JPH06204720A - Resonant frequency adjustment method for dielectric resonator and dielectric filter - Google Patents

Abstract

(57) [Summary] (Modified) [Purpose] To provide an adjustment method that allows adjustment in the direction of lowering the resonance frequency and that is possible even after assembly. [Structure] Short-circuit end face 1 of outer conductor 12 of dielectric resonator 10
At a position close to 1, the outer conductor is ground so that the dielectric is linearly exposed in a direction parallel to the short-circuit end face 11, and the deletion portion 13 is provided. The resonance frequency can be lowered to a predetermined value depending on the position and length of the conductor film to be removed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dielectric resonator and a method for adjusting the resonance frequency of a filter using the dielectric resonator, and more particularly to an adjustment method for lowering the resonance frequency.

[0002]

2. Description of the Related Art Various dielectric resonators and filters are used in the UHF band to the microwave band. The most common one is a quarter-wave coaxial TEM resonator and a filter combining it.

In this resonator, an inner conductor is formed in a through hole of a cylindrical dielectric material, and an outer conductor is formed on an outer peripheral surface of the resonator.
A short-circuit conductor is formed on one of the end surfaces of the through hole. The other end of the through hole is an open end face where the dielectric is exposed.

The resonance frequency of this dielectric resonator is usually determined by the length from the open end face to the short end face of the dielectric. However, since the ceramic dielectric material is obtained by firing, variations in characteristics due to firing conditions are unavoidable, and a method of polishing the open end face after forming the conductor film and adjusting the length is generally used. Further, fine adjustment is often performed by shaving the dielectric on the open end face or the conductor on the short-circuited end face, or by adding a conductor or a dielectric to the open end face.

[0005]

Among the methods of adjusting the resonance frequency of the dielectric resonator as described above, the polishing of the open end face cannot be performed after assembly, and is not suitable as a fine adjustment method. Further, it is difficult to process the open end surface and the short-circuited end surface after the element is housed in the case or mounted on the substrate because the connecting conductors between the inner conductor and the input / output end or the coupling element are close to each other.

The present invention solves the above problems,
The present invention provides a method for adjusting the resonance frequency of a dielectric resonator and a filter, which can be easily adjusted even after assembling and mounting of elements.
Further, the present invention provides a method in which control of processing for adjustment is easy.

[0007]

SUMMARY OF THE INVENTION The present invention solves the above problems by removing the conductor film of the outer conductor in a direction parallel to the short-circuited end face to expose the dielectric.

That is, one end surface of the through hole of the cylindrical dielectric having a through hole is defined as an open end surface, and the other end surface is defined as a short-circuit end surface including a conductor film. In a resonant frequency adjusting method of a dielectric resonator short-circuited with an inner conductor or a dielectric filter using the same, a part of the outer conductor is linearly removed in a direction parallel to the short-circuited end face to expose the dielectric. It is characterized by

[0009]

By removing a part of the outer conductor, the resonance frequency of the dielectric resonator can be lowered. This effect is more remarkable on the side closer to the short-circuited end face of the outer conductor, and the amount of frequency change can be changed by the length in the direction parallel to the short-circuited end face.

Although Q is slightly lowered by removing the conductor film, it can be suppressed to a range where there is practically no problem.

[0011]

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

FIG. 1 is a perspective view showing an embodiment of the present invention. Dielectric resonator composed of rectangular parallelepiped ceramic dielectric having a hole formed in the center from one end face to the opposite end face
Here are 10 examples. A conductor film is formed on one end face where the through hole opens to form a short-circuit end face 11. The conductor film of the short-circuit end face 11 is for conducting and short-circuiting the inner conductor formed in the through hole and the outer conductor 12 formed on the side surface of the through hole which is not open. A conductor film is not formed on the end surface of the through hole that is opposed to the short-circuited end surface 11 and is an open end surface.

In the present invention, a linear outer conductor 12 is provided at a position at a predetermined distance L from the short-circuited end face 11 in a direction parallel to the short-circuited end face 11. The length of the deletion portion 13 is represented by W. The resonance frequency is changed by changing the distance L and the length W.

The distance L from the short-circuited end face to the open end face, that is, the total length is about 9.5 mm, and the initial resonant frequency is about 838 MHz. Table 1 below shows how the resonance frequency and Q change when the values are used. The width of the excised part 13 is approximately
It was set to 0.3 mm. The distance L and the length W are changed for each sample.

[0015]

[Table 1]

FIG. 2 shows the state of changes in the resonance frequency and Q when the length W is changed and the distance L from the short-circuit end face 11 is 2.7 mm. In this position,
Both the resonance frequency and Q decrease as the length W increases. It is possible to change (decrease) about 20MHz at the resonance frequency.

As shown in Table 1, it has been found that the closer the position is to the short-circuited end face, the greater the amount of reduction in the resonance frequency, and the greater the width W, the greater the amount of reduction. However, when the position is close to the open end face, the resonance frequency tends to rise conversely. Therefore, in order to lower the resonance frequency, it is preferable to form the deletion portion near the short-circuit end face.

FIG. 3 is a perspective view showing an example for showing more concretely the change when the distance of the deletion part 33 from the short-circuit end face 31 is changed. The total length is 4.73mm and the resonance frequency is about 1673MH.
The following Table 2 shows changes in the resonance frequency and Q when the deleted portion 33 is formed at three places, which are divided into 4 equal parts in the length direction of the z dielectric resonator, and the length W is changed.

[0019]

[Table 2]

At each position, the resonance frequency is lowered as the length W is increased, which is similar to the example shown in FIG. Also, as long as the length is the same, the resonance frequency lowers more at positions closer to the short-circuited end face, as in the above case. Therefore, when it is desired to increase the width of decreasing the frequency, the deleted portion may be formed close to the short-circuited end face, and when the width of decreasing the frequency is small, it may be separated from the short-circuited end face.

It has been confirmed that when the deleted portion is formed in a linear shape extending in the direction perpendicular to the short-circuited end face, the resonance frequency is hardly adjusted and Q is slightly reduced.

Although the above description shows an example of a single dielectric resonator, it can be applied to a dielectric filter in which a plurality of such resonators are arranged and connected. In that case, it is not necessary to remove the outer conductors of all the dielectric resonators, and adjustment can be performed by removing one or more outer conductors according to the characteristics. Further, when the cylindrical resonator is used, the deleted portion can be similarly formed. In this case, it can be adjusted by controlling the cutting depth.

[0024]

According to the present invention, the resonance frequency can be easily adjusted, and fine adjustment can be performed while measuring, especially during assembly and mounting.

Further, since the deletion can be formed in a linear shape and the length can be adjusted, the number of adjustment steps can be reduced and the automation can be facilitated.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of the present invention.

FIG. 2 is an explanatory diagram of changes in characteristics according to the present invention.

FIG. 3 is a perspective view showing another embodiment of the present invention.

[Explanation of symbols]

 11, 31: Short-circuited end face 13, 33: Deleted part

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] August 20, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0021

[Correction method] Added

[Correction content]

It has been confirmed that when the deleted portion is formed in a linear shape extending in the direction perpendicular to the short-circuited end face, the resonance frequency is hardly adjusted and Q is slightly reduced.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] 0022

[Correction method] Change

[Correction content]

Although the above description shows an example of a single dielectric resonator, it can also be applied to a dielectric filter in which a plurality of such resonators are arranged and connected. In that case, it is not necessary to remove the outer conductors of all the dielectric resonators, and adjustment can be performed by removing one or more outer conductors according to the characteristics. Further, when the cylindrical resonator is used, the deleted portion can be similarly formed. In that case, it can be adjusted by controlling the cutting depth.

[Procedure 3]

[Document name to be amended] Statement

[Name of item to be corrected] 0023

[Correction method] Change

[Correction content]

[0023]

According to the present invention, the resonance frequency can be easily adjusted, and fine adjustment can be performed while measuring, especially during assembly and mounting.

[Procedure amendment 4]

[Document name to be amended] Statement

[Name of item to be corrected] 0024

[Correction method] Change

[Correction content]

Further, since the deletion can be formed in a linear shape and the length thereof can be adjusted, the number of adjustment steps can be reduced and the automation can be facilitated.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Name of item to be corrected] 0025

[Correction method] Delete ───────────────────────────────────────────── ────────

[Procedure amendment]

[Submission date] March 18, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be amended] Detailed explanation of the invention

[Correction method] Change

[Correction content]

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dielectric resonator and a method for adjusting the resonance frequency of a filter using the dielectric resonator, and more particularly to an adjustment method for lowering the resonance frequency.

[0002]

2. Description of the Related Art Various dielectric resonators and filters are used in the UHF band to the microwave band. The most common one is a quarter-wave coaxial TEM resonator and a filter combining it.

In this resonator, an inner conductor is formed in a through hole of a cylindrical dielectric material, and an outer conductor is formed on an outer peripheral surface of the resonator.
A short-circuit conductor is formed on one of the end surfaces of the through hole. The other end of the through hole is an open end face where the dielectric is exposed.

The resonance frequency of this dielectric resonator is usually determined by the length from the open end face to the short end face of the dielectric. However, since the ceramic dielectric material is obtained by firing, variations in characteristics due to firing conditions are unavoidable, and a method of polishing the open end face after forming the conductor film and adjusting the length is generally used. Further, fine adjustment is often performed by shaving the dielectric on the open end face or the conductor on the short-circuited end face, or by adding a conductor or a dielectric to the open end face.

[0005]

Among the methods of adjusting the resonance frequency of the dielectric resonator as described above, the polishing of the open end face cannot be performed after assembly, and is not suitable as a fine adjustment method. Further, it is difficult to process the open end surface and the short-circuited end surface after the element is housed in the case or mounted on the substrate because the connecting conductors between the inner conductor and the input / output end or the coupling element are close to each other.

The present invention solves the above problems,
The present invention provides a method for adjusting the resonance frequency of a dielectric resonator and a filter, which can be easily adjusted even after assembling and mounting of elements.
Further, the present invention provides a method in which control of processing for adjustment is easy.

[0007]

SUMMARY OF THE INVENTION The present invention solves the above problems by removing the conductor film of the outer conductor in a direction parallel to the short-circuited end face to expose the dielectric.

That is, one end surface of the through hole of the cylindrical dielectric having a through hole is defined as an open end surface, and the other end surface is defined as a short-circuit end surface including a conductor film. In a resonant frequency adjusting method of a dielectric resonator short-circuited with an inner conductor or a dielectric filter using the same, a part of the outer conductor is linearly removed in a direction parallel to the short-circuited end face to expose the dielectric. It is characterized by

[0009]

By removing a part of the outer conductor, the resonance frequency of the dielectric resonator can be lowered. This effect is more remarkable on the side closer to the short-circuited end face of the outer conductor, and the amount of frequency change can be changed by the length in the direction parallel to the short-circuited end face.

Although Q is slightly lowered by removing the conductor film, it can be suppressed to a range where there is practically no problem.

[0011]

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

FIG. 1 is a perspective view showing an embodiment of the present invention. Dielectric resonator composed of rectangular parallelepiped ceramic dielectric having a hole formed in the center from one end face to the opposite end face
Here are 10 examples. A conductor film is formed on one end face where the through hole opens to form a short-circuit end face 11. The conductor film of the short-circuit end face 11 is for conducting and short-circuiting the inner conductor formed in the through hole and the outer conductor 12 formed on the side surface of the through hole which is not open. A conductor film is not formed on the end surface of the through hole that is opposed to the short-circuited end surface 11 and is an open end surface.

In the present invention, a linear outer conductor 12 is provided at a position at a predetermined distance L from the short-circuited end face 11 in a direction parallel to the short-circuited end face 11. The length of the deletion portion 13 is represented by W. The resonance frequency is changed by changing the distance L and the length W.

The distance L from the short-circuited end face to the open end face, that is, the total length is about 9.5 mm, and the initial resonant frequency is about 838 MHz. Table 1 below shows how the resonance frequency and Q change when the values are used. The width of the excised part 13 is approximately
It was set to 0.3 mm. The distance L and the length W are changed for each sample.

[0015]

[Table 1]

FIG. 2 shows the state of changes in the resonance frequency and Q when the length W is changed and the distance L from the short-circuit end face 11 is 2.7 mm. In this position,
Both the resonance frequency and Q decrease as the length W increases. It is possible to change (decrease) about 20MHz at the resonance frequency.

As shown in Table 1, it has been found that the closer the position is to the short-circuited end face, the greater the amount of reduction in the resonance frequency, and the greater the width W, the greater the amount of reduction. However, when the position is close to the open end face, the resonance frequency tends to rise conversely. Therefore, in order to lower the resonance frequency, it is preferable to form the deletion portion near the short-circuit end face.

FIG. 3 is a perspective view showing an example for showing more concretely the change when the distance of the deletion part 33 from the short-circuit end face 31 is changed. The total length is 4.73mm and the resonance frequency is about 1673MH.
The following Table 2 shows changes in the resonance frequency and Q when the deleted portion 33 is formed at three places, which are divided into 4 equal parts in the length direction of the z dielectric resonator, and the length W is changed.

[0019]

[Table 2]

At each position, the resonance frequency is lowered as the length W is increased, which is similar to the example shown in FIG. Also, as long as the length is the same, the resonance frequency lowers more at positions closer to the short-circuited end face, as in the above case. Therefore, when it is desired to increase the width of decreasing the frequency, the deleted portion may be formed close to the short-circuited end face, and when the width of decreasing the frequency is small, it may be separated from the short-circuited end face.

It has been confirmed that when the deleted portion is formed in a linear shape extending in the direction perpendicular to the short-circuited end face, the resonance frequency is hardly adjusted and Q is slightly reduced.

Although the above description shows an example of a single dielectric resonator, it can also be applied to a dielectric filter in which a plurality of such resonators are arranged and connected. In that case, it is not necessary to remove the outer conductors of all the dielectric resonators, and adjustment can be performed by removing one or more outer conductors according to the characteristics. Further, when the cylindrical resonator is used, the deleted portion can be similarly formed. In this case, it can be adjusted by controlling the cutting depth.

[0023]

According to the present invention, the resonance frequency can be easily adjusted, and fine adjustment can be performed while measuring, especially during assembly and mounting.

Further, since the deletion can be formed in a linear shape and the length thereof can be adjusted, the number of adjustment steps can be reduced and the automation can be facilitated.

Claims (3)

[Claims] 1. A cylindrical dielectric body having a through hole, wherein one end face of the through hole of the through hole is an open end face, and the other end face is a short-circuit end face having a conductor film. In a method of adjusting a resonance frequency of a dielectric resonator short-circuited with an inner conductor, a part of the outer conductor is linearly removed in a direction parallel to the short-circuit end face to expose the dielectric. Resonance frequency adjustment method. 2. A cylindrical dielectric having a through hole, wherein one end face of the through hole of the through hole is an open end face, and the other end face is a short-circuit end face having a conductor film. A method for adjusting a resonance frequency of a dielectric resonator short-circuited with an inner conductor, characterized in that a part of the outer conductor near the short-circuited end face is linearly removed in a direction parallel to the short-circuited end face to expose the dielectric. Method for adjusting resonance frequency of dielectric resonator. 3. A cylindrical dielectric having a through hole, wherein one end surface of the through hole of the through hole is an open end surface, and the other end surface is a short-circuit end surface having a conductor film. In a resonance frequency adjusting method for a dielectric filter in which a plurality of dielectric resonators short-circuited with an inner conductor are arranged, at least one outer conductor of the dielectric resonator is partially removed linearly in a direction parallel to the short-circuited end face. A method of adjusting a resonance frequency of a dielectric filter, characterized by exposing the dielectric.