JPS63302601A - Dielectric filter - Google Patents

Abstract

PURPOSE:To adjust the degree of coupling between resonators, by constituting a conductor case of metal or a dielectric between adjacent resonators, and providing a degree of coupling adjusting means which changes the degree of coupling between the resonators. CONSTITUTION:An adjusting screw 21 is provided between partitions 13, 13 provided between the resonators 4 and 5 in a conductor hollow case 1 as the degree of coupling adjusting means. The screw 21 consists of the dielectric of the metal or ceramics, and is screwed in a screw hole 22 formed on the case 1. The screw 21 is moved in the directions shown in arrow heads A1 and A2 by turning the screw, and the inserting quantity of the screw into the case 1 is adjusted. By changing the inserting quantity of the screw 21, the perturbative quantities of an electric field and a magnetic field change variously, thereby, the degree of coupling of the adjacent resonators 4 and 5 can be adjusted. In such a way, it is possible to easily adjust a filter.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a dielectric filter constituted by a resonator comprising a dielectric column and a conductive cavity surrounding the dielectric column.

(Prior art) In recent years, in the field of communication equipment that uses microwaves,
An incident type bandpass filter is used that utilizes the T Mo lo mode of a dielectric cylindrical resonator constructed using a dielectric material with a high dielectric constant.

A vertical cross-sectional view of a conventional band-pass filter of this type is shown in FIG. 9, and a cross-section taken along the line 2-IV is shown in FIG.

The above bandpass filter is a two-stage bandpass filter of T M o + o mode dielectric cylindrical resonator parallel arrangement type, and each has a dielectric column 2 and this dielectric column 2 inside a metal conductor cavity case 1. Two sets of resonators 4.5 each consisting of a conductive cavity 3 surrounding the resonators 4.5 are arranged, and these resonators 4.5 are electromagnetically coupled to each other. Each of the above dielectric columns 2 has a circular cross section, and both ends are conductor cavity cases! The conductor cavities 3 are fitted into holes 6 and 7 formed in each conductor cavity 3 and fixed therein. In the conductor cavity case l,
A coaxial connector 8 for signal input and a coaxial connector 9 for signal output are attached. And these coaxial connectors 8
and 9 are coated with a dielectric resin material 12 such as Teflon (registered trademark) and arranged in parallel with each of the dielectric columns 2. It is an excitation line. The space between the adjacent resonators 4.4 constitutes a TE1o rectangular cut-off waveguide.

Conventionally, the degree of coupling between the adjacent resonators 4.4 is TE between the resonators 4.4. Metal partitions 13, 13 are made to protrude from the conductor cavity case 1 into the rectangular cut-off waveguide, and the dimensions of the partitions 13, 13 are changed to adjust to a desired value. By the way, as mentioned above, in order to adjust the degree of coupling between the adjacent resonators 4, 4 to a desired value using the partition 13.13, the partition 13.13
The problem is that the dimensional accuracy of the resonator 4.5 and the positional accuracy of the resonator 4.5 are very strictly required, and it is difficult to obtain a desired degree of coupling.

(Object of the Invention) An object of the present invention is to provide a dielectric filter in which the degree of coupling between resonators can be easily adjusted to a desired value.

(Structure of the Invention) Therefore, in the present invention, a plurality of resonators each consisting of a dielectric column and a conductor cavity surrounding the dielectric column are arranged inside a conductor cavity case, and the resonators are arranged adjacent to each other. In a dielectric filter in which matching resonators are electromagnetically coupled to each other, the conductive cavity case is provided with a degree of coupling adjustment means made of metal or dielectric so as to be able to adjust the position or attitude between adjacent resonators. The present invention is characterized in that the coupling degree between adjacent resonators is adjusted by this coupling degree adjusting means.

The coupling degree adjusting means generates electric field and magnetic field perturbations between the resonators. Changing the position of the coupling degree adjusting means changes the electric and magnetic field perturbations, thereby changing the coupling degree.

(Effects of the Invention) According to the present invention, when the position or orientation of the coupling degree adjusting means is changed, the electric field and magnetic field perturbation change and the coupling degree between the resonators changes. The degree of coupling can be freely changed, making adjustment of the dielectric filter very easy.

(Example) Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

TM explaining the present invention with FIG. 9 and FIG. 1θ. FIG. 1 shows a vertical cross-sectional view of an embodiment applied to a two-stage bandpass filter of a 10 mode dielectric cylinder resonator arranged in parallel. Further, FIG. 2 shows a cross-sectional view taken along the line ■-■ in FIG. 1.

The dielectric filter includes a resonator 4 in a conductive cavity case 1.
．． An adjusting screw 21 is provided between the partitions 13 and 13 provided between the connecting holes 5 and 5 as means for adjusting the degree of coupling. This adjustment screw 21 is made of a dielectric material such as metal or ceramic, and is formed in a screw hole 22 formed in the conductor cavity case 1.
screwed into. Thereby, by rotating the adjustment screw 21, the adjustment screw 21 moves in the directions shown by arrows A1 and A in FIG. 1, and the amount of insertion into the conductor cavity case 1 is adjusted.

In addition, in Fig. 1 and Fig. 2, Fig. 9 and Fig. 1
Portions corresponding to those in Figure O are indicated with corresponding reference numerals, and duplicate explanations will be omitted.

The electromagnetic field distribution of the T Mo 1° mode of the adjacent resonators 4.5 constituting the dielectric filter described above is as shown in Fig. 3 in the even mode.
In the odd mode, it becomes as shown in FIG.

However, in FIGS. 3 and 4, E represents an electric field, and M represents a magnetic field.

As mentioned above, the adjustment screw 21 is inserted between adjacent resonators 4.5.
When inserted, electric and magnetic field perturbations occur, but as can be seen from FIGS. 3 and 4, in the even mode, the magnetic field surrounds the dielectric column 2.2 of the adjacent resonator 4.5. Since it is running, the amount of perturbation is different from the Otsudo mode.

Therefore, by changing the insertion amount of the adjustment screw 21, the degree of the difference in the amount of perturbation can be changed, and the degree of coupling between adjacent resonators 4.5 can be adjusted.

As mentioned above, adjacent resonators 4. of the conductor cavity case I.
Instead of inserting and removing the adjusting screw 21 between the resonators 4.5 and 5, as shown in FIGS.
, 23 as shown by arrow A3 (see FIG. 6) to adjust the degree of coupling between the resonators 4.5.

The adjusting plate 23 is attached to one end of a support shaft 24, which is inserted into a support shaft insertion hole 25 formed in the conductor cavity case 1 and is prevented from coming out by a retaining washer 26. Further, a spring washer 27 is interposed between the large diameter portion 24a formed at the one end of the support shaft 24 and the conductor cavity case 1, and the spring washer 27 allows the adjusting plate 23 to The position of is kept from changing.

In place of the adjustment plate 23, as shown in FIG. 7, a rectangular frame-shaped adjustment ring 28 may be used to adjust the rotational position of the adjustment ring 28, thereby adjusting the degree of coupling.

Also, as shown in Figure 8, a conductor cavity case! The degree of coupling between the resonators 4.5 may be adjusted by displacing an Eta member made of metal or dielectric in the direction shown by the arrow A4 or A between the resonators 4.5.

In the above embodiments, a filter having two stages of resonators has been described, but the present invention is not limited to this, and it goes without saying that it can be applied to a band-pass filter having three or more stages.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view of one embodiment of a dielectric filter according to the present invention, FIG. 2 is a cross-sectional view of the dielectric filter of FIG. 1 along the line ■-■, and FIGS. 3 and 4 are respectively Fig. 1 is an explanatory diagram of the electromagnetic field distribution in even mode and odd mode of the dielectric filter, Fig. 5 is a vertical cross-sectional view of a modification of the dielectric filter shown in Fig. 1, and Fig. 6 is a diagram of the dielectric filter shown in Fig. 5. FIGS. 7 and 8 are longitudinal and cross-sectional views of another modified example and yet another modified example of the dielectric filter shown in FIG. 1, respectively; The figure is a longitudinal cross-sectional view of a conventional dielectric filter, and the 1.theta. figure is a cross-sectional view of the dielectric filter of FIG. 9 taken along the line IV--IV. l...Conductor cavity case, 2...Dielectric column, 3...
・Conductor cavity, 4...resonator, 4.5...
Resonator, 2...adjustment screw, 22...screw hole, 23...adjustment plate, 28...adjustment ring,
29... Adjustment member. Patent Applicant Murata Manufacturing Co., Ltd. Agent Patent Attorney Aobai Ao and 2 others Figure 3B Figure 5 Figure 8

Claims (1)

[Claims] (1) A plurality of resonators each consisting of a dielectric column and a conductor cavity surrounding the dielectric column are arranged inside a conductor cavity case, and adjacent resonators electromagnetically interact with each other. In the dielectric filter, the conductive cavity case is made of metal or dielectric material between adjacent resonators, and the degree of coupling between the resonators is changed by changing the position or orientation. 1. A dielectric filter comprising adjusting means, the coupling degree adjusting means adjusting the degree of coupling between adjacent resonators.