JP2000295006A - Dielectric resonator filter - Google Patents

Abstract

(57) [Problem] To provide a dielectric resonator filter which can be reduced in size, can be reduced in height, and can be surface-mounted. SOLUTION: In the dielectric resonator filter 10 having a rectangular parallelepiped or polygonal pillar-shaped metal cavity in which one or more dielectric resonators 1 are arranged between a pair of input / output probes 2 and 3, the rectangular metal cavity is provided. The input / output probes 2 and 3 were attached to the corners.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a dielectric resonator filter, and more particularly, to an improvement in a filter having low loss characteristics.

[0002]

2. Description of the Related Art Conventionally, a dielectric resonator filter has a structure disclosed in, for example, JP-A-60-98702, and FIG. 8 shows a typical example.

FIG. 8 is a view showing a part of the structure of a conventional dielectric resonator filter. FIG. 8A is a plan view showing a state where a cover is removed, and FIG. FIG. 8A and 8B, the dielectric resonator filter 100 has a metal case 5 forming a metal cavity.
5 are provided with dielectric resonators 51 to 54 provided on the bottom surface via support tables 61 to 64, respectively. This support 6
As the materials 1 to 64, those which do not deteriorate the Q of the dielectric resonator as much as possible are usually used.

On both sides of the metal case 55, input / output terminals 59, 60 having input / output probes 57, 58 are provided, respectively. Metal case 5 for metal cavities
A metal cover 56 is provided so as to cover the opening at the upper end of 5. The metal cover 56 is provided with frequency adjusting metal screws 71 to 74 at positions facing the upper surfaces of the dielectric resonators 51 to 54, respectively. The frequency can be adjusted by adjusting the distance between each of the dielectric resonators 51 to 54 and the metal screws 71 to 74.

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.

In addition, La, S ₁₂ ,
S 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 and j + 1} of the j-th and j + 1-th dielectric resonators are expressed by the following equation (1).

[0008]

(Equation 1)

Here, in the above equation ₁ , ω ₁ ′,
g ₀ , g _1, ..., g _{n + 1} are values theoretically obtained in n filters, and ω ₀ , ω ₁ , ω ₂ are quantities obtained in the pass characteristics of the filters. And w is ω ₀ , ω
_1, it is a quantity determined from 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 , k _{j, j + 1 become} Uniquely determined.

In an actual dielectric resonator filter as shown in FIG. 8, dielectric resonators 51 to 54 are arranged in a metal cavity constituted by a metal case 55 and a cover 56, and the dielectric resonance The coupling between the dielectric resonators is determined by electromagnetic coupling using the mode TE _01δ .

Therefore, the electromagnetic coupling amount k _{j, j + 1} between the j-th and j + 1-th dielectric resonators is determined by the distance S _{j, j + 1} between the dielectric resonators, The electromagnetic 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 example of four stages in FIG. 8, the coupling amount k
_12, k _23, k ₃₄ is uniquely determined by the spacing _{S 12, S 23, S 34} , (Qe) a, (Qe) b are determined by the distance La and Lb, a dielectric resonator filter is designed, It will be produced.

[0014]

However, the mounting position of the antenna probe of the conventional dielectric resonator filter 100 is, as shown in FIG.
Input / output probes 57 and 58 are mounted inside the metal case 55 at the center of the side, and the size of the metal case 55 is the same as that of the input / output probes 57 and 58 and the cylindrical dielectric resonator 51. , 54, it is unambiguously determined, so that miniaturization is difficult.

Accordingly, a first technical problem of the present invention is to provide a dielectric resonator filter that can be reduced in size.

A second technical problem of the present invention is to provide a dielectric resonator filter that can be reduced in height and can be surface-mounted.

[0017]

SUMMARY OF THE INVENTION In the present invention, a dielectric resonance is achieved by utilizing a corner portion of a rectangular parallelepiped metal cavity and mounting a probe so as to short-circuit two surfaces forming the corner portion of the rectangular metal cavity. It is intended to reduce the size of the filter.

That is, according to the dielectric resonator filter of the present invention, there is provided a dielectric resonator filter having a rectangular parallelepiped metal cavity in which at least one dielectric resonator is disposed between a pair of input / output probes. Characterized in that the input / output probe is attached to a corner portion.

Further, in the dielectric resonator filter according to the present invention, in the dielectric resonator filter, the input / output probe is attached so as to short-circuit two surfaces forming a corner portion of the metal cavity. It is characterized by.

Further, in the dielectric resonator filter according to the present invention, in the dielectric resonator filter, the input / output probe is formed of a linear conductor.

Further, in the dielectric resonator filter according to the present invention, in the dielectric resonator filter, the input / output probe is formed of a strip line.

Further, in the dielectric resonator filter according to the present invention, in any one of the dielectric resonator filters, the outer shape of the metal cavity is not a rectangular parallelepiped but a polygonal column shape other than a rectangular parallelepiped. .

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION A communication device used in a 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.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows an arrangement of a dielectric resonator filter according to a first embodiment of the present invention. FIG. 1A is a plan view showing a state where a metal cover is removed. FIG. 1B is a front sectional view.

In the description of the dielectric resonator filter of the present embodiment, the same components as those of the dielectric resonator filter shown in FIGS. 1 and 3 to 5 are denoted by the same reference numerals.

In the dielectric resonator filter 10 according to the first embodiment of the present invention shown in FIGS. 1 (a) and 1 (b),
One dielectric resonator 1 and input / output probes 2 and 3 provided on a metal case 5 via a support 11 are arranged in a metal cavity constituted by a metal case 5 and a metal cover 6. .

The input / output probes 2 and 3 are adapted to be coupled to one dielectric resonator 1, and are provided with input / output connectors 7 and 8 protruding outward near corner portions of the metal case 5. Connected to each other.

More specifically, the internal dimensions of the metal case 5 are about 20 × 20 × 13 mm, and the input probe 2 has a diameter of 0.5 mm.
mm of copper wire, one end is connected to the input connector 7 and the other end is short-circuited to the other surface of the two surfaces of the metal case 5 near the corner where the input connectors 7 and 8 are not installed. . The copper wire serving as the input probe 2 is linear, and the distance between the dielectric resonator 1 and the input probe 2 is about 3 mm. Further, the output probe 3 is manufactured in the same manner as the input probe 2.

In the first embodiment of the present invention, as a result of measuring the dielectric resonator characteristics by electromagnetic coupling using the resonance mode TE _01δ , the distance between the dielectric resonator 1 and the input / output probes 2 and 3 was measured. Is about 3mm, the center frequency is about 7G
Hz, load Q _L was about 100 0. Thereafter, the center frequency can be adjusted to a predetermined frequency by the metal screw 4 for frequency adjustment attached to the metal cover 6.
When the distance between the dielectric resonator 1 and the input / output probes 2 and 3 is about 1 mm, the center frequency is about 7 GHz and the load Q _L
Was about 280.

[0031] FIG. 2 shows the measurement results of the load Q _L. The solid line indicates that the distance between the dielectric resonator 1 and the input / output probes 2 and 3 is
Shows a load Q _L in the case of about 3 mm, whereas the dashed line is the distance of the input and output probes 2, 3 and the dielectric resonator 1, about 1.5
indicative of the load Q _L in the case of a mm.

Further, the relationship between the load Q _L and output of the electromagnetic field coupling amount Qe is _{2 / Qe = 1 / Q L} -1 / Q 0 ( where, Q ₀ is Q of a resonator).

The shape of the dielectric resonator 1 is about 15 × 6 m in diameter.
m, and is set by the support base 11 so that the center position of the height of the dielectric resonator 1 is located at the position of the input / output probes 2 and 3. Only the corners of the metal case 5 have room for space, and the miniaturization has been achieved. By attaching input and output probes 2 and 3 to the corners,
Work is easy, and the length of the probe can be accurately attached.

FIGS. 3A and 3B and FIGS.
(B) is the top view and sectional drawing which show the dielectric resonator filter by the 2nd and 3rd embodiment of this invention, respectively.

FIGS. 3A and 3B and FIGS.
1 (a) and 1 (b), but the dielectric resonator filter 3 shown in FIGS. 3 (a) and 3 (b) is similar.
Reference numeral 0 denotes an embodiment in which the copper wires serving as the input / output probes 2 'and 3' are not straight, but are bent substantially at right angles and short-circuited to other sides.

In the dielectric resonator filter 20 shown in FIGS. 4A and 4B, the copper wire provided with the input / output probes 2 ″ and 3 ″ is not a straight straight line, but the copper wire is circular. It is an embodiment that is bent into a shape and short-circuited to another side.

FIGS. 3A and 3B and FIGS.
In either case of (b), it is selected so that the electromagnetic coupling with the dielectric resonator 1 is optimized.

In the first to third embodiments, the input / output probes 2, 2 ', 2'', 3, 3',
Another surface near the corner where the other end of 3 '' is short-circuited and where the input connectors 7 and 8 are not installed includes a vertex which is a boundary between two surfaces of the corner.

FIGS. 5A and 5B show an arrangement of a dielectric resonator filter according to a fourth embodiment of the present invention. FIG. FIG. 5B is a front sectional view.

In FIGS. 5A and 5B, a dielectric resonator filter 40 according to a fourth embodiment has a metal cavity 15 including a metal cover 16 and a metal plate 15 to which a dielectric substrate 21 is attached. , One dielectric resonator 1 and input / output probes 12 and 13 are arranged. The dielectric substrate 21 and the metal plate 15 may be bonded and integrated. The input / output probes 12 and 13 are formed by strip lines made of copper foil.

The internal dimensions of the metal cover 16 are approximately 20 × 2
0x13mm, input probes 12 and 13 are about 1m wide
m is formed by a strip line made of copper foil, one end is connected to the input terminal, and the other end is short-circuited to another surface near the corner where the input terminal is not provided.
The strip line made of copper foil as the input probe 12 has a flat band shape, and the length between the dielectric resonator 1 and the strip line is about 3 mm. The output probe 13 is manufactured similarly to the input probe 12.

When strip lines are used as the input / output probes 12 and 13, not only the size can be reduced, but also the height can be reduced, and surface mounting is possible.

In the embodiment of the present invention described above,
Although the case where the number of the dielectric resonator 1 is one is described,
With respect to a device provided with two or more dielectric resonators 1, the size can be reduced by installing the input / output probe near the corner of the metal cavity. An example in that case will be described in a fifth embodiment.

FIGS. 6A and 6B are views showing a dielectric resonator filter according to a fifth embodiment of the present invention. FIG. 6A is a plan view with a cover removed, and FIG. 6B is a sectional view.

The dielectric resonator filter shown in FIG. 6 has the same configuration as that of the first embodiment except that two dielectric resonators 1 and 1 are used.

The dimensions of the metal cavity are about 20 × 40 ×
13 mm, and the shape of the dielectric resonator 1 is about 15 × φ.
6 mm, I / O probes 2 and 3 and dielectric resonator 1
Is about 3 mm, and the distance between the two dielectric resonators 1 and 1 is about 5 mm. Further, a screw 14 for adjusting the coupling is arranged between the dielectric resonators.

FIG. 7 is a diagram showing characteristics of the dielectric resonator filter of FIG. As shown in FIG. 7, the center frequency was about 7 GHz.

In the embodiment of the present invention described above, the metal cavity has a rectangular parallelepiped shape. However, it is needless to say that the metal cavity may be a cylindrical shape or a polygonal prism shape other than a rectangular parallelepiped.

[0049]

As described above, in the dielectric resonator filter according to the present invention, the input / output probe can be downsized by installing the input / output probe at the corner of the rectangular cavity. In the case of forming a strip line, it is possible to provide a dielectric resonator filter that can be reduced in height and can be surface-mounted.

[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. (B) is a sectional view of the dielectric resonator filter of (a).

2 is a diagram showing the measurement results of the load Q _L of the dielectric resonator filter in FIG.

FIG. 3A is a plan view of a dielectric resonator filter according to a second embodiment of the present invention. (B) is a sectional view of the dielectric resonator filter of (a).

FIG. 4A is a plan view of a dielectric resonator filter according to a third embodiment of the present invention. (B) is a sectional view of the dielectric resonator filter of (a).

FIG. 5A is a plan view of a dielectric resonator filter according to a fourth embodiment of the present invention. (B) is a sectional view of the dielectric resonator filter of (a).

FIG. 6A is a plan view of a dielectric resonator filter according to a fifth embodiment of the present invention. (B) is a sectional view of the dielectric resonator filter of (a).

7 is a graph showing measurement results of the load Q _L of the dielectric resonator filter in FIG.

FIG. 8A 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).

[Description of Signs] 1,51-54 Dielectric resonator 2,2 ′, 2 ″, 3,3 ′, 3 ″, 12,13,5
7,58 I / O probe 4,71-74 Metal screw for frequency adjustment 5,16,55 Metal case 6,56 Metal cover 7,8,59,60 I / O connector 10,20,30,40,50,100 Dielectric resonator filter 11, 61 to 64 Support 15 Metal plate 21 Dielectric substrate

Claims (5)

[Claims] 1. A dielectric resonator filter having a rectangular parallelepiped metal cavity in which one or more dielectric resonators are arranged between a pair of input / output probes, wherein the input / output probe is attached to a corner of the metal cavity. A dielectric resonator filter characterized in that: 2. The dielectric resonator filter according to claim 1, wherein said input / output probe is attached so as to short-circuit two surfaces forming a corner portion of said metal cavity. Resonator filter. 3. The dielectric resonator filter according to claim 2, wherein said input / output probe is formed of a linear conducting wire. 4. The dielectric resonator filter according to claim 2, wherein said input / output probe is formed of a strip line. 5. The dielectric resonator filter according to claim 1, wherein the outer shape of the metal cavity is a polygonal prism other than a rectangular parallelepiped instead of a rectangular parallelepiped. Dielectric resonator filter.