxial resonators adjacent to disturb.

[0008]

The electromagnetic fields generated by the adjacent dielectric coaxial resonators whose through holes are orthogonal to each other in the dielectric block are orthogonal to each other. The coupling means disturbs the orthogonality of this electromagnetic field. As a result, the adjacent dielectric coaxial resonators are electromagnetically coupled to each other.

[0009]

According to the present invention, since the resonator electrodes of the adjacent dielectric coaxial resonators are orthogonal to each other in the dielectric block, the coupling means arranged between the adjacent dielectric coaxial resonators. Therefore, even if the electromagnetic field generated by each of the adjacent dielectric coaxial resonators is disturbed, the high-frequency current distribution flowing through each dielectric coaxial resonator is not significantly affected. It is possible to obtain a small-sized and narrow-band dielectric microwave filter with almost no deterioration of the unloaded Q.

[0010]

Embodiments of the present invention will be described below with reference to the accompanying drawings. The construction of one embodiment of the dielectric microwave filter according to the present invention is shown in FIGS.

The above-mentioned dielectric microwave filter is arranged in a dielectric block 11 (see FIG. 2) made of, for example, a titanium oxide-based ceramic dielectric, similarly to the conventional dielectric microwave filter described in FIGS. , A dielectric coaxial resonator 12 on the input side to which a signal is input from an external circuit (not shown), an intermediate dielectric coaxial resonator 12 adjacent to the input dielectric coaxial resonator 12, and a dielectric coaxial resonator 12 adjacent to the intermediate dielectric coaxial resonator 12 Output side dielectric coaxial resonator 1 for outputting
Two sets of two dielectric coaxial resonators 12, 12, 12 are configured. The ground electrodes 15, 15, ... Are formed on the six surfaces of the dielectric block 11, and the dielectric block 11 is covered with the ground electrodes 15, 15 ,.

Three sets of the above dielectric coaxial resonators 12, 12,
12, adjacent resonator electrodes 14 are orthogonal to each other in the dielectric block 11.

That is, the dielectric coaxial resonator 12 on the input side located on one end side of the dielectric block 11 has one surface of the dielectric block 11 as an open end and the surface opposite to this surface. The resonator electrode 14 is formed on the inner wall surface of the through hole 13 that penetrates the dielectric block 11 between the shorted ends. The resonator electrode 14 reaches the short-circuit end from the open end side of the dielectric coaxial resonator 12 on the input side with a gap G, and is short-circuited to the ground electrode 15 around the short-circuit end. The earth electrode 15 serves as a short-circuit electrode and connects the resonator electrode 14 to another earth electrode 15.

The dielectric coaxial resonator 12 on the input side is also provided.
The intermediate dielectric coaxial resonator 12 adjacent to is the open end of the surface adjacent to the surface of the dielectric block 11 where the open end of the dielectric coaxial resonator 12 on the input side is present, and is opposed to this surface. The resonator electrode 14 formed on the inner wall surface of the through hole 13 penetrating the dielectric block 11 between the surfaces is
Have. The resonator electrode 14 reaches the short-circuit end from the open end side of the intermediate dielectric coaxial resonator 12 with a gap G, and is short-circuited to the surrounding ground electrode 15 at the short-circuit end. The earth electrode 15 serves as a short-circuit electrode and connects the resonator electrode 14 to another earth electrode 15.

Further, the intermediate dielectric coaxial resonator 12 is provided.
The dielectric coaxial resonator 12 on the output side adjacent to is the open end of the surface of the dielectric block 11 on which the open end of the dielectric coaxial resonator 12 on the input side is present, and the surface opposite to this surface. The resonator electrode 14 is formed on the inner wall surface of the through hole 13 penetrating the dielectric block 11 between the shorted ends. The resonator electrode 14 reaches the short-circuited end with a gap G from the open end side of the dielectric coaxial resonator 12 on the output side.
This short-circuited end is short-circuited to the surrounding earth electrode 15. The earth electrode 15 serves as a short-circuit electrode and connects the resonator electrode 14 to another earth electrode 15.

The dielectric block 11 is short-circuited between the dielectric coaxial resonator 12 on the input side and the dielectric coaxial resonator 12 in the middle from the surface on the open end side of the dielectric coaxial resonator 12 on the input side. A coupling hole 17 penetrating the end surface is provided. Similarly, the dielectric block 11 is short-circuited between the intermediate dielectric coaxial resonator 12 and the output dielectric coaxial resonator 12 from the surface on the open end side of the output dielectric coaxial resonator 12. A coupling hole 17 penetrating the end surface is provided.

A signal from the external circuit is shown in each of the through holes 13 of the dielectric coaxial resonator 12 on the input side and the dielectric coaxial resonator 12 on the output side located at both ends of the dielectric block 11. 1 and input to the dielectric microwave filter of FIG. 2 and not specifically shown,
In order to extract a signal from the dielectric microwave filter, a coupling rod similar to that described with reference to FIGS. 3 and 4 in which a dielectric material such as a resin is attached to the outer peripheral portion is inserted. . A signal is supplied from an external circuit to one of the coupling rods, and a signal filtered by the dielectric microwave filter is taken out from another coupling rod. For connection with an external circuit, a capacitor (not shown) connected to the resonator electrode 14 of the dielectric coaxial resonator 12 on the input side or the dielectric coaxial resonator 12 on the output side in addition to the coupling rod as described above. ).

As described above, if the adjacent resonator electrodes 14 of the three sets of the dielectric coaxial resonators 12, 12, 12 are orthogonal to each other in the dielectric block 11, the dielectric block 11 is formed. The electromagnetic fields generated by the adjacent dielectric coaxial resonators 12, 12 in which the through holes 13 are orthogonal to each other are orthogonal to each other. In this way, if the electromagnetic fields of the adjacent dielectric coaxial resonators 12, 12 are orthogonal to each other, no coupling will occur between the dielectric coaxial resonators as they are.

However, in the above embodiment, the coupling hole 17 exists between the dielectric coaxial resonator 12 on the input side of the dielectric block 11 and the intermediate dielectric coaxial resonator 12, and the coupling hole 17 is provided. Near, the electromagnetic fields generated in the dielectric coaxial resonator 12 on the input side and the dielectric coaxial resonator 12 in the middle are disturbed. Therefore, the orthogonality between the electromagnetic field of the dielectric coaxial resonator 12 on the input side and the electromagnetic field of the intermediate dielectric coaxial resonator 12 is disturbed, and the electromagnetic field between the electromagnetic field of the dielectric coaxial resonator 12 on the input side and the intermediate field Coupling with the electromagnetic field of the dielectric coaxial resonator 12 occurs. Similarly, due to the coupling hole 17 existing between the intermediate dielectric coaxial resonator 12 and the output-side dielectric coaxial resonator 12, the electromagnetic field of the intermediate dielectric coaxial resonator 12 and the output-side dielectric material are formed. The orthogonality of the coaxial resonator 12 with the electromagnetic field is disturbed, and coupling between the dielectric coaxial resonator 12 in the middle and the dielectric coaxial resonator 12 on the output side occurs. At this time, the dielectric coaxial resonator 1 on the input side
2. Since the resonator electrodes 14 of the intermediate dielectric coaxial resonator 12 and the output-side dielectric coaxial resonator 12 are orthogonal to each other in the dielectric block, the adjacent dielectric coaxial holes are formed by the coupling holes 17. Even if the electromagnetic fields generated by the resonators 12 and 12 are disturbed, the dielectric coaxial resonators 1
The high frequency current distribution flowing through 2 is not significantly affected. Therefore, the unloaded Q of each dielectric coaxial resonator 12 is hardly deteriorated.

Further, since the adjacent dielectric coaxial resonators 12 and 12 which are originally not coupled are coupled by disturbing the orthogonality of the electromagnetic field by the coupling hole 17, the dielectric coaxial resonators 12 and 12 are coupled. The degree of coupling between them is small, and therefore the distance between the dielectric coaxial resonators 12 and 12 is small,
A compact and narrow band dielectric microwave filter can be obtained.

In the above embodiment, the dielectric block 11
Is not limited to three sets, and two or more sets of 1/4 wavelength dielectric coaxial resonators 12 or 1/2 wavelength dielectric coaxial resonators may be configured. The dielectric block 11
In addition, in the case where a plurality of half-wavelength dielectric coaxial resonators are configured, both ends of the resonator electrode 14 of the dielectric coaxial resonator have a gap with the ground electrode. Further, instead of the coupling hole 17, a coupling electrode that disturbs the electromagnetic field of the dielectric coaxial resonator 12 may be formed in the dielectric block 11.

[Brief description of drawings]

FIG. 1 is a perspective view of an example of a dielectric microwave filter according to the present invention.

FIG. 2 is a cross-sectional view of the dielectric microwave filter of FIG. 1 taken along the line I-I.

FIG. 3 is a perspective view of a conventional dielectric microwave filter.

4 is a sectional view taken along line II-II of the dielectric microwave filter of FIG.

[Explanation of symbols]

 11 Dielectric Block 12 Dielectric Coaxial Resonator 13 Through Hole 14 Resonator Electrode 15 Earth Electrode 17 Coupling Hole

Claims (1)

[Claims] 1. A dielectric block, a plurality of through holes penetrating from one of the surfaces facing each other to the other, resonator electrodes formed on the inner wall surface of each through hole, and an outer surface of the dielectric block. A plurality of dielectric coaxial resonators are formed in the dielectric block by the dielectric constituting the dielectric block existing between the resonator electrode, the ground electrode and the ground electrode, A dielectric microwave filter in which adjacent dielectric coaxial resonators are electromagnetically coupled to each other, wherein through holes of adjacent dielectric coaxial resonators are orthogonal to each other in the dielectric block, and The electromagnetic fields generated by the respective body coaxial resonators are orthogonal to each other, and the electromagnetic coaxial fields are arranged between the adjacent dielectric coaxial resonators and disturb the orthogonality of the electromagnetic fields to adjoin the adjacent dielectric coaxial resonances. 1. A dielectric microwave filter, characterized in that it comprises a coupling means for electromagnetically coupling the chambers with each other.