JP2001156512A - Dielectric resonator filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dielectric resonator filter that can be miniaturized. SOLUTION: In the dielectric resonator filter 10 having metallic cavities 5, 6 between a pair of input output blocks 2, 3 of which at least one dielectric resonator 1 is placed, at least one or more electromagnetic wave absorbing bodies f1 and f2 are fitted to the inside of the metallic cavities.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dielectric resonator filter, and more particularly, to an improvement in a dielectric resonator filter having low loss characteristics.

[0002]

2. Description of the Related Art Conventionally, a dielectric resonator filter has a structure disclosed in, for example, Japanese Patent Laid-Open No. 60-98702, and FIG. 15 shows a typical example.

FIG. 15 is a view showing a part of the structure of a conventional dielectric resonator filter. FIG. 15A is a plan view showing a state where a cover is removed, and FIG. FIG. In FIGS. 15A and 15B, the dielectric resonator filter 100 includes dielectric resonators 51 to 54 provided on a bottom surface of a metal case 55 forming a metal cavity through support bases 61 to 64, respectively. Each is equipped.
The materials of the supports 61 to 64 are usually such that the Q value of the dielectric resonator is not deteriorated as much as possible.

On both sides of the metal case 55, input / output terminals 59, 65 having input / output probes 57, 58 are provided, respectively. Metal case 5 forming a metal cavity
A metal cover 56 is provided so as to cover the opening at the upper end of 5. Frequency adjusting metal screws 71 to 74 are attached to the metal cover 56, and the frequency can be adjusted by adjusting the distance between the dielectric resonators 51 to 54 and the metal screws 71 to 74, respectively. Can be.

The input / output probes 57 and 58 are mounted inside the metal case 55 to be electromagnetically coupled to the dielectric resonators 51 and 54, respectively. Are mounted at substantially the same height as the center position of the height of the dielectric resonators 51 and 54.

Further, La, S ₁₂ , S shown in FIG.
₂₃ , S ₃₄ , and Lb indicate physical lengths, and (Q
e) _a , k ₁₂ , k ₂₃ , k ₃₄ , and (Qe) _b indicate the amount of electromagnetic coupling, respectively.

In general, the input / output electromagnetic coupling (Qe)
_a , (Qe) _b and the electromagnetic coupling amounts k _{j, j + 1} of the j-th and j + 1-th dielectric resonators are expressed by the following equation (1).

[0008]

(Equation 1) Where ω ₁ ′, g ₀ , g ₁ ... G
_{n + 1} is a value theoretically obtained in n filters, ω ₀ , ω ₁ , ω ₂ are quantities obtained in the pass characteristics of the filters, and w is ω ₀ , ω ₁ is the amount determined by the omega _2, an amount corresponding to the bandwidth.

As described above, ω ₁ ′, g ₀ , g ₁ ... G
_{Since n + 1} is a value determined from the filter theory,
When the bandwidth ω ₂ −ω ₁ and the center frequency ω _{0 of the} filter are determined, (Qe) _a , (Qe) _b , and k _{j, j + 1} are uniquely determined.

In an actual dielectric resonator filter as shown in FIG. 15, dielectric resonators 51 to 54 are arranged in a metal cavity formed by a metal case 55 and a cover 56, and the dielectric resonator Using the mode TE _01δ , coupling between the dielectric resonators is determined by electromagnetic coupling.

Therefore, the electromagnetic coupling amount k _{j, j + 1} of the j-th and j + 1-th dielectric resonators is determined by the distance S _{j, j + 1} between the dielectric resonators, and the input / output electromagnetic coupling The coupling amounts (Qe) _a and (Qe) _b are determined by the distances La and Lb between the input / output probe and the input / output dielectric resonator, respectively.

Referring to the four-stage example of FIG.
k₁₂, K₂₃, K₃₄Is the interval S ₁₂, S₂₃, S₃₄
Is uniquely determined by (Qe)_a, (Qe)_bIs distance
Determined by La and Lb, the dielectric resonator filter is
It will be designed and manufactured.

[0013]

However, in the conventional dielectric resonator filter, the unnecessary resonance modes of the dielectric resonators 51 to 54 shown in FIG. 15 and the shape and size of the metal case 55 containing the resonators are not shown. There is an unnecessary resonance mode determined by Therefore, the fundamental resonance mode (TE
_{01 δ} mode), a plurality of unnecessary resonance modes (HE, TM, EH mode, etc.) in a band of about 1.25 times or more of the frequency f0.
There is a problem that occurs.

Such an unnecessary resonance mode can be suppressed by adding a low-pass filter or the like, for example, but there is a drawback that it is difficult to reduce the size of the system.

Therefore, a technical object of the present invention is to provide a dielectric resonator filter that can be downsized.

[0016]

According to the present invention, one or more electromagnetic wave absorbers are mounted inside a metal cavity constituting a part of a dielectric filter by using an electromagnetic wave absorber to suppress the unnecessary resonance mode. By making the low-pass filter or the like unnecessary or simple, the size of the entire system including the dielectric resonator filter is reduced.

That is, the dielectric resonator filter of the present invention comprises:
In a dielectric resonator filter having a metal cavity in which at least one dielectric resonator is arranged between a pair of input / output probes, at least one or more electromagnetic wave absorbers are further mounted inside the metal cavity. It is characterized by.

Further, the dielectric resonator filter of the present invention comprises:
In the dielectric resonator filter, the metal cavity is preferably a rectangular parallelepiped.

Further, the dielectric resonator filter of the present invention comprises:
In the dielectric resonator filter, the input / output probe is attached so as to short-circuit two surfaces forming a corner of the rectangular parallelepiped metal cavity.

Further, the dielectric resonator filter according to the present invention is characterized in that, in any of the above dielectric resonator filters, the electromagnetic wave absorber is a magnetic material having ferromagnetic resonance absorption in a specific frequency band. And

[0021]

Embodiments of the present invention will be described below with reference to the drawings.

First, a communication device used in the microwave region, in which an original clock oscillation signal is formed using a dielectric filter using a dielectric ceramic resonator, is used. Further, such a dielectric filter has a 1 Gbit /
It is also mounted on digital communication equipment used in a communication network having a transmission capacity of about sec or more.

Therefore, in the embodiment of the present invention, such a dielectric resonator will be described.

(First Embodiment) FIG. 1 shows an arrangement of a dielectric resonator filter according to a first embodiment of the present invention, and FIG. FIG. 1B is a plan view showing a state in which the shape is removed, and FIG. 1B is a front sectional view.

In the dielectric resonator filter 10 shown in FIGS. 1A and 1B, one end of the input probe 2 is connected to the connector 7, and the other end is connected to the connectors 7 and 2 of the two surfaces of the metal case 5. 8 is short-circuited to the other surface near the corner where it is not installed. Also, for the output probe 3,
It is manufactured similarly to the input probe 2.

In the dielectric resonator filter 10 shown in FIGS. 1A and 1B, two electromagnetic wave absorbers f1 and f2 are arranged inside the metal case 5.

FIG. 2 is a diagram showing frequency characteristics of the dielectric resonator filter 10 of FIG. 1. Electromagnetic wave absorbers f1 and f2 are provided at two corners on the lower surface of the metal case 5 (near the input / output connectors 7 and 8). Adhered to.

FIG. 3 shows a configuration of a dielectric resonator filter prototyped as Comparative Example 1 with respect to the first embodiment of the present invention, and FIG. 3A shows a state where a metal cover on an upper surface is removed. FIG. 3B is a plan view, and FIG. 3B is a front sectional view. When the frequency characteristics were examined, the characteristics were as shown in FIG.

The electromagnetic wave absorbers f1 and f2 used in the dielectric resonator filter shown in FIG. 1 have an absorption characteristic in a band of about 15 GHz, and the dielectric material according to the first embodiment of the present invention shown in FIG. It can be seen that the frequency characteristics of the resonator filter suppress unnecessary resonance in the 15 to 17 GHz band (region D) as compared with the frequency characteristics of the comparative example shown in FIG.

(Second Embodiment) FIGS. 5A and 5B show a dielectric resonator filter according to a second embodiment of the present invention, wherein FIG. FIG. 2 is a plan view from which is removed, and FIG. 2B is a front sectional view.

The dielectric resonator filter 20 shown in FIGS. 5A and 5B is provided on the metal case 5 via the support 11 in a metal cavity formed by the metal case 5 and the metal cover 6. One end of the input (output) probe 2 is connected to the connector 7, and the other end is provided with the connectors 7 and 8 of the two surfaces of the metal case 5. Is short-circuited to the other side near the corner that is not open. The output (input) probe 3 is also manufactured in the same manner as the input (output) probe 2.

In the dielectric resonator filter 20 shown in FIGS. 5A and 5B, two electromagnetic wave absorbers f1 and f2 are arranged inside the metal case 5.

FIG. 6 is a graph showing the frequency characteristics of the dielectric resonator filter shown in FIG.
8).

FIGS. 7 (a) and 7 (b) are a plan view and a front sectional view showing a prototyped dielectric resonator filter as Comparative Example 2 with respect to the second embodiment of the present invention. FIG.
As shown in (a) and (b), the device according to Comparative Example 2 is the same as the device according to the second embodiment except that no electromagnetic wave absorber is provided. When the frequency characteristics of the dielectric resonator filter according to Comparative Example 2 were examined, the characteristics shown in FIG. 8 were obtained.

The electromagnetic wave absorbers f1 and f2 used in the dielectric resonator filter shown in FIG. 5 have an absorption characteristic in a band of about 15 GHz, and the dielectric material according to the second embodiment of the present invention shown in FIG. It can be seen that the frequency characteristics of the resonator filter suppress unnecessary resonance in the 15 to 17 GHz band (region D) as compared with the frequency characteristics of Comparative Example 2 shown in FIG.

(Third Embodiment) FIGS. 9A and 9B are views showing a dielectric resonator filter according to a third embodiment of the present invention, wherein FIG. FIG. 2 is a plan view from which is removed, and FIG. 2B is a front sectional view.

In the dielectric resonator filter 30 shown in FIGS. 9A and 9B, the dielectric resonator filter 30 is provided on the metal case 5 via the support 11 in a metal cavity formed by the metal case 5 and the metal cover 6. Input / output connectors 7 and 8 having two dielectric resonators 1 and input / output probes 2 and 3 are provided, respectively.

The electromagnetic wave absorbers f1 and f2 are bonded to two corners on the lower surface of the metal case 5.

In the above-described dielectric resonator filter, the electromagnetic wave absorbers f1 and f2 are provided at the lower corners 2 of the metal case 5.
The frequency characteristics of the dielectric resonator filter when it is adhered to the locations (near the input / output connectors 7 and 8) are almost the same as those in FIG.

FIGS. 10A and 10B show a third embodiment of the present invention.
FIGS. 7A and 7B are views showing a dielectric resonator filter prototyped as Comparative Example 3 with respect to the embodiment of FIG. 7A, in which FIG. 7A is a plan view in which a metal cover on an upper surface is removed, and FIG.
As shown in FIG. 10, the dielectric resonator filter according to Comparative Example 3 has 70 except that the electromagnetic wave absorber is not provided.
This is the same as that according to the third embodiment of the present invention. Examination of the frequency characteristics of the device according to Comparative Example 3 showed that the characteristics were almost the same as those shown in FIG.

(Fourth Embodiment) FIGS. 11A and 11B show a dielectric resonator filter according to a fourth embodiment of the present invention. FIG. It is the top view which removed and (b) is a front sectional view.

The dielectric resonator filter 40 shown in FIGS. 11A and 11B is manufactured using a ring-shaped dielectric resonator.

In the dielectric resonator filter 40 shown in FIGS. 11A and 11B, two electromagnetic wave absorbers f1 and f2 are arranged inside the metal case 5.

FIG. 12 is a diagram showing the frequency characteristics of the dielectric resonator filter of FIG. 11. The electromagnetic wave absorbers f1 and f2 are located at two corners on the lower surface of the metal case 5 (near the input / output connectors 7 and 8). Glued.

FIGS. 13A and 13B show a fourth embodiment of the present invention.
FIGS. 7A and 7B are diagrams showing a prototype dielectric resonator filter as Comparative Example 4 with respect to the first embodiment, in which FIG. 7A is a plan view in which a top metal cover is removed, and FIG.
Dielectric resonator filter 8 shown in FIGS. 13A and 13B
No. 0 has the same configuration as that according to the fourth embodiment except that no electromagnetic wave absorber is provided.

Dielectric resonator filter 80 according to comparative example 4
Investigation of the frequency characteristics shown in FIG.

The electromagnetic wave absorbers f1 and f2 used in the dielectric resonator filter shown in FIG. 11 have an absorption characteristic in a band of about 15 GHz, and have a dielectric material according to the fourth embodiment of the present invention shown in FIG. FIG. 1 shows the frequency characteristics of the resonator filter.
It can be seen that unnecessary resonance in the band of about 15 GHz (region D) is suppressed as compared with the frequency characteristic of Comparative Example 4 shown in FIG.

[0048]

As described above, in the dielectric resonator filter according to the present invention, the unnecessary resonance mode can be suppressed by disposing the electromagnetic wave absorber at the corner of the rectangular cavity.

[Brief description of the drawings]

FIG. 1A is a plan view of a dielectric resonator filter according to a first embodiment of the present invention, from which a metal cover on an upper surface is removed. (B) is a sectional view of the dielectric resonator filter of (a).

FIG. 2 is a diagram illustrating a frequency characteristic of the dielectric resonator filter of FIG. 1;

FIG. 3A is a plan view illustrating a dielectric resonator filter according to a first comparative example with respect to the first embodiment of the present invention, in which a metal cover on an upper surface of the dielectric resonator filter is removed. (B) is a sectional view of the dielectric resonator filter of (a).

FIG. 4 is a diagram illustrating a frequency characteristic of the dielectric resonator filter of FIG. 3;

FIG. 5A is a plan view of a dielectric resonator filter according to a second embodiment of the present invention, from which a metal cover on an upper surface is removed. (B) is a sectional view of the dielectric resonator filter of (a).

FIG. 6 is a diagram illustrating a frequency characteristic of the dielectric resonator filter of FIG. 5;

FIG. 7A is a plan view illustrating a dielectric resonator filter according to a second comparative example with respect to the second embodiment, in which a metal cover on an upper surface of the dielectric resonator filter is removed. (B) is a sectional view of the dielectric resonator filter of (a).

FIG. 8 is a diagram illustrating frequency characteristics of the dielectric resonator filter of FIG. 7;

FIG. 9A is a plan view of a dielectric resonator filter according to a third embodiment of the present invention, from which a metal cover on an upper surface is removed. (B) is a sectional view of the dielectric resonator filter of (a).

FIG. 10A is a plan view illustrating a dielectric resonator filter according to a third comparative example of the third embodiment, in which a metal cover on an upper surface of the dielectric resonator filter is removed. (B) is a sectional view of the dielectric resonator filter of (a).

FIG. 11 (a) is a plan view of a dielectric resonator filter according to a fourth embodiment of the present invention, from which a metal cover on an upper surface is removed. (B) is a sectional view of the dielectric resonator filter of (a).

FIG. 12 is a diagram illustrating a frequency characteristic of the dielectric resonator filter of FIG. 11;

FIG. 13A is a plan view illustrating a dielectric resonator filter according to a fourth comparative example with respect to the fourth embodiment, in which a metal cover on an upper surface of the dielectric resonator filter is removed. (B) is a sectional view of the dielectric resonator filter of (a).

FIG. 14 shows frequency characteristics of a fourth comparative example.

FIG. 15A is a plan view showing an example of the structure of a conventional dielectric resonator filter. (B) is a sectional view of the dielectric resonator filter of (a).

[Explanation of symbols]

1, 51 to 54 Dielectric resonator 2, 3, 57, 58 Input / output probe 4, 71 to 74 Metal screw for frequency adjustment 5, 55 Metal case 6, 56 Metal cover 7, 8, 59, 65 Input / output connector 10 , 20,30,40,50,60,70,80,1
00 dielectric resonator filter 11, 61 to 64 support base f1, f2 electromagnetic wave absorber

 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Akihiro Isomura 7-7-1, Koriyama, Taihaku-ku, Sendai-shi, Miyagi F-term (reference) 5J006 HC03 HC04 HC12 JA01 JA33 LA03 NA02 PA01

Claims (4)

[Claims] 1. A dielectric resonator filter having a metal cavity in which at least one dielectric resonator is arranged between a pair of input / output probes, wherein at least one or more electromagnetic wave absorbers are provided inside the metal cavity. A dielectric resonator filter having a body attached. 2. The dielectric resonator filter according to claim 1, wherein said metal cavity is a rectangular parallelepiped. 3. The dielectric resonator filter according to claim 2, wherein said input / output probe is mounted so as to short-circuit two surfaces forming corners of said rectangular parallelepiped metal cavity. Body resonator filter. 4. The dielectric resonator filter according to claim 1, wherein the electromagnetic wave absorber is a magnetic material having a ferromagnetic resonance absorption in a specific frequency band. Dielectric resonator filter.