JPS62136102A - Microwave band pass-filter - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Summary] The present invention enables easy adjustment of magnetic field coupling between the input/output conductor of a microwave bandpass filter using a dielectric resonator and the dielectric resonator.

[Industrial application field]

The present invention relates to a bandpass filter, and particularly to the structure of an electromagnetic coupling circuit of a microwave input/output section using a dielectric resonator.

[Conventional technology]

FIG. 3 shows a structural diagram of a conventional microwave bandpass filter.

In the figure, an input conductor 1 is composed of a conductor rod directly connected to the center of an input plug 1a, and is supported by penetrating a housing (outer conductor) 2. 3 is a dielectric resonator made of cylindrical ceramic mainly composed of titanium or barium, and is installed on the bottom of the housing 2 with an insulator interposed therebetween, with its axial direction perpendicular to the axis of the input conductor 1. and the distance between the axes is .

4 is a dielectric resonator made of the same material and shape as 3, and is installed parallel to the dielectric resonator 3 with the distance between its axes set to a predetermined length L2;
The plane containing the respective axes of the dielectric resonators 3 and 4 is arranged in a direction perpendicular to the axis of the input conductor 1, and the tip of the input conductor 1 is λ/4 (λ is the direction of the microwave) from the plane containing the axis. wavelength) is set so that it sticks out.

Reference numeral 5 denotes an output conductor having the same material, shape and dimensions as the input conductor 1, and is directly connected to the output plug 5a, and is supported in parallel to the input conductor 1 through the casing (outer conductor) 2. The distance between the axes of the output conductor 5 and the dielectric resonator 4 is L3, and the distance between the axes of the input conductor 1 and the output conductor 5 is L.

Here, a microwave bandpass filter using two dielectric resonators will be explained.

In such a microwave bandpass filter, each dielectric resonator resonates at the natural frequency of the T E or delta mode.
Each input/output conductor 1, 5 is magnetically coupled to each dielectric resonator.

The coupling coefficient KOI between the input and output conductors 1, 5 and each dielectric resonator 3゜4 and! 3 are determined by the distances L1 and L1 between the input and output conductors 1.5 and each dielectric resonator 3, 4, respectively.

Also, the coupling coefficient Kl between each dielectric resonator 3.4! is determined by the distance L2 between each dielectric resonator 3.4.

+H+K+t+Kts for each coupling coefficient is given by the desired filter bandwidth.

[Problem that the invention seeks to solve]

In such a microwave bandpass filter, the human conductor 1
In order to change the coupling coefficient KOI between the input conductor 1 and the dielectric resonator 3 and the coupling coefficient between the output conductor 5 and the dielectric resonator 4 by 23 when the distance between the axes of the input conductor 1 and the output conductor 5 is constant, 1. At the same time as adjusting the distances MLt and L3, the distance MLz between the dielectric resonators also changes, and therefore the coupling coefficient between the dielectric resonators changes to <+z.

If the distance between the shafts of the input plug 1a and the output plug 5a is kept constant, the coupling coefficients KOI and Kzs cannot be adjusted independently. In other words, the coupling coefficient K corresponds to the distance between the axes.
. l and KI! 3 has the disadvantage that it is difficult to adjust.

Furthermore, conventionally, when the band characteristics of a filter are changed, the coupling coefficient changes, and the distance of each coupling section changes. That is, in the past, when narrowing the band characteristics, the physical dimensions became large. (As the coupling coefficient becomes smaller, the distance of the coupling section becomes longer.) In this way, the physical dimensions of the filter had to be changed as well.

The present invention was created in view of the above-mentioned conventional drawbacks, and it not only makes it possible to independently and easily adjust the coupling coefficients K (11 and KZ3) regardless of the distance between the shafts, but also makes it possible to adjust the coupling coefficients K (11 and KZ3) independently and easily. To provide a microwave bandpass filter in which different bandwidths can be obtained with the same axial distance without increasing the physical dimensions of the filter due to changes in coupling coefficient that occur when using a microwave bandpass filter with a narrow bandwidth. With the goal.

(Means for solving the problem) As shown in FIG. 1, the microwave bandpass filter of the present invention has the following features:
Input/output conductor 1. 5 and a plurality of dielectric resonators 3.4 each magnetically coupled in TEOIδ mode, a shielding cylinder that shields the input/output conductor 1.5 from a high frequency magnetic field. 6
, 7 are rotatably provided, and elongated coupling windows 8, 9 are bored in the surfaces of the shielding cylinders 6, 7 along their axes.

[Effect]

By providing a shielding cylinder 6 that shields the input conductor 1 from a high-frequency magnetic field, the coupling coefficient KO to the dielectric resonator 3 can be increased.
I is determined only by the effect of the high-frequency magnetic field on the dielectric resonator 3 in the leakage direction, which is controlled in accordance with the direction of rotation of the coupling window 8 . The same holds true for adjusting the coupling coefficient to 0. Therefore, the distance between the axes L1. Adjustment is possible without depending on L2.

Furthermore, by using the method of adjusting the coupling between the input/output connector conductor and the dielectric resonator of the present invention, the distance L2 between the dielectric resonators can be effectively changed (increased) while keeping the distance between the axes constant. ), it becomes possible to obtain a microwave bandpass filter with narrow band characteristics.

〔Example〕 Embodiments of the present invention will be described in detail below with reference to the drawings.

In order to make the description of the configuration and operation easier to understand, the same parts will be designated by the same reference numerals throughout the design and their repeated description will be omitted.

FIG. 1 is a structural diagram of a microwave bandpass filter according to an embodiment of the present invention, and FIG. 2 is a perspective view of a shielding cylinder installed in FIG. 1. Hereinafter, referring to FIG. 2, FIG. I will explain about it.

In the figure, 6 is a shielding cylinder that shields the input conductor 1 from a high frequency magnetic field. Since a shielding cylinder 7 having the same structure as this is also provided on the output conductor 5 side, the structure will be explained below on the input conductor 1 side, and the explanation on the output conductor 5 side will be omitted.

The shielding cylinder 6 has one end loosely engaged with a bearing 12 provided concentrically with the input conductor 1a on the back side of the front panel of the housing 2 to which the input connector 1a is attached, and the longitudinal direction of the cylinder is connected to the input conductor 1.
are concentrically shielded from a high-frequency magnetic field, and the other end passes through the back plate corresponding to the front panel and is rotatably engaged with the other end, and the end protruding to the outside of the housing is connected to the knob 10.

A long hole connecting window 8 is bored in the central surface of the shielding cylinder 7 along its axis. Therefore, the coupling coefficient K is obtained when the coupling window 8 faces the dielectric resonator 3 by rotating the knob 10. It is understood that I is maximized.

That is, in the present invention, the coupling between the input conductor 1 and the dielectric resonator 3 is made relatively dense (short distance) in advance, and the knob 10 is arranged to make the coupling loose by attaching the shielding cylinder 7. The amount of binding can be varied in different directions.

The above explanation was about a microwave bandpass filter using two dielectric resonators, but the number of dielectric resonators is not limited to this, and even when n dielectric resonators are used, The method of the present invention can be used to adjust the coupling between the input conductor and the output conductor and the dielectric resonator.

〔Effect of the invention〕

As described above in detail, the microwave bandpass filter of the present invention has the advantage that the amount of input/output coupling can be easily adjusted regardless of the distance between the input/output connectors.

Moreover, by utilizing the above effect, it is possible to easily obtain microwave bandpass filters having different band characteristics while keeping the distance between the input and output connectors constant.

[Brief explanation of drawings]

Fig. 1 is a structural diagram of a microwave bandpass filter according to an embodiment of the present invention, Fig. 2 is a perspective view of a shielding cylinder attached to Fig. 1, and Fig. 3 is a structure of a conventional microwave bandpass filter. Show the diagram. In the figure, l is the input conductor, 3 and 4 are dielectric resonators, and 5
denotes the output conductor, 6 and 7 the shielding cylinder, and 8 and 9 the coupling window, respectively. Honkaku Akinoshiro Koshi l Nose drawing No. 1 Figure 10f53n Enemy Enka n Mitsutsuki No. 2 Flash

Claims (1)

[Claims] A plurality of dielectric resonators (3, 4) magnetically coupled to input/output conductors (1, 5) in TE_0_1_δ mode, respectively.
), the input/output conductors (1, 5) are rotatably provided with shielding cylinders (6, 7) that respectively shield high frequency magnetic fields, and the shielding cylinders (6, 7) are rotatably provided. ) with long hole coupling windows (8, 9) along the axis.
) A microwave bandpass filter characterized by having a perforation.